The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon [4th rev. exp. ed., Reprint 2019] 9780520930438

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T H E LIGHT A N D S M I T H MANUAL

The Light and Smith Manual INTERTIDAL INVERTEBRATES FROM CENTRAL C A L I F O R N I A TO O R E G O N

FOURTH EDITION, COMPLETELY REVISED AND

E d i t e d by J A M E S T. C A R L T O N

U N I V E R S I T Y OF C A L I F O R N I A PRESS Berkeley Los Angeles London

EXPANDED

University of California Press, one of the most distinguished university presses in the United States, enriches lives around the world by advancing scholarship in the humanities, social sciences, and natural sciences. Its activities are supported by the UC Press Foundation and by philanthropic contributions from individuals and institutions. For more information, visit www.ucpress.edu. University of California Press Berkeley and Los Angeles, California University of California Press, Ltd. London, England © 2007 by the Regents of the University of California

Library of Congress Cataloging-in-Publication Data Light, Sol Felty, 1886-1947. The Light & Smith manual: intertidal invertebrates from central California to Oregon / edited by James T. Carlton. — 4th ed. p. cm. Includes bibliographical references. ISBN-13: 978-0-520-23939-5 (case : alk. paper) ISBN-10: 0-520-23939-3 (case : alk. paper) 1. Marine invertebrates—California. 2. Marine invertebrates— Pacific Coast (North America) I. Carlton, James T. II. Light, Sol Felty, 1886-1947. Light's manual. III. Title. QL164.L53 2007 592'.177—dc22 Manufactured in Canada 10 09 08 07 10 9 8 7 6 5 4

2007005842

3 2 1

The paper used in this publication meets the minimum requirements of ANSI/NISO Z39.48-1992 (R 1997) (Permanence of Paper). °o Cover photograph: The rocky shore at Bastendorff Beach, Coos Bay, Oregon, July 2005. Photograph by Deniz Haydar. Title page artwork: The "Big Three" (Pisaster ochraceus, Mytilus californianus, Pollicipes polymerus) of the outer wave-swept coast. Drawing by Joel W. Hedgpeth.

CONTENTS

LIST OF CONTRIBUTORS / vii

Placozoa / 81

Monogenea / 219

PREFACE / xi

VICKI BUCHSBAUM PEARSE

ARMAND M, KURIS

A C K N O W L E D G M E N T S / xiii S. F. LIGHT AND R. I. SMITH / xv

Introduction Intertidal Habitats and Marine Biogeography of the Oregonian Province / 3 THOMAS M. NIESEN

Porifera / 83 WELTON L. LEE, WILLARD D. HARTMAN, M. CRISTINA DÍAZ

Nemertea / 221

Cnidaria / 118

PAMELA ROE, JON L, NORENBURG,

Hydrozoa: Polyps, Hydromedusae, and Siphonophora / 118 CLAUDIA E. MILLS, ANTONIO C. MARQUES, ALVARO E. MIGOTTO, DALE R. CALDER, CADET HAND, JOHN T. REES, STEVEN H.

Intertidal Meiobenthos / 18

D. HADDOCK, CASEY W. DUNN,

JAMES W. NYBAKKEN, ROBERT P. HIGGINS

PHILIP R. PUGH

Intertidal Parasites and Commensals / 24

Scyphozoa: Scyphomedusae, Stauromedusae, and Cubomedusae / 168

ARMAND M. KURIS

Cestoda / 219 ARMAND M. KURIS

SVETLANA MASLAKOVA

Nematoda / 234 W. DUANE HOPE

Gastrotricha / 267 WILLIAM D. H U M M O N

Kinorhyncha, Loricifera, and Priapulida / 269 ROBERT P. HIGGINS

Nematomorpha / 274

Introduced Marine and Estuarine Invertebrates / 28

CLAUDIA E. MILLS, RONALD J. LARSON

ARMAND M. KURIS

Anthozoa / 173

Acanthocephala / 275

JAMES T. CARLTON, ANDREW N. COHEN

DAPHNE G. FAUTIN, CADET HAND

ARMAND M. KURIS

Molecular Identification / 32

Octocorallia / 184

Gnathostomulida / 276

JONATHAN B. GELLER

GARY C. WILLIAMS

RICHARD FARRIS

Methods of Preservation and Anesthetization of Marine Invertebrates / 37 GARY C. WILLIAMS, ROBERT VAN SYOC

Taxonomic Accounts

Ctenophora / 189

Rotifera / 280

CLAUDIA E. MILLS, STEVEN H. D.

STEVEN C. FRADKIN

HADDOCK

Dicyemida (Rhombozoa) / 200 DANNA JOY SHULMAN, F. G. HOCHBERG

Orthonectida / 203 EUGENE N, KOZLOFF

Protista / 45 Introduction / 45 Foraminiferida / 46 MARY MCGANN

Parasitic and Commensal Marine Protozoa / 69 ARMAND M. KURIS

Symbiotic and Attached Ciliated Protozoans / 70 STEPHEN C. LANDERS

Platyhelminthes / 206 "Turbellaria" / 206 JOHN J. HOLLEMAN

Acoela / 214 MATTHEW D. HOOGE

Kamptozoa (Entoprocta) / 283 KERSTIN WASSON, RICHARD N. MARISCAL

Sipuncula and Echiura / 288 MARY E. RICE

Tardigrada / 293 LELAND W. POLLOCK, ALBERT CARRANZA

Annelida / 298 Oligochaeta / 298 DAVID G. COOK, RALPH 0. BRINKHURST, CHRISTER ERSÉUS

Fecampiida / 216

Hirudinida / 303

ARMAND M. KURIS

EUGENE M. BURRESON

Trematoda / 217

Polychaeta / 309

ARMAND M. KURIS

JAMES A. BLAKE, R. EUGENE RUFF

Arthropoda / 411 Introduction / 411 JOEL W. MARTIN

Mystacocarida / 413 JAMES T. CARLTON, JOEL W. MARTIN

Cephalocarida / 414 ROBERT HESSLER

Branchiopoda / 414 DENTON BELK

Ostracoda / 417 ANNE C. COHEN, DAWN E. PETERSON, ROSALIE F. MADDOCKS

Copepoda / 446 JEFFERY R. CORDELL

Free-Living Copepoda (Calanoida, Cyclopoida, and Harpacticoida) / 446 Commensal and Parasitic Copepoda (Cyclopoida, Siphonostomatoida, and Monstrilloida) / 464 Branchiura / 475 ARMAND M. KURIS

Cirripedia / 475 WILLIAM A. NEWMAN

ARMAND M. KURIS, PATRICIA S.

Pelagic Gastropoda (Heteropods, Pteropods, and Janthinids) / 766

SADEGHIAN, JAMES T. CARLTON,

ROGER R. SEAPY, CAROL M. LALLI

Decapoda / 632

ERNESTO CAMPOS

Pycnogonida / 656

Opisthobranchia Clades and Onchidiacea / 780

C. ALLAN CHILD, JOEL W. HEDGPETH

GARY C. WILLIAMS

Arachnida / 665

Reproduction and Egg Masses of Benthic Opisthobranchs / 781

Acari / 665

JEFFREY H. R. GODDARD

IRWIN M. NEWELL, ILSE BARTSCH

Key to Major Opisthobranch Clades / 783

Pseudoscorpiones / 669

VINCENT F. LEE

Insecta / 670 Orders of Intertidal Insects / 670 HOWELL V. DALY

Bivalvia / 807

Collembola / 672

/ 495

LES WATLING

Isopoda / 503 RICHARD C. BRUSCA, VÂNIA R. COELHO, STEFANO TAITI

Tanaidacea / 542 ANDREW N. COHEN

Phoronida / 860

PETER BELLINGER

RÜSSEL ZIMMER

Hemiptera / 680

Brachiopoda / 864

HOWELL V. DALY

F. G. HOCHBERG

Diptera / 681 EVERT I. SCHLINGER

Coleoptera / 686 DAVID WHITE, AMANDA NELSON

Mollusca / 694

Crinoidea / 914

DAVID R. LINDBERG

JOHN S. PEARSE,

Aplacophora / 695

Scaphopoda / 695 RONALD L. SHIMEK

CHARLES G. MESSING

Echinoidea / 914 JOHN S. PEARSE, RICH MOOI

Asteroidea / 922 CHRISTOPHER MAH

F. G. HOCHBERG,

BERTHA E. LAVANIEGOS

Introduction / 913 JOHN S. PEARSE, RICH MOOI

Introduction / 694

BOUSFIELD AND DARL E. BOWERS

Hyperiidea / 630

KEITH H. WOODWICK,

Echinodermata / 913

Cephalopoda / 697

JOEL W. MARTIN, TODD A. HANEY

Hemichordata / 909

RICHARD HOFFMAN, JAMES T. CARLTON

CONTRIBUTIONS BY EDWARD L.

Cyamidae / 629

ERIK V. THUESEN

CHRISTOPHER B. CAMERON

JOHN W. CHAPMAN, WITH

LES WATLING, JAMES T. CARLTON

Chaetognatha / 905

Chilopoda / 692

AMELIE H. SCHELTEMA

Caprellidae / 618

Bryozoa / 866 DOROTHY F. SOULE, JOHN D. SOULE, PENNY A. MORRIS, HENRY W. CHANEY

Amphipoda / 545 Gammaridea / 545

PAUL VALENTICH-SCOTT

KENNETH CHRISTIANSEN,

HOWELL V. DALY

Cumacea

GARY R. MCDONALD

EUGENE V. COAN,

TODD A. HANEY, JOEL W. MARTIN,

RICHARD F. MODLIN

Sacoglossa and Nudibranchia / 788

HELMUT STURM

Dermaptera / 686

Mysidacea / 489

C. WILLIAMS

Archaeognatha / 672

Leptostraca / 484 ERIC W. VETTER

TERRENCE M, GOSLINER, GARY

DANNA JOY SHULMAN

Polyplacophora / 701 DOUGLAS J. EERNISSE, ROGER N. CLARK, ANTHONY DRAEGER

Gastropoda / 713 Shelled Gastropoda / 713

Ophiuroidea / 930 GORDON HENDLER

Holothuroidea / 941 PHILIP LAMBERT

Chordata / 949 Ascidiacea / 949 DONALD P. ABBOTT, CHARLES C. LAMBERT, GRETCHEN LAMBERT,

Stomatopoda / 630

JAMES H. MCLEAN

A. TODD NEWBERRY

ROY L. CALDWELL

Patellogastropoda / 753 DAVID R. LINDBERG

Appendicularia (Larvacea) and Thaliacea / 964

Littorina

LAURENCE P. MADIN

Eucarida / 631 Euphausiacea / 631 LANGDON QUETIN, ROBIN ROSS

/ 761

DAVID REID

Index / 965

LIST OF C O N T R I B U T O R S

p. ABBOTT ( D E C E A S E D ) Hopkins Marine Station, Stanford University, Pacific Grove, California DONALD

ILSE BARTSCH

Germany

Forschungsinstitut Senckenberg, Hamburg,

c.

D E N T O N BELK ( D E C E A S E D )

San Antonio, Texas

Our Lady of the Lake University,

Northridge

California State University,

ENSR Marine and Coastal Center, Woods Hole, Massachusetts

J A M E S A. BLAKE

EDWARD L. B O U S F I E L D DARL E. B O W E R S

o.

RICHARD

Arizona

Victoria, British Columbia, Canada

Oakland, California

BRINKHURST

c.

BRUSCA

Bethesda, Maryland

ALLAN CHILD

K E N N E T H CHRISTIANSEN

College, Iowa

PETER B E L L I N G E R ( D E C E A S E D )

RALPH

w. C H A P M A N Department of Fisheries and Wildlife, Mark O. Hatfield Marine Science Center, Oregon State University, Newport

JOHN

Lebanon, Tennessee

Arizona-Sonora Desert Museum, Tucson,

Eagle Mountain, Utah

ROGER N . CLARK EUGENE

v.

Palo Alto, California

COAN

Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael VANIA R. C O E L H O

ANDREW N. COHEN

California ANNE

c.

COHEN

DAVID G . C O O K

Bodega Bay, California Greely, Ontario, Canada

School of Aquatic and Fishery Sciences, University of Washington, Seattle HOWELL

v.

DALY

Kensington, California

Museo Marino de Margarita, Boca del Rio, Peninsula de Macanao, Nueva Esparta, Venezuela

Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada

M . CRISTINA DÍAZ

ROY L. C A L D W E L L Department of Integrative Biology, University of California, Berkeley

A N T H O N Y DRAEGER

DALE R. C A L D E R

Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada C H R I S T O P H E R B. C A M E R O N

Laboratorio de Sistemâtica de Invertebrados, Facultad de Ciencias, Universidad Autonoma de Baja California, Baja California, Mexico ERNESTO C A M P O S

Maritime Studies Program, Williams College-Mystic Seaport, Mystic, Connecticut

J A M E S T. C A R L T O N

Bodega Marine Laboratory, University of California, Bodega Bay ALBERT CARRANZA

HENRY W . CHANEY

San Francisco Estuary Institute, Oakland,

J E F F E R Y R. C O R D E L L

Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point EUGENE M. BURRESON

California

Department of Biology, Grinnell

Santa Barbara Museum of Natural History,

Kensington, California

w. D U N N Kewalo Marine Laboratory, University of Hawaii, Honolulu

CASEY

j. EERNISSE Department of Biological Science, California State University, Fullerton DOUGLAS

Department of Zoology, Göteborg University, Sweden CHRISTER ERSÉUS

RICHARD FARRIS Biology Department, Linfield College, McMinnville, Oregon

Department of Ecology and Evolutionary Biology and Natural History Museum, University of Kansas, Lawrence D A P H N E G . FAUTIN

c. FRADKIN Lake Crescent Laboratory, Olympic National Park, Port Angeles, Washington STEVEN

J O N A T H A N B. GELLER

Moss Landing Marine Laboratories,

California Marine Science Institute, University of California, Santa Barbara

J E F F R E Y H . R. G O D D A R D

Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco

T E R R E N C E M . GOSLINER

RONALD J . LARSON

U.S. Fish and Wildlife Service, Klamath

Falls, Oregon Departamento de Oceanografía Biológica, Centro de Investigación Científica y Educación Superior de Ensenada, Baja California, Mexico BERTHA E. LAVANiEGOs

Department of Entomology, California Academy of Sciences, San Francisco V I N C E N T F. LEE

W E L T O N L . LEE

Oakland, California

Department of Integrative Biology, University of California, Berkeley

STEVEN H. D. H A D D O C K

Monterey Bay Aquarium Research Institute, Moss Landing, California

DAVID R. LINDBERG

Bodega Marine Laboratory, University of California, Bodega Bay

ROSALIE F. M A D D O C K S

T O D D A. H A N E Y

Natural History Museum of Los Angeles County, California

L A U R E N C E P. MADIN

Peabody Museum of Natural History, Yale University, New Haven, Connecticut

C H R I S T O P H E R MÄH Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

C A D E T HAND ( D E C E A S E D )

W I L L A R D D. H A R T M A N

Department of Marine Biology, CEES, University of Groningen, Haren, Netherlands DENIZ HAYDAR

JOEL

w.

HEDGPETH (DECEASED)

Santa Rosa, California

Natural History Museum of Los Angeles County, California GORDON HENDLER

Scripps Institution of Oceanography, University of California, San Diego, La Jolla ROBERT HESSLER

ROBERT

p.

Asheville, North Carolina

HIGGINS

F. G . H O C H B E R G

Santa Barbara Museum of Natural History,

California Virginia Museum of Natural History,

RICHARD H O F F M A N

Martinsville JOHN

j.

Department of Biology, Woods Hole Oceanographic Institution, Massachusetts

Department of Biological Science, Florida State University, Tallahassee RICHARD N.' MARISCAL

c. M A R Q U E S Departmento de Zoología, Instituto de Biociencas, Universidade de Sao Paulo, Brasil

ANTONIO

w. MARTIN Natural History Museum of Los Angeles County, California

JOEL

Friday Harbor Laboratories, University of Washington, Washington

SVETLANA MASLAKOVA

Joseph M. Long Marine Laboratory, Institute of Marine Sciences, University of California, Santa Cruz GARY R. M C D O N A L D

U.S. Geological Survey, Coastal and Marine Geology Team, Menlo Park, California MARY M C G A N N

HOLLEMAN

San Andreas, California

Natural History Museum of Los Angeles County, California

MATTHEW D. HOOGE

Department of Biological Sciences, University of Maine, Orono

JAMES H. MCLEAN

w. D U A N E H O P E Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

CHARLES G. MESSING

WILLIAM D. HUMMON

Department of Biological Sciences,

Athens, Ohio

Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara

A R M A N D M . KURIS

Institute of Ocean Sciences, Department of Fisheries and Oceans, Sidney, British Columbia, Canada C A R O L M . LALLI

c. L A M B E R T Seattle, Washington, and Friday Harbor Laboratories, University of Washington, Washington

CHARLES

Seattle, Washington and Friday Harbor Laboratories, University of Washington, Washington

G R E T C H E N LAMBERT

Royal British Columbia Museum, Victoria, British Columbia, Canada PHILIP LAMBERT

c. LANDERS Department of Biological and Environmental Sciences, Troy University, Alabama

STEPHEN

L I S T OF

Nova Southeastern University, Oceanographic Center, Dania Beach, Florida Centro de Biología Marinha, Universidade de Säo Paulo, Säo Sebastiäo, SP, Brasil ALVARO E . M I G O T T O

Friday Harbor Laboratories, University of Washington, Washington C L A U D I A E. MILLS

Friday Harbor Laboratories, University of Washington, Washington E U G E N E N . KOZLOFF

vi i i

Department of Geosciences, University

of Houston, Texas

CONTRIBUTORS

Department of Biological Sciences, University of Alabama in Huntsville, Alabama

RICHARD F. M O D L I N

Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco RICH M O O I

Department of Natural Science, University of Houston-Downtown, Texas P E N N Y A. MORRIS

Hancock Biological Station, Murray State University, Kentucky AMANDA N E L S O N

Institute of Marine Sciences, University of California, Santa Cruz

A. T O D D N E W B E R R Y

IRWIN M . N E W E L L ( D E C E A S E D )

Riverside

University of California,

i. S C H L I N G E R The World Spider-Endoparasitoid Laboratory, Santa Ynez, California

W I L L I A M A. N E W M A N

Scripps Institution of Oceanography, University of California, San Diego, La Jolla

EVERT

Department of Biology, San Francisco State University, California

ROGER R. SEAPY Department of Biological Science, California State University, Fullerton

Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

R O N A L D L. SHIMEK

T H O M A S M . NIESEN

J O N L. N O R E N B U R G

w. NYBAKKEN Moss Landing Marine Laboratories, California

JAMES

JOHN

s.

PEARSE

University of California, Santa Cruz

VICKI B U C H S B A U M PEARSE

University of California, Santa Cruz

DAWN E. PETERSON Museum of Paleontology, University of California, Berkeley

Department of Biology, Drew University, Madison, New Jersey LELAND W . POLLOCK

National Oceanography Centre, Southampton, United Kingdom PHILIP R. P U G H

Marine Science Institute, University of California, Santa Barbara LANGDON QUETIN

Department of Biological Sciences, California State University, East Bay, Hayward, California

J O H N T. REES

DANNA J O Y S H U L M A N Stanford University, Hopkins Marine Station, Pacific Grove, California D O R O T H Y F.

souLE ( D E C E A S E D )

J O H N D. S O U L E ( D E C E A S E D )

H E L M U T STURM

Istituto per lo Studio degli Ecosistemi, CNR, Sesto Fiorentino (Firenze), Italy v. T H U E S E N Laboratory One, The Evergreen State College, Olympia, Washington ERIK

PAUL V A L E N T I C H - S C O T T

History, California

Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco ERIC

w.

VETTER

Department of Biological Sciences, California State University, Stanislaus Turlock

DAVID W H I T E

Marine Science Institute, University of California, Santa Barbara

GARY

R. E U G E N E RUFF

Ruff Systematics, Puyallup, Washington

s. SADEGHIAN History, California PATRICIA

Santa Barbara Museum of Natural

Santa Barbara Museum of Natural

ROBERT VAN S Y O C

LES WATLING

ROBIN ROSS

University of Hildesheim, Germany

STEFANO TAITI

Smithsonian Marine Station at Fort Pierce, Smithsonian Institution, Florida PAMELA ROE

University of Southern California,

Los Angeles

KERSTIN WASSON

MARY E. R I C E

University of Southern

California, Los Angeles

Department of Zoology, Natural History Museum, London, United Kingdom

DAVID REID

Wilsall, Montana

Hawaii Pacific University, Kaneohe

Elkhom Slough National Estuarine Research Reserve, Watsonville, California Department of Zoology, University of Hawaii at Manoa, Honolulu Hancock Biological Station, Murray State University, Kentucky

c. W I L L I A M S Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco KEITH H. W O O D W I C K

Fresno, California

RUSSEL Z I M M E R Department of Biological Sciences, University of Southern California, Los Angeles

Department of Biology, Woods Hole Oceanographic Institution, Massachusetts

AMELIE H. SCHELTEMA

LIST OF C O N T R I B U T O R S

ix

PREFACE

This manual represents a progress report on the state of our knowledge of the intertidal and selected planktonic and shallow-water invertebrates of a portion of the Pacific coast of North America. Since the third edition, 30 years have passed, and one of many results is that less than 10 percent of the previous book has been carried forward to this new edition. The book continues to grow, roughly doubling in size with every edition; the much-increased length of the present book over the last edition is in part disguised by the larger format you hold in your hands. More phyla are treated now, and groups once passed over in a paragraph, such as nematodes, now properly constitute an entire chapter. Formally founded in 1941 as a class syllabus for undergraduates in invertebrate zoology, this manual has become a guidebook for many users including graduate students, professional zoologists, and ecologists. As noted in the previous edition, we cannot go backward, we cannot make it simpler or easier to use, but we hope we have made it better. The team of authors has likewise grown with each edition: From 22 (second edition, 1954) to 43 (third edition, 1975) to 120 (in this fourth edition). Five authors from the second edition are still represented, four posthumously (Donald Abbott, Cadet Hand, Joel Hedgpeth, and Irwin Newell), and 25 authors from the third edition rejoin this new effort; of these, in addition to Abbott, Hand, Hedgpeth, and Newell, J o h n and Dorothy Soule, the bryozoologists, have also passed away. We are saddened to note that none of the previous editors are still with us; S. F. Light died in 1947, Don Abbott in 1986, Ralph Smith in 1993, Frances Weesner in 2002, and Frank Pitelka in 2003. We present a memorial to Light and Smith following this preface. Joel W. Hedgpeth, who died at 94 in July 2006, contributed to Light's unpublished class syllabus in 1937, and authored or coauthored the sea-spider chapter in 1941, 1954, 1975, and 2007. We also note the passing of contributors Denton Belk and Peter Bellinger while this edition was in preparation. The previous editions focused on the central California region encompassed by the radius of teachings of Dr. Light based in Berkeley and on the regions most useful for those working at and between Hopkins Marine Station on the Monterey Peninsula and Bodega Marine Laboratory on Bodega Head. For the present work, we have sought to expand the coverage south to Point Conception and north to the Oregon-

Washington border. North of Oregon, the monographic works of Eugene Kozloff and colleagues document the Pacific Northwest fauna. South of Point Conception, a warmer-water biota adds many hundreds, if not thousands, of species that could not be treated here. Thus, the utility of this manual will lessen with distance from these boundaries. Some chapters, however, treat species north and south of the book's limits, especially if the addition of several more species essentially completed the treatment of the genus, family, or other group in question. In all, over 3,700 species are keyed or discussed in this fourth edition. Distributions are shown for species whose ranges are limited or unusual and for groups that are poorly known. We have generally (but without complete consistency) not shown the distribution for the many species ranging from Alaska or British Columbia to Mexico. The treatment of planktonic organisms has expanded since the previous edition for the benefit of those working with a dipnet around piers or floats or in a small boat in places such as Monterey Bay, San Francisco Bay, or Coos Bay. However, the treatment has not been exhaustive across the phyla, nor intended to cover all nearshore or deeper waters, nor enough to change the title of the book. Also included are more species found just below the tides—additions Ralph Smith referred to as the contributions of long-armed and water-resistant intertidal collectors. Gone are chapters on intertidal seaweeds and fishes, represented in previous editions, but now replaced by large and readily available monographs and books. We have permitted the authors a good deal of nomenclatural and systematic flexibility, although no new species are described. We are given to understand that most of the taxonomic changes shown here will, in due course, be published in the journal literature, and our judgment was to proceed with expert opinion such that this work would not go out of date too quickly. As is true for all works of this kind, and by nature of the animals themselves and those who study them, the user of this book will find the treatment of groups uneven and, very likely, will wish for more. The keys will be found to vary in their completeness of coverage, geographical range of usefulness, ease of use, and accuracy, an inevitable result of the differences in the numbers of species in various groups, the ease of separating species from each other, the completeness of knowledge of the xi

group, the professional background of each author, and his or her success in constructing the key. Only use by students and investigators will tell us how suitable a given key may be: The editor and contributors welcome comments and information leading to improvements, corrections, and revisions. Species lists follow most keys. These lists are of species reliably reported from central California to Oregon, although we have no doubt that some species have been inadvertently omitted. Taxa not included in the keys are noted in the lists by asterisks. Some lists and species have been annotated with general information about habitat, ecology, or references that may be interesting or helpful; no collection of references can now be complete, and most users will turn to electronic resources for additional information and journal literature. Users of this book will doubtless add to these notations, and such marginalia will be of great value in future revisions. Finally, because of the much more extensive treatment of most invertebrate groups in this edition, because the systematics and classification of the invertebrates of coastal California and Oregon are better documented for some groups than others, and because of the very wide variety of taxonomic hierarchies employed in some chapters and not others, we have not formatted the same taxonomic levels (such as classes, orders, or families) in the same manner across all phyla. In the previous edition, family names were presented in all capital letters in all chapters. Family names—and most other hierarchical levels—across phyla are not biologically co-equal. In this edition, taxonomic levels are formatted within the context of the surrounding hierarchies. The second and third editions of this book carried on a tradition, not previously mentioned in these pages and born at Hopkins Marine Station in Pacific Grove, that we would be remiss not to mention, and which readers who have a hand lens and a copy of either edition can discover for themselves. In the late 1940s, an intertidal rock near Hopkins, with a pecu-

xii

PREFACE

liarly prominent proboscis-like portion, became popularly known among students as "Snadrock." The rock was the subject of a study on vertical zonation of barnacles by Don Abbott, John Davis, and Cadet Hand. "Snadrock," whose name (as "Professor Snadrock") would appear on the blackboard of the invertebrate zoology teaching lab in the Agassiz Building at the station, became a mythical figure. If one takes a hand lens to the drawing of the tusk shell (which has not been reproduced in this fourth edition), on page 213 of the second edition or on page 498 of the third edition, and looks carefully on the line representing the sediment surface, the word "Snadrock" can be found written as part of the mud ripple. The drawing was made by Ralph Smith. A small sketch (drawn by Abbott) itself forms the chapter head block on page xi, and the word "Snadrock" appears on a book spine in the chapter block on page 685 of the third edition. While Ralph permitted us to index the word "mermaid" in the third edition (although no one has inquired about it in the past 30 years)—amazing us by actually reading the draft index for the last edition—he removed the entry for "Snadrock." While this book was in press, we learned of several dozen additional changes that would alter treatments here, only a few of which we were able to capture. This is a cause for celebration: While larval recruitment to systematics and taxonomy has steadily declined (only 20 percent of our authors are under the age of 50), such changes indicate that work continues. As Ralph Smith remarked near the completion of the previous edition, "the job will never really be ended." Much remains to be learned about the thousands of species of invertebrates that live along the shores of the northeastern Pacific Ocean. fames T. Carlton Stonington, Connecticut January 2007

ACKNOWLEDGMENTS

For many years, almost 120 zoologists donated their time to this book, which generates no royalties, and I am indebted to them all. Many bore considerable personal costs, freely given to this labor of cooperation and devotion with no material reward, supported by many hundreds of assistants, spouses, and significant others, who have sacrificed, along with the authors, and with endless patience and understanding, uncountable days, nights, and weekends. I am grateful to Bonnie Bain, Patrick Baker, Kitty Brown, Barbara Butler, John Chapman, Victor Chow, Andrew Cohen, Peter Connors, Howell Daly, Stanley Dodson, Richard Everett, Jonathan Geller, Jeff Goddard, the late Cadet Hand, Chad Hewitt, Janet Hodder, Armand Kuris, Jody Martin, Claudia Mills, Chris Patton, John Pearse, Vicki Pearse, Gregory Ruiz, Isabel Stirling, Les Watling, and Joseph Wible, all of whom contributed importantly along the way with information or assistance. Deniz Haydar logged many hours assisting with artwork for a number of chapters. My good staff of the Williams College-Mystic Seaport Maritime Studies Program in Mystic, Connecticut, aided in all aspects of production over the years, and legions of Williams-Mystic students, exploring with me the tidepools of the California and Oregon coasts, helped keep me from switching Atlantic and Pacific names too often. Debby Carlton and Bridget Holohan spent hundreds of hours reading the page proofs of this Fourth Edition, and the result is, thus, immeasurably improved. The staff of the

University of California Press, including Charles Crumly, Danette Davis, and Scott Norton, provided constant support and encouragement. It was also a pleasure to work with Joanne Bowser of Aptara during the production phase. You would not be holding this book were it not for Bridget Holohan. Bridget has been my left and right hands throughout the book's creation, from working at the beginning with individual authors to, toward the end, producing the final artwork inventories for the entire book. Bridget's memory of events over the past decade has been critical in solving hundreds of challenges—virtually bridging the unbridgeable. After a long workday at her "regular" job, Bridget would start work all over again at 5 or 6 p.m. and would urge, cajole, and encourage me and everyone else to push on regardless. And so it is that you now hold the Light and Smith Manual—because Bridget would call and ask me a thousand times over a thousand days, "How's it going?" My wife Debby has been my anchor since 1975; it impossible to imagine how far I would have drifted without her. I cannot imagine anyone else who would have had the lifetime of tolerance and patience that Debby has shown and allowed me, oblivious, to keep my head in the tidepools and in vast piles of paper while the real world flowed by. fames T. Carlton Stonington, Connecticut January 2007

xiii

S. F. LIGHT AND R. I. SMITH

The namesakes of this manual are two zoology professors both of whom enjoyed productive and inspiring careers at the University of California at Berkeley: Sol Felty Light (1886-1947) and Ralph Ingram Smith (1916-1993). S. F. Light was born in Elm Mills, Kansas, was an undergraduate at Park College, Missouri, and took his Ph.D. at Berkeley in 1926 under Charles A. Kofoid. Light stayed at Berkeley until his death in 1947 when he drowned in Clear Lake while on a fishing holiday. Light's research career focused on termite systematics and biology (particularly symbiotic flagellates) and freshwater copepods. The 1937 anniversary "Golden Book of California" (University of California Alumni Association) featured a photo of Light standing before large racks of what the late Ted Bullock described as "staggering numbers of laboratory colonies" of termites. Most students who worked with Light referred to him as "Dr. Light"; his wife Mary referred to him in correspondence

Sol Felty Light

after his death as "S. F." Light taught "Zoology 112," Berkeley's core course in invertebrate zoology. In the 1930s, he began taking students to the seashore for 5-week summer courses, based in various locales, including the dining room of a tavernrestaurant in Moss Beach (south of San Francisco) and a former dance hall in the, then, beach-resort of Dillon Beach (north of the city). Many of the undergraduate student papers produced in Light's classes, beginning in the 1920s, on marine and freshwater organisms of the San Francisco Bay area still remain and are housed in the Cadet Hand Library at the Bodega Marine Laboratory (having been moved there from the Berkeley campus). By the late 1930s, Light had developed an extensive "Laboratory Syllabus" for his course, with species lists, keys, and laboratory and field exercises. A 1937 copy of this syllabus is 122 pages long; recommended for the reading list for Moss Beach that summer is "Between Pacific Tides" by E. F. Ricketts and J. Calvin, although it was not to be published until 1939. Among the contributors to the 1937 syllabus was the 25-yearold Joel W. Hedgpeth, who wrote a one-page key on pycnogonids (and is late co-author of the same chapter in the present edition, 70 years later). Light's laboratory syllabi formed the foundation for the "Laboratory and Field Text in Invertebrate Zoology" published in 1941 by the "Associated Students Store" of the University. This constituted the first edition of what was eventually to be known as Light's Manual; a rich resource reflecting the central California biota of the 1920s and 1930s, this green paperback is surely one of the rarest marine biology books of the 20th century. "In those days," wrote Joel Hedgpeth in 1985, "more was being done for the cause of what we now so glibly call marine biology by a somewhat old-fashioned professor at Berkeley, S. F. Light, who conducted field trips to such places as Moss Beach attired in his gray business suit, complete with vest and starched collar." Ted Bullock and colleagues, in their 1947 Memoriam, wrote that Light "took great pains in planning and executing his courses, which were outstanding in their appeal and challenge to the serious s t u d e n t . . . . His unique courses in marine zoology given at the seashore under difficult conditions . . . maintained standards of excellence unsurpassed by any center of instruction in marine biology in the country. . . . Those who were taken behind an outer reserve found a xv

Much of his work was on nereid polychaetes; in the late 1980s, Smith's attention was drawn to terebellid biology as well. Smith's remarkable academic tree—a "Ph.D.logenetic tree" as he called it—of his first, second, third, and fourth generation students was published in 1988. Smith, like Light, lost n o time u p o n his arrival in Berkeley heading for the seashore with his students. He was scheduled to co-teach invertebrate zoology with Light at Hopkins Marine Station in Pacific Grove in the summer of 1947, but Light passed away in June. Smith was joined that summer by Ted Bullock and Frank Pitelka. In the course were graduate students Cadet Hand (late co-author of the Hydrozoan and anthozoan chapters in the present edition) and Donald Abbott (late co-author of the ascidian chapter in this edition). Smith took over revisions of Light's 1941 manual and became lead editor of both the second (1954) and third (1975) editions of this book. Remarkably, Smith also found time to produce the vade mecum guide to the marine invertebrates of Cape Cod, on the eastern shore of the United States in 1964. I did not know Light; he died the year before I was born. But I first met Ralph in the summer of 1965 and had the immense pleasure of knowing him for 28 years. I was in high school when John Holleman (author of the flatworm chapter of the present edition) directed me to Ralph on the Berkeley campus, so that I could examine some of Light's students' papers of the 1920s and 1930s on Lake Merritt in Oakland. Ralph allowed me access to the famous invertebrate reading room (now gone) on the fourth floor of Berkeley's Life Sciences Building (now renovated). After several hours of locating and scanning (with my eyes) the papers I needed, I returned to Ralph's office to ask if I could photocopy some of the documents. Ralph looked at me and said, "No—you should read them instead."

Ralph I. Smith (photo by Donald L. Mykles)

warm and sensitive personality with a discerning appreciation of the good in others and the values to be found in even the most trying situations. In all of his friends and students, whether intimates or not, he inspired something more than respect—a personal confidence and an attachment to his ideals that could hardly be separated from an attachment to the man. He will be remembered for his modesty, extending to an underestimation of self, for exacting criticism in the use of words and ideas, which drove him now to caution and again to very forward positions, for a sincere interest in h u m a n relations, and for a strong appreciation of natural beauty." Remarkably, this description would also fit Light's successor, Ralph I. Smith, who arrived in Berkeley in the fall of 1946. Smith was born in Cambridge, Massachusetts and took all of his degrees from Harvard University, including the Ph.D. in 1942 under John H. Welsh. Smith rose to full professor at Berkeley where he stayed until his retirement in 1987. In his years at Berkeley, he taught invertebrate zoology and invertebrate physiology. For 30 years, Smith was also a Sierra Club ski tour leader, and for over a decade, led Boy Scout backpacking trips in the mountains. In this love of the mountains, he mirrored a long tradition at Berkeley: Joseph LeConte, one of the founders of science at the University of California, similarly spent as much time as he could in the Sierra Nevada. LeConte's interest had been seeded by an excursion with John Muir in the summer of 1870. Smith's research career focused o n physiology (often o n adaptations to variable salinity regimes) and reproduction. xvi

S. F. L I G H T A N D R. I. S M I T H

By 1973, I was once again spending many hours in that room, this time helping Ralph with the third edition of Light's Manual. Ralph's dry humor was remarked upon by many. At one point, a graduate student had written on the old black board in the invertebrate library, "Study Nature, Not Books— Louis Agassiz." Underneath was written, "Then Return the Books—Ralph Smith." Colin Hermans, in his 1997 obituary of Ralph, noted Ralph's prodigious field stamina. One of my most vivid memories of him is during an early morning low tide in late July 1973 at Bodega Bay. A year before, in the summer of 1972, Ralph became interested in the identity of a large tube-dwelling cerianthid anemone, living in the goopy, sloppy mudflats in the back corner of Bodega Harbor where, as Ralph wrote to Mary Needier Arai, "No one in his right mind goes collecting." By the end of that summer Ralph had described this elusive animal as "too slippery to grab, too deep to dig," but suggested that he might eventually "be able to outwit one." In the summer of 1973, convinced it was important to include this animal in the next (third) edition of Light's Manual, Ralph laid out plans to tackle this creature living one meter straight down into soft black mud. Unhappily, in early June 1973, Ralph failed to negotiate a turn around a steel post near the Berkeley campus while riding his bicycle and ended up with his left arm in a cast. And so off we marched at 5:30 a.m. on July 30. Every step out was a foot down into the oozing sediment as Ralph proceeded steadily, the injured arm in a sling, far out to the water's edge. Shoveling with one hand, Ralph soon had himself prostrate on the flats, his good arm u p to his shoulder in the mud, doing battle with a massive gelatinous contortion that eventually produced most of the anemone.

Ralph wrote to Ted Bullock two weeks later, "I have had a good summer with the seashore course, though somewhat slowed down with my left arm in a full c a s t . . . . Still, I am righthanded, and am now perhaps the first person to have dug out a cerianthid with one arm from three feet of mud. That sentence rather sounds as if one-armed cerianthus were rare, but it is the sort of writing I get from my contributors. It was a messy job—I'm not sure Dr. Light would have approved." In 1974, several years into nearly continuous work on the next edition of the manual, Eugene Kozloff (author of the chapter on orthonectids in this edition), knowing of Ralph's long struggle with endless name changes perpetrated upon well-known species, wrote to Ralph referring to him as "one of you systematists." Ralph wrote back: "I can hardly take that lying down! I am not a systematist by any stretch of the imagination, which is one reason why I work on things like the Light Manual. If I were a systematist, I would be getting everyone confused instead of trying to clarify matters, but just because I end up getting everyone confused does not of itself make me a systematist." Reminiscent of his predecessor's predilection "for exacting criticism in the use of words and ideas," Ralph spent hundreds of hours copy-editing the third edition, taking on matters ranging from the proper rendition of women's hyphenated maidenmarried names, to whether "intertidal" was a noun, to the elimination of the umlaut over the second o of zoóid and zoology. In responding to an inquiry from Donald Abbott on the latter question, Ralph wrote, "In respect to umlauts: I realize that modern zoologists do not spell zoology with an ó, and I will try to cooperate with you in deleting them." In the final

days of production, Ralph patiently removed scores of commas inserted by UC Press editors. Responding to the Press's meticulous touching up of the artwork for the book, Ralph sent a note back that "one very small animal was removed entirely— apparently mistaken for a dirt spot." Ralph Smith died in May 1993 at the age of 76, following a heart attack after finishing a 3-kilometer foot race in Santa Rosa, California—the "Human Race," a charity event. At the time, Ralph had begun writing contributors about a revision of the third edition of this book. A rich recounting of Ralph's life and character is found in Colin Hermans' 1997 reminiscence. Ralph, at one and the same time, offered an often firm and demanding exterior over a generous and kind personality of great depth; in the California mountains his concern for others and his great generosity would emerge, as it did when he guided undergraduates, graduates, and colleagues in the laboratory and field. Smith was, above all, as Eugene Kozloff once remarked, a "Practical Zoologist. First Class." This book is the living tribute to the careers that S. F. Light and Ralph Smith invested in students and the ocean. fames T. Carlton Bullock, Theodore H. 1947. S. F. Light 1 8 8 6 - 1 9 4 7 . Science 1 0 6 : 4 8 3 - 4 8 4 . Carlton, James T., Daphne G. Fautin, Michael G. Kellogg, Barbara E. Weitbrecht, and Armand M. Kuris. 1988. Professor Ralph I. Smith: A tribute to his manuals of marine invertebrates and to his academic progeny. Veliger 31: 1 3 5 - 1 3 8 (from which some of the above material was directly drawn). Hermans, Colin O. 1997. Ralph Ingram Smith, July 3, 1916-May 12, 1993. Bulletin of Marine Science 60: 2 2 4 - 2 3 4 .

S. F. L I G H T AND R. I. SMITH

xvii

Intertidal Habitats and Marine Biogeography of the Oregonian Province T H O M A S M. N I E S E N

We enter the 21st century when accurate identification of marine organisms is essential in the face of declining biodiversity (Carlton 1993, Tegner et al. 1996, Carlton et al. 1999), documented faunal shifts linked to coastal warming (Barry et al. 1995, Larson et al. 1997, Sagarin et al. 1999), and, in some habitats, the wholesale reshuffling of the faunal deck by the unchecked barrage of introduced species (Cohen and Carlton 1995). I have approached this introductory chapter with the history of this manual's utilization in mind, knowing it will continue to be used by students in upper division and graduate courses with limited familiarity of our varied coastal environments. Therefore, I hope to introduce this variety briefly and pass on some suggestions for successful field observation of marine invertebrates. Borrowing from the previous edition, I will first characterize the main biological and physical considerations at play in the intertidal zone, briefly characterize the main intertidal habitats of the region, and finally suggest the biogeographical underpinnings of our varied marine invertebrate fauna.

No picture of organisms that ignores their physical and organic environment can be even approximately complete. Studies of dead animals or their parts, or even of living animals in the laboratory, give but a partial picture. For fuller understanding, we must seek firsthand knowledge of living organisms in their natural settings. Field trips are of prime importance in gaining such knowledge and understanding. They make possible a study of the environment itself. This includes the study of the distribution of organisms within specific habitats, the behavior and interrelationships of species, and the influence of physical and biotic factors on the distribution of organisms. Only through information gained in field studies is it possible to establish correlations between the structure and behavior of an organism and its habitat and ecological niche. One of the original purposes of this manual was to aid in the inclusion of extensive field studies of marine intertidal invertebrates in courses for advanced undergraduates and graduate students. We hope this tradition continues and offer these suggestions for successful field trips.

Field Studies

Where to Look?

The Physical Setting

Virtually any site that is accessible along central and northern California's and Oregon's coastal counties can be a rewarding place to investigate marine invertebrates. Be careful when descending coastal bluffs because many are unstable and a serious fall can result. Two of the most useful books available to the student are the California Coastal Access Guide and its companion text, the California Coastal Resource Guide. These books provide maps and information about access for all the coastal counties and include details about parking, camping facilities, and special points of interest. They are widely available at local libraries, as well as at nature and sporting goods stores, museums, and state parks.

As you round Point Conception heading north and encounter the spectacle of Morro Rock, you realize you aren't in southern California any more. Gone is the west to east tending sea coast sheltered by the offshore Channel Islands. In its place, an exposed north to south coastline prevails, unprotected from the onslaught of the Pacific swells. Also gone is the dry, semi-desert weather of southern California. As you proceed north into more rainy climes, you are confronted with the reality of large watersheds draining into rivers, which harbor extensive estuaries at their drowned mouths. The rugged coastal mountain chains reflect the tectonically active nature of this coastline with protected bays and estuaries, like San Francisco and Tomales Bays, nestled in their folds. Soaring coastal headlands and rocky points have extensive exposed rocky intertidal habitat at their bases and protected embayments in their lee. It is truly a wondrous place to study marine invertebrates.

When searching soft sediment habitats, most discoveries will be made by digging. Sandy beaches have virtually n o organisms that live exposed on the surface. Protected sand flats and mud flats may have a few hardy species obvious on the surface, but the majority of the organisms will be burrowed beneath the substrate. Most will be in the upper 1 5 - 2 0 cm of the substrate to maintain contact with the water to breathe. 3

WARNING The tidal cycle is just o n e aspect of local ocean conditions of w h i c h t h e s t u d e n t should be aware. Periods of low wave action coupled with very low tides can provide t h e most o p p o r t u n e times for observation, while high waves can prove very dangerous n o matter w h a t t h e tidal level. Never turn your back to t h e sea. Be very careful that you k n o w w h e t h e r t h e tide level is rising or falling. This is especially critical if you are exploring a cove or pocket beach that might get cut off as t h e tide rises. Similarly a rocky intertidal area that has lowlying areas between you a n d t h e shore might flood as t h e tide comes in. Also be very careful of large floating objects t h a t lodge o n t h e b e a c h . This is especially true in n o r t h ern California a n d Oregon w h e r e large logs o f t e n acc u m u l a t e o n o p e n s a n d y beaches. Never get b e t w e e n a log a n d t h e water o n a rising tide. If you can, use t h e b u d d y system w h e n exploring t h e intertidal a n d take s o m e o n e else a l o n g . C o m m o n sense c o u p l e d w i t h a knowledge of t h e local tides a n d an awareness of local o c e a n c o n d i t i o n s can provide a safe, productive field trip.

Some of t h e larger clam species in protected e m b a y m e n t s are f o u n d considerably deeper, t h u s o n l y t h e m o s t dedicated stud e n t will see t h e m o n a n y given day. R e m e m b e r as y o u dig t h a t m a n y of t h e m o s t interesting organisms will b e quite small, a few c e n t i m e t e r s or less, so a d j u s t y o u r search image accordingly. In rocky habitats, it is easy to b e d r a w n t o t h e large a n d colorful organisms first. However, after you've r u n o u t of big, obvious organisms, o n c e again a d j u s t y o u r search p a t t e r n a n d explore t h e diversity of t h e smaller, m o r e cryptic organisms. M a n y small animals seek t h e shelter of crevices or seaweed, a n d others live u n d e r loose rocks a n d boulders. Careful searching of a n y of these m i c r o h a b i t a t s will be rewarded w i t h n e w treasures. A word of caution a b o u t t u r n i n g rocks: animals live attached to t h e rock's b o t t o m as well as u n d e r n e a t h it, so be careful w h e n t u r n i n g t h e rock n o t to crush a n y of t h e inhabitants. W h e n y o u ' v e finished exploring, t u r n t h e rock back over t h e way y o u f o u n d it—but again, m a k e sure n o t t o crush t h e animals y o u just observed! Place t h e free-living a n i m a l s u n d e r other rocks or a m o n g seaweed so they w o n ' t dry out. Remember t h a t organisms in t h e rocky intertidal zone are usually f o u n d in fairly specific locations relative t o t h e tide a n d exposure. D o n ' t m o v e t h e m o u t of their preferred locations.

When to Look T h e serious s t u d e n t soon realizes t h a t m o r e can b e seen during low tide t h a n h i g h , t h e r e f o r e it b e c o m e s necessary t o learn a b o u t tides a n d tide tables t o g u a r a n t e e a successful field trip. Tidal h e i g h t o n t h e West Coast is m e a s u r e d f r o m a n arbitrary zero p o i n t called " m e a n lower low w a t e r " (MLLW). 4

HABITATS OF THE O R E G O N I A N

PROVINCE

This zero p o i n t is t h e average of all t h e lower low tides t h a t occur in a year. A h i g h tide listed in t h e tide table as + 6.0 ft m e a n s t h e tide at its peak will be 6 ft above 0 MLLW, again t h e average level of lower low water. A low tide listed as - 1 . 5 ft m e a n s t h e tide will b e a f o o t a n d a half b e l o w this average level. T h e latter tide is referred to as a " m i n u s tide" a n d represents t h e best t i m e t o explore, as m o r e of t h e intertidal z o n e will be exposed. Tides are caused b y t h e gravitational pull of t h e sun a n d t h e m o o n o n t h e earth's surface. Tide tables can be m a d e u p years in a d v a n c e because t h e position a n d effect of t h e sun a n d t h e m o o n are highly predictable. However, tide tables c a n n o t anticipate local weather conditions, w h i c h can significantly alter t h e actual tide t h a t occurs o n a given day. Large storm waves p u s h e d by strong o n s h o r e winds can completely wash o u t a scheduled low tide a n d cause a h i g h tide t o b e several feet above t h e tide table prediction. Likewise, a strong high-pressure area over t h e coast can p u s h d o w n o n t h e water causing b o t h h i g h a n d low tides t o be lower t h a n predicted. Intertidal observation at low tide is usually best approximately two hours before to two hours after t h e scheduled low tide. Obviously, t h e lower t h e tide, t h e more area that will be exposed. This is important for rocky habitats, as t h e organisms are distributed in somewhat distinct tidal zones. The lower intertidal zones are t h e more diverse because they experience less exposure t o drying. The recommended m e t h o d is to explore t h e lowest exposed tidal zone first a n d move u p into t h e intertidal as t h e tide rises.

Biological and Physical Factors Influencing Marine Invertebrates of the Intertidal Zone To be of m a x i m u m value, studies of marine invertebrates should be cumulative a n d comparative. Each n e w situation should be c o m p a r e d t o o t h e r s already studied, n o t i n g similarities a n d differences a m o n g f a u n a s and t h e e n v i r o n m e n t a l c o n d i t i o n s t h e y experience. In p u r s u i n g field studies, it is well to keep in m i n d certain f u n d a m e n t a l s . All animals have similar basic needs or requirem e n t s . Ultimately these can be reduced t o food, oxygen, protection, a n d t h e proper c o n d i t i o n s for r e p r o d u c t i o n . In situations w h e r e a n a n i m a l occurs regularly a n d in h i g h n u m bers, we m a y be sure t h a t these needs are met, t h o u g h t h e m a n ner in w h i c h they are m e t is n o t always obvious. FOOD as used here, includes all substances (except oxygen a n d water) f r o m t h e e n v i r o n m e n t necessary to provide a n i m a l s w i t h energy a n d body-building materials. T h e intertidal is a region of a b u n d a n t light a n d food. In areas of hard substrate, there is o f t e n m u c h p l a n t life. This includes n o t o n l y t h e larger algae a n d occasional flowering plants, such as t h e surfgrass Phyllospadix, b u t also t h e film of microscopic p l a n t life growing o n exposed surfaces of rocks a n d larger plants. A few organisms (e.g., t h e kelp crab Pugettia producta, t h e red sea u r c h i n Strongylocentrotus franciscanus, a n d t h e limpet Lottia instabilis) graze directly o n t h e attached larger algae. Seaweeds b r o k e n loose a n d washed i n t o crevices a n d pools or ashore o n beaches provide a rich source of f o o d for o t h e r f o r m s (e.g., t h e purple sea u r c h i n Strongylocentrotus purpuratus a n d t h e b e a c h a m p h i p o d s Traskorchestia a n d Megalorchestia). Plant material, g r o u n d i n t o a fine organic detritus by t h e act i o n of t u r b u l e n t waters against t h e substrate, provides f o o d for a host of creatures t h a t feed in m a n y different ways. Detritus s u s p e n d e d in m o v i n g waters is taken, t o g e t h e r w i t h living p l a n k t o n , by a variety of particle feeders. Some use m u c o u s

FIGURE 1 The m o o n l i k e landscape of holes and burrows created by t h e intertidal ghost shrimp Neotrypaea californiensis (photo by T h o m a s Niesen).

nets or webs to trap this food (e.g., the echiuran Urechis, the polychaete Chaetopterus and the attached gastropod Petaloconchus), whereas others use cilia, often in conjunction with sheets or strands of mucus (e.g., most bivalves, brachiopods, bryozoans, tunicates, serpulid and sabellid polychaetes, sand dollars, sponges). Still other feeders on suspended detritus and plankton use combs of fine bristles or setae to catch particles (e.g., the decapods Petrolisthes and Emérita, barnacles, and many other lower crustaceans); yet others use tentacles (e.g., the sea cucumber Pseudocnus curatus, terebellid and spionid polychaetes, and ctenophores). Organic detritus of plant and animal origin also accumulates on and in soft substrates, and here it forms food for another complex of organisms. Some of these organisms "vacuum" up the surface layer of detritus (e.g., some species of the clam Macoma)-, others, such as many annelids, swallow the muddy substrate more or less unselectively. Still others burrow and sift the bottom material for edible particles (a good example is the shrimplike Neotrypaea, fig. 1). Finally, organic detritus tends to cling to exposed surfaces of rocks and plants. Here, macroscopic encrusting algae, together with the microscopic plants, bacteria, and protozoa, serve as food for animals with rasping or scraping organs, particularly the gastropods and chitons. The variety of organisms living on plant and animal detritus and plankton provides food in plenty for intertidal predators. Micropredators, like hydroids and the sea anemone Metridium, feed upon animal plankton brought in by the tides. Predators on larger organisms (e.g., most sea stars [but not Patiria]; the gastropods Nucella, Acanthinucella, and Ceratostoma; crabs, nemerteans) find a rich diet of clams, snails, worms, barnacles, and other small crustaceans. Fishes as well as invertebrates are significant predators when the tides are high; whereas shore birds and humans, and a surprising variety of other mammals (Carlton and Hodder 2003) have their impact when the waters recede. When studying an organism keep in mind these questions: What does it eat? How does it get its food? What is its role in the food web of the area? OXYGEN presents a lesser problem for most intertidal organisms. In most areas, continual movement of the shallow wa-

ters ensures full oxygenation at all times. The oxygen tension in air is the same as in saturated water, and as long as animals remain damp, atmospheric oxygen can readily diffuse across respiratory membranes. The oxygen requirements of sessile and sedentary animals are not large, and some species are capable of withstanding temporary anaerobic conditions. Some intertidal organisms, however, do have adaptations to meet specialized needs with respect to oxygen. Species living high in the intertidal zone may show structural modifications, enabling them to carry on aerial respiration. Some species of the periwinkle Littorina have considerable vascularization of the wall of the mantle cavity, which serves in some degree as a lung. Crabs, such as Pachygrapsus, have gills reduced in size and stiff enough for self-support, in addition to arrangements for retaining water in the gill cavity and vascularization of the wall of the cavity itself. Mudflat forms, stranded in the substrate with a limited water and oxygen supply, face a severe problem. Yet even in this harsh environment, there are physiological mechanisms to cope. REPRODUCTION can be more difficult to study in the field. Many intertidal benthic forms shed eggs and sperm into the sea, where developing embryos and feeding larvae lead a pelagic existence for a time. Pelagic stages may be collected in plankton tows but otherwise are seldom seen. However, a large number and variety of marine and brackish-water organisms retain, carry, or brood their eggs (e.g., the sea cucumbers Pseudocnus curatus and Lissothuria nutriens, the sea star Leptasterias, many crustaceans, colonial ascidians, and the viviparous polychaete Neanthes limnicola).

Other invertebrates produce characteristic egg cases (e.g., those of the snails Nucella and Acanthinucella, most nudibranchs and cephalopods, certain polychaete worms). These early stages should be observed and, if possible, connected with the animals that produced them. Still other animals reproduce asexually and may form extensive colonies or aggregations of individuals (the aggregating anemone Anthopleura elegantissima, colonial ascidians, hydroids, bryozoans, the hydrocoral Stylantheca, the alcyonarian Clavularia, sponges). Observations of such reproductive features in the field or in individuals collected and brought to the laboratory are important in natural history studies and may well result in previously unrecorded discoveries. HABITATS OF T H E O R E G O N I A N

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Physical Factors The questions of protection and of the environmental conditions from which organisms require shelter are crucial to field studies. Animals persistently present at any particular spot must be adapted to survive the most unfavorable extremes of environmental conditions that occur there. All mechanisms— morphological, physiological, and behavioral—through which an animal internally preserves the conditions for cellular life are implied here in the term protection. Therefore, protection includes the sheltered places sought by motile forms like crabs, the production of anchored fortresses of lime by barnacles, the capacity of brackish-water (and freshwater) organisms to osmoregulate, the ability of the brine shrimp to tolerate warm and hypersaline medium, and a myriad other adaptations that enable organisms to withstand conditions externally that they could not tolerate internally. Owing to the regular rise and fall of the sea, the intertidal zone is a region of great periodic fluctuations in environmental conditions. It is a region of transition between sea and land, but the boundary between aquatic and terrestrial conditions is less sharp and far more complex than that at the shorelines of lakes and ponds. In the intertidal region, animals are subjected to conditions that are alternately marine and semi-terrestrial. Even with their various protective adaptations, animals at the seashore are more or less limited to particular habitats. Physical factors of the environment, coupled with specific requirements and adaptations of animals (for food, oxygen, reproduction, and protection, as discussed below), definitely limit the distribution of each species. The most important of the physical environmental factors with which we will be concerned are outlined here. NATURE OF THE SUBSTRATE The nature of the substrate is of cardinal importance in limiting animal and plant distribution. The substrate may vary from nearly unbroken cliffs and rocky ledges, through a series of such intergrades as broken rocky reefs, boulders, and pebbles, to the finer substrates of sand, mud, and clay. Rocky substrate habitats provide m a n y places for organisms to live. Depending on the nature of the rock and how it weathers, rocky areas can have considerable topographic relief. Broad rocky reefs with ledges, crevices, outcroppings, boulder fields, and tide pools provide myriad microhabitats for organisms to occupy. Even the hardness of the rock (e.g., hard granite versus relatively soft sandstone or shale) is of great importance, particularly for attached and rock-boring forms. Soft substrates, such as the sand on a sandy beach or the m u d of an estuarine m u d flat, provide many fewer sites for organisms. Because the surface of a soft substrate provides n o fixed sites for attachment and is usually quite flat and exposed, the only place to live is beneath the substrate surface. As a general rule the marine community living in a soft substrate habitat will have a relatively low diversity of organisms but can have high numbers of individual species. Hard substrate communities tend to be highly diverse with smaller numbers of individual organisms. DEGREE OF WAVE SHOCK AND CURRENT ACTION The pOUnding and abrasive action of waves has many effects on both environment and biota (Koehl and Rosenfeld 2006). Where severe, wave action prevents the accumulation of substrates of m u d and clay, it restricts the distribution of animals that are not tough, flexible, firmly rooted, or capable of clinging tightly to (or burrowing or boring into) the substrate. Wave action also makes possible the presence of aquatic or semi-aquatic forms

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in a splash zone above the highest level reached by the surface of the sea. Currents may erode soft substrates in one area and redeposit them elsewhere. The shifting bottom materials and the scouring action of particle-laden water m a y have important effects on the bottom-dwelling organisms present. Ricketts et al. (1985), in Between Pacific Tides, clearly recognized the importance of the degree of exposure to wave shock as a factor in limiting animal distribution; their primary ecologic divisions of the Pacific intertidal zone, based on this factor, are " o p e n coast," "protected outer coast," and "bay and estuary," with appropriate subdivisions of each according to the nature of the substrate. ALTERED TEMPERATURES At low tides on sunny summer days and windy winter nights, the temperature extremes for exposed animals markedly exceed those found in the sea. Ability to withstand great changes in temperature, particularly the higher temperatures, is one important factor in determining the intertidal distribution of organisms. DESICCATION Most dwellers in the intertidal zone have come up from the sea; few are invaders from the land. It follows that withstanding desiccation is a great problem for m a n y intertidal species, and surviving prolonged submersion is far less so. Marine organisms must remain moist in order to breathe, and exposure to air dries them out, particularly during low tides on hot, sunny days, and the problem is closely related to that of withstanding higher temperatures. The higher in the intertidal zone an organism is located relative to the low tide mark, the longer it will be exposed to air. Not surprisingly then, the only organisms found in the highest tidal zone will be those that have special adaptations or behaviors to avoid drying out. Motile forms m a y show a protective behavior, shifting to positions under rocks or ledges or seeking the slighter protection of depressions and shallow crevices. Sedentary and sessile forms may have protective shells, adherent layers of sand or gravel, tough a n d often mucus-covered integuments, or large internal stores of water. As you m o v e lower into the intertidal zone, the degree of exposure an organism encounters is reduced, and more diversity will be discovered, with the most diverse areas occurring at tidal levels exposed by only the lowest tides. This effect is especially noticeable in rocky substrate habitats where organisms are attached to the rocks and directly exposed to air. The effect of tidal position can be somewhat reduced for organisms living in soft substrate habitats if the substrate remains saturated with water at low tide. ALTERED SALINITY On hot days at low tide, the salinity of high tide pools may rise owing to evaporation. During rains, direct precipitation and runoff from streams and beaches m a y greatly reduce the salinity in some areas. Organisms on high rocks, in high pools, and near stream mouths must be able to avoid, regulate against, or tolerate at least temporary hypersaline and/or brackish conditions.

LOWERED OXYGEN AVAILABILITY O n l y in c e r t a i n i n s t a n c e s is

this an important factor. It becomes important where intertidal forms are desiccated to a degree that exposed surfaces n o longer serve as respiratory membranes. It may also be important for dwellers in mudflats exposed by tides. As a result of all these factors and of many others that usually are less accessible to study, intertidal environments, floras, and faunas may vary greatly, even within relatively restricted regions of the coast. Therefore, along with this review of the main biological and physical environmental factors influencing marine invertebrates, a brief overview of how these factors

interact to shape our marine intertidal habitats available for study is appropriate.

Intertidal Habitats of Central and Northern California and Oregon Sandy Beaches Sandy beaches dominate much of the open coastline of central and northern California and Oregon, stretching uninterrupted for miles in many regions. These sandy beaches represent the most physically controlled of all the intertidal marine habitats and, as such, one of the most difficult to live in. Sandy beaches have one thing in common: all are composed of sediment particles that overlay a rocky beach platform. Beyond that, they can vary considerably. The sediments that make up these beaches are small pieces of rock, mainly the minerals quartz and feldspar. These minerals are either weathered from the continental rocks and washed down to the ocean in rivers or are the products of coastal erosion. Once these sediment particles reach the sea, they are carried along the coast until they find their way onto a sandy beach or offshore and perhaps down a submarine canyon. The transport of sediment along the coast requires water movement in the form of waves and currents. Waves come from all directions along the open coast, and the direction is related to prevailing wind patterns. When the waves come onshore and break, they often break at an angle to the shoreline, generating currents that run along the beach. These are called longshore currents, and as they move along the coast, they carry sand particles with them. This movement of sediment along the beach is called longshore transport. In the summer, the prevailing longshore current flows toward the south, and the net longshore transport of sediment is likewise southerly. However, the net longshore current direction and transport of sediment are to the north in the winter. It should be pointed out that along the coast local conditions can vary considerably, and the deposition of sediment in the form of sand bars and sand spits can likewise vary considerably from place to place. Because sandy beaches are subject to relatively continuous wave action, only the larger sediment particles, known as sands, accumulate and remain on the beach. The size of the sand particles on the beach is directly related to the size of the waves that hit the beach. On beaches that experience vigorous wave action, the finer sand grains will be resuspended and removed, leaving only large sand grains behind that feel coarse to the touch. Beaches with fine sands develop when only gentle wave action occurs, and thus only finer particles are transported to and deposited on them. Beaches will also undergo drastic changes in the type of sediment present. Many beaches go through an annual cycle of sand accumulation during the spring and summer months as small waves return fine grains to the beach, creating a gentle, sloping beach. This is followed by a drastic loss of sand with the first strong winter storm that leaves the beach in a winter condition. The storm waves strip the beach of sand or leave only the largest particles behind. Sandy beaches are truly dynamic habitats. What's it like to live there? First there is the sediment to contend with. It doesn't stay put; living on the surface or trying to excavate and live in a permanent burrow are not options. Because the sediment can shift so rapidly and unpredictably, any organism

living on the beach must be able to swim and/or burrow rapidly to keep from being swept away (good examples are the sand crab Emerita and haustoriid amphipods). Then there is a problem with drainage. As the tide recedes, water drains from between the sand grains, leaving organisms burrowed in the sand in danger of drying out. The spaces between the grains on coarse beaches are too large to hold water by capillary action. These beaches can become quite dry at high tide, especially if the sun is shining or the wind is blowing. This is less of a problem on beaches made up of fine sand grains, as water is held in the small spaces between the grains by capillary action. Finally, there are predators. Fishes, crabs, shrimps, worms, and an occasional predatory snail forage on the beaches at high tide. Birds, small mammals, and insects take over at low tide. Why live on a sandy beach? Because there is abundant food. The same wave and current action that accounts for the beach's dynamic physical nature also delivers food to the sandy beach. Food can vary from the carcasses of large animals, such as fish and marine mammals, to large seaweeds that have been torn form their attachment offshore. However, the majority of food available to beach dwellers is detritus. Detrital particles are derived from large and small organisms produced elsewhere in the ocean that have been broken up and carried along by the moving water. Not surprisingly the marine invertebrates found on sandy beaches are typically rapidly burrowing filter feeders (e.g., the sand crab Emerita analoga, and the razor clam Siliqua patula) or animals that live high up on the beach and feed on deposited plant material known as wrack (e.g., beach hoppers, Megalorchestia spp.).

Quiet Water, Soft Bottom Habitats The coastline of the northeastern Pacific is constantly changing. Sandy beaches can be transformed in a matter of hours during winter storms. Coastal bluffs are continuously weathered by wind and waves. Sea level changes and plate tectonic activity over geologic time have alternately inundated and uncovered vast areas of coastal land. Against this backdrop of change, a number of habitats become shielded from the onslaught of waves and develop into quiet water habitats. For example, estuaries are typically formed when a large river is flooded by rising sea level. The sediment carried from the land accumulates as a delta in the drowned river mouth. Sand flats, mudflats, and finally salt marshes develop as the delta grows and stabilizes. A long, fingerlike sand spit may form along the interface between the estuary and the ocean, as is seen all along the coast of northern California and central Oregon. Another example would be a strong longshore current transporting sediment along the coastline and depositing it behind a headland. The deposited sediment builds up a sand bar, and finally a sand spit gradually cuts off a cove behind the headland, forming a protected coastal embayment. As tidal action moves water in and out of the embayment, the fine sediments are deposited and sand flats and mudflats are formed. Quiet water, soft bottom habitats provide an environment that is very different from that of the sandy beach. Here organisms can create burrows that will be somewhat permanent in the soft substrate. An organism can move across the substrate at high tide and not be washed away by wave action. Tidal action continues to bring suspended food into these habitats, which combines with local plankton production to provide ample resources for a host of filter feeders. In HABITATS OF T H E O R E G O N I A N

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estuarine areas, organic detritus is brought downstream by fresh water flows. Finally, as the water becomes quiet in the most sheltered regions of these habitats, the fine organic material carried in suspension is deposited, providing food for deposit feeders. As the types of substrates and available food are similar in quiet water habitats, they tend to host similar types of animals. However, there are some differences. Coastal embayments typically contain normal, undiluted seawater. In comparison, estuaries have a gradient of salinities, from fresh water at the head of the estuary, where the river or other freshwater source enters, to pure seawater at the mouth of the estuary where it enters the sea. Salt water lagoons vary in salinity depending on the source(s) of water supplying them. I will briefly describe the unique features of estuaries, and then treat the common protected soft bottom habitats collectively.

ESTUARIES Estuaries are an aquatic interface between the riverine (freshwater) and marine environments. They serve a vital role for many organisms whose life cycles require both these environments. Most obvious of these are the salmonid fishes that spawn in upstream freshwater habitats and then migrate to the sea to feed and mature. These fishes typically pass through an estuary to reach the sea. The graded range of salinities found in the estuary allows the young salmonids to acclimate gradually from fresh to salt water. Another good example is the Chinese mitten crab Eriocheir sinensis, which lives in large populations in the freshwater rivers of central California and migrates to the estuaries to reproduce. Species that go to fresh water to reproduce are anadromous; species that return to the sea from fresh water to reproduce are catadromous. Estuaries also play important roles as nurseries for early stages in the life cycles of many marine organisms. A key commercial species that uses the estuary as juveniles is the Dungeness crab, Cancer magister. Advanced larvae enter the estuary from offshore and soon metamorphose and settle to the bottom as young crabs. The crabs may spend up to three years feeding and growing in the estuary before they move toward the mouth and out to sea. In large estuaries such as Humboldt Bay, adult populations of Dungeness crabs can be found yearround in the more saline waters of the estuary mouth. The internal body fluids of marine invertebrates are essentially isotonic to pure seawater. When the salinity of the water varies, these animals become osmotically stressed. The more saline water of a lagoon, a coastal embayment, and at the mouth of an estuary can all potentially support similar marine fauna. However the upper, less saline reaches of the estuary will harbor a unique fauna adapted to the lower salinities that occur there. Very few marine invertebrate groups have successfully evolved the ability to withstand the low and fluctuating salinities found in estuaries. On the other hand, those groups that have adapted to estuarine conditions tend to be hardy. Unfortunately, such creatures are easily transported by human conveyances, such as in the ballast water tanks of ships, or among estuarine food species imported for human consumption, such as oysters. The estuarine invertebrate fauna along the coast of the northeastern Pacific is poorly developed, and the native fauna found in a given estuary contains comparatively few species. Because the estuaries of the northeastern Pacific have such limited faunas, and because estuaries, such as San Francisco and Humboldt Bays tend to be such in8

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tense sites of international human commerce, large numbers of estuarine animals from around the world have been successfully introduced there.

THE MUDFLAT Although mudflats and sand flats are treated as separate habitats, they are part of a continuum of sediment types that grade from the finest clay mud to cobblestone beaches. In the quiet water habitats discussed here, the soft substrate is often a mixture of several sediment sizes reflecting the different types of water movement that occur over a particular area. Marine biologists might describe one such sediment as a sandy mud and another, with slightly more sand, as a muddy sand—that is to say, arbitrary terms suggest the general composition of the substrate. Therefore, although this section is titled mudflats, many of the invertebrates mentioned may be found over a range of soft sediment habitats. Because of the gradual way mudflats are formed, they tend to be quite flat with little physical relief. However, the surface signs of the burrowing and feeding activities of the resident organisms can sometimes be quite extensive (fig. 1). Mudflats might seem to be the last place to find seaweeds, but sometimes extensive growths of a variety of species of the enteromorphine green algae Ulva can be found. Red algae will also sometimes grow attached to an exposed shell or other debris. These algae occasionally accumulate in dense layers and smother fragile organisms in the sediment below. The surface of the mudflat is often covered with a slick coating of benthic diatoms, adding a further source of local primary production. Finally, mud flats may often be fringed by salt marsh vegetation, which provides a rich source of particulate plant detritus for mudflat dwellers. Particulate organic matter settles out of the water at about the same rate as clay particles do. Therefore, mudflats are rich in deposited organic matter, both on the surface and buried within the substrate. Mud snails, tube-dwelling amphipods, and vacuum cleaner clams feed on the surface deposit, while lugworms, sea cucumbers, sipunculans, ghost shrimp, and others feed on organic matter buried by sedimentation. Thus the mudflat can support a variety of species on this rich, abundant source of food. The very small silt and clay particles that make up mudflats develop a very strong capillary action. As a result, mudflats typically do not dry out during low tide. However, with the exception of a shallow surface sediment layer, there is little circulation with the water above the mudflat and the water in the sediment. Beneath this thin surface layer, oxygen is depleted by decomposing bacteria, and the substrate is colored dark brown to black by hydrogen sulfide and has the odor of rotten eggs. Obviously this is not a hospitable place for an aerobic (oxygen-consuming) organism, and many infaunal invertebrates are excluded. However it is perfect for invertebrates like clams that can burrow safely into this anaerobic mud and reach the surface with their siphons. Often the shells of clams such as Tresus nuttallii and Saxidomus spp. taken from such a substrate will be stained black.

THE SAND FLAT Many mudflat invertebrates overlap the burrowers. Sand flats occur in where there is an appreciable flow of iment. For example, in an estuary,

into sand flats, especially protected environments water and a source of sedsand flats typically form

near the estuarine mouth adjacent to the main channel where relatively constant tidal currents keep the finer sediment particles in suspension and only the larger sand grains settle out. Sand flats are also common in coastal embayments for similar reasons. The combination of tidal currents and locally generated waves transport sand into the embayment where it is deposited when the water movement slows. The most attractive feature of sand flats to marine invertebrate enthusiasts is that they are firm and easily traversed. With a little patience, a good shovel and a decent low tide, sand flats are very rewarding places to explore. The sand flat is a more physically active habitat than the mudflat. It is subjected to stronger water currents and sometimes, especially in coastal embayments, wave action. For the animals that live here, this means that a burrow may occasionally be disrupted or buried. For example, sand flat clams live more shallowly in the substrate than those on mudflats and have corresponding shorter siphons. To compensate for the occasional disruption that can sometimes wash them out of the sand, these clams, such as Clinocardium nuttalli and Leukoma staminea, have a large digging foot and are excellent burrowers. Sandy sediments pack more loosely than mud, which creates more space between the particles. This allows for an effective circulation of oxygenated water through the sediment, and an anaerobic layer does not readily form. Because water movement over sand flats is more rapid than over mudflats, particulate organic matter tends to remain in suspension. Thus sand flats are typically dominated by beds of filter feeders like clams and echiuran and phoronid worms. These beds can be quite extensive. On some sand flats in central California, such as those in Elkhorn Slough in Monterey County; or Drakes Estero on Point Reyes in Marin County, patches of substrate in the low intertidal zone seem suddenly firm under foot. Careful excavation will reveal the closely packed, flexible chitinous tubes of the phoronid worm Phoronopsis harmed. The phoronid bed may consist of many thousands of these slender, 10-cm-long worms. More obvious, motile invertebrates of the sand flats include the scavenging olive snail, Callianax biplicata, and the predatory moon snail, Euspira lewisii, whose telltale calling card—a clam shell with a circular, counter-sunk bore hole (fig. 2)—is a familiar sight on these flats. Other large invertebrate predators on sand flats include sea stars (such as Pisaster brevispinus and Pycnopodia heliartthoides) and cancroid crabs (Cancer gracilis, juvenile Cancer magister, Cancer productos and Cancer antennarius).

SALT MARSHES

Protected coastal environments are typically created by the flow of sediment into a bay, river mouth, or other shallow area, forming a delta. As the delta builds up, it can be colonized by special plants adapted to seawater-inundated soils, and a salt marsh is born. Once the salt marsh plants take hold, their spreading root and underground stem systems trap more sediment. The level of the marsh is raised, and the margin of the marsh increases outward until it reaches a dynamic equilibrium with the local pattern of water movement that controls sedimentation. As the marsh becomes more extensive, drainage channels, called tidal creeks, develop that direct the flow of water out of the marsh as the tide recedes. These tidal creeks can become deeply eroded, and their bottoms and banks create a habitat for marine invertebrates. The West Coast does not contain the vast acreage of salt marshes as is seen along our Atlantic and Gulf coasts. In addi-

FIGURE 2 A moon snail bore hole in the clam Leukoma (photo by Thomas Niesen).

staminea

tion, much of the salt marsh habitat has been diked, drained, and turned into pasture or commercial real estate in California and Oregon. The value of salt marshes and other coastal wetlands has become apparent to policymakers, and movements to preserve and even restore wetlands are in place, including coastal salt marshes. What salt marsh habitat we do have is now generally well protected by regulations and will hopefully be preserved. The average student of marine invertebrates will not venture too far into a salt marsh. The vegetation is thick and the underfooting often unsure. Likewise, the bottom of tidal creeks can be very muddy and hard to traverse. Many salt marshes in California, and some in Oregon, do provide viewing platforms, and a few, such as the Palo Alto marsh on San Francisco Bay, have catwalks that extend over the marsh or have trails built along the marsh uplands. The portion of the marsh affected by the tides is dominated by two plants. Along the lower intertidal, a fringe of the tall (up to 1 m) cord grass Spartina spp. can be found. In San Francisco Bay, the native species Spartina foliosa is being replaced by an East Coast species, Spartina altemiflora, and in some places they have hybridized. The Spartina fringe may be fairly extensive but eventually gives way to species of the shorter pickleweed or glasswart, Salicornia spp., that grow at higher tidal elevations and typically dominate the salt marsh. Above the pickleweed is a community of upland marsh plants. The tidal marsh is incised by meandering tidal creeks that usually drain out across a low intertidal flat. The marsh itself is home to a mixture of terrestrial and marine organisms. The terrestrial component includes many insects, small mammals, and of course birds. Living among the plants are many small marine invertebrates, including crustaceans and mollusks. The tidal creeks are invaded by many of the same animals that occur on mud- and sand flats. HABITATS OF THE OREGONIAN PROVINCE

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EELGRASS BEDS

Rocky Intertidal Zone

A final protected, soft substrate habitat that may be visited is the eelgrass bed. Eelgrass, Zostera marina, grows along the lower intertidal edge of mud- and sand flats and in shallow, subtidal protected habitats. In Oregon, this native seagrass is joined by extensive mid- and upper-intertidal meadows of the introduced Japanese eelgrass Zostera japónica. If the water is clear, subtidal beds of Z. marina can be quite extensive, such as those of Elkhorn Slough and Humboldt Bay. Eelgrass beds create important habitat for fishes, shrimps, juvenile crabs, and water fowl.

The interaction of physical and biological factors outlined earlier in this chapter reach their zenith in the rocky intertidal zone. The main physical factors affecting the distribution of marine intertidal organisms—tidal exposure, degree of exposure to wave action, and the type of substrate—merit particular consideration for the rocky intertidal zone. The degree of wave exposure a given habitat receives is due to a combination of the proximity of offshore protection, the direction of the prevailing waves, and the geographic orientation of the habitat. For example, along the coast of central and northern California and Oregon, there are no large islands and few offshore submarine banks to intercept waves. Waves approach the shoreline primarily from the northwest in the summer and from the west and southwest in the winter. Therefore, a rocky headland facing the west will experience the full brunt of the heavy Pacific waves. The only organisms capable of living here will have to be able to attach and grow under the onslaught of the pounding waves. Behind the headland, a small sheltered cove that faces southeast will experience decidedly less wave action and many, more fragile organisms may survive and flourish here.

The eelgrass beds accessible intertidally will yield a number of familiar marine invertebrates, including many clam and worm species. The matted root mass of the grass is a particularly good place to observe polychaetes. There are also a number of unique marine invertebrates that can be found here (e.g., the attached jellyfish Haliclystus sp., and Taylor's sea hare, Phyllaplysia taylori). The California sea hare, Aplysia califomica, comes into eelgrass beds to mate, sometimes in large numbers. After exchanging sperm, the sea hares extrude long, sticky strings of jelly-encased fertilized eggs that they attach to the eel grass.

Hard Substrates PIER PILINGS

Pier pilings represent a hard substrate that receives normal tidal exposure. As a result, it harbors a variety of organisms that prefer and/or tolerate these conditions. The upper part of a piling is usually the domain of hardy barnacles and a smattering of limpets and shore crabs (Pachygrapsus crassipes) typical of the upper intertidal zone of the rocky coast. Below the barnacles, at approximately middle tide level, mussels (Mytilus spp.) will be common, often in sizable clumps. The mussels provide attachment sites for a variety of organisms, including barnacles, limpets, sea anemones, and encrusting forms such as sponges and bryozoans. If the clump is especially well developed, it can harbor sea star predators and a myriad of small invertebrates.

FLOATING DOCKS

The sides and bottoms of floating boat docks, such as in marinas, are the other common hard substrates that may be found in quiet water habitats. These are typically made up of panels of high-density plastic foams that have high flotation properties and are imperious to seawater. However, they are not imperious to marine invertebrates. Unlike the pier piling discussed above, these substrates are never exposed to tidal action. Consequently, they harbor a suite of fragile, spacegrabbing invertebrates, many of which grow in flat, encrusting colonies. Here are the bright reds and yellows of marine sponges, the purple and orange colonies of compound tunicates, and the delicate basket-weave patterns of encrusting bryozoan colonies. Erect or branching bryozoan colonies are also common, along with a variety of hydroid cnidarians. Barnacles and mussels will also grow on these structures, providing yet more substrate for the encrusting species. Marina floats are richly encrusted with many nonnative species in our estuaries.

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Rocky intertidal substrates vary in their composition. Remember that the basic materials making up the rocky coastline you see today probably had their origin in a previous geological epoch. The rocks were most likely formed under vastly different circumstances compared to their present situation (McPhee 1993). Some habitats are hewn from sturdy igneous rocks that originated from fiery volcanic activities. Other rocky habitats consist of sedimentary rocks, formed by pressure on the compacted layers of sands, silts, and clays that once formed the bottoms of coastal embayments or estuaries, or the conglomerate rocks composed of compressed glacial till. Sedimentary rocks like limestone, sandstone, siltstone, and mudstone are softer and provide less secure attachment sites for animals like barnacles and mussels. These substrates are eroded by wave action in different patterns than are the igneous rocks. Sedimentary rocks are also more easily penetrated by boring organisms, which in turn weaken the rocky substrates and influence the way they will erode. Very hard, dense, igneous rocks like basalts will resist erosion and tend to weather evenly. Sedimentary rocks are more easily broken up by wave action, and often intertidal boulder fields will be found, consisting of broken pieces of the reef surface. Likewise, the weathering of coastal cliffs can contribute loose rocky material to the intertidal zone at their base. In places where different types of rocks intergrade, an uneven pattern of erosion can result. Wave-cut surge channels, tunnels and caves, shallow and deep tide pools, upraised outcroppings, fringing tidal reefs, and even towering headlands and seastacks, so familiar to Pacific seascapes, all can be formed from differential erosion patterns. The extent of the rocky intertidal zone depends on the slope of the wave-cut bench. This slope is again related to the type of rock and the immediate geography of the area. Rocky intertidal areas are often found at the base of steep, rocky cliffs. These areas tend to be likewise steep with vary narrow, vertical intertidal habitats. Other rocky intertidal areas occur on broad, wave-cut terraces. These tend to have extensive rocky intertidal areas with a very gradual slope. The result of the interaction of wave and substrate is a rocky intertidal habitat that can vary considerably from place to place.

The reef may be simple bedrock with little diversity of habitat. In contrast, it may consist of a mix of flat areas strewn with algae and boulder fields, upraised substrate, tide pools, and surge channels and contain a myriad of microhabitats for organisms to inhabit. The extensive rocky intertidal of the Monterey Peninsula is a striking example of such habitat diversity.

TIDAL ZONATION SCHEME

The rocky intertidal habitat is really several subhabitats stacked vertically on one another along a gradient of tidal exposure. The rocky intertidal zones, as suggested by the pioneer marine biologist Ed Ricketts, are the standard utilized to delineate the intertidal habitats found along the coast of the northeastern Pacific (Ricketts et al. 1985). He provided a general scheme of intertidal zonation for rocky shorelines in which each zone is described separately. These zones and the tidal elevations relative to MLLW (mean lower low water, the zero point of the tide tables) that they typically encompass in California and Oregon are: 1. the high intertidal zone, which includes the uppermost area wetted by the sea down to 5 ft above MLLW 2. the upper intertidal zone, which includes the tidal elevations from 5 ft to 2.5 ft above MLLW 3. the middle intertidal zone, which extends from 2.5 ft down to 0 ft MLLW 4. the low intertidal zone, which extends from zero ft MLLW down to the lowest level the tides reach Exposure to wave action, tidal level, presence or absence of standing water, slope, rocky substrate type, and erosion pattern, and many other factors contribute to the make-up of these zones. Therefore, although these zones are delineated separately, you will observe that they are seldom discrete units. The pattern and causation of rocky intertidal zonation are thoroughly described in Ricketts et al. (1985), and an attempt to recreate that description here would be redundant. However a brief review of the main subhabitats of the rocky intertidal zone is appropriate. These are the supralittoral splash zone, high tide pool, exposed-rock surface, and mussel clump subhabitats of the high, upper, and middle intertidal zones, and the open reef flat, under-rock, low tide pool, and surge channel subhabitats of the middle and low intertidal zones. Although these descriptions are presented separately, you will observe that they often intergrade with and overlap one another. Similarly, many invertebrates will be present in several different subhabitats, while others will be unique to only one.

SUPRALITTORAL

An easily accessed, extraordinarily interesting, and yet rarely studied marine habitat is the uppermost fringe of the intertidal shore, submerged by the highest tides or by storm action. This facies has been called the supralittoral zone, the wrack line, the drift line, the maritime zone, and the strand line. The supralittoral, an area hardly more than 1 or 2 m in width and bounded by an inhospitable world above and below, is an ecotonal habitat that suffers from low subscription by either terrestrial or marine biologists. This habitat has been subjected to extensive obliteration, having been replaced in many regions by sea-

walls, marinas, riprap, parking lots, beach tourism development, housing developments, and so forth. Marine invertebrates living in the supralittoral occur under rocks, stones, and drift materials; in recent centuries, humangenerated debris has added to the beach habitat. Most animals living here are adapted to the vagaries of both terrestrial conditions (e.g., desiccation and exposure to fresh water) and marine conditions (e.g., immersion and exposure to salt). A variety of terrestrial invaders, such as spiders, may co-occur with truly halophilic species as well. A window into this world can be had by placing "pit traps" on the beach at dusk and retrieving them at dawn. A simple trap can be made from a large coffee can with a funnel fitted at the top (into which the animals may fall but generally cannot exit) and a finer-gauge mesh secured at the bottom for drainage. The can is placed flush with the surface. Quantitative and experimental work can be conducted by anchoring "litter bags" (filled with different drift materials and of different mesh sizes) on the upper shore. The supralittoral biota differs on high and low energy shores. On more exposed coasts, talitrid amphipods (the sand hoppers or beach hoppers), oniscid isopods (especially the sandburrowing Alloniscus), the pseudoscorpion Garypus californicus, mites, geophilid centipedes, and a host of other arthropods (e.g., the silverfish NeomachUis halophila, the seaside earwig Anisolabis marítima, and a superb assortment of staphylinid beetles and coelopid and helcoymizid kelp and sea-beach flies) are characteristic elements along the Californian and Oregon coasts. On the lower-energy shores of bays and estuaries, the semiterrestrial nemertean "Pantinonemertes" californiensis occurs under logs and stones that turn over infrequently. Look for small white worms beneath damp wood; these are likely enchytraeid "oligochaetes." An often overlooked polychaete worm in this habitat is Namanereis pontica. Oniscid isopods of the genera Armadilloniscus and Detonella, talitrid amphipods (a mixture of open-coast and quiet water species), the pseudoscorpion Halobisium occidentale (also found under cobblestones on the open coast), geophilid centipedes, mites, and a variety of insects cooccur in these quieter water high-shore communities, as do the snails Myosotella myosotis, Assiminea californica, and Littorina subrotundata, which are also common in salt marshes. SPLASH ZONE

The splash zone subhabitat, called the uppermost horizon or Zone 1 by Ricketts, is the region covered only by the highest tides and the narrow strip above the high-water mark that is still influenced by the sea, primarily by the splash from waves and windborne sea spray. This is a zone of transition between the land and the sea, and many of the organisms dwelling here take advantage of aspects of both environments. Here you will often find lichens at the top of the uppermost tidal horizon. Prominent here also are algae, such as the enteromorphine Ulva spp., that depend on the sea spray and fresh water seeping out of cliffs that often back rocky intertidal zones. A few hardy rockweeds (e.g., Fucus sp.) hang on in the lower part of this subhabitat. Other algae grow here, such as small blue-green algae and diatoms that grow close to the rock surface and are not readily visible. These microscopic plants are most important to the few invertebrates that live here— primarily marine snails that feed on the thin algal film growing on the rocks (e.g., the periwinkle Littorina keenae and the limpets Lottia digitalis and Lottia scabra).

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A semi-terrestrial isopod, Ligia pallasii, known as the rock louse, treads the fine line between air and water in this zone. A more obvious crustacean, the green-lined shore crab Pachygrapsus crassipes, is sometimes found here tucked into crevices.

HIGH TIDE POOLS

Tide pools are considered by many to be the most interesting of all the intertidal subhabitats. Tide pools are formed by depressions in the rocky substrate that trap water at low tide and thus provide a refuge from desiccation. Therefore tide pools may contain a more diverse and often different association of organisms than found on adjacent, exposed substrate. Tide pools are not without physical stresses, however—especially during low-tide periods. A small volume of seawater trapped in a tide pool can experience a critical elevation in temperature on a warm, sunny day. Similarly, evaporation caused by wind and sun can raise the salinity to a sometimes dangerous level. Conversely, a very cold day can cause a decrease in water temperature during low tide, and a rainy low-tide period may cause a reduction in salinity. The change in physical factors experienced within a tide pool is related to the tidal level of the pool, its shape, and the volume of water it contains. A small, shallow pool located in the high intertidal zone would experience the greatest fluctuations, while a large, deep pool in the low intertidal zone would experience the least change. Therefore, instead of visualizing tide pools as a single subhabitat, it becomes obvious that they constitute a continuum of subhabitats, depending on the particular situation of the individual pool. With this in mind, two tide pool subhabitats are described here. The first, called the high tide pool, encompasses the tide pools of the upper, high, and middle tidal zones, from approximately + 9 to 0.0 ft above MLLW. In all but the highest pools, some form of coralline algae will appear. Because of their crusty texture, coralline algae are tough fodder for most intertidal herbivores. The industrious hermit crabs (Pagurus spp.) can be seen moving around the pool during the day and night. Other rapidly moving, but less-often seen, animals are small shrimp, Heptacarpus spp. These small shrimp (2.5 cm long or smaller) can be quite numerous in lower pools. A variety of carnivores occur in tide pools, including the stationary hunters, the anemones (Anthopleura elegantissima, Anthopleura xanthogrammica, and Epiactis prolifera) and sea stars (Leptasterias spp., Dermasterias imbricata, Patiria miniata, and Pisaster ochraceus). If a mid-level pool is fairly deep and contains small boulders and a little sediment, another group of invertebrates may occur. In this under-rock habitat, look for crabs (e.g., Cancer antennarius and Lophopanopeus bellus) and small, delicate brittle stars (Amphipholis squamata and Amphiodia occidentalis). Look on the undersides of the rocks for motile invertebrates (e.g., flatworms and the isopods Idotea spp. and Cirolana spp.) and attached (spirorbid worms and the rock scallop Crassadoma gigantea) and sedentary species (e.g., chitons and juvenile Strongylocentrotus purpuratus). If there is a substantial amount of fleshy algae in a pool, searching through it will usually produce a swarm of small amphipod crustaceans and a number of small snails and perhaps the spidery-looking kelp crab, Pugettia producía. EXPOSED ROCK/OUTCROPPINGS

Often, portions of the rocky intertidal reef rise up above the flat bedrock of the reef face. These upraised areas are called out12

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croppings, and they provide rocky surfaces exposed to desiccation more than adjacent flat reef areas. Similarly, large boulders that remain relatively stationary also provide this elevated subhabitat. In unprotected intertidal areas exposed to considerable wave action, this upper exposed rock surface subhabitat grades into the mussel clump subhabitat as subtle changes in tidal height and the degree of wave exposure occur. Thus, many species occur in both subhabitats. In general, the exposed rock subhabitat is higher in tidal elevation and thus more subject to drying than is the mussel clump. The main line of demarcation between these two subhabitats represents the upper physiological limit of the California sea mussel, Mytilus californianus, which provides the superstructure of the mussel clump subhabitat. The most abundant invertebrate found on these exposed rocks often is the volcano-shaped, acorn barnacle. The small barnacles found highest on the outcrop are Balanus glandula and Chthamalus dalli, the most desiccation-resistant of the common barnacles. A larger species, Semibalanus cariosus, is found lower on the sides of the outcrop mixed with Balanus glandula and Chthamalus. A fourth barnacle species, the stalked barnacle Pollicipes polymerus, will also be found in sheltered cracks on the outcrop but reaches its peak abundance in mussel clumps. The ribbed and digit limpets, Lottia scabra and Lottia digitalis, share the highest elevations of the outcropping with the barnacles. In the lower, more shaded portion of the exposed rock subhabitat, the abundant, stationary acorn barnacles provide ready prey items for several carnivorous snails: the emarginate dogwinkle or whelk, Nucella emarginata; the angular unicorn, Acanthinucella spirata; and circled dogwhelk, Ocinebrina circumtexta. These barnacle-eating snails share the lower outcropping with several species of herbivorous limpets (the shield limpet, Lottia pelta; the file limpet, Lottia limatula; the plate limpet, Lottia scutum; and the owl limpet Lottia gigantea). The shore crabs Hemigrapsus nudus and Pachygrapsus crassipes can also be found in this exposed rock subhabitat, holed up in cracks and crevices.

MUSSEL CLUMP

Large beds or clumps of the California sea mussel Mytilus californianus are common all along the open coast of the northeastern Pacific. The mussel thrives in areas of high wave energy, and indeed, its distribution corresponds to the most exposed, wave-tossed rocky intertidal habitat. The mussel's upper distribution is limited by its physiological tolerance to exposure. In areas of consistent wave action, the mussels can inhabit high intertidal zones successfully because of the wave splash, but in areas of periodic calm, their upper limit is the middle intertidal zone. Another control of the mussel is the Pacific sea star, Pisaster ochraceus. Pisaster's predation on the mussel is sufficient to preclude it from moving into and monopolizing the lower intertidal zone in the way it can dominate the middle intertidal zone. Thus Pisaster keeps the lower substrate open for other species to colonize and inhabit, allowing for a more diverse assemblage of organisms attached to primary space than in the mussel clump subhabitat (Paine 1974). In addition to Pisaster and Mytilus, several other prominent organisms inhabit the mussel clump. The stalked barnacle, Pollicipes polymerus, occurs in round aggregations, sometimes surrounded by mussels. The solitary giant owl limpet, Lottia gigantea, is a conspicuous loner compared to the "togetherness" of Mytilus and Pollicipes, with individual L. gigantea

to the upraised rocks and outcrops, the middle and low intertidal zones can contain extensive stretches of flat, open reef and areas where small boulders have accumulated, called boulder fields. Both of these subhabitats grade relatively seamlessly between the middle and low intertidal zones (below 0.0 MLLW). The flat, open areas of the middle intertidal zone are usually characterized by lawns of short-growing (5 cm-10 cm) red algae and are sometimes referred to as red algal "turfs." The flat reef has little relief to break up the sweeping surf, and consequently, the diversity of large invertebrates is relatively low here. The lush growth of red algae does provide ample fodder for herbivorous snails such as the turbans Chlorostoma funebralis and Chlorostoma brunnea. The trapped moisture makes a hospitable setting for clones of the aggregating sea anemone, Anthopleura elegantissima, which can be quite extensive. A layer of sand and small pebbles accumulates at the base of these plants, harboring many small invertebrates, including numerous worms, small snails, and a variety of crustaceans (amphipods and juveniles of the crabs Pugettia producta and Cancer antennarius). Interspersed among the algal turf are occasional large invertebrate predators (e.g., the sea stars Pisaster ochraceus and Dermasterias imbricata).

SURFGRASS

FIGURE 3 A grazed-out territory created by the limpet Lottia gigantea (photo by Thomas Niesen).

actively maintaining territories in the middle of a dense mussel clump (fig. 3). The surface of the mussels' shells also serves as available living space for acorn barnacles, numerous small limpets of several species, and anemones. With this abundance of small invertebrate prey, it is not surprising to find that the small, predatory six-rayed sea star, Leptasterias spp., and the barnacleeating whelk, Nucella emarginata, occur here. These are only the larger, obvious animals of this subhabitat. Close scrutiny of the clump will reveal myriad smaller, motile animals and encrusting forms that combine to form one of the most diverse intertidal assemblages. In addition to the shells of the mussels, the webs created by their collective attachment (byssal) fibers provide a maze of nooks and crannies for marine invertebrates to inhabit. Young sea urchins find shelter at the base of the clump. Worms are especially able to maneuver here, and a wide variety of species occurs. Prominent are the polychaetes (e.g., Nereis vexillosa and Halosynda brevisetosa), nemerteans, and flat worms. Crabs abound in the interstices of the mussel clump. Young of the shore crabs Pachygrapsus crassipes and Hemigrapsus nudus are common. Other common crabs are the porcelain crabs (Petrolisthes spp., Pachycheles spp.).

The red of the algal turf is occasionally broken up by the bright green of the surfgrass Phyllospadix, of which three species occur in our region (P. scouleri, P. torreyi, and P. serrulatus, the latter as far south as Cape Arago in southern Oregon). Unlike the algae, which attach to bare rock with their holdfasts, surfgrass is a flowering plant that sinks its roots into soft sediment. Surfgrass takes up nutrients necessary for continued growth principally through the root system, while algae absorb nutrients directly from the water across their entire surface. The root mass of the surfgrass traps sediments and provides a living space for many small invertebrates, such as sipunculans, polychaetes, and small crustaceans. As sediments accumulate, the surfgrass sends out rhizomes trapping still more sediment and allowing it to increase its coverage. The lower intertidal zone remains submerged much longer than the middle intertidal, and surfgrass can grow quite lush here as a result. Extensive surfgrass beds that cover not only the solid rock substrate, but also small boulders and sandy areas as well, are common sights in many rocky intertidal areas of the California and Oregon coats. Surfgrass is a favorite lowtide resting spot of large rock crabs, Cancer spp., and mated pairs can often be discovered in the spring. Hermit crabs, Pagurus spp., and kelp crabs, Pugettia producta, are also common. Although they probably spend low tide under or among adjacent rocks, octopuses are occasionally seen during low tide seeking the refuge of the surfgrass bed, especially if it is still partially covered by water. The surfgrass beds and the standing pools of kelp like oar-weed, Laminaria spp., left by the lowest of the low tides often harbor nudibranchs among the vegetation (common are Hermissenda crassicornis, Aeolidia papulosa, Peltodoris nobilis, Doris montereyensis, Diaulula sandiegensis, Triopha catalinae, and Okenia rosacea).

REEF FLAT

BOULDER FIELD

In many rocky intertidal habitats with a gradual slope, the middle and low intertidal zones can be quite extensive. In addition

In low-lying regions of the middle and low rocky intertidal, small boulders will accumulate, forming boulder fields. In HABITATS OF THE OREGONIAN PROVINCE

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open, exposed rocky intertidal habitats, small boulders are frequently moved around and broken up, or swept off t h e reef platform entirely by wave action. Therefore, boulder fields are more characteristic of rocky intertidal areas t h a t are semiprotected from direct wave action. Here rocks of dinner plate size and larger stand a good chance of staying in place for sustained period of time. Thus the boulder field subhabitat provides a relatively protected, stable, under-rock environment that supports a rich and varied assemblage of invertebrates. Look for rocks that have well-developed algal growth. This is an indication that they have remained in place for some time and will constitute fruitful searching. The c o m m o n seaweed species include the flat-bladed Mastocarpus spp., Chondracanthus spp., and Mazzaella spp. growing in profusion. The under-rock habitat is prime crab-viewing territory for the student. Among the most prominent crabs are the purple shore crab, Hemigrapsus nudus; the large, red rock crabs, Cancer antennarius and Cancer productus; and t h e small pygmy cancer crab, Cancer oregonensis. Several spider crabs are also found here (Pugettia spp., Mimulus foliatus, and Scyra acutifrons). Also, hermit crabs and hordes of the flattened porcelain crab Petrolisthes spp. are c o m m o n under rocks. If there is any sediment beneath the boulder, look for sipunculan worms, shallow-burrowed polychaete worms, brittle stars (Ophiopteris papulosa), and small sea stars (Leptasterias spp. and Henricia spp.). Larger sea stars can be occasionally seen o n the tops and sides of rocks {Patina miniata, Pisaster ochraceus, Pisaster giganteus, and Pycnopodia helianthoides). Sea cucumbers are very successful dwellers of the tight under-rock quarters (Eupentacta quinquesemita and Cucumaria miniata); small ( < 2 cm in diameter) purple sea urchins, Strongylocentrotus purpuratus, also occur here. Among t h e rocks of t h e middle and low intertidal zones, a number of shelled gastropods can be f o u n d (Haliotis rufescens, Diodora aspera, Fissurellidea bimaculata, Acmaea mitra, Ceratostoma foliatum, Lirabuccinum dirum, Chlorostoma spp., Calliostoma ligatum, and Amphissa versicolor). Attached to the bottom of the rocks will be sea anemones (Epiactis prolifera), t h e calcium carbonate tubes of filter-feeding polychaete worms (spirorbid worms and Serpula columbiana), and t h e intertwined shells of vermetid gastropods (Serpulorbis squamigerus). Also seen attached to t h e under-rock surface are attached bivalve mollusks (Crassadoma gigantea, Pododesmus macrochisma), and a variety of chitons (Mopalia spp., Tonicella spp., Placiphorella velata, and Lepidozona mertensii). The rocks and boulders found in intertidal boulder fields are derived from a variety of sources. Some material may come from t h e weathering of cliffs that abut the intertidal zone. Much rocky debris may be thrown o n t o t h e reef from the subtidal zone by wave action. However, the majority of rocks are often composed of pieces broken from the solid reef substrate itself, especially if the reef is made u p of soft, sedimentary rock like shale, sandstone, or siltstone. If t h e rocks of the boulder field are soft, the student might notice round holes in them. These are the burrows of the rockboring bivalve mollusks known as pholads or rock piddocks (e.g., Penitella penita, Zirfaea pilsbryi). The burrows excavated by these unique clams appear round from the surface and conical w h e n viewed from the side. These clams riddle the soft, rocky reef in the mid- and lower-intertidal zones until it becomes unstable and pieces break away under the p o u n d i n g surf. W h e n t h e boring clams die, the now vacant burrows become t h e h o m e of a variety of other animals (sipunculans, polychaetes, snails, small sea stars, nestling clams, sponges, bryozoans, and the lumpy porcelain crab, Pachycheles rudis). 14

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LOW TIDE POOL

Low intertidal pools are unique subhabitats. The nature of t h e rocky substrate has to be such that dished-out areas occur in t h e low intertidal region, and t h e exposure to wave action plays an important role, as well. Therefore students won't find tide pools at every rocky area they visit, and of course, viewing t h e m requires that the tide for the day be below t h e zero tidal level (MLLW). However, they are easily recognized for t h e unique group of organisms they support. The first and foremost inhabitant is the purple sea urchin, Strongylocentrotus purpuratus, one of the most c o m m o n marine animals along t h e open coast. At very low tides ( - 1 . 0 ' MLLW or lower), large numbers of urchins can be found exposed o n flat, seaward portions of the lower reef. In both this exposed, lowest intertidal region and in the low tide pools, the urchins occur in rounded depressions or pits, thought to be excavated by the urchins using their spines and their special, five-jawed chewing apparatus called Aristotle's lantern. Look for small purple-colored invertebrates, including crustaceans a n d flatworms, in these urchin holes. In the low tide pool, the dark purple of the urchins is contrasted against the lighter pastel purple and pinks of coralline algae, a b u n d a n t here because their calcium carbonate-impregnated tissues are too hard for the urchins to graze. Other bright spots of color on the walls and floor of the low tide pool are provided by sponges and brightly colored cnidarians (Balanophyllia elegans, Corynactis californica, Epiactis prolifera, Anthopleura xanthogrammica, and Urticina spp.). Tube-dwelling polychaetes are also c o m m o n here (Dodecaceria fewkesi, Serpula columbiana). Several mollusks contribute to these colorful tide pools: the lined chiton, Tonicella spp.; the dunce cap limpet, Acmaea mitra; the beaded top snail, Calliostoma annulatum; and t h e rock scallop, Crassadoma gigantea, distinguished by its bright orange mantle and blue eyespots that are visible w h e n the shell gapes open. During the quiet morning, minus low tides of spring and summer, t h e low tide pools feature the showiest of all the mollusks, the nudibranchs, or sea slugs. It is in the low tide pool, with its smaller area and beautiful background colors, that nudibranchs can be most appreciated. Because the pools harbor sponges, cnidarians, and bryozoans that serve as food for sea slugs, it is not unusual to find several species in a single pool. Look among the coralline algae and on the surface of the pool itself for nudibranchs crawling along upside down, using the surface tension created at the air-water interface as a foothold. Sea stars are seen in the low tide pools. The Pacific sea star Pisaster ochraceus; sea bat Patiria miniata; leather star, Dermasterias imbricata; and the sunflower star Pycnopodia helianthoides are all occasionally discovered here. Smaller species of sea stars more commonly seen in these pools include small blood stars, Henricia sp., and six-rayed sea stars, Leptasterias spp. These two small stars often sport mottled colors that blend in with t h e coralline algae.

SURGE CHANNEL

Surge channels are formed by the differential weathering of the reef platform by t h e ocean. They are sometimes cut below the tidal level and thus never completely drain, even during the lowest tides. These submerged channels are typically at the very edge of the reef and support large stands of the oar-weed kelp, Laminaria spp., and other kelps o n t h e bottom, as well as

feather-boa kelp, Egregia menziesii, o n the sides. Other surge channels extend well into t h e reef, in some cases reaching u p into t h e mid-tidal level and above. Besides tidal level, another variable in t h e surge channel subhabitat is orientation. Channels that extend directly into the reef, essentially perpendicular to the reef's edge, receive the direct force of the waves. Surge channels that turn to parallel t h e reef's edge are quieter and receive a somewhat less forceful flow of water. Finally, the shape of t h e surge channels must be considered. Channels with straight sides tend to harbor a more meager cast of organisms t h a n d o channels that have substantial undercutting and overhangs. Channels with dished out bottoms tend to trap small boulders that bounce around and scour the walls, while channels with bottoms that slope continuously seaward are swept free of such material by wave action. The surge channel subhabitat is thus a varied one. What you discover in a given channel depends on all t h e variables listed above and a number of others, including t h e time of the year. One t h i n g the student should remember about surge channels: they are high-energy environments. They require that organisms be able to attach and hold on against the m o v e m e n t of strong water currents. They are also food-rich environments, in that t h e surging water contains m a n y small organisms and organic detritus swept from t h e reef and brought in from offshore. It is not surprising t h e n that m a n y surge channel animals are attached filter-feeders t h a t take advantage of this waveborne bounty. A final note of caution: the same high energy that characterizes the surge channel can catch you off guard! Watch out for waves. These are fascinating areas to explore, and you are more often t h a n n o t b e n t over or o n your hands and knees. Have a lookout watch for incoming swells and u n a n n o u n c e d surges of chilling seawater. Remember the surge channels are t h e avenues through which the tide floods into the intertidal zone. Be alert. The organisms occurring along the top of the surge channel walls reflect the general organismal association for the particular tidal height and exposure. Thus, some walls are relatively barren, others are cloaked in thick algal growth, and still others support the spill-over from a well-developed mussel clump. However, it is in the shade of deeply undercut or overhanging walls in the lowest intertidal that the surge channel subhabitat achieves its glory. These strongly undercut habitats are also f o u n d along the low intertidal, seaward edge of some semi-protected reefs. W h e n you first observe one of these well-developed, low intertidal surge channel overhangs, you will be taken by t h e variety of colors, shapes, and textures. Because the overhang is in deep shade, only t h e hardiest encrusting coralline algae will occur, and these are in competition with a variety of space-monopolizing, encrusting marine invertebrates. The roof of the overhang often has sea anemones (Epiactis prolifera and Anthopleura elegantissima) and hydroids (Aglaophenia latirostris, Pinauay sp., Abietinaria spp.) hanging d o w n and, occasionally, large barnacles (Balanus spp. and Tetraclita rubescens). The back wall of an overhang typically harbors several species of sponge growing in red, yellow, purple, brown, gray, and off-white sheets; c o m p o u n d and solitary tunicates, such as Aplidium californicum and Styela montereyensis; and clones of the asexually produced light-bulb tunicate, Clavelina huntsmani. Scattered a m o n g t h e other encrusting invertebrates are colonies of bryozoans such as Eurystomella bilabiata; solitary orange cup corals, Balanophyllia elegans; and the tubes of feather-duster worms (Serpula columbiana and Eudistylia polymorpha).

Invertebrates o n t h e bottom of the surge channel overhang include more c o m p o u n d tunicates, sponges, and patches of the colonial polychaete, Dodecaceria fewkesi. The giant green sea anemone, Anthopleura xanthogrammica, is frequently f o u n d o n the bottom of surge channels, waiting patiently for dislodged prey to be swept into its grasp. Motile animals are also found in surge channels. Large cancer crabs, especially female Cancer antennarius brooding embryos, seek out cracks and crevices along t h e overhang walls. Several sea stars appear to use surge channels as avenues in and out of t h e intertidal zone and may be encountered here o n occasion (Pisaster spp., Pycnopodia helianthoides, and Dermasterias imbricata). Six-rayed sea stars, Leptasterias spp.; blood stars, Henricia spp.; and sea bats, Patiria miniata appear t o be more permanent residents. Gastropods with tenacious grips are found in surge channels. Chlorostoma spp., Calliostoma annulatum, Ceratostoma foliatum, Haliotis rufescens, and Diodora aspera are a m o n g t h e c o m m o n species usually seen. Nudibranchs also occur occasionally. The sea lemon Peltodoris nobilis; t h e ring-spotted dorid Diaulula sandiegensis; and t h e red sponge nudibranch, Rostanga pulchra are c o m m o n species. Chitons are sometimes seen in surge channels, with t h e vividly colored lined chiton, Tonicella spp., being t h e most c o m m o n .

Biogeography of the Oregonian Province To a new student of marine invertebrate zoology, t h e diversity of the shallow water invertebrate fauna of the northeastern Pacific is initially staggering. To master the variety of types, let alone the names of t h e m a n y species, seems impossible. However it can be done, and after becoming acquainted with the modern species, t h e student's curiosity often questions where all these invertebrates came from. The answer lies in t h e province of biogeography; as an example, here we discuss zoogeography, t h e study of the origin and distribution of animals. Marine biogeographers look at the geographic distributions of all t h e members of a group, extinct and extant. Based o n the patterns of co-occurrence they see, they determine t h e degree of relatedness a m o n g faunas. Biogeographers use t h e taxonomic hierarchy as their yardstick. For example, two areas harboring m a n y of t h e same species probably were connected more recently t h a n two areas that share few species b u t have m a n y genera in c o m m o n . For the northeastern Pacific biogeographers recognize a distinct cold-water province, t h e Arctic Province, that includes m u c h of Alaska, and a warm-water or tropical province, t h e Panamic Province, which includes the Gulf of California and the tip of Baja California. In between these two is an area referred to as a cold-temperate region, including California, Oregon, Washington, and British Columbia. The cold temperate region is divided into several provinces— the Canadian, Oregonian, and Californian. This manual covers a good portion of t h e Oregonian Province, with Point Conception generally recognized as its southern boundary. There is less t h a n u n a n i m o u s agreement o n the location of t h e northern boundary of the Oregonian Province, which has been designated as occurring as far south as central Oregon, to as far north as Dixon Landing, Alaska (Ekman 1953; Briggs 1974). Before considering the modern distribution and relationship of these faunal provinces of t h e northeastern Pacific, some background is necessary. All shallow water marine faunas are related to t h e Tethyan fauna, which originated 190 million years ago w h e n there was a single landmass known as Pangea. HABITATS OF T H E O R E G O N I A N P R O V I N C E

15

When Pangea divided into northern and southern continental land masses, Laurasia and Gondwana, the Tethys Sea was formed in between as a shallow, trans-equatorial sea. The Tethys Sea is considered the evolutionary point of origin for all modern marine invertebrate groups. Remnants of this ancient tropical fauna and flora can be seen today in the circumtropical distribution of many families and genera. Anyone who has observed coral reefs in both the Caribbean and equatorial west Pacific cannot help but notice the striking similarity in reef faunas, especially among the conspicuous reef-forming corals and brightly colored reef fishes. The Laurasia and Gondwana landmasses divided into smaller continents, which gradually aligned in their current north-south orientation separated by the Pacific and newly formed Atlantic Ocean basins. As this alignment developed, the Tethys Sea became divided, and the two isolated portions of Tethyan fauna evolved into two distinct shallow water tropical faunas, the Indo-West Pacific and the Atlanto-East Pacific. These names reflect the global consequences of continental drift and sea floor spreading. As the continents were moving about and realigning, the shallow water tropical marine habitats of the East and West East Pacific remained continuously separated by a large expanse of deep oceanic water. The Atlantic and tropical East Pacific were joined across the Isthmus of Panama and shared a similar fauna, the Atlanto-East Pacific. The Indian Ocean and the vast island arcs of the tropical West Pacific shared the Indo-West Pacific warm water fauna. During the Tertiary (70 mya) global climate became colder, more water was tied up as ice at the poles, and as the ocean level dropped, land emerged. The Isthmus of Panama was closed by the formation of a land bridge dividing the Atlanto-East Pacific faunal region. The ocean temperature cooled with an equatorto-polar decrease in temperature resulting in distinct zones or "provinces" of water temperature that were to some degree physically separated. This physical separation set the stage for the formation of the modern shallow water marine faunal provinces along the continental coasts that we recognize today. But how were these modern shallow water provinces derived and how are they related to each other? Since the Tertiary, the global climate has been dominated by periods of glaciation and warmer interglacial periods. In the recent past, the coast of the northeastern Pacific has been influenced by the last ice age. About 12,000-15,000 years ago, much of the northern hemisphere was covered by a thick ice sheet. This ice sheet spread as far south as Puget Sound. The water sequestered in glaciers worldwide caused sea level to drop about 400 ft. This exposed much of the shallow continental shelf. As the ice sheet melted and sea level rose, many changes occurred along the coast. The advancing water weathered the soft sedimentary rocks of the Coastal Range, cutting flat marine terraces that typify much of our coast and providing much of the sediment that formed many of our sandy beaches and sand dune systems. Harder basaltic rocks that had been formed by volcanic processes and intruded into the sedimentary rock of the Coastal Range resisted erosion and became sea stacks and coastal headlands, such as Morro Rock and Point Sur. Coastal river valleys were flooded with the rising seawater. As sediment washed down from the mountains, it became trapped in these drowned river mouths to form estuaries such as Humboldt Bay. This last Pleistocene glaciation was only one in a series of such events that occurred periodically over the past 100,000 years. These were periods of vigorous physical and biological disturbance and change that collectively have contributed most directly to the fauna we see today. For example, as sea16

HABITATS OF THE O R E G O N I A N

PROVINCE

water temperatures have fluctuated along our coast over geological time, dynamic faunal changes have likewise occurred. During periods of warmer water, elements of the tropical Panamic fauna to the south have migrated northward. Conversely, when the water cooled, elements of the Arctic fauna moved southward. When the seawater temperature began to change again, these animals either adjusted to the new water temperature, retreated back to their respective provinces, or evolved into new species capable of existing with the new seawater temperature. The effect of these dynamic changes in species distribution with seawater temperature can be seen by looking at the extant fauna in our Oregonian Province. There is an element of the warm water province present, albeit faint. The spiny lobster, Panulirus interruptus, which is seen occasionally as far north as the Monterey Bay subtidal, is a reminder of the subtropical influence. The relationship with the cold water faunal provinces is much more apparent. For example the echinoderm genera represented in our fauna, Strongylocentrotus, Leptasterias, and Henricia, all have their origin in the Arctic. The list of cold water genera and even families of marine invertebrates represented in our Oregonian fauna is quite extensive, and it is easily understood why there is a stronger representation of cold water elements than warm. First, the cold waters of the southerly flowing California Current bathes the Oregonian Province. Second, the Oregonian Province experiences the strongest and most persistent spring and summer upwelling of the entire northeastern Pacific coast (Parrish et al. 1981, Bakun 1996). The cold, upwelled water inundates the nearshore, negating any summer warming of seawater temperature. Obviously these cold water influences would more strongly favor the success of cold water faunal invaders than warm. Finally, we come to the fact that on average across all faunal groups, approximately half of the species of the Oregonian Province are endemic (i.e., evolved in our province). The explanation for this unusually high degree of species endemism (provincial endemism usually ranges from 10%-25%) is rooted in the dynamic scenario of glaciations and interglacials outlined above, along with strong seasonal upwelling. This glaciation/interglaciations account for waves of cold water invaders followed by periods of relative isolation and biological accommodation, while seasonal upwelling potentates the food chain with a high level of predictable primary productivity. This combination of highly transitory faunal distributions and high levels of available food energy fostered spectacular adaptive radiation and speciation across the range of invertebrate phyla (e.g., the decapod genera Cancer and Crangon and the gastropod genera Haliotis and Lottia). In summary, the Oregonian faunal province that we deal with in this manual thus has a high degree of species endemism, with little affinity to the warm water region to the south. Although the ancient tropical faunas were the seed beds of evolution of modern marine invertebrates, the tropical influence on the Oregonian fauna is seen only at a distance via limited overlap at the generic level. This suggests that for some time the fauna of the Oregonian Province developed independently of the present day warm water fauna. What we can see in present day species and particularly genera found in the Oregonian Province is the high degree of overlap with the Arctic cold water fauna, which demonstrates the importance of the migration of northern fauna down the coast as temperatures cooled since the late Tertiary. What does all this mean to today's student exploring the modern shallow water invertebrate fauna of the Oregonian Province?

Basically, it m e a n s w h e n y o u e x p l o r e a habitat in t h e s o u t h e r n e n d of t h e area c o v e r e d b y this m a n u a l , y o u will e n c o u n t e r s o m e m a r i n e invertebrates t h a t h a v e t h e m a j o r i t y of their close relatives in t h e w a r m w a t e r p r o v i n c e s t o t h e s o u t h . These a n i m a l s usually also h a v e a distinct n o r t h e r n limit t o their distribution a l o n g t h e o p e n coast. A n e x a m p l e o f this w o u l d be Kellet's whelk, Kelletia kelletii, a s o u t h e r n species seen in t h e shallow subtidal o f M o n t e r e y Bay, but rare n o r t h of M o n t e r e y Bay. Conversely, e x p l o r i n g h a b i t a t s a t t h e n o r t h e r n e n d o f r e g i o n c o v e r e d b y this m a n u a l will reveal a c e r t a i n p o r t i o n o f t h e org a n i s m s w i t h affinities t o c o l d w a t e r relatives a n d d i s t i n c t s o u t h e r n limits t o t h e i r d i s t r i b u t i o n . An e x a m p l e o f t h i s is t h e s u n star, Solaster dawsoni.

This sea star o c c u r s in t h e r o c k y in-

tertidal z o n e in H u m b o l d t C o u n t y b u t is o n l y f o u n d subtidally s o u t h t o M o n t e r e y Bay (Morris et al. 1 9 8 0 ) . Remember, however, along with the w a r m and cold water species, y o u will find a m u c h larger g r o u p of i n v e r t e b r a t e s t h a t s w e e p a l o n g t h e e n t i r e c o a s t f r o m Alaska t o Baja California, inc l u d i n g s u c h w o n d e r f u l a n d c h a r i s m a t i c species as t h e o c h r e seastar Pisaster ochraceus anus—two

a n d t h e sea m u s s e l Mytilus

californi-

o f t h o u s a n d s o f species t h a t f o r m s o m e o f t h e m o s t

s p e c t a c u l a r m a r i n e p r o v i n c e s a n y w h e r e in t h e w o r l d .

References Bakun, A. 1996. Patterns in the ocean: ocean processes and marine population dynamics. California Sea Grant College System, NOAA, 323 pp. Barry, J. P., C. H. Baxter, R. D. Sagarin, and S. E. Gilman. 1995. Climaterelated, long-term faunal changes in a California rocky intertidal community. Science 267: 8 7 2 - 8 7 5 . Briggs, J. C. 1974. Marine zoogeography. McGraw-Hill. California Coastal Commission. 2003. California coastal access guide. 6th ed. Berkeley: University of California Press, 304 pp. California Coastal Commission. 1987. California coastal resource guide. Berkeley: University of California Press, 384 pp.

Carlton, J. T. 1993. Neoextinctions of marine invertebrates. Amer. Zool. 33: 4 9 9 - 5 0 9 . Carlton, J. T. and J. Hodder. 2003. Maritime mammals: terrestrial mammals as consumers in marine intertidal communities. Mar. Ecol. Prog. Ser. 256: 2 7 1 - 2 8 6 . Carlton, J. T„ J. B. Geller, M. L. Reaka-Kudla, and E. A. Norse. 1999. Historical extinction in the sea. Annu. Rev. Ecol. Syst. 30: 5 1 5 - 5 3 8 . Cohen, A. and J. T. Carlton. 1995. Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of San Francisco Bay and Delta. Report for the U.S. Fish and Wildlife Service and National Sea Grant Program, Connecticut Sea Grant. No. PB96166525. Ekman, S. 1953. Zoogeography of the sea. Sidgwick and Jackson, London 417 pp. Koehl, M. and A. W. Rosenfeld. 2006. Wave-swept shore. The rigors of life on a rocky coast. University of California Press, Berkeley, 179 pp. Larson, R. J., W. S. Alevison, T. M. Niesen, and S. L. Clark. 1997. Changes in fish communities off Santa Cruz Island, California, over the last 25 years: Effects of ocean warming and habitat change. Abstracts Amer. Soc. Ichthyologists and Herpetologists; 77th annual meeting; Seattle. McPhee, J. A. 1993. Assembling California. Farrar, Straus and Giroux, New York, 224 pp. Morris, R. H., D. P. Abbott, and E. C. Haderlie. 1980. Intertidal invertebrates of California. Stanford University Press, Stanford, California, 6 9 0 pp. Parrish, R. H., C. S. Nelson, and A. Bakun. 1981. Transport mechanisms and reproductive success in fishes of the California Current. Biol. Oceanog. 1: 1 7 5 - 2 0 3 . Paine, R. T. 1974. Intertidal community structure. Experimental studies on the relationship between a dominant competitor and its principal predator. Oecologia 15: 9 3 - 1 2 0 . Ricketts, E., F.J. Calvin, J. W. Hedgpeth, and D. Phillips. 1985. Between Pacific Tides. 5th ed. Stanford University Press, Stanford, California, 6 5 2 pp. Sagarin, R. D„ J. P. Barry, S. E. Gilman, and C. H. Baxter. 1999. Climate related changes in an intertidal community over short and long time scales. Ecol. Monogr. 69: 4 6 5 - 4 9 0 . Tegner, M. J., L. V. Bäsch, and P. K. Dayton. 1996. Near extinction of an exploited marine invertebrate. Trends Ecol. Evol. 11: 2 7 8 - 2 8 0 .

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Intertidal Meiobenthos J A M E S W. N Y B A K K E N A N D R O B E R T P. H I G G I N S

In addition to the larger intertidal benthic invertebrates associated with sand and mud and visible to the naked eye that inhabit the intertidal areas of the Pacific coast, there are a large number of microscopic benthic invertebrates hidden in sediment. These organisms, which when sieved pass through a 1-mm-mesh sieve and are retained on a 62-pm-mesh sieve, are termed meiobenthos or meiofauna. Meiobenthic invertebrates can be further divided according to their specific habitat: those living o n the surface of the sediment at the water-sediment interface are referred to as epibenthic. Those living in sediment where they displace sediment particles in their movement (burrowing) are called endobenthic. Those living in the interstices of particulate matter are referred to as mesobenthic or interstitial. In such habitats as coarse shell-gravel, all three types may exist because fine particles may be present in all or part of the interstitial spaces. Note that the term interstitial applies to any organism living in interstices. Meiobenthic invertebrates, which are exclusively sand dwellers, may be referred to as psammon from the Greek term psammos (= sand). In such cases, the terms epipsammon, mesopsammon, and endopsammon are applicable. In the marine environment, six animal phyla are exclusively meiobenthic: Placozoa, Kinorhyncha, Tardigrada, Loricifera, Gastrotricha, and Gnathostomulida. The meiobenthos includes the smallest members of 16 other phyla, such as Cnidaria, Mollusca, and Annelida, that otherwise are dominated by relatively large organisms. Some of these phyla, for example Brachiopoda and Sipuncula, may have only one or two species that can be considered meiobenthic, in contrast with the Arthropoda, Annelida, Platyhelminthes, and Nematoda, which have numerous meiobenthic representatives. The meiobenthos is relatively well-studied in Europe and on the Atlantic coast of North America, but these animals are virtually unknown on the Pacific coast. We take this opportunity to strongly encourage students to enter this open field of research. That much remains to be known is revealed by our sampling of the shores of Monterey Bay, in central California, alone. Here we found many remarkable species, including at least three taxa previously unknown from the Eastern Pacific Ocean: the hydroid Halammohydra, the nudibranch Pseudovermis, and the tiny mystacocarid crustaceans. 18

Two essential texts for meiobenthic studies are Higgins and Thiel (1988) and Giere (1993).

Habitat Meiobenthic diversity usually is highest in subtidal and, to a lesser extent, intertidal coarse sand, such as that found on high-energy marine beaches (fig. 4A), and lowest in the finer sediments, especially in fine sand. In terms of abundance, intertidal mudflats may have as many as 8 million meiobenthic organisms per square meter, which occupy only the upper few centimeters depending on the amount of available oxygen. The depth at which meiofauna are found in sediment is primarily dependent upon the oxygen gradient. In fine sediments as silt or mud, meiobenthos rarely penetrate more than a few centimeters of the substrate. In coarse sediments (e.g., medium sand, coarse sand, or shell gravel), especially where these sediments are part of a high-energy beach ecosystem, meiobenthos may be found as deep as 1 m or more (Kristensen and Higgins 1984). In general, they are not found in fine sand, but occasionally they may be present in the narrow stratum of silt or flocculent material at the fine sand-water interface. Most meiobenthos will exist only in the oxygenated sediment. The depth to which meiobenthos penetrate, therefore, is also dependent on the particle size. In fine sediment, both intertidal and subtidal, only the upper few centimeters of substrate should be sampled; in coarse sediments, one should concentrate on sampling the upper strata (between 0-10 cm in subtidal sediment, 5-50 cm in intertidal high-energy beach habitat, and between 0-20 cm in other intertidal coarse sediments). The most likely habitat in which to find meiobenthos in both numbers and diversity is a stable mud or muddy-sand bottom where salinity is at or slightly below 34%. Beaches and mud or sand flats exposed during low tide also require the meiobenthos to be euryhaline and eurythermal. Exposure to intense solar radiation as well as torrential rainfall at low tide require the meiobenthic organisms to be tolerant of wide variations of physical factors. Horn (1978), for example, found the kinorhynch Echinoderes coulli in intertidal m u d in North Carolina with salinities ranging from 1 ppt to 42 ppt during a tidal cycle.

FIGURE 4 Collecting and processing techniques for sampling intertidal sand. A, Profile of typical beach showing intertidal zone marked by mean high water (MHW) and mean low water (MLW); B, obtain seawater and pour through 62-^im mesh sieve into, C, clean bucket; D, transfer some filtered seawater to wash bottle and "back-wash" (clean) the plankton from the sieve so as to avoid contamination in later steps; from a determined depth on the beach (e.g., the first 10-cm layer) remove sand (K) and place in bucket of filtered seawater (E); F, with hand or some item suitable for stirring, mix the sand with filtered seawater to suspend the meiobenthos; G, decant the water with suspended meiobenthos into a clean (D) 62-jim mesh sieve and catch filtered seawater for additional use; L-N, repeat this step, each time sampling the next 10 cm horizon until ground water is encountered (N); figures K-M also indicate coring procedure to qualitatively sample these same horizons; O, quantitative sample core may be subdivided into 1-cm layers if desirable; I, P-R, show how to preserve samples (either qualitative or quantitative) by (P) adding sufficient formalin to achieve a 5%-10% formalin fixation; Q, both material that is fixed or unfixed for live-sorting should have a label placed in the container; R, preserved or live material should be sorted with the aid of a stereomicroscope with 25x-50x magnification; S, specimens, both live and preserved, should be removed from the sample with the finest of Irwin loops, usually indicated by blue color of handle (see Higgins and Thiel 1988 for further information).

Meiobenthos are also often associated with plant material or even other organisms. It is not uncommon to find interesting meiobenthos associated with the holdfasts of macroalgae (Moore 1973), or even among the filaments of some of the smaller, attached algae. And meiobenthos have been found in colonies of bryozoans (Higgins 1977a), in the cavities of sponges (Higgins 1977b), and occasionally in the alimentary cavities of larger invertebrates (Martorelli and Higgins 2004) or fishes (Millward 1982).

Collecting and Processing Meiobenthos A complete description of sampling meiofauna is found in Introduction to the Study of Meiofauna (Higgins and Thiel 1988). The first consideration is whether one is studying the quantitative (number of given taxon per unit volume, usually per 10 sq cm) or qualitative (taxa only) aspects of meiofauna. INTERTIDAL QUANTITATIVE S A M P L I N G - M U D I n t e r t i d a l q u a n t i -

tative sampling generally requires the use of a coring device. Several replicate cores are required to have sufficient statistical confidence. Cores are best taken using a plastic cylinder that has a cross-sectional area of 10 sq cm (see Higgins and Thiel 1988). The generally accepted procedure is to take a series of cores, slice off 1-cm-thick sections (fig. 4 0 ) , preserve the section using 5% formalin (fig. 4P), and add Rose Bengal if staining is preferred; if material is to be processed alive, pass the sections through a 62-pm mesh sieve to eliminate the finest fraction, and then place it in a dish and sort the organisms using a stereomicroscope with at least 50 x magnification (fig. 4R). Some investigators pass each section through a series of graded sieves, but each sieving runs the risk of losing specimens, and the small amount of material from a core usually make this process unnecessary. Because meiobenthos rarely exist deeper than 4 cm in mud, make a series of test cores to determine the extinction level and then slice off only those strata known to contain meiobenthos. INTERTIDAL

QUANTITATIVE

SAMPLING-SAND

(figs.

4J-M,

4 0 - R ) . Because depth of oxygen penetration increases considerably in a sandy habitat, coring down to as much as 1 m may be necessary. It is nearly impossible to take a core in sand that will properly penetrate more than 10 cm without significant compaction. Thus, some investigators find it more useful to take a series of progressively deeper 5-cm or 10-cm cores (figs. 4K-M) and treat each of these as a unit for counting and identifying the meiobenthic components rather than slicing off portions (fig. 4 0 ) . After the first 5-cm or 10-cm sample has been extracted, we have found it best to carefully remove all surrounding sand from that zone and then proceed to sample the next stratum. This allows for sufficient replicate samples and, at the same time, facilitates deeper penetration until the extinction zone is reached. Each fraction is treated the same as the mud fractions described previously (figs. 4P-R). INTERTIDAL QUALITATIVE S A M P L I N G - M U D

Intertidal

qualita-

tive sampling can be done in muddy substrates; the meiobenthic zone rarely exceeds 3 cm deep. Because this procedure is intended to determine what taxa are present and to obtain some idea as to their relative abundance in the sample, most any device can be used to collect a 3-cm-deep sample. A spatula is an excellent tool for this. Depending on the purpose of the sampling, one can use a series of sieves or simply sieve whatever material necessary through the smallest sieve, usually one with a 62-pm mesh size. If material is to be examined alive, small amounts can be placed in a dish, which is then placed under a 20

INTERTIDAL

MEIOBENTHOS

stereomicroscope and sorted. Otherwise, the sample may be fixed and stained. INTERTIDAL QUALITATIVE S A M P L I N G - S A N D S a m p l i n g t h e s a n d

from a high-energy beach is usually very productive. Equipment includes at least three clean plastic pails, a 62-pm mesh sieve, 0.5 liter or 1.0 liter wash bottle, and formalin if material is to be fixed in the field and sorted in the laboratory. First, obtain a bucket of seawater (figs. 4A, B). Pour the seawater through the 62-pm mesh net into a clean bucket (fig. 4C). Use some of this filtered seawater to back-flush the sieve to remove any organisms (fig. 4D). Fill the wash bottle with filtered seawater. This procedure is necessary to ensure that there is no plankton contamination in the sample. In the area to be sampled, carefully remove the upper few centimeters of sand; this removes plankton that has been deposited in the uppermost sediment. With a shovel or trowel, remove whatever amount of sand is desired (figs. 4K-N)—we prefer a volume of about 3 liters— and place it into a bucket half-filled with filtered seawater (fig. 4E). With a stirring device or simply by using one's arm, stir this mixture vigorously until all of the sediment is suspended (fig. 4F). Immediately pour off the water and suspended meiobenthos through the sieve (fig. 4G) and catch the decanted water in a third clean bucket (fig. 4H). Repeat this process at least five times, each time retaining the seawater that passes through the sieve. Depending on the amount of silt in the sand, it may be necessary to use new seawater source after a few sievings. If the filtered seawater becomes unusable because of an excess of silt in the sand, simply refilter a new bucket of seawater and continue the process. After several such sample treatments, the material in the sieve should be carefully washed either into a container (fig. 41) that can be used for live examination, or into a container that can be fixed (figs. 4P-R) in the manner noted previously. Live sorting of this material is often rewarding. If the sample(s) are to be transported back to the laboratory, keep the sample cool. Note that preserved samples of coarse sediment must be transported with great care. Samples transported by car over a bumpy road for any length of time literally "sandpapers" the meiobenthos, destroying most of the soft-bodied taxa and variously damaging the hard-bodied taxa. Some meiobenthos cling tenaciously to the sand particles. A method developed by Higgins and Kristensen (1986) involves a technique called "freshwater shock." This method simply causes osmotic imbalance in the organisms when the sand sample is placed the first bucket, which now contains fresh water. The sample is treated identically with the first step outlined above, but it must be done rapidly, and the material collected in the sieve must be immersed carefully in a second bucket of filtered seawater after each treatment (an alternative is to rinse the material in the sieve with seawater from a wash bottle). When sieving the material, catch the fresh water in a labeled bucket so the procedure can be repeated successfully. When the sampling is completed, the material in sieve is washed into containers for live sorting, or fixed in 5% formalin. M E I O B E N T H O S ASSOCIATED WITH PLANTS OR OTHER A N I M A L S

Plant material, especially, can provide some interesting meiobenthos. Place the plant material in a plastic bag of filtered seawater and agitate. Then decant the seawater and (hopefully) detached meiobenthos through a series of sieves, or at least a 62-pm mesh sieve, and treat as above. A small amount of ethanol added to the seawater in the plastic bag may assist in narcotizing any attached meiofauna. An interesting assemblage of meiobenthos exists in macroalgae

holdfasts. Just the holdfast needs be rinsed in the plastic bag. Similarly, meiobenthos also associate with bryozoan colonies, sponges, and other organisms and can be treated in a manner similar to that used for plant material. Certain meiobenthos, however, remain attached by specialized devices and will not be shaken free. FLOTATION T E C H N I Q U E The so-called "flotation-technique" developed by Higgins (1964) effectively removes many hardbodied meiobenthos (meiobenthos with cuticle) from subtidal mud (Higgins and Thiel 1988). Subtidal is the focal point: this technique is often ineffective when used to remove meiobenthos from intertidal mud. Such organisms are often adapted to resist being trapped in the surface tension of seawater. Without such adaptation, they would be removed by each incoming tide. The "flotation technique" is not quantitative, nor is it effective with all taxa in subtidal mud, but for organisms such as crustaceans, nematodes, kinorhynchs, and many others, bubbles passing upward through a mixture of mud and seawater cause the organisms to be trapped on the surface film.

pipettes. The careful use of an Irwin loop can make a difference. THE " M E R M A I D B R A " (figs. 4B, 41). This useful and wellknown sieve, made by the junior author's wife, is a sieve with a base diameter of about 28 cm made with 62-pm mesh nylon cloth. Seams are sealed with silicon caulking. The supporting loop is made from plastic coated "clothesline" wire. The circumference is obtained by bending the wire around the lidgroove of a U.S. 1 gallon paint can. The handle is made from plastic tubing of suitable diameter and length.

Originally, this technique involved taking several liters of mud, preferably the uppermost layer, adding seawater (at least twice the volume of the mud), stirring the mud to make a soup-like slurry, and then pump air into the mixture using any pump device attached to an aquarium air-stone. We have determined that a quicker way to process this material is merely to lift the slurry mixture about a meter and pour the contents rapidly into a second, clean bucket. After either bubbling or pouring methods have brought the organisms to the surface film, gently place a piece of copy paper on the surface, quickly remove it, and, using a wash-bottle filled with filtered seawater, wash the material adhering to the paper into a fine-mesh net. Repeating this process—pouring or bubbling, blotting, and washing—one can often obtain an interesting assemblage of meiobenthos. This method has been used by Higgins for more than 50 years to sample Kinorhyncha, but it is excellent for ostracodes, amphipods, and many other crustaceans as well.

Cnidaria

Investigators have found that the use of an artificial medium in conjunction with centrifugation may successfully remove many if not most of the intertidal mud-inhabiting meiobenthos. A review of the literature about meiobenthos extraction techniques will provide many suggestions, but we have found that the use of a sugar solution is very effective, inexpensive, and nontoxic. To prepare the solution, place enough sugar in a flask to reach the 1-liter mark. Then pour in boiling water so that after going into solution, the water level is at the 1-liter mark. After cooling, mix equal volume of the sugar solution with an equal volume of (drained) intertidal mud sample (untreated or fixed in formalin). Gently shake the mixture to suspend the particulate material, pour equal amounts into 50 ml centrifuge tubes and centrifuge the samples at relatively slow rate. The centrifuge speed and duration must be adjusted to the sample. The decanted material can be sieved through a 62-pm mesh using filtered seawater to reestablish osmotic equilibrium and then can be placed in a sorting dish or in container where a proper formalin concentration and Rose Bengal fixes and preserves the meiobenthos for later study. CENTRIFUGARON

THE I R W I N LOOP (fig. 4S). A final note in the processing of a sample. Sorting—that is, the removal of organisms from whatever medium is involved—should be done with Irwin loops (see Higgins and Thiel 1988). Using pipettes, especially with living material, is hazardous. Fixed or unfixed, these tiny organisms have a tendency to adhere to the inside of glass

Taxonomic Survey of Meiobenthos Placozoa There are no reports of placozoans occurring on the Pacific Coast.

Only a few cnidarians are known to be meiofaunal in size. Although all the classes are represented in the meiofauna, only the hydrozoans are represented by more than one species. The chapter by Mills and colleagues on hydroids notes that polyps of Euphysa are interstitial and that the tiny Protohydra leuckarti occurs in sandy mud in Puget Sound. The hydrozoan subclass Actinulidae includes meiofaunal species that are solitary, ciliated individuals presumably moving in the interstices by ciliary motion. We have found the actinulid Halammohydra sp. on a sandy beach near Moss Landing in Monterey Bay.

Platyhelminthes "Turbellarian" flatworms are abundant in marine sediments of all kinds. They are often conspicuous members of the meiofauna. Turbellarians can usually be extracted by the seawater ice method or the magnesium chloride method. Holmquist and Karling (1972) described two interstitial species from Oregon and California (see the chapter on "Turbellaria" by Holleman).

Nemertea Nemerteans in the genus Ototyphlonemertes may occur on intertidal sand beaches. See the nemertean chapter by Roe, Norenburg, and Maslakova.

Nematoda Nematodes are exceedingly abundant in meiofauna samples and easily placed into the phylum because of their shape and characteristic writhing movement. Consult the chapter by Hope.

Gastrotricha Gastrotrichs are not uncommon in sand beaches of Oregon and California. See the gastrotrich chapter by Hummon. INTERTIDAL MEIOBENTHOS

21

Loricifera This phylum was described by Kristensen (1983) from specimens found along the Normandy coast. Eight other species representing two additional genera were found off the North Carolina coast, a tenth species was found at hadal depths in the North Pacific, and an additional species was described from shallow water off the coast of Italy. Additional specimens are known from many other places. One specimen was collected in the shallow water sand of a South Pacific reef, a larval loriciferan was found off the west coast of Panama, and others have been collected from varying depths at other localities around the world. Loriciferans thus appear to occur in a wide variety of sediment from shallow to hadal depths. The freshwater shock method is a preferred extraction technique but is not a requirement. Where general meiobenthic collections have been looked at more carefully, loriciferans have been found. Their abundance and distribution may depend more on the diligence and expertise of sorting than on their biology. Illustrations of an adult and Higgins-larva of an example of the two most abundant known genera are found in the Kinorhyncha, Loricifera, and Priapulida chapter.

fragile, often disintegrating before one can get them under a microscope. Another habitat to look for these animals is in the anaerobic sand around the roots of the surfgrass Phyllospadix. For further information, see the chapter on Gnathostomulida by Farris.

Rotifera Rotifers are reported to be abundant in the meiofauna of fairly coarse marine intertidal sands generally in the top 2-4 cm. In our experience, however, they do not appear to be abundant on Monterey Bay beaches. See the Rotifera chapter by Fradkin, who notes that species in the genera Philodina and Rotatoria are to be expected.

Tardigrada A number of tardigrade species have been reported along the Oregon and California coasts. These are treated in the chapter on Tardigrada by Pollock and Carranza.

Kinorhyncha Most kinorhynch taxa are subtidal; few have been found intertidally, and only two species are known from the Pacific coast of the United States: Cephalorhyncha nybakkeni from medium to coarse sand at Carmel Beach, California, and Echinoderes kozloffi from a tidally exposed stony habitat at Friday Harbor, Washington. Although both of these represent the order Cyclorhagida, it is likely that some of the homalorhagid taxa, especially Kinorhynchus ilyocryptus, may be found on intertidal or shallow subtidal mudflats. Careful sampling of the region's tidally-exposed muddy creek sediments has a highly probable chance of yielding species of Echinoderes similar to the group typified by E. coulli Higgins, 1977a, found in these habitats along the southeastern coast of the United States and other similar habitats throughout the world. Some cyclorhagids are associated with algal holdfasts. Occasionally kinorhynchs, especially members of the genus Echinoderes, are washed up on beaches by heavy wave action. For additional details, including illustrations, see the Kinorhyncha, Loricifera, and Priapulida chapter.

Priapulida Of the 19 described species of Priapulida, half are of meiobenthic size but only the Indo-Pacific Meiopriapulus fijiensis Morse, 1981, has been found intertidally in coarse shell-gravel beach sediment. The remaining meiobenthic representatives are restricted to subtidal habitats. Among the temporary meiobenthos (young stages), priapulids are represented in California and Oregon intertidal mudflats by the larval stages of Priapulus caudatus. See the Kinorhyncha, Loricifera and Priapulida chapter for additional details, including illustrations.

Annelida Tiny polychaetes (grouped, in the past, in a taxon called Archiannelida) are common inhabitants of the meiobenthos. Blake's chapter on Polychaeta covers the nine families of meiofaunal polychaetes found in our region. Although oligochaetes are relatively abundant in marine and estuarine sediments, little attention has been paid to them on the Pacific coast. The chapter by Cook et al. on tubificid, enchytraeid, and randiellid oligochaetes should be consulted. Among the few regional interstitial species described are Aktedrilus locyi, A. oregonensis, and Randiella litoralis.

Crustacea COPEPODA

Most crustaceans are large enough that they do not qualify as meiofaunal organisms as adults. However, there are a number of crustacean groups that have abundant meiofaunal representatives. Perhaps the most abundant meiofaunal crustaceans are the harpacticoid copepods and may only be second in abundance to the ubiquitous nematodes. The chapter by Cordell on free-living copepods provides an introduction.

OSTRACODA

Another abundant meiofaunal group is the Ostracoda. Some of these bivalved crustaceans are meiofaunal in size and may be abundant in sediments. See the chapter by Cohen et al., which provides further information on interstitial taxa.

Gnathostomulida ISOPODA

On the Pacific coast gnathostomulids have been found in certain anaerobic sediments but are often not seen because they are difficult to extract from the sediments and are extremely 22

INTERTIDAL

MEIOBENTHOS

Interstitial isopods include Caecianiropsis psammophila from Tomales Point and Asilomar and Coxicerberus abbotti from the

sandy beach at Hopkins Marine Station. See the chapter by Brusca et al. on Isopoda.

around the San Juan Archipelago. We have found a species of the nudibranch Pseudovermis in coarse sand intertidally in Monterey Bay.

MYSTACOCARIDA

Other Phyla

A final crustacean group is the Mystacocarida. There are only a few species in this class, and they have not been previously reported from Pacific coast beaches. However, the senior author has extracted specimens from a sandy beach at Moss Landing in Monterey Bay.

Although meiobenthic representatives are known from other phyla including Echinodermata, Bryozoa, Brachiopoda, Sipuncula, and Tunicata (Urochordata), virtually all are found in subtidal habitats and even then, uncommonly.

Pycnogonida

References

The interstitial Rhynchothorax philopsammum is recorded from central California. Joel Hedgpeth, in the second edition (1954) of this manual, noted that on the inner side of Tomales Point "it occurs several inches beneath the surface of the sand in association with several other forms, including harpacticoids, small holothurians and isopods."

Acari Interstitial species in the genera Scaptognathus, Anomalohalacarus, and Actacarus in coarse sand are to be expected in our region. See the chapter by Newell and Bartsch.

Collembola Interstitial collembolans may occur; see the chapter by Christiansen and Bellinger.

Mollusca Although many mollusks are tiny and may in early life history stages be small enough to be considered meiofaunal, as adults they usually exceed the size range of meiofaunal organisms. Exceptions include the tiny tubular snails in the Caecidae and the 800-yim-tall scissurellid snail Sinezona rimuloides, both treated in the gastropod chapter by McLean. Also found interstitially are microscopic opisthobranch slugs. Acochlidiacea are found interstitially in both marine and freshwater habitats. Robilliard and Kozloff (1996) report an undescribed acochlidiacean slug in sand in Puget Sound and

Giere, O. 1993. Meiobenthology: the microscopic fauna in aquatic sediments. Berlin, Springer-Verlag, 3 2 8 pp. Higgins, R. P. 1964. A method for meiobenthic invertebrate collection. Am. Zool. 4: 291. Higgins, R. R 1977a. Two new species of Echinoderes (Kinorhyncha) from South Carolina. Trans. Amer. Micros. Soc. 96: 3 4 0 - 3 5 4 . Higgins, R. P. 1977b. Redescription of Echinoderes dujardinii (Kinorhyncha) with descriptions of closely related species. Smithson. Contr. Zool. 248: 1 - 2 6 . Higgins, R. P. and R. M. Kristensen. 1986. Kinorhyncha from Disko Island, West Greenland. Smithson. Contr. Zool. 458: 1 - 5 6 . Higgins, R. P. and J. Thiel, eds. 1988. Introduction to the study of meiofauna. Smithsonian Institution Press, Washington. Holmquist, C. and T. G. Karling 1972. Two new species of interstitial marine triclads from the North American Pacific coast, with comments on evolutionary trends and systematics in Tricladida (Turbellaria). Zool. Scripta 1: 1 7 5 - 1 8 4 . Horn, T. D. 1978. The distribution of Echinoderes coulli (Kinorhynchs) along an interstitial salinity gradient. Trans. Amer. Micros. Soc. 97: 586-589. Kristensen, R. M. 1983. Loricifera, a new phylum with Aschelminthes characters from the meiobenthos. Zeitschrift für zoologische Systematik und Evolutionsforschung 21: 1 6 3 - 1 8 0 . Kristensen, R. M. and R. P. Higgins. 1984. A new family of Arthrotardigrada (Tardigrada: Heterotardigrada) from the Atlantic coast of Florida, U.S.A. Trans. Amer. Micros. Soc. 103: 2 9 5 - 3 1 1 . Martorelli, S. and R. P. Higgins. 2004. Kinorhyncha from the stomach of the shrimp Pleoticus muelleri (Bate 1888) from Comodoro Rivadavia, Argentina. Zool. Anz. 243: 8 5 - 9 8 . Millward, G. E. 1982. Mangrove-dependent biota, pp. 1 2 1 - 1 3 9 . In Mangrove ecosystems in Australia. Structure, function and management. B. F. Clough, ed. Australian Institute of Marine Science, Townsville. Moore, P. G. (1973). Campyloderes macquariae J o h n s t o n , 1938 (Kinorhyncha: Cyclorhagida) from the northern hemisphere. Journal of Natural History 7: 3 4 1 - 3 5 4 . Morse, P. 1981. Meiopriapulus fljiensis n. sp.: an interstitial priapulid from coarse sand in Fiji. Trans. Am. Micros. Soc. 100: 2 3 9 - 2 5 2 . Robilliard, G. A. and E. N. Kozloff. 1996. Subclass Opisthobranchia, pp. 232-258. In Marine invertebrates of the Pacific Northwest. E. N. Kozloff, ed. University of Washington Press, Seattle, 539 pp.

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Intertidal Parasites and Commensals A R M A N D M. KURIS

E = mc 2 . Without mass (m) there can be no energy (E). Although parasites, being often small and hidden, are usually out of our sight lines, they are sometimes present in impressive numbers, in critical locations, influence food webs, and sometimes have considerable biomass. Some intriguing parasites and commensals that demonstrate these aspects can be readily observed in our region in the marine intertidal zone. Beyond their importance—and their medical and economic significance is well described in parasitology books—parasites are also interesting. Although the "degenerate" epithet is often tossed their way, some features of parasites are fascinating. They have highly evolved, distinctive adaptations, complex life cycles, and sometimes alter host behavior, physiology, and morphology. Parasites are certainly small compared to the size of their hosts. Most parasites are less than 1% of the weight of their hosts (Lafferty and Kuris 2002). However, compared to their free-living relatives, parasites are quite large. The largest dinoflagellates are parasitic. So are the largest flatworms (compare even the biggest polyclad with a beef tapeworm) and nematodes (compare any free-living nematode with the human roundworm, Ascaris lumbricoides). Parasitic entoniscid isopods are large compared to most free-living isopods, rhizocephalans and whale barnacles are large compared to most filter-feeding free-living barnacles, and almost all parasitic copepods are much larger than free-living copepods. Parasites are also long-lived. Although a free-living flatworm usually lives for weeks or months, at most a few years, human schistosomes may live for decades, larval trematodes in snails for more than a decade and some filarial worms may also live for many years. A remarkable adaptation for many parasitic groups is hypermetamorphosis. Many marine invertebrates undergo remarkable morphological transformations (metamorphoses) to complete their life cycles. Adding a metamorphosis to a life cycle makes it hypermetamorphic. An intertidal crustacean parasite offers a striking example (Hoeg 1995). A free-living barnacle hatches from an egg and completes two metamorphoses: nauplius to cyprid, cyprid to pinhead postlarval barnacle. This grows as a juvenile until it gradually reaches adulthood. For a rhizocephalan barnacle, such as Heterosaccus californicus, which parasitizes various California spider crabs, after the nauplius, 24

the cyprid, having found a crab, metamorphoses into the kentrogon, adding a metamorphosis to the typical barnacle life cycle. The kentrogon (a living hypodermic needle) then metamorphoses into a vermigon (a wormlike form) that is injected into the crab. The vermigon then metamorphoses into the rootlike interna, which finally metamorphoses to the adult when the virgin externa emerges from the cuticle of the crab to await fertilization from a male. This totals three additional metamorphoses compared to free-living barnacles. Meanwhile, the male rhizocephalan also adds some radical changes to complete its life cycle. Its cyprid attaches to the virgin externa and metamorphoses to a trichogon, a bristly stage that makes its way to a chamber in the female externa, molts again, and becomes little more than a clump of testicular cells (one additional metamorphosis compared to a free-living barnacle). Behavior modification by parasites is increasingly being studied, although few associations with invertebrates have been investigated on the Pacific coast. To return to the rhizocephalans, infected males develop female secondary sexual characteristics (become feminized) and exhibit brood care behavior (grooming the parasites' externa instead of its own egg mass). Infected male crabs also make a breeding migration with normal females (Rasmussen 1959). Many other examples of parasite-induced behavior modification are described in Zimmer (2000). Pacific coast invertebrates harbor some interesting and often species-rich parasite groups. These include larval trematodes in snails and clams, rhombozoans in cephalopods, pea crabs in bivalves, ciliates and turbellarians in echinoderms, and nemerteans, parasitic barnacles, parasitic isopods in crustaceans and copepods on many kinds of hosts. Beyond the scope of this guide, many marine fishes have rich parasite faunas including Myxozoa, Monogenea, Digenea, Cestoda, and Copepoda of diverse forms and habits.

Some Easily Observed and Abundant Parasites of Invertebrates Certain snails are hosts for a diverse assemblage of larval trematodes. These block reproduction of their snail hosts and alter their growth and abundance. These larval trematodes vigorously

compete for resources in the snail to the extent that dominant species eliminate subordinate species. These interactions have been extensively studied for the 18+ species in the native horn snail Cerithidea califortiica, abundant in the salt marshes of central and southern California. (Sousa and Gleason 1989, Kuris 1990, Lafferty 1993, Kuris and Lafferty 1994). Other snails that are often heavily parasitized include species of Littorina, Callianax biplicata, the introduced Batillaria attramentaria and Ilyanassa obsoleta, and the small clams Nutricola spp. All of these are easily observed. Potential hosts can be kept alive in seawater and the container checked the next day for swimming cercariae released from the snail. Snail shells can then be cracked, releasing hundreds of wormlike sporocysts, rediae, and swimming cercariae. Ching (1991) provides a list of larval helminthes from Pacific coast invertebrates. The list is remarkably short, and many more interesting species remain to be discovered. It includes 73 trematodes, seven cestodes, five acanthocephalans, and five nematodes. Almost half come from only four genera of hosts (Cerithidea, Littorina, Leukoma, and Macoma). Some readily available and virtually unexamined groups of hosts include polychaetes, sea anemones, small species of bivalves and gastropods, nudibranchs, small crustaceans (peracarids, juvenile crabs), shrimps, seastars and brittle stars. Some of these are hard to dissect (echinoderms, polychaetes, sea anemones), and others are just too pretty to cut up (nudibranchs). However, there will be some remarkable findings as a reward for those who do investigate this vast, unknown fauna. Intertidal octopuses and nearshore squids and sepiolids will almost always have their kidneys filled with Rhombozoa. Young hosts may harbor the nematogen phase that asexually produces more of the same. When the host ceases to grow, most of the nematogens become rhombogens and sexually produce the infusoriform larvae that exit the host. Various clams in mud flats sometimes contain a large white nemertean, Malacobdella grossa. Its relations with the clam are still not well understood. Mussels on the outer coast fairly often harbor large soft-shelled females of the pea crab, Fabia subquadrata, which causes damage to the gills (Pearce 1966). Male pea crabs are small and hard-shelled, moving between mussels that contain the female crabs. Some limpets are specialized feeders and are essentially parasitic on their host plants. These include Lottia paleacea on surfgrasses, L. instabilis on Laminaria dentigera, and L. insessa on the kelp Egregia menziesii. Echinoderms harbor very interesting parasites. The common intertidal sea urchins, Strongylocentrotus spp., have a diverse array of ciliates in the gut. They are also often parasitized by two species of turbellarians—the red Syndisyrinx franciscanus and the tan Syndesmis sp. Both are often spotted when they move across the yellow gonads during an urchin dissection. Syndisyrinx franciscanus sometimes feeds on the rich gut ciliate fauna of the host (Shinn 1981). Related dallyellioid turbellarians can be found in sand dollars and Stichopus spp. sea cucumbers. Sea cucumbers also have interesting large ciliates in their respiratory trees. Further examination may turn up little-studied parasitic castrators. These include wormlike gastropods in the body cavities of sea cucumbers and starfishes, Orchitophrya sp. ciliates in the testes of starfishes, orthonectids in the bursas of brittle stars, and ascothoracican barnacles in starfishes. Rhizocephalan barnacles parasitize several decapods including majids, xanthids, hermit crabs, and porcellanids. All are parasitic castrators with feminizing effects. Most remain to be investigated for prevalences and behavior modification. A variety of caridean shrimps, thalassinids, hermit crabs, and porce-

lain crabs are sometimes parasitized by bopyrid isopods. Their relations with host reproduction, behavior, and molting are all topics worth pursuing. Female bopyrids are readily detected. Most species are in the gill chamber. They cause the host to expand the carapace over the gill chamber, forming an obvious blister to cover the isopod. Other species are under the abdomen. Dwarf males cling to the female isopod. In contrast, the even more unusual entoniscid isopods are fully internal parasites enclosed in a sheath formed by host blood cells (Kuris et al. 1980). They are common in Hemigrapsus oregonensis and are sometimes found in H. nudus. To see them, one must lift the carapace. To extract an intact adult, the posterior of the midgut of the host must be carefully severed; the large female isopod can then be gently lifted and flopped into the carapace. The anterior and posterior ends of the isopod are freed by carefully teasing away host tissue. The males are dwarf and are not highly modified, looking like little isopods. They crawl about the female. Other hosts that may harbor undiscovered entoniscids are the spider crabs, snapping shrimp, and anomurans. To study behavior modification leading to trophic transmission of helminths, one could investigate a variety of mollusks such as razor clams, shore crabs, or mole crabs, as these often harbor a variety of larval digenean trematodes, tapeworms, acanthocephalans, and nematodes. Final hosts can be fishes, shore birds or sea otters.

Symbiotic Egg Predators Ovigerous female brachyuran crabs, anomurans, and lobsters often harbor symbiotic nemertean egg predators, mostly in the genus Carcinonemertes. Carcinonemerteans are usually pink and readily seen with the naked eye under the abdominal flap of their crab hosts or in the limb axillae. They are not parasites because they do not attack the host crab itself. Instead, they wait for the female crab to oviposit her eggs, migrate to the egg mass, and begin to feed on the embryos. Hence, they are egg predators. They live in a durable, intimate association with their host; hence they are considered "symbiotic." Carcinonemertes errans on the Dungeness crab, Cancer magister, may have delayed or prevented the recovery of that important fishery (Hobbs and Botsford 1989). Locally, other nemerteans have been recovered from several other Cancer species, grapsid crabs, pea crabs, spider crabs, the spiny lobster Panulirus interruptus, and the pebble crab Randallia ornata (Wickham and Kuris 1988, Sadeghian and Kuris 2001). Their life cycles are often complex, and they have remarkable adaptations for surviving on nonovigerous hosts (Kuris 1993). Some amphipods associated with spider crabs are egg predators. Examination of other decapod crustaceans will likely reveal further new and interesting species of symbiotic egg predators.

Some Abundant and Interesting Commensals Tube dwellers and burrowing invertebrates offer an array of commensals whose interactions with their hosts merit further study. For example, the rich fauna of symbionts associated with the innkeeper echiuran, Urechis caupo, includes the currentstealing clam Cryptomya californica, shrimp, pea crabs, and scaleworms. Some of these are also associated with the large burrowing mud shrimp, Upogebia pugettensis, and other larger infaunal species. A notable association is the frequent occurrence of the highly modified pea crab, Pinnixa longipes (several INTERTIDAL PARASITES AND C O M M E N S A L S

25

times wider than it is long), with the maldanid bamboo worm, Axiothella rubrocincta. Several large, slow-moving invertebrates harbor scale worms, other polychaetes, and symbiotic shrimps. Some of these are host specific. Some also may be mutualistic associations because the large invertebrate provides a home while the crustacean or worm bites the potential predator. Some species of amphipods are associated with sea urchins, others with compound tunicates or large crabs. In most cases the nature of the relationships is not known. The snails Chlorostoma spp. and Norrisia norrisi, often serve as hosts for filter-feeding species of Crepidula, the grazing specialized limpet Lottia asmi and as a nursery for juvenile limpets, particularly L. strigatella (Jessica Bean, personal communication). The clam, Mytilimeria nuttallii, is highly evolved for a specialized habitat, embedded in compound tunicates, most often in sea pork, Cystodytes lobatus. The shell of this clam is paperthin. How this interaction is initiated is not known, nor is how the clam avoids decalcification by the highly acidic fluids in its host. Some small snail species are micropredators, the marine equivalents of mosquitoes or ticks. They take a small bite from a host and may move on to another for their next meal. These include several species of pyramidellid and eulimid snails. Some can be seen on Mytilus califomianus, the boring clam, Netastoma rostratum, sea urchins, and sea stars. The beautiful Epitonium tinctum is a micropredator of sea anemones, Anthopleura spp. Many species of nudibranchs also feed as micropredators on solitary hosts or by killing zooids of clonal hosts. Good examples are Aeolidia papulosa feeding on sea anemones and Rostanga pulchra feeding on sponges. Most pycnogonids are also micropredators of hydroids or bryozoans, although some are truly parasitic embedded in the tissues of hosts such as abalone. A number of encrusting and bioeroding invertebrates form a facultative association with snail shells occupied by hermit crabs. The living snail prevents fouling within the shell aperture and umbilicus. The association of organisms with hermit crab shells is called pagurization because the shell-dwelling organisms are at those locations that the living snail's mantle keeps completely free of fouling organisms. Most of these species can be found elsewhere, but some are predominantly hermit crab-associated. Along the coast of California these associates are most often seen on hermit crab-occupied shells of Chlorostoma funebralis and C. brunnea. They include several species of spirorbid polychaetes (usually the first organisms to pagurize the shell), serpulid polychaetes, acorn barnacles, and hydroids. Hydractinia hydroids are almost always seen on shells inhabited by Isocheles pilosus on sandy beaches. Studies elsewhere indicate that these are actually mutualistic associates, reducing the risk of the occupant hermit crab to octopus predation and to loss of the shell to competitor hermit crabs (Wright 1973). More invasive, sometimes even eroding shells of living snails, are endolithic fungi, the boring sponge, Cliona californium, a boring bryozoan, Immergentia californica (recognizable as a row of little pores in the shell aperture), and Polydora spp. (spionid polychaetes, recognizable by paired openings often at the base of the columella; see Walker 1988). The distinctive acrothoracican barnacles, Trypetesa spp., bore into the upper whorls of hermit crab shells and can only be seen by cracking open the spire of the shell and examining the inner surface of the upper whorls. Pagurization can be detected on 50% of the Chlorostoma funebralis shells within six weeks of hermit crab occupation. 26

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A C. funebralis shell completely breaks down in 12-15 months, mostly from the activities of the boring organisms (A. Kuris, J. T. Carlton, and M. Brody, unpublished observations). Information about hermit crab associates has been well summarized by Walker (1992) and Williams and McDermott (2004). The dynamics of the pagurization process are a fruitful topic for observation and experimental study. Large mollusks such as rock scallops, jingle shells, abalone, and Kellet's whelks are often eroded by several interesting species. These can include large colonies of the boring sponge, Cliona califomiana; several spionids, mostly in the genus Polydora; and a small species of pholad clam Penitella conradi. These often greatly weaken the shell and cause the living mollusk to secrete additional laminar shell that may protrude as a blister on the inner surface of the shell. Once the mollusk has died, these organisms quickly degrade the rest of the shell until it breaks apart. Because these shell borers may affect the fitness of their hosts, these relationships are equivalent to parasitism. Although it appears to be extinct in nature in California, it is worth mentioning the introduced species Terebrasabella heterouncinata. This small sabellid polychaete was accidentally introduced to California abalone mariculture facilities from its native South Africa. It escaped into the rocky intertidal zone near Cayucos, California, but was fortunately apparently eradicated (Culver and Kuris 2000). This was the first successful eradication of an established introduced marine pest. The biology of T. heterouncinata is quite interesting because it has a unique ability to foil the defenses against fouling organisms provided by the mantle of gastropods. The newly settled worm cannot be killed or dislodged by the mantle. It is then able to pervert the next line of defense of the host, stimulating the mantle to secrete additional layers of nacre, guided by the worm to form a tube for itself (Kuris and Culver 1999). As the worms grow they can subsequently enlarge these tubes. To advance our knowledge of these and the many other parasitic and commensal relationships in the marine environment, perhaps the most efficient starting point is to carefully sample the hosts and detail the information on the distribution and abundance of the symbiotic relationship. A quantitative analysis of host and site specificity can also be very informative. The extent to which the symbiont is aggregated among hosts, changes in abundance with host size, sex, and location will generally lead to interesting and testable hypotheses about the nature of the relationship between the host and symbiont and perhaps the effect of the symbiont on host physiology, host population dynamics, and their role in community structure.

References Ching, H. L. 1991. Lists of larval worms from marine invertebrates of the Pacific Coast of North America. J. Helminthol. Soc. Wash. 58: 57-68. Culver, C. S. and A. M. Kuris. 2000. The apparent eradication of a locally established introduced marine pest. Biol. Invasions 2: 2 4 5 - 2 5 3 . Culver, C. S., A. M. Kuris, and B. Beede. 1997. Identification and Management of the Exotic Sabellid Pest in California Cultured Abalone. La Jolla, California Sea Grant College Program, Publ. T-041, 29 pp. Hobbs, R. C. and L. W. Botsford. 1989. Dynamics of an age-structured prey with density-, and predator-dependent recruitment: the Dungeness crab and a nemertean egg predator worm. Theor. Pop. Biol. 36: 1-22. Hoeg, J. T. 1995. The biology and life cycle of the Rhizocephala (Cirripedia). J. Mar. Biol. Assoc. U.K. 75: 5 1 7 - 5 5 0 . Kuris, A. M., G. O. Poinar, and R. T. Hess. 1980. Post-larval mortality of the endoparasitic isopod castrator Portunion conformis (Epicaridea: Entoniscidae) in the shore crab, Hemigrapsus oregonensis, with a description of the host response. Parasitology 80: 2 1 1 - 2 3 2 .

Kuris, A. K. 1990. Guild structure of larval trematodes in molluscan hosts: prevalence, dominance and significance of competition, In Parasite Communities: Patterns and Processes. G. W. Esch, A. O. Bush, and J. M. Aho, eds. Chapman and Hall, pp. 69-100. Kuris, A. M. 1993. Life cycles of nemerteans that are symbiotic egg predators of decapod Crustacea: adaptations to host life histories. Hydrobiologia 266: 1-14. Kuris, A. M. and K. D. Lafferty. 1994. Community structure: Larval trematodes in snail hosts. Ann. Rev. Ecol. Syst. 25: 189-217. Lafferty, K. D. 1993. Effects of parasitic castration on growth, reproduction and population dynamics of the marine snail Cerithidea califomica. Mar. Ecol. Prog. Ser. 96: 229-237. Lafferty, K. D. and A. M. Kuris. 2002. Trophic strategies, animal diversity and body size. Trends Ecol. Evol. 17: 507-513. Pearce, J. B. 1966. The biology of the mussel crab, Fabia subquadrata, from the waters of the San Juan Archipelago, Washington. Pac. Sci. 20: 3-35. Rasmussen, E. 1959. Behaviour of sacculinized shore crabs (Carcinus maenas Pennant). Nature 183: 479-480. Sadeghian, P. S. and A. M. Kuris, 2001. Distribution and abundance of a nemertean egg predator (Carcinonemertes sp.) on a leucosiid crab, Randallia ornata. Hydrobiologia 456: 59-63.

Shinn, G. L. 1981. The diet of three species of umagillid neorhabdocoel turbellarians inhabiting the intestine of echinoids. Hydrobiologia 84: 155-162. Sousa, W. P. and M. Gleason. 1989. Does parasitic infection compromise host survival under extreme environmental conditions?: the case for Cerithidea califomica (Gastropoda: Prosobranchia). Oecologia 80: 456-464. Walker, S. E. 1988. Taphonomic significance of hermit crabs (Anomura: Paguridea): epifaunal hermit crab—infaunal gastropod example. Palaeogeogr. Palaeoclim. Palaeoecol. 63: 45-71. Walker, S. E. 1992. Criteria for recognizing marine hermit crabs in the fossil record using gastropod shells. J. Paleontol. 66: 535-558. Wickham, D. E. and A. M. Kuris. 1988. Diversity among nemertean egg predators of decapod crustaceans. Hydrobiologia 156: 23-30. Williams, J. D. and J. J. McDermott. 2004. Hermit crab biocoenoses: a worldwide review of the diversity and natural history of hermit crab associates. J. Exp. Mar. Biol. Ecol. 305: 1-128. Wright, H. O. 1973. Effect of commensal hydroids on hermit crab competition in the littoral zone of Texas. Nature 241: 139-140. Zimmer, C. 2000. Parasite Rex. New York: Free Press, 298 pp.

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Introduced Marine and Estuarine Invertebrates JAMES T. CARLTON AND A N D R E W N. C O H E N

The arrival of numerous species from other parts of the world has complicated the task of identifying Pacific coast invertebrates, especially in estuaries, bays, ports, and harbors. Although this manual contains many of the introduced species documented on this coast, there are doubtless many nonnative species that remain misidentified or mistaken as native species, and new invaders continue to arrive on a steady basis. Such further additions to our fauna will of course not "key out" in this manual. An introduced species is one that has been transported by human activities to a region where it is not native and that has become established there by maintaining a reproducing population. More than 150 years of transporting marine organisms to the Pacific coast, either intentionally or accidentally, has resulted in the establishment of a minimum of 300 introduced species of nonnative protists, invertebrates, fish, algae, and seagrasses, although the actual number may be many times this. All larger and most smaller invertebrate phyla are represented among the nonnative biota, with the exception of the Echinodermata, indicating that few groups are immune to potential taxonomic challenges. Most of these species are restricted to bay and estuarine environments, although the open rocky coast, open sandy beaches, and the continental shelf itself have documented invasions as well. This largely estuarine restriction may be the result, in part, of the paucity of transport mechanisms that would serve to introduce species to nonestuarine areas from other regions of the world.

Transport Vectors of Introduced Species S h i p Fouling Beginning as long as 500 years ago, the earliest wooden sailing vessels that entered (and occasionally sank in) Pacific coast bays may have introduced hull fouling and boring organisms from the Atlantic Ocean or from the southern or western Pacific Ocean. A signature event in the history of marine invasions on the Pacific coast was the California Gold Rush commencing in 1849: a great influx of ships from around the world arrived in a matter of a few years, and many of these lay at anchor or pierside for many weeks or months, or were entirely abandoned. 28

Thus the North Atlantic barnacle Balanus improvisus was first collected in 1853 in San Francisco Bay, and many of our nonnative hydroids may have arrived in these early years, as well. In later years, ships from Asia brought the Japanese isopod Sytiidotea laevidorsalis, now one of the most abundant fouling organisms on hydroid substrates in San Francisco Bay; ships from New Zealand brought the burrowing isopod Sphaeroma quoianum, and its tiny commensal isopod Iais californica (the latter being one of a number of introductions to the Pacific coast that were mistakenly described as native species and given local geographic names, the southern hemisphere hydroid Garveia franciscana being another). Wood-boring invertebrates, including gribbles (small isopods in the genus Limnoria) and shipworms (highly modified bivalve mollusks) in the genera Lyrodus and Teredo, arrived by the 19th and early 20th centuries, causing catastrophic damage to unprotected wharves and piers. Near the close of World War I, the Australian tubeworm Ficopomatus enigmaticus appeared in San Francisco Bay, where its large aggregations were described in local newspapers as "coral reefs." The density of ship-fouling was reduced over the last century by the development of ever more effective antifouling paints, faster ships, and faster port turnarounds by cargo vessels (with less time for organisms to attach to hulls). Nevertheless, the introduction of species as fouling organisms continues: today there are more vessels, with much larger hull surfaces, making more voyages than in previous centuries; often there are some areas on a ship's hull where antifouling paint is not applied or where it wears away on poorly maintained vessels; certain fouling organisms, such as the encrusting bryozoan Watersipora subtorquata, are unaffected by some of the toxic materials used in antifouling paints, and when such organisms colonize painted hull surfaces they provide a nontoxic substrate for other, more susceptible, species. A vessel's seachest (the compartment where water is drawn into the ship to supply the ballast, engine-cooling, and fire-fighting systems) may also harbor a well-developed fouling community. Further, the characteristic modern transporter of significant fouling communities may not be a cargo ship in normal operation, but rather a vessel that remains in one place for a long period without hull cleaning or maintenance and then sails or is towed at relatively low speed to a new location, such as an ocean-going barge or a semi-submersible drilling platform.

Recent examples of probable hull-fouling introductions include a large array of seasquirts (ascidians) that arrived in California harbors over the past few decades. A noninvertebrate example is the Asian seaweed Undaria pinnatifida, discovered in Los Angeles Harbor in 2000. It may have initially arrived as fouling o n a cargo ship, while its rapid spread u p the coast to Monterey Bay was probably accomplished as fouling on the hulls of pleasure craft, which mechanism must also account for t h e spread of many ballast water introductions to boat harbors that are distant from cargo ports.

Ship Ballast Ships transport many species in ballast water, which is taken aboard to reduce buoyancy and thus increase stability when a cargo ship is empty or lightly loaded, to adjust trim, and for other purposes related to navigation and cargo management. Water taken aboard from a bay or estuary or from coastal waters o n shores as distant as Australia or the Atlantic and released in a bay along t h e Pacific coast may lead to t h e successful introduction of nonnative species. Examples include t h e arrival of the Asian shrimp Palaemon macrodactylus in San Francisco Bay in the early 1950s, coincident with increased vessel traffic during the Korean War, and, commencing in the 1970s and 1980s, the arrival in San Francisco Bay of various Asian copepods and mysid shrimp, as well as the Asian clam Corbula amurensis, coincident with increased vessel traffic from mainland C h i n a , Japan, and other Pacific Rim countries linked to t h e liberalization and expansion of international trade. Many other invasions along the Pacific coast are also believed to be ballast-mediated. Prior to the 1900s, ballast was often carried in the form of rocks, sand, and other heavy and cheap materials from coastal environments. Many maritime plants and insects were distributed globally by this "dry" or "solid" ballast. Lumber ships returning in beach ballast from Chile or New Zealand thus served to bring the beach hopper Transorchestia enigmático to California. In this interesting case, this species remains known only from San Francisco Bay, although recognized as a member of the Transorchestia chiliensis species complex native to the southern hemisphere. Although the d u m p i n g of solid ballast was regulated in California waters by t h e first half of the 19th century (largely due to concerns about filling navigable channels), the discharge of water ballast was erroneously believed to be entirely benign and thus remained unregulated over most of its history. In 2000, California became t h e first U.S. state to require midocean exchange of ballast water originating from overseas to reduce the release of nonnative coastal organisms.

Oyster Industry and Other Mariculture Extensive importations of adult and seed oysters of Crassostrea virginica from the Atlantic coast (from the 1860s to the 1920s, and continuing in small numbers thereafter) and Crassostrea gigas from Japan (commencing in commercial quantities in the 1920s) led to the translocation of a large number of estuarine organisms from the western Atlantic and western Pacific. These oysters were imported and planted in northeastern Pacific estuaries with the hopes of establishing a "natural" fishery, for growing to market size, temporarily relaid for freshening purposes,

or simply held for the market. Early shipments in particular were apparently rich with epizoic organisms and sediments bearing infaunal organisms, including sponges, cnidarians, polychaetes, mollusks, crustaceans, bryozoans, and other invertebrates. Ironically, many of these species became established and proliferated on the Pacific coast, although the oysters themselves failed to become established at most sites (the Pacific or Japanese oyster C. gigas reproduces and maintains natural beds in Washington and British Columbia; it may also be established in southern California). Atlantic oyster-mediated contributions to our molluscan fauna include the slipper limpets Crepidula fornicata, Crepidula convexa, and Crepidula plana; the mudsnail llyanassa obsoleta; the oyster drill Urosalpinx cinerea; and the bivalves Gemma gemma, Macoma petalum, Geukensia demissa, Mya arenaria, and Petricolaria pholadiformis. Contributions from Japan include the snail Batillaria attramentaria and the bivalves Musculista senhousia and Venerupis philippinarum. Although the importation of ship- or plane-loads of living oysters from distant lands for laying out in Pacific coast estuaries has ceased and cleaner processing has greatly reduced t h e inadvertent transport of associated organisms in oyster shipments compared to the "old days" when oysters, mud, and water were roughly packed in barrels or boxes, substantial quantities of oysters continue to be shipped between bays and countries o n the Pacific coast (between Mexico, the United States, and Canada), and these are sometimes heavily fouled. Shipments between certain locations are banned, and inspections of shipments are required in other cases, but these inspections are focused on a small number of known oyster pests and, even for those species, are not likely to detect small infestations. Meanwhile, some shipments n o doubt move under the regulatory radar screen, and small quantities of oysters from overseas may continue to make their way to our shores, sanctioned or not, for "experimental" mariculture operations. More recently developed forms of mariculture may also introduce new and harmful species, as demonstrated by the importation, statewide distribution, and accidental release of a South African shell parasite, the sabellid worm Terebrasabella heterouncinata, by California abalone farms.

Fishing Bait Starting in t h e early 1960s, live marine polychaete worms (glycerids and nereids) harvested in New England have been packed in seaweed, primarily the intertidal rockweed Ascophyllum nodosum, and shipped by air express to California bait shops. The worms, still packed in seaweed, are sold to anglers, w h o frequently discard the seaweed and any New England invertebrates contained therein into local waters. Occasional specimens of t h e Atlantic periwinkle snail Littorina littorea turn u p o n rocks in San Francisco and Newport Bays, and another Atlantic periwinkle, Littorina saxatilis, has established populations throughout San Francisco Bay; b o t h of these snails are abundant in the worm shipments, which undoubtedly transported t h e m to the Pacific. Juveniles of the Atlantic shore crab Carcinus maenas also occur in the seaweed packing; Carcinus became established in San Francisco Bay by the early 1990s and has spread along the coast. Other species are to be expected from the same pathway. Meanwhile the global trade in live marine bait, primarily consisting of polychaetes but sometimes including other types of organisms, is expanding, and new species, packed in a variety of materials, are sometimes imported and sold in California. This opens up opportunities for

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introductions of other bait species or associated organisms from other regions of the world.

Aquariums, Seafood, Research, and Education A web-based trade in marine aquarium organisms and live seafood, the use of live nonnative marine specimens in research and education, and the legal importation of these species into Pacific states provides a source for additional invasions. Unwanted aquarium organisms and live specimens used in research or education may be discarded directly into coastal waters or down the storm drains that lead to them by individuals unaware of the potential consequences, and live seafood species may be released in deliberate attempts to establish them in California. To be expected are occasional specimens of the Atlantic quahog Mercenaria mercenaria, oysters of a variety of species, the Atlantic crab Callinectes sapidus, Atlantic lobsters Homarus americanus, the Atlantic horseshoe crab Limulus polyphemus, and other popular aquarium, research, or seafood species. The Chinese mitten crab Eriocheir sinensis, which is considered a delicacy in parts of Asia, may also have been released intentionally into San Francisco Bay in the early 1990s; although it has been illegal to import this species into California since 1987, persons arriving from Asia and carrying live mitten crabs were regularly intercepted at California airports in the late 1980s and early 1990s. Introduced species are not restricted to sites where they are initially released; secondary distribution can and does occur. This distribution may be mediated by either natural processes (e.g., by currents moving planktonic larvae, or by rafting of adults) or human activities (e.g., by pleasure craft, fishing boats, or cargo ships moving along the coast). Species initially introduced with oyster shipments or by cargo vessels may thus occur in lagoons or estuaries that have had neither oyster culture nor ship traffic.

Identification of Introduced Species The recognition of a species as introduced and its correct identification are complicated by several factors. First, the systematics of the endemic species of a group on the Pacific coast may not be sufficiently advanced to distinguish natives from nonnatives. Second, the source or donor area of an introduced species could potentially be in any climatically appropriate coastal region of the world, requiring a command of the knowledge of the world fauna of a given taxon. Third, in some cases an introduced species may not yet be recognized or described in its native region. Secondary evidence may suggest whether a species is introduced, including highly localized occurrence (disjunct distributions), recent spread to new areas on the coast, direct association with a suitable transport vector, and absence from the recent fossil record and from Native American shellmounds of species that would be expected to occur there (for the latter, edible shelled species, as well as certain epizoics such as barnacles and bryozoans). Disjunct distributions are often obscured in the published literature by over-generalizations of a species' range: we may thus find a certain species reported as occurring from "Puget Sound to San Francisco," when in fact it may be known only from Puget Sound and San Francisco Bay. Recent arrivals of introduced species must be distinguished from seasonal fluctuations in abundance of endemic 30

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species and from temporary range extensions of southern species during El Niño years. It is sometimes mistakenly assumed that a taxon must be endemic if it cannot be referred to a species described elsewhere. However, many species remain undescribed or unknown in their native regions, and this especially holds true for smaller or taxonomically more difficult groups. The tubeworm Ficopomatus enigmaticus, native to western Australia, was first described from France, the Japanese oyster flatworm Pseudostylochus ostreophagus was first described after its accidental introduction to Puget Sound, and the South African shell parasite worm Terebrasabella heterouncinata was recognized and described in the 1990s only after it had been accidentally introduced into and infested California abalone farms. In addition, not a few introduced species have been redescribed as new species through failure to match the species to a known entity elsewhere. Such erroneous "new" species names given to introduced species may last for several months to hundreds of years, masking the species' true status, before they are corrected. The Atlantic soft-shelled clam Mya arenaria was surprisingly redescribed as Mya hemphilli from San Francisco Bay shortly after its introduction; the Japanese clam Venerupis philippinarum was described as a new species Paphia bifurcata, from British Columbia; the Japanese oyster copepod Mytilicola orientalis as M. ostrea; the Atlantic ostracode Eusarsiella zostericola as Sarsiella tricostata; and many similar cases are known among polychaetes, seasquirts, mollusks, and crustaceans on the Pacific coast.

Establishment and Ecology of Introduced Species The reasons for the successful introduction of so many nonnative species on the Pacific coast are varied and not fully known. There are, as described above, numerous vectors that have transported marine and estuarine species to the Pacific coast from other regions of the world. The extensive modification of Pacific coast estuaries through filling, dredging, damming, pollution, and the construction of wharves and marinas greatly modified aboriginal habitats and in some cases may have eliminated native populations, while at the same time providing a great deal of new hard-substrate habitat for fouling species to colonize. Certain areas on the Pacific coast are now dominated by an introduced fauna that would not be unfamiliar to biologists from Massachusetts or Japan. Consider the south end of San Francisco Bay, where the majority of macroscopic invertebrates (and several of the fish and algae) are introduced species. On the pilings and floats are rich assemblages of organisms hailing from other coasts, including the beautiful orange-pink colonies of the tubularian hydroid Pinauay crocea (and its tiny nudibranch predator Tenellia adspersa), the white barnacle Balanus improvisus, the bryozoan Conopeum tenuissimum, the kamptozoan Barentsia benedeni, the seasquirt Molgula manhattensis, and the sea anemone Diadumene lineata. The Asian isopod Synidotea laevidorsalis is abundant, as are several species of introduced amphipods in the genus Corophium. Boring into the pilings is the introduced gribble Limnoria tripunctata (whose native region is unknown) and into the styrofoam of the floats the New Zealand isopod Sphaeroma quoianum (with its introduced commensal Iais californica riding on its belly), which also burrows in mud banks.

INVERTEBRATES

On the mud b o t t o m below the marina floats are great hordes of the mudsnail Ilyanassa obsoleta from New England and dense nests of the little green mussel Musculista senhousia from Japan. Burrowing in the m u d are the Japanese cockle Venerupis philippinarum, the Atlantic softshell clam Mya arenaria, and the Japanese amphipod Grandidierella japónica. The Korean shrimp Palaemon macrodactylus swims rapidly over the b o t t o m and rests in fouling communities. In nearby salt marshes are dense stands of the New England mussel Geukensia demissa and abundant populations of the Atlantic marsh snail Myosotella myosotis. The striking faunal changes caused by the introductions of these estuarine wanderers warrants detailed investigation of their distributions and ecological relationships.

Control of Invasions There have been relatively few efforts to control or eradicate populations of introduced marine or estuarine invertebrates. Several general considerations—including the high fecundity of m a n y marine invertebrates relative to freshwater or terrestrial species, the rapid and wide dispersal of planktonic life stages, and the relative difficulty of locating populations, effectively applying biocides, finding acceptable species-specific biocontrol agents, or otherwise working cheaply and efficiently in marine environments—suggest that such efforts will be difficult or impossible in most individual cases and, as an overall approach to the aggregate problem of marine invasions, unworkable. There have been only two successful eradications of introduced marine invertebrates to date: the elimination of an infestation in northern Australia of the black-striped mussel Mytilopsis sallei by pouring large quantities of biocides (chlorine and copper sulphate) into an enclosed boat basin (connected to the ocean by a lock), and the removal of a very localized infestation of the South African fanworm Terebrasabella heterouncinata from a small rocky cove in southern California by reducing (through manual collection) the density of its potential host snails. It is possible that advances in molecular genetics may someday allow the construction of safe and effective "killer genes" that would remove introduced marine species from invaded regions. Until that time, it appears that the greatest gains in managing marine introductions are to be had by reducing the flood of organisms being transported around the world by shipping, mariculture, the bait trade, and other vectors. It thus behooves students of Pacific coast marine biodiversity to remain on the watch for, to document, and to report o n the arrival of new species and the extent and impacts of their introduction to provide support for and track the success of vector management efforts.

References Byers, J. E. 1999. The distribution of an introduced mollusc and its role in the long-term demise of a native confamilial species. Biol. Invasions 1: 339-353. (Batillaria and the native Cerithidea) Byers, J. E. 2000. Mechanisms of competition between two estuarine snails: implications for exotic species invasion. Ecology 81: 1225-1239. (Batillaria and the native Cerithidea) Carlton, J. T. 1996. Biological invasions and cryptogenic species. Ecology 77: 1653-1655. Carlton, J. T. 2001. Introduced species in U.S. coastal waters: environmental impacts and management priorities. Pew Oceans Commission, Arlington, Virginia, 28 pp. Carlton, J. T. and A. N. Cohen. 2003. Episodic global dispersal in shallow water marine organisms: the case history of the European shore crabs Carcinus maenas and Carcinus aestuarii. J. Biogeogr. 30: 1809-1820. Carlton, J. T. and J. B. Geller. 1993. Ecological roulette: the global transport of nonindigenous marine organisms. Science 261: 78-82. Carlton, J. T. and J. Hodder. 1995. Biogeography and dispersal of coastal marine organisms: experimental studies on a replica of a 16th-century sailing vessel. Mar. Biol. 121: 721-730. Carlton, J. T. and G. M. Ruiz. 2005. The magnitude and consequences of bioinvasions in marine ecosystems: implications for conservation biology, pp. 123-148, in: Elliott A. Norse and Larry B. Crowder, eds. Marine Conservation Biology: The Science of Maintaining the Sea's Biodiversity. Island Press, Washington, D.C., 470 pp. Carlton, J. T., J. K. Thompson, L. E. Schemel, and F. H. Nichols. 1990. Remarkable invasion of San Francisco Bay (California, U.S.A.) by the Asian clam Potamocorbula amurensis. I. Introduction and dispersal. Marine Ecology Progress Series 66: 81-94. Cohen , A. N. and J. T. Carlton. 1995. Biological Study. Nonindigenous Aquatic Species in a United States Estuary: A Case Study of the Biological Invasions of the San Francisco Bay and Delta. A Report for the United States Fish and Wildlife Service, Washington, D.C., and The National Sea Grant College Program, Connecticut Sea Grant, NTIS Report Number PB96-166525, 246 pp. Cohen, A. N. and J. T. Carlton. 1997. Transoceanic transport mechanisms: The introduction of the Chinese mitten crab, Eriocheir sinensis, to California. Pac. Sci. 51: 1-11. Cohen, A. N. and J. T. Carlton. 1998. Accelerating invasion rate in a highly invaded estuary. Science 279: 555-558. Culver, C. S. and A. M. Kuris. 2000. The apparent eradication of a locally established introduced marine pest. Biol. Invasions 2: 245-253 (the abalone worm Terebrasabella heterouncinata) Lambert, C. C. and G. Lambert. 2003. Persistence and differential distribution of nonindigenous ascidians in harbors of the Southern California Bight. Marine Ecology Progress Series 259: 145-161. Nichols, F. H. and J. K. Thompson. 1985. Persistence of an introduced mudflat community in South San Francisco Bay, California. Mar. Ecol. Prog. Ser. 24: 83-97. Race, M. S. 1982. Competitive displacement and predation between introduced and native mud snails. Oecologia 54: 337-347. (Cerithidea and Ilyanassa). Ruiz, G. M., P. W. Fofonoff, J. T. Carlton, M. J. Wonham, and A. H. Hines. 2000. Invasion of coastal marine communities in North America: apparent patterns, processes, and biases. Ann. Rev. Ecol. Syst. 31:481-531. Wasson, K., C. J. Zabin, L. Bedinger, C. M. Diaz, and J. S. Pearse. 2001. Biological invasions of estuaries without international shipping: the importance of intraregional transport. Biol. Conserv. 102: 143-153 (invasions of Elkhorn Slough in Monterey Bay).

INTRODUCED MARINE AND ESTUARINE INVERTEBRATES

31

Molecular Identification JONATHAN B. GELLER

The previous edition (1975) of this work was published as genetic methods began to be widely applied to a study of the systematics and phylogenetics of Pacific coast marine invertebrates. Such investigations revealed several taxa that were in fact groups of two or more species that are difficult to distinguish with morphological characters but demonstrate genetic distinctiveness (appendix 2). Work prompted by these earlier discoveries and enthusiasm for phylogeography will uncover many additional cases, and identification of such species will be an increasing challenge. Because molecular techniques will be an increasingly applied identification tool, this chapter will discuss molecular identification of sibling species and other morphologically challenging specimens. The existence of large numbers of sibling or cryptic species in the marine environment is an important revelation (Knowlton 1993), and understanding why genetic differentiation is often not reflected in apparent morphological change will be equally important. However, there is a difference between real and apparent absence of morphological divergence among species. Size differences, if not standard morphological characters, that distinguish solitary and clonal varieties of the sea anemone Anthopleura elegantissima were long known before allozyme analyses indicated genetic differences that revealed two distinct species were involved (Hand 1955, McFadden et al. 1997, Pearse and Francis 2000). In other cases, multiple morphological differences were noticed after genetic tools have confirmed that multiple species are present; the periwinkle snails Littorina scutulata and L. plena are examples (Mastro et al. 1982, Murray 1982, Chow 1987). For other taxa, it will be difficult or impossible to identify species without genetic techniques. For example, mussels of the Mytilus edulis complex cannot reliably be identified by morphology due to overlapping shell variation. In California, both the native M. trossulus and the introduced M. galloprovincialis may be encountered (McDonald and Koehn 1988, McDonald et al. 1991, Sarver 1991, Geller et al. 1994, Suchanek et al. 1997). Without a genetic test, one can only guess to which species an individual belongs using habitat (which is not reliable, because both species can occur together) and perhaps geography (because the introduced species is most common in southern California). Critical determination requires genetics, especially in

32

central California where the two species geographically overlap, and genetics will provide the tools necessary to detect a new invasion should the Atlantic Mytilus edulis appear in our area. In other cases, extensive morphological variation has been noticed, but whether this variation might sort individuals into groups conforming to species concepts is not clear. For example, the dogwhelk Nucella lamellosa exhibits a wide array of shell thicknesses and sculpture (Kincaid 1957, Spight 1973), yet no discrete morphological boundaries appear to separate them. At times, species level uncertainty may not be a severe handicap. It may be sufficient to know the genus of an organism for environmental monitoring, or the functional or trophic group of an organism in an ecological study. However, it is clearly important to have species-level information when diversity or biogeographic patterns are at issue. Also, sibling species are probably never entirely ecologically equivalent, so misidentification or lumping of two or more species together will raise the noise relative to signal in community-level manipulative experiments or correlative studies. Harger (1968, 1972) performed elegant experiments to demonstrate the competitive superiority of "Mytilus edulis" over M. califomianus in a protected southern Californian embayment. We now know that Harger was almost certainly studying Mytilus galloprovincialis, although the extent to which the native M. trossulus may have been involved in his studies we do not know. Studies of population dynamics will also suffer when different species are ignored or inadvertently grouped together: if similar-looking species are not adequately resolved, both shortand long-term changes in the community may go undetected. For example, the remarkable replacement of the native Mytilus trossulus by the introduced Mytilus galloprovincialis in southern California in the mid-20th century was undetected as it transpired (Geller 1999). Even where morphological differences between species are profound and easily noted, this may not be true for all life stages. The morphology of larval and juvenile life stages are described for a minority of marine invertebrates, and these stages are often notoriously difficult to identify, even when descriptions exist. In contrast, genetic markers are not dependent on life stage and can therefore be more generally applied. For example, genetic markers for Mytilus have been used to detect

newly settled juveniles in recruitment studies on the Pacific coast (Martel et al. 1999; Johnson and Geller 2006). For all these reasons, there is a good reason to consider the use of genetic markers for the purpose of identification. It has been proposed that standardized genetic markers be developed for all living organisms (Tautz et al. 2002; Hebert et al. 2003a, b; Tautz et al. 2003). Should such a database be accomplished for the marine invertebrates of the Pacific coast, it will be a great boon to systematic, phylogenetic, and ecological research in our region.

Molecular Identification vs. Molecular Classification A common misunderstanding is the difference between molecular identification and molecular classification. Molecular identification is the use of genetic markers to assign an individual specimen to an already recognized and properly described species. This is useful when gross morphological differences are absent or slight, or when detection of diagnostic characters requires a high level of expertise or extensive sample preparation. Molecular identification is also useful when diagnostic characteristics are known only for a particular life stage, typically the adult, but the specimen belongs to a different life stage. Molecular identification does not replace the traditional systematist, who remains called upon to investigate and adjudicate species boundaries. Instead, it provides a potentially applicable and available set of tools for students and professional biologists who are not taxonomic experts. Indeed, molecular tools may relieve taxonomic experts from the burden of identification services and allow greater attention to actual taxonomic problems. At the species level, molecular classification is the use of genetic markers to discover discontinuities among genotypes of a collection of organisms previously thought to represent one species, either within one region, or over a larger geographic distance. When discrete groups based on genetic markers are detected, the existence of species boundaries may be suggested and new species described. Similar procedures could apply to higher taxonomic levels, as well. A group of organisms diagnosed by shared molecular markers, or monophyly in gene phylogenetic trees (the phylogenetic species concept), does not conform to the biological species concept of Mayr (1963) that requires evidence for reproductive isolation from other groups. Of course, this is not different from classical systematics, which diagnoses groups of organisms by shared morphological characters, and thus also does not conform to the biological species concept. In practice, the systematist combines molecular and morphological methods. For example, species differences in the snails Littorina and Nucella and the sea anemone Anthopleura were suspected from morphological or life history differences, and molecular classification supported the hypotheses (Mastro et al. 1982, Palmer et al. 1990, McFadden et al. 1997, Marko et al. 2003).

Future Approaches to Molecular Identification Methods for molecular identification are likely to change considerably, and any detailed protocols given here would be shortly outdated. Hillis et al. (1996) and Avise (2004) have provided comprehensive reviews of methods of genetic analysis,

and numerous practical guides exist. Although the methods by which DNA-based identification are done will change over time, in all cases DNA from specimens will be needed. The basic steps for preparing specimens for DNA analysis are shown in appendix 1. Exhaustive databases of DNA sequences for Californian and Oregonian intertidal invertebrates do not yet exist. Molecular markers that are useful for identification exist where researchers have conducted population genetic, phylogeographic, or phylogenetic studies of the marine animals of California and Oregon, but few of these concern taxa where morphology is not a more convenient indicator of identity, at least for adults. However, several researchers have proposed a system of "DNA barcodes" (Tautz et al. 2002; Hebert et al. 2003a, b; Tautz et al. 2003). This would entail the development of a database of unique, identifying DNA sequences (the "barcodes") for all described species. In principle, one could isolate DNA from an animal of unknown identity, use the polymerase chain reaction (PCR) to amplify a gene present in all animals using universal primers, and sequence the resulting PCR products (or use other methods to detect specific DNA sequences, such as hybridization with DNA probes). By comparing the newly determined sequence to the DNA database, one would determine the identity of the unknown organism. Hebert et al. (2003a, b) has proposed that the gene encoding mitochondrial cytochrome oxidase c subunit I (COI) is an appropriate choice for the DNA barcode database because interspecific variation in COI is said to be sufficient to find unique sequences for all taxa and because universal primers (Folmer et al. 1994) have been used on a wide variety of organisms with success. Criticism of DNA barcoding has focused on its potential use for molecular classification (Lipscomb et al. 2003, Seberg et al. 2003, Will and Rubinoff 2004), although its greater value will be for molecular identification. Despite some encouraging results (Hebert et al. 2004), there are practical problems with DNA barcoding. First, taxa such as anthozoan cnidarians show very slow rates of COI evolution, to the extent that no or little variation exists within genera (Shearer et al. 2002). Second, it will be difficult to establish that a given COI sequence is truly unique to one species, or conversely universal within that species, at least until the database is complete. Third, although so called "universal" primers may indeed be used to amplify PCR products from a large array of taxa, it will nonetheless be necessary to develop specific primers for many others. Last, a database of a single genetic locus may not provide the information needed for reliable molecular identification (Belfiore et al. 2003). However, to the extent that genetic polymorphisms do in fact delineate species, multilocus databases can provide for the needed reliability, and sequence detection technologies will be used to quickly determine DNA sequences of PCR products from unidentified samples. Regardless of whether there is a compelling practical need for genetic identification in any particular case, it is likely that the needed DNA sequence information will become available for a great many of the marine invertebrates of the Pacific coast, and genetic identification will become an increasing option. Nonetheless, it is hoped that this book will remain a primary tool for identification, for it is both the organism's phenotype and genotype that is of interest to the naturalist, biogeographer, ecologist, and evolutionary biologist.

MOLECULAR

IDENTIFICATION

33

Appendix 1 : How to Preserve Tissue Samples for Later Molecular Identification; DNA Preparation In all cases, it is important to retain whole animals as morphological vouchers; label specimens with as much taxonomic, geographic, and habitat information as possible, and to cross index morphological, tissue, and DNA samples (e.g., with corresponding sample numbers) such that they can be confidently matched for subsequent work, perhaps decades or centuries later. Work must be done in as clean a manner as possible, as cross contamination of samples can easily occur and lead to false results. Thus, always clean dissection surfaces and tools with dilute bleach between samples. Alternatively, use sheets of plastic wrap or aluminum foil as disposable dissection surfaces, and use single-use razor blades to excise tissue samples.

DNA Preparation Purified DNA is a stable molecule that can be stored frozen in aqueous solution or dry at room temperature and remain viable for PCR for years (Gerstein 2001). Thus, if one has the time and resources to isolate DNA from fresh tissue, this is the best option for long-term storage. General procedures for DNA isolation can be found in molecular biology handbooks (Gerstein 2001, Sambrook and Russell 2001, Ausubel 2002) or guides specifically written for molecular systematists (Hillis et al. 1996). In general, tissues are homogenized in one of many possible lysis buffers, and DNA is separated from other constituents by organic extraction and precipitation. Some commercially available kits for DNA isolation work well and avoid the need for toxic organic compounds such as phenol or chloroform by binding DNA from the lysis buffer to resins or solid substrates, from which they can be eluted into an aqueous solution. As a rule, no single method works optimally for every organism or tissue, so some experimentation is usually needed. When possible, work with soft, easily homogenized tissues, and avoid tissues that produce large amounts of mucous compounds. Little tissue is needed to produce sufficient DNA for genetic analysis, so limit tissue slices to 100 mg when working with lysis buffer in volumes < 1 ml. For all methods, essential equipment includes pipetters, heated water bath or dry heat block, and a microcentrifuge. Simply boiling a tissue sample in the chromatography resin Chelex-100™ (Bio-Rad) may be sufficient to produce lowquality DNA that is nevertheless sufficient for PCR. This method has worked well for small crustaceans (Sotka et al. 2004). Digestion of tissue homogenates with proteinase-K, followed by isolation of DNA by organic extraction (Sambrook and Russell 2001) or capture on commercially available affinity columns (e.g., Qiagen™ or Promega™) often produces high-quality DNA. Some invertebrate tissues become viscous from mucus,

34

MOLECULAR

IDENTIFICATION

which interferes with purification. Incubation in hexadecyltriethylamine bromide (CTAB) (Gerstein 2001) can assist in reducing sample viscosity. In general, consult recent publications reporting results of molecular studies on taxa closely related to a novel study organism.

Tissue Storage for Later DNA Isolation The best method is to freeze a small (5 mm 3 -10 mm 3 ) section of soft, nucleated cellular tissue in liquid nitrogen and store at -70°C until needed. This is often not practical for lack of liquid nitrogen and ultra low freezers. Freezing a sample in a consumer quality manual defrost freezer (-20°C) will usually allow later isolation of DNA usable for PCR. Repeated defrost cycling in most conventional automatic defrost household freezers will result in greatly degraded DNA, which may prove unreliable for genetic analysis. Preservation of a small (5 mm 3 -10 mm 3 ) section of soft, nucleated cellular tissue in 70%-100% ethanol is often satisfactory. Isopropanol, available widely in drugstores, can be used when ethanol is unavailable. DNA from alcohol-preserved tissues is usually highly degraded, yet PCR amplification of targets 6 . 0 mm, reaching 15.0 mm; peduncular article 4 of antennule with four or five robust apical setae; posterior margins of pleonites 5-7 with highly acute teeth (plate 219C) Nebalia hessleri Body length typically < 6 . 0 mm; peduncular article 4 of antennule with two or less robust apical setae; posterior margins of pleonites 5-7 with subacute or blunt-ended teeth 4 Eyes with pigment on distal third of eyestalk; posterior margins of pleonites 5-7 with subacute teeth; terminal seta shorter than uropod (plate 219D) Nebalia gerkenae Eyes with pigment on distal two-thirds of eyestalk; posterior margins of pleonites 5-7 with distally rounded teeth; terminal seta 1.7x length of uropod (plate 219E) Nebalia kensleyi

List of Species NEBALIIDAE

Nebalia daytoni Vetter, 1996. Oligotrophic sands, 8 mm-33 mm, off La Jolla; occurring farther north. See Vetter 1996, Mar. Ecol. Prog. Ser. 137: 83-93 (enrichment and population cycles). Nebalia gerkenae Haney and Martin, 2000. Surface mats of Gracilaria and Ulva, as well as beneath small rocks partly embedded in mud; high intertidal; Bennett Slough, an arm of Elkhorn Slough, Monterey Bay. Nebalia kensleyi Haney and Martin, 2005. Intertidal mats of Ulva in Tomales Bay. *Nebaiia sp. A widespread species in the Pacific Northwest; the figure here is of a specimen close to the original collecting site of N. pugettensis; some diagnostic figures of the species were noted by Martin et al. 1996. Nebalia hessleri Martin, Vetter, and Cash-Clark, 1996. Deeper water off the southern California coast; noted here on the possibility it may be discovered in shallower water. *Nebalia "pugettensis Clark, 1932" (=Epinebalia pugettensis). Martin et al. (1996) declared this species a nomen nudum, until it can be determined that there is only one species in the immediate vicinity of Clark's original collecting site at Friday Harbor. * = Not in key.

NEBALIOPSIDIDAE Nebaliopsis sp. Deeper water off the California coast.

References Bowman, T. E. 1971. The case of the nonubiquitous telson and the fraudulent furca. Crustaceana 21: 165-175. Cannon, H. G. 1927. On the feeding mechanism of Nebalia bipes. Transactions of the Royal Society of Edinburgh 55: 355-369. Clark, A. E. 1932. Nebalia Caboti, n. sp., with observations on other Nebaliacea. Transactions of the Royal Society of Canada 26: 217-235. Conlan, K. E., and D. V. Ellis. 1979. Effects of wood waste on sand-bed benthos. Marine Pollution Bulletin 10: 262-267. Dahl, E. 1985. Crustacea Leptostraca, principles of taxonomy and a revision of European shelf species. Sarsia 70: 135-165. Dahl, E. 1987. Malacostraca maltreated—the case of the Phyllocarida. Journal of Crustacean Biology 7: 721-726. Dahl, E. 1990. Records of Nebalia (Crustacea Leptostraca) from the Southern Hemisphere—a critical review. Bulletin of the British Museum of Natural History (Zoology) 56: 73-91. Gerken, S. 1995. The population ecology of the leptostracan crustacean, Nebalia pugettensis (Clark, 1932), at Elkhorn Slough, California. M.S. thesis, University of California, Santa Cruz, 53 pp. Haney, T. A., R. R. Hessler, and J. W. Martin. 2001. Nebalia schizophthalma, a new species of leptostracan (Crustacea: Malacostraca) from deep waters off the eastern United States. Journal of Crustacean Biology 21: 192-201. Haney, T. A., and J. W. Martin. 2000. Nebalia gerkenae, a new species of leptostracan (Crustacea, Phyllocarida) from the Bennett Slough region of Monterey Bay, California. Proceedings of the Biological Society of Washington 113: 996-1014. Haney, T. A., and J. W. Martin. 2005. Nebalia kensleyi, a new species of leptostracan (Crustacea: Phyllocarida) from Tomales Bay, California. Proceedings of the Biological Society of Washington 118: 3-20. LaFollette, R. 1914. A Nebalia from Laguna Beach. Journal of Entomology and Zoology 6: 204-206. Martin, J. W., E. W. Vetter, and C. E. Cash-Clark. 1996. Description, external morphology, and natural history observations of Nebalia hessleri, new species (Phyllocarida: Leptostraca), from southern California, with a key to the extant families and genera of the Leptostraca. Journal of Crustacean Biology 16: 347-372. Nishimura, S., and M. Hamabe. 1964. A case of economical damage done by Nebalia. Publications of the Seto Marine Biological Laboratory 12: 173-175. Okey, T. A. 2003. Macrobenthic colonist guilds and renegades in Monterey Canyon (U.S.A.) drift algae: partitioning multidimensions. Ecological Monographs 73: 415^440. Packard, A. S. 1883. A monograph of the phyllopod Crustacea of North America, with remarks on the order Phyllocarida. F. V. Hayden ed., in Twelfth Annual Report of the U.S. Geological and Geographical Survey of the Territories of Wyoming and Idaho: a report of the progress of the exploration of Wyoming and Idaho for the year 1878, Part I. (Washington, D.C.: Government Printing Office), pp. 295-497. Rainer, S. F., and P. Unsworth. 1991. Ecology and production of Nebalia sp. (Crustacea: Leptostraca) in a shallow-water seagrass community. Australian Journal of Marine and Freshwater Research 42: 53-68. Ruiz, G. M„ P. W. Fofonoff, J. T. Carlton, M.J. Wonham, and A. H. Hines. 2000. Invasion of coastal marine communities in North America: apparent patterns, processes, and biases. Annual Review of Ecology and Systematics 31: 481-531. Sharov, A. G. 1966. Basic Arthropodan Stock with Special Reference to Insects. (Oxford: Pergamon Press), 271 pp. Vetter, E. W. 1994. Hotspots of benthic production. Nature 372: 47. Vetter, E. W. 1995. Detritus-based patches of high secondary production in the nearshore benthos. Marine Ecology Progress Series 120:251-262. Vetter, E. W. 1996a. Life-history patterns of two Southern California Nebalia species (Crustacea, Leptostraca)—the failure of form to predict function. Marine Biology 127: 131-141. Vetter, E. W. 1996b. Secondary production of a Southern California Nebalia (Crustacea, Leptostraca). Marine Ecology Progress Series 137: 95-101.

Vetter, E. W. 1996c. Nebalia daytoni, n. sp., a leptostracan from southern California (Phyllocarida). Crustaceana 69: 379-386. Vetter, E. W. 1998. Population dynamics of a dense assemblage of marine detritivores. Journal of Experimental Marine Biology and Ecology 226: 131-161. Walker-Smith, G. K., and G. C. B. Poore. 2001. A phylogeny of the Leptostraca (Crustacea) with keys to the families and genera. Memoirs of Museum Victoria 58: 383-410.

Mysidacea RICHARD F. MODLIN (Plates 2 2 0 - 2 2 3 )

Mysids are inconspicuous, but abundant and diverse, shrimplike peracaridan crustaceans. They are rarely collected if conventional sampling techniques are utilized because of the variety of microhabitats they occupy. Generally, m a n y coastal species inhabit the sediment surface or shoal within the water column contiguous with, or a few meters above, the bottom. Other species are truly planktonic and exist in the water column for their entire life cycle. Others opt for more cryptic habitats such as the interstices of sponges, corals, discarded gastropod shells, and holdfasts of macroalgae. Some even establish symbiotic relationship with sponges, anemones and scyphozoans. Consequently, sampling mysid populations usually requires a variety of specialized collecting techniques. Except for Mysis relicta, which is strictly freshwater and may be endemic, or introduced into, some deep-water and glacial lakes of northern California and Oregon, mysids are marine crustaceans. However, because of its adaptations to estuarine habitats, Neomysis mercedis occurs in some freshwater tributaries to the Sacramento-San Joaquin Estuary, as well as those of other estuarine systems along the northwestern coast of North America. Taxonomically, the Mysidacea are divided into two suborders: the Lophogastrida and Mysida. Lophogastrids are large, pelagic, deep-ocean mysids very rarely collected in coastal environments, while species of the Mysida dominate most coastal habitats from intertidal to pelagic environs and occupy both benthic and planktonic habitats. The two suborders are easily distinguished. Specimens of Lophogastrida have branchial gills extending from the base of some thoracic legs, well-developed, unmodified biramous pleopods in both sexes, and lack a statocyst on the endopods of the uropod (plate 220A, 220B). Statocysts on the endopods of the uropod are obvious in the Mysida, branchia are absent, and pleopods of females are rudimentary (uniramous and platelike) or absent in the Mysida (plate 220C, 220D). Lophogastrida are not treated here; Kathman et al. (1986) provide taxonomic information on Lophogastrida reported along the northwestern coast of the United States. Juvenile and mature females are easily separated from males by the presence of an obvious brood pouch (marsupium) (plate 220C). The brood pouch is composed of a number of large paired, interlocking plates (oostegites) ballooning posteriorly from ventral surface of the thorax. The number of oostegites can be important in the identification of some mysid species. Males, juvenile and mature, are easily identified by a pair of penes located at the junction of the thorax and abdomen on the ventral surface. Also, depending on species, male third, fourth, and/or fifth pleopods are sexually dimorphic to enable the possible transfer of spermatophores. Modified males pleopods are an important character for taxonomic diagnosis. The magnitude of male pleopod dimorphism in some mysid taxa varies between juveniles and mature individuals of the MYSIDACEA

489

B

eye stalk

uropod endopod

PLATE 220 A, order Mysidacea, suborder Lophogasterida, Gnathophausia sp.; B, telson-uropod complex, dorsal view, of Gnathophausia sp.; C, order Mysidacea, suborder Mysida, generalize mysid species; D, telson-uropod complex, ventral view, of species in suborder Mysida (figures are not to scale).

same species (plate 2 2 1 H , 2211). This variation can sometimes lead to misidentification. T a x o n o m y of the Mysida, except in some limited cases, is well established. Their identification is based on a variety of obvious, and for t h e most part invariable, morphological characteristics. Consequently, with the use of a hand lens, mysids collected in the field can usually be identified to genus. Microscopic examination and limited dissection enable easy identification of a mysid to species. Identification of t h e species considered in this section is based primarily o n variations in the morphology of telson, uropods, male pleopods, and antennal scales. Except for the male pleopods, t h e design of the other key characteristics does not vary between t h e sexes. For information on Mysidacea 490

ARTHROPODA

south, of our region the reader should e x a m i n e the t a x o n o m i c atlas edited by Blake and Scott (1997), and for coastal areas to the north, Daly and Holmquist ( 1 9 8 6 ) a n d Kathman et al. (1986). The only comprehensive global treatment of mysid biology and t a x o n o m y is t h e older s u m m a r y of M a u c h l i n e (1980).

Key to Mysidacea 1. — 2.

Eye stalk length normal (plate 220A, 2 2 0 C ) 2 Eye stalk length elongated (plate 221A) Alienacanthomysis macropsis Lateral margins of telson completely or partially armed with spines, but if partial, a group of spines also located

PLATE 221 A, Alienacanthomysis macropsis, anterio-dorsal view; B, Alienacanthomysis macropsis, telson; C, Deltamysis holmquistae, telson; D, Deltamysis holmquistae, male pleopod 5; E, Deltamysis holmquistae, uropodal exopod and endopod; F, Archeomysis grebnitzkii, uropodal exopod and endopod; G, Archeomysis grebnitzkii, telson; H, Archeomysis grebnitzkii, pleopod 3 of immature male; I, Archeomysis grebnitzkii, pleopod 3 of mature male; J, Hippacanthomysis platypoda, telson; K, Hippacanthomysis platypoda, male pleopod 4; L, generalized pleopod 4 of Neomysis spp. and Acanthomyis spp. (figures are not to scale).

— 3. — 4. —

5. — 6.

—

7. — 8. —

9. — 10. — 11. — 12. — 13. —

proximally (plates 221B, 223A) 3 Lateral margins of telson armed with spines only in distal half (plate 221C) Deltamysis holmquistae Exopod of uropods without spines along lateral margin (plate 22IE) 4 Exopod of uropods with spines along lateral margin (plate 221F) Archaeomysis grebnitzkii Exopod of male fourth pleopod two segmented, cylindrical in cross section (plate 221L) 5 Exopod of male fourth pleopod with proximal segment flattened, bladelike, distal segment cylindrical (plate 221K) Hippacanthomysis platypoda Abdominal segments smooth, without furrows or folds 7 Abdominal segments with furrows or folds, some may be faint and/or disconnected (plate 222A-222D) 6 Telson sharply triangular with longest marginal spines in distal half, apex with one pair of minute spines and one pair of long spines (plate 222F) Exacanthomysis davisi Telson broadly triangular with longest lateral spines along entire margin, apex with one pair of minute spines and two pair of long spines (plate 222E) Holmesimysis costata Distal tip of antennal scale sharply pointed (plate 222G) 8 Distal tip of antennal scale rounded (plate 222H) 10 Length of telson greater than two times width measured proximally at broadest interval 9 Length of telson two times or less than width measured proximally at broadest interval (plate 2221) Neomysis mercedis Lateral spines on margin of telson 25 or less (plate 222J) Neomysis rayii Lateral spines on margin of telson > 2 5 (plate 222K) . . . . Neomysis kadiakensis Lateral margins of telson completely armed with spines (plate 223C, 223F, 2231) 12 Spination along lateral margins of telson interrupted proximally (plate 223A, 223B) 11 Endopod of uropod with four to five spines in vicinity of statocyst (plate 223D) Acanthomysis califomica Endopod of uropod with two spines in vicinity of statocyst (plate 223E) Hyperacanthomysis longirostris Margin of telson armed with long spines interspersed with 13 minute spines (plate 223F, 2231) Margin of telson armed with 35-40 subequal (of about the same length) spines Columbiaemysis ignota Endopod of uropod with single spine in vicinity of statocyst (plate 223H) Acanthomysis aspera Endopod of uropod with 4 spines in vicinity of statocyst Acanthomysis hwanhaiensis

List of Species Acanthomysis califomica Murano and Chess, 1987. A probable mid-water species collected offshore of the Big Sur region at 119 m (at a site 143 m deep) (Murano and Chess 1987); specimens occasionally collected off shallow exposed beaches. Hyperacanthomysis longirostris Ii, 1936 (=Acanthomysis bowmani Modlin and Orsi, 1997; see Fukuoka and Murano 2000, 492

ARTHROPODA

Plankton Biol. Ecol. 47: 122-128). An exotic Asian species collected in Suisun Bay of the Sacramento-San Joaquin Estuarine system. In low-salinity waters. Acanthomysis aspera Ii, 1964. An exotic brackish-water Japanese species established in the delta region of the SacramentoSan Joaquin Estuary (Modlin and Orsi 1997). Acanthomysis hwanhaiensis Ii, 1964. This exotic Korean species has been collected in the Sacramento-San Joaquin Estuary delta (Modlin and Orsi 2000). Alienacanthomysis macropsis (Tattersall, 1932) (=Neomysis macropsis Tattersall, 1932a, Acanthomysis macropsis). Uncommon; San Francisco Bay to Alaska. Closely related to Acanthomysis pseudomacropsis (Tattersall), which inhabits eastern Pacific coastal waters from Alaska to Japan (Banner 1948, Tattersall 1951, Ii 1964). Some mature females of A. macropsis from the Columbia River Estuary harbor the ectoparasitic copepod Hansenulus trebax Heron and Damkaer, 1986, in their marsupium (Daly and Damkaer 1986). Archaeomysis grebnitzkii Czerniavsky 1882 (=Archaeomysis maculata Holmes, 1894; Callomysis maculata; Bowmaniella banned Bacescu, 1968). Common off sandy and gravelly beaches from central California northward. Columbiaemysis ignota Holmquist, 1982 (=Acanthomysis brunnea Murano and Chess, 1987; see Fukuoka and Murano, 2001). Freshly caught specimens are rich brown in color, closely resembling their habitat of the brown macroalgae Laminaria and Nereocystis (Murano and Chess 1987). A coastal species reported from British Columbia and from Albion Cove, Mendocino County. Deltamysis holmquistae Bowman and Orsi, 1992. Collected in the Sacramento-San Joaquin Estuary; tolerant of low salinity waters, l.l°/oo-2.2%o (Bowman and Orsi 1992). Exacanthomysis davisi (Banner, 1948) (=Acanthomysis davisi). From deeper coastal bays and inlets from northern California to British Columbia. Hippacanthomysis platypoda Murano and Chess, 1987. Males of fresh specimens are dark brown, while females tend to be green; common in the vicinity of coarse sandy bottoms, moving in a manner resembling the swimming behavior of sea horses. Known from Albion and Mendocino Coves, California. Holmesimysis costata (Holmes, 1900) (=Neomysis sculpta Tattersall, 1933; = Acanthomysis costata). Littoral species common under Macrocystis fronds and other kelp species forming canopies on or near water surface (Turpen et al. 1994); bays and inlets from central California north. *Neomysis japonica Nakazawa, 1910. This Japanese species was first collected in San Francisco Bay in 2004 (Petaluma River Boat Basin, and probably more widely distributed; John Chapman, personal communication); it appears to occupy a similar habitat as the native N. mercedis. Easily separated from N. mercedis by the following characteristics: antennal scale 10 times as long as broad, distal tip articulated; telson broadly triangular, length 2.5 times width measured proximally at broadest expanse, lateral margins armed with 40 or more uniformly small, regularly spaced spines. See Tattersall 1951 (illustrations); Nakazawa 1910, Annotationes Zoologicae Japonenses 7: 247-261. Neomysis kadiakensis Ortmann, 1908. Common in deep-water bays and inlets from San Francisco Bay north to British Columbia. Neomysis mercedis Holmes, 1897 (=Neomysis awatschensis of Banner; N. intermedia of Simmons et al. 1974, Calif. Fish Game 60: 23-25 and 60: 211-212, and Simmons and Knight 1975, * = Not in key.

•N

H

PLATE 222 A, Holmesimysis costata, abdominal segments 4-6, dorsal view; B, Holmesimysis costata, abdominal segments 4-6, lateral view; C, Exacanthomysis davisi, abdominal segments 3-6, dorsal view; D, Exacanthomysis davisi, abdominal segments 3-6, lateral view; E, Holmesimysis costata, telson; F, Exacanthomysis davisi, telson; G, Neomysis spp., antenna 2 and scale; H, Acanthomysis spp., antenna 2 and scale; I, Neomysis mercedis, telson; J, Neomysis rayii, telson; K, Neomysis kadiakensis, telson (figures are not to scale).

PLATE 223 A, Acanthomysis caìifornica, telson; B, Hyperacanthomysis ¡ongirostris, telson; C, Columbiaemysis ignota, telson; D, Acanthomysis californica, uropodal exopod and endopod; E, Hyperacanthomysis longirostris, uropodal endopod; F, Acanthomysis aspera, telson; G, Acanthomysis aspera, design of terminal spines on apex of telson; H, Acanthomysis aspera, uropodal endopod; I, Acanthomysis hwanhaiensis, telson (fìgures are not to scale).

C o m p . B i o c h e m . Physiol. (A) 5 0 : 1 8 1 - 1 9 3 , t h e latter o n respir a t i o n as related t o salinity a n d t e m p e r a t u r e ) . E u r y h a l i n e ; o n e o f t h e m o s t a b u n d a n t species i n h a b i t i n g s h a l l o w c o a s t a l estua r i n e b a y s a n d inlets, f r o m b r a c k i s h t o fresh water, t h r o u g h o u t o u r e n t i r e area. In s o m e o f its e n d e m i c h a b i t a t s p r o b a b l y bei n g r e p l a c e d b y e x o t i c m y s i d species ( B o w m a n a n d Orsi 1 9 9 2 ; M o d l i n a n d Orsi 1 9 9 7 ) . Neomysis

mercedis

is o m n i v o r o u s , feed-

i n g b o t h o n p h y t o p l a n k t o n a n d z o o p l a n k t o n , w i t h its diet selective a n d v a r y i n g w i t h life stage, season, a n d p r e y availability (Siegfried a n d K o p a c h e 1 9 8 0 , Biol. Bull. 1 5 9 : 1 9 3 - 2 0 5 ; M u r t a u g h 1 9 8 1 E c o l o g y 6 2 : 8 9 4 - 9 0 0 , 1 9 8 3 , C a n . J . Fish. A q u a t . Sci. 40: 1 9 6 8 - 1 9 7 4 ) , and o n meiobenthic harpacticoid copepods ( J o h n s t o n a n d L a s e n b y 1 9 8 2 , C a n . J. Zool. 6 0 : 8 1 3 - 8 2 4 ) . In s o m e locations, m a t u r e females m a y harbor the ectoparasitic c o p e p o d Hansenulus

trebax H e r o n a n d D a m k a e r , 1 9 8 6 , in their

m a r s u p i u m (Daly a n d D a m k a e r 1 9 8 6 ) . Neomysis

rayii

(Murdoch,

H o l m e s , 1 9 0 0 ; Neomysis

1885) (=Neomysis

franciscorum

toion D e r z h a v i n , 1 9 1 3 ) . A m o r e off-

s h o r e species, also c o l l e c t e d in d e e p e r bays a n d inlets, f r o m San F r a n c i s c o B a y n o r t h a c r o s s t h e Pacific r i m t o n o r t h e a s t Asia.

References Banner, A. H. 1948. A taxonomic study of the Mysidacea and Euphausiacea (Crustacea) of the northeastern Pacific, Part II. Mysidacea, from tribe Mysini through subfamily Mysidellinae. Transactions of the Royal Canadian Institute 27: 6 5 - 1 2 4 . Blake, J. A., and P. H. Scott (eds.). 1997. Taxonomic atlas of the benthic fauna of the Santa Maria Basin and western Santa Barbara Channel, Volume 10, The Arthropoda, The Crustacea Part 1. Santa Barbara: Santa Barbara Museum of Natural History, 151 pp. Bowman, T. E., and J. J. Orsi. 1992. Deltamysis holmquistae, a new genus and species of Mysidacea from the Sacramento-San Joaquin Estuary of California (Mysidae: Mysinae: Heteromysini). Proceeding of the Biological Society of Washington 105: 7 3 3 - 7 4 2 . Daly, K. L., and D. M. Damkaer. 1986. Population dynamics and distribution of Neomysis mercedis and Alienacanthomysis macropsis (Crustacea: Mysidacea) in relation to the parasitic copepod Hansenulus trebax in the Columbia River Estuary. Journal of Crustacean Biology 6: 8 4 0 - 8 5 7 . Daly, K. L., and C. Holmquist. 1986. A key to the Mysidacea of the Pacific Northwest. Can. J. Zool. 64: 1 2 0 1 - 1 2 1 0 . Fukuoka, K., and M. Murano. 2001. Telacanthomysis, a new genus, for Acanthomysis columbiae, and redescription of Columbiaemysis ignota (Crustacea: Mysidacea: Mysidae). Proceedings of the Biological Society of Washington 114: 1 9 7 - 2 0 6 . Heron, G. A., and D. M. Damkaer. 1986. A new nicthoid copepod parasitic on mysids from northwestern North America. Journal of Crustacean Biology 6: 6 5 2 - 6 6 5 . Holmes, S. J. 1900. California Stalk-eyed Crustacea. Occasional Papers of the California Academy of Sciences VII: 1 - 2 6 2 + 4 plates. Holmquist, C. 1973. Taxonomy, distribution and ecology of the three species Neomysis intermedia (Czerniavsky), N. awatschensis (Brandt) and N. mercedis Holmes (Crustacea, Mysidacea). Zoologische Jahrbucher, Abteilung fur Systematik, Ökologie und Geographie der Tiere 100: 1 9 7 - 2 2 2 . Holmquist, C. 1975. A revision of the species Archaeomysis grebnitzkii Czerniavsky and A. maculata (Holmes) (Crustacea, Mysidacea). Zoologische Jahrbucher, Abteilung fur Systematik, Ökologie und Geographie der Tiere 102: 5 1 - 7 1 . Holmquist, C. 1979. Mysis costata Holmes, 1900, and its relations (Crustacea, Mysidacea). Zoologische Jahrbücher, Abteilung fur Systematik, Ökologie und Geographie der Tiere 106: 4 7 1 ^ 9 9 . Holmquist, C. 1980. Xenacanthomysis—a new genus for the species known as Acanthomysis pseudomacropsis (W. M. Tattersall, 1933) (Crustacea, Mysidacea). Zoologische Jahrbucher, Abteilung fur Systematik, Ökologie und Geographie der Tiere 107: 5 0 1 - 5 1 0 . Holmquist, C. 1981a. The Genus Acanthomysis Czerniavsky, 1882 (Crustacea, Mysidacea). Zoologische Jahrbucher, Abteilung fur Systematik, Ökologie und Geographie der Tiere 108: 3 8 6 - 4 1 5 .

Holmquist, C. 1981b. Exacanthomysis gen. nov., another detachment from the genus Acanthomysis Czerniavsky (Crustacea, Mysidacea). Zoologische Jahrbucher, Abteilung fur Systematik, Okologie und Geographie der Tiere 108: 2 4 7 - 2 6 3 . Ii, N. 1964. Fauna Japonica Mysidacea. Biogeographical Society of Japan, Tokyo, 6 1 0 pp. Kathman, R. D„ W. C. Austin, J. C. Saltman, a n d j . D. Fulton. 1986. Identification manual to the Mysidacea and Euphausiacea of the Northeast Pacific. Canadian Special Publication of Fisheries and Aquatic Sciences 93, Department of Fisheries and Game, Ottawa, Canada, 401 pp. Mauchline, J. 1980. The Biology of Mysids, Part I. Yonge (eds.), Advances in marine biology, Vol. 18. J. H. S. Blaxter, F. S. Russell, and M. Yonge, eds. New York: Academic Press, pp. 1 - 3 6 9 . Modlin, R. F., and J. J. Orsi. 1997. Acanthomysis bowmani, a new species, and A. aspera Ii, Mysidacea newly reported from the Sacramento-San Joaquin Estuary, California (Crustacea: Mysidae). Proceeding of the Biological Society of Washington 110: 4 3 9 - 4 4 6 . Modlin, R. F., and J. J. Orsi. 2000. Range extension of Acanthomysis hwanhaiensis Ii, 1964, to the San Francisco estuary, California, and notes on its description (Crustacea: Mysidacea). Proceedings of the Biological Society of Washington 113: 6 9 0 - 6 9 5 . Murano, M., and J. R. Chess. 1987. Four new mysids from California coastal waters. Journal of Crustacean Biology 7: 1 8 2 - 1 9 7 . Siegfried, C.A., and M. E. Kopache. 1980. Feeding of Neomysis mercedis (Holmes). Biological Bulletin 159: 1 9 3 - 2 0 5 . Tattersall, W. M. 1932a. Contributions to a knowledge of the Mysidacea of California, I. On a collection of Mysidae from La Jolla, California. University of California Publications in Zoology 37: 301-314. Tattersall, W. M. 1932b. Contributions to a knowledge of the Mysidacea of California, II. The Mysidacea collected during the survey of San Francisco Bay by the U.S.S. Albatross in 1914. University of California Publications in Zoology 37: 3 1 5 - 3 4 7 . Tattersall, W. M. 1951. A review of the Mysidacea of the United States National Museum. United States National Museum Bulletin 201, 2 9 2 pp. (and supplement by A. H. Banner, 1954, Proc. U.S. Natl. Mus. 103: 575-583). Turpen, S., J. W. Hunt, B. S. Anderson, and J. S. Pearse. 1994. Population structure, growth, and fecundity of the kelp forest mysid Holmesimysis costata in Monterey Bay, California. Journal of Crustacean Biology 14: 6 5 7 - 6 6 4 .

Cumacea LES WATLING (Plates 2 2 4 - 2 3 0 )

C u m a c e a n s a r e s m a l l c r u s t a c e a n s , g e n e r a l l y r a n g i n g in size f r o m 1 m m t o 1 c m ; h o w e v e r , a few species, s u c h as t h e A r c t i c Diastylis goodsiri,

m a y b e 3 c m or m o r e in l e n g t h . T h e C u m a c e a

currently c o n t a i n s m o r e t h a n 1 , 2 0 0 species worldwide.

Of

these, 4 9 species are k n o w n f r o m t h e Pacific c o a s t o f t h e U n i t e d States. M a n y o f t h e h a b i t a t s w h e r e c u m a c e a n s are likely t o be f o u n d , s u c h as estuaries, s h a l l o w e m b a y m e n t s , b e a c h e s , tidal flats, a n d t h e i n n e r c o n t i n e n t a l shelf, h a v e n o t y e t h a d t h e i r c u m a c e a n f a u n a d o c u m e n t e d . In c o n t r a s t , t h e far less diverse c u m a c e a n f a u n a o f t h e n o r t h e a s t e r n U n i t e d States is c o m pletely k n o w n (Watling 1 9 7 9 ) . C u m a c e a n s a r e m a l a c o s t r a c a n s , d i s t i n g u i s h e d b y t h e foll o w i n g c o m b i n a t i o n o f features: t h e c a r a p a c e c o v e r s t h e first t h r e e o r four, or rarely six, t h o r a c i c s o m i t e s ; t h e a n t e r i o r m a r g i n o f t h e c a r a p a c e is e x t e n d e d

in f r o n t o f t h e h e a d

as

p s e u d o r o s t r a l lobes; t h e t e l s o n m a y b e p r e s e n t , r e d u c e d , or inc o r p o r a t e d i n t o t h e last a b d o m i n a l s o m i t e ( p l e o n i t e ) ; t h e eyes are u n i t e d dorsally i n all b u t a v e r y few g e n e r a ; t h e s e c o n d a n t e n n a e lack a n e x o p o d ; a n d p l e o p o d s are a b s e n t in f e m a l e s ( w i t h t h e e x c e p t i o n o f o n e d e e p - s e a species) a n d o f t e n r e d u c e d in n u m b e r or a b s e n t i n m a l e s (plate 2 2 4 ) .

CUMACEA

495

pseudorostral lobes

PLATE 2 2 4 Basic cumacean morphology: Al, antenna 1; A2, antenna 2; Md, mandible; M x l , first maxilla; Mx2, second maxilla; M x p l , first maxilliped (from Sars, 1 8 9 9 - 1 9 0 0 ) .

The cumacean body is externally divided into carapace, thorax, and abdominal regions (plate 224). Externally the body can be divided into three regions, the carapace (which covers the head and first three thoracic somites), the pereon (consisting of the remaining thoracic somites), and the abdomen 496

ARTHROPODA

or pleon. The pereon usually consists of five somites, but fewer may be visible depending on the extent of the carapace. The abdomen always contains six somites, of which pleonite 5 is usually the longest. An articulated telson may or may not be present terminally.

PLATE 225 Basic cumacean morphology (continued): Al, antenna 1; A2, antenna 2; Mxp3, third maxilliped; P1-P5, pereopods 1 through 5; Pip, pleopod (from Sars, 1 8 9 9 - 1 9 0 0 ) .

The carapace is expanded ventrally and laterally to form a branchial chamber. Each side of the carapace is produced anteriorly in the form of pseudorostral lobes that meet, but are not fused, in front of the head, forming a pseudorostrum (plate 224). Reaching to the end of, or projecting beyond, the pseudorostrum are the tips of the branchial epipods of the first maxilliped, which together form the branchial siphon, or exhalant canal, for the respiratory current. The

pseudorostrum may be directed anteriorly at various angles, or be completely reflexed such that the branchial opening is dorsal. As in all crustaceans the head bears five pairs of appendages, viz., the first and second pairs of antennae, mandibles, and first and second pairs of maxillae. The first antenna (plate 224, Al) consists of a three-articulate peduncle, the distal-most of which bears two rami, a main CUMACEA

497

A

Anchicolurus

occidentalis

PLATE 226 A, Anchicolurus occidentalis; B, Diastylopsis dawsoni; C, Diastylis abbotti (drawings not to scale).

flagellum of two to six articles, and an accessory flagellum (when present) of o n e to four articles. In several families, the accessory flagellum consists of a single article ranging in size from minute to nearly as long as t h e main flagellum. The main flagellum is often festooned with long sensory setae, especially in males of the genus Leptostylis. T h e second antenna (plate 2 2 4 , A2) is generally rudimentary in the female, whereas in the male it typically consists of a fivearticulate peduncle bearing a very long multiarticulate flagellum. Peduncle articles four and five bear a strong brush of sensory setae, and peduncle article five is m u c h longer t h a n ar498

ARTHROPODA

ticle four (plate 225). In the immature male, the setal brush and elongate flagellum are not present; instead t h e second antenna is shaped like an elongate club. In cumaceans the mouth appendages (mandible, first and second maxillae, first and second maxillipeds) are well enclosed by the carapace fold. The morphology of these appendages does not need to be known for routine identifications, so they will not be dealt with here. T h e outermost of the m o u t h appendages is the third maxilliped. It is also the third thoracic appendage. The third maxilliped is the most leglike of t h e three pairs of maxillipeds (plate 2 2 5 , M x p 3 ) . It consists of an elongate

PLATE 227 A, Diastylis pellucida;

B, Diastylis santamariensis;

scale bars = 1 m m (photographs from Watling and McCann 1997).

basis and five-articulate endopod and usually possesses an exopod. The shape of this appendage ranges from very elongate to broad and operculate. Whether truly opercular or not, the third maxilliped usually covers the ventral aspect of the mouth field. Pereopod 1 is the first true ambulatory appendage, but is, in fact the fourth thoracic appendage (plate 225, PI). Its structure is much the same as for the third maxilliped, but the endopod is generally more elongate. An exopod is usually present. The remaining pereopods decrease in length and robustness posteriorly (plate 225, P3, P4, P5); exopods may or may not be present, and if present, may be very small, on pereopods 2 - 4 . An exopod is never present on pereopod 5. The appendages of abdominal somites 1 - 5 are known as pleopods and are present (with a single exception in a deep-sea species) only in males (plate 225, Pip). Depending on the fam-

ily, there may be one to five pairs of pleopods, or they may be absent altogether. The last pair of abdominal appendages are the uropods. They consist of a uniarticulate peduncle bearing two rami, the endopod, and exopod (plate 225). The exopod is always two-articulate, but the endopod may consist of one to three articles. The cumacean body terminates with a telson, on the ventral side of which is located the anus and anal valves. In the Bodotriidae, Leuconidae, and Nannastacidae, the telson is very short and is fused to the sixth pleonite; in these families the telson is said to be absent. Freely articulated telsons of varying length can be found in the other families (plate 225). Cumaceans can be found in all sedimentary habitats, from mud to sand, but they are usually more diverse in sandy areas. They also occur in a range of salinities and are found at all ocean depths. Along our coast, the best areas for obtaining cumaceans CUMACEA

499

A

Mesolamprops

dillonensis

PLATE 228 A, Mesolamprops dillonensis; B, Hemilamprops californictis; C, Lamprops triserratus; D, Lamprops obfuscatus; E, Lamprops tomalesi (drawings not to scale).

are the shallow offshore sand bars and most sandy to muddysand subtidal areas where currents are not too strong.

K e y t o t h e F a m i l i e s of C u m a c e a

Cumaceans can be collected by many devices, including b o x

1.

W i t h freely articulated telson

cores, grabs, and dredges lined with a fine mesh. On sandy or grassy bottoms, an effective method for obtaining large numbers of cumaceans is to drag a plankton net with a weight at-

— 2. —

Without freely articulated telson Telson with zero or two terminal setae Telson with three or more terminal setae

tached about a meter in front of the net. As the weight drags along the bottom cumaceans are stirred out of the sediment and caught by the net.

3. —

Uropod endopod uniarticulate Uropod endopod two-articulate

500

ARTHROPODA

2 3 Diastylidae Lampropidae Nannastacidae 4

PLATE 229 A, Nippoleucon hinumensis; B, Cumella vulgaris; C, Campylaspis canaliculata; D, pereopod 2 and uropods of Campylaspis hartae; E, Campylaspis rubromaculata (drawings not to scale).

4.

Male with zero or two pairs of pleopods, females with exopods on pereopods 1-3 Leuconidae — Male with five pairs of pleopods; females with exopods on pereopod 1 only Bodotriidae, Subfamily Bodotriinae

Key to Species with Free Telson 1. Telson very short, less than one-third the length of uropod peduncles (plate 226A) Anchicolurus occidentalis — Telson more than half the length of uropod peduncle, or longer than peduncle 2 2. Telson bearing two terminal setae 3

— Telson bearing more than two terminal setae 6 3. Body with pereonite 4 greatly enlarged, especially as seen in dorsal view (plate 226B) Diastylopsis dawsoni — Body with pereonite 4 no more than twice length of pereonite 3 as seen in dorsal view 4 4. Uropod exopod slightly longer than peduncle; telson slightly shorter than uropod peduncle (plate 226C) Diastylis abbotti — Uropod exopod about half the length of peduncle; telson half to three-quarters the length of uropod peduncle 5 5. Carapace with two oblique lines; telson about half the length of uropod peduncle (plate 22 7A) Diastylis pellucida CUMACEA

501

PLATE 230 A, Eudorella pacifica; B, Campylaspis rubromaculata; C, Campylaspis hartae; scale bars = 1 mm (photographs from Watling and M c C a n n 1 9 9 7 ) .

Carapace surface very rough and with several oblique lines; telson about three-quarters the length uropod peduncle (plates 227B) Diastylis santamariensis Uropod exopod equal to or longer than endopod (plate 228A) Mesolamprops dillonensis Uropod exopod clearly shorter than endopod 7 502

ARTHROPODA

Carapace with oblique lateral ridges or falcate lateral ridge appearing as faint lines 8 Carapace without any ridges 9 Carapace with falcate lateral ridge (plate 228B) Hemilamprops californicus Carapace with oblique lateral ridges (plate 228C)

Lamprops triserratus Uropod exopod equal in length to proximal two articles of endopod (plate 228D) Lamprops obfuscatus — Uropod exopod extends beyond end of second article of endopod (plate 228E) Lamprops tomalesi 9.

Key to Species with No Free Telson 1. Uropod endopod composed of two distinct articles 2 — Uropod endopod uniarticulate 3 2. First antenna with conspicuous "elbow"; carapace with large tooth at anteroventral corner; first pereonite very narrow (plate 230A) Eudorella pacifica — First antenna without elbow; carapace anteroventral corner rounded; first pereonite wide enough to be easily seen in lateral view (plate 229A) Nippoleucon hinumensis 3. Carapace extended posteriorly, overhanging first few pereonites so that pereonites 1 and 2 are much narrower than pereonites 3-5 4 — Carapace not overhanging pereon, pereonites 1 and 2 same length as pereonites 3-5 (plate 229B) Cumella vulgaris 4. Carapace smooth, female with a small groove extending posteriorly from anterior margin (plate 229C) Campylaspis canaliculata — Carapace with bumps or large ridges 5 5. Carapace with series of large ridges, no bumps or tubercles (plates 229D, 230C) Campylaspis hartae — Carapace with series of tubercles, some organized into shallow ridges; carapace, legs and uropods with many pigment spots (plates 229E, 230B) Campylaspis rubromaculata

List of Species LAMPROPIDAE

Hemilamprops californicus Zimmer, 1936. Lamprops tomalesi Gladfelter, 1975. Lamprops obfuscatus (Gladfelter, 1975) (=Diastylis obfuscata). This species and L. triserratus were assigned by Gladfelter to the genus Diastylis, which belongs to a different family. Lamprops quadriplicata Smith, 1879. Lamprops triserratus (Gladfelter, 1975) (=Diastylis triserrata). Mesolamprops dillonensis Gladfelter, 1975. This species may be the same as Hemilamprops californicus.

DIASTYLIDAE

Anchicolurus occidentalis (Caiman, 1912). Diastylopsis dawsoni Smith, 1880. One of the most common shallow-water species. Diastylis abbotti Gladfelter, 1975. Diastylis santamariensis Watling and McCann, 1997. Diastylis pellucida Hart, 1930.

LEUCONIDAE

Eudorella pacifica Hart, 1930. Nippoleucon hinumensis (Gamo, 1967) (=Hemileucon hinumensis). This species was introduced from Japan in ballast water and

occurs along much of the coast in estuaries and bays; it is particularly common, for example, in San Francisco Bay and Coos Bay.

NAN N ASTACI DAE

Campylaspis canaliculata Zimmer, 1936. Campylaspis rubromaculata Lie, 1971 (=C. nodulosa 1969). Campylaspis hartae Lie, 1969. Cumella vulgaris Hart, 1930.

Lie,

References Caiman, W. T. 1912. The Crustacea of the Order Cumacea in the collection of the United States National Museum. Proceedings of the U.S. National Museum 41: 603-676. Gladfelter, W. B. 1975. Quantitative distribution of shallow-water cumaceans from the vicinity of Dillon Beach, California, with descriptions of five new species. Crustaceana 29: 2 4 1 - 2 5 1 . Hart, J. F. L. 1930. Some Cumacea of the Vancouver Island region. Contributions to Canadian Biology and Fisheries 6: 1-8. Lie, U. 1969. Cumacea from Puget Sound and off the Northwestern coast of Washington, with descriptions of two new species. Crustaceana 17: 19-30. Lie, U. 1971. Additional Cumacea from Washington, U.S.A., with description of a new species. Crustaceana 21: 33-36. Sars, G. O. 1899-1900. Cumacea. An Account of the Crustacea of Norway. Volume 3. Christiania, Bergen, Norway. Watling, L. 1979. Marine fauna and flora of the Northeastern United States: Cumacea. National Marine Fisheries Service, Circular 423, 22 pp. Watling, L., and L. D. McCann. 1997. Cumacea, pp. 121-180. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and western Santa Barbara Channel. Volume 11: The Crustacea Part 2—The Isopoda, Cumacea and Tanaidacea. J. A. Blake and P. H. Scott, eds. Santa Barbara: Santa Barbara Museum of Natural History, Santa Barbara, California, 278 pp.

Isopoda RICHARD C. BRUSCA, VANIA R. COELHO, A N D STEFANO TAITI (Plates 2 3 1 - 2 5 2 )

Isopods are often common and important members of many marine habitats. They can be distinguished from other peracarids, and other crustaceans in general, by the following combination of characteristics: 1. Body usually flattened (except in Anthuridea and Phreatoicidea). 2. Head (cephalon) compact, with unstalked compound eyes, two pairs of antennae (first pair minute in Oniscidea), and mouthparts comprising a pair of mandibles, two pairs of maxillae (maxillules and maxillae), and one pair of maxillipeds. 3. A long thorax of eight thoracomeres, the first (and also the second in Gnathiidea) fused with the head and bearing the maxillipeds, the remaining seven (called pereonites) being free and collectively comprising a body division called the pereon. 4. Seven pairs of uniramous legs (pereopods), all more or less alike (hence, "iso-pod"), except Gnathiidea, which have only five pairs of walking legs. 5. Appendages never chelate (i.e., the subterminal article, or propodus, is not modified into "hand" that works with the terminal article, or dactyl, as a true claw). ISOPODA

503

flagellum \

antennule

preopod 1

— 1st pereopod articles of appendage 1 2 3 4 ~5 A 6 ^ 7

coxa basis ischium merus carpus propodus dactylus

3rd pereopod

oostegites (covering egg)

5th pereopod

pereopod 7

7th pereopod uropod

pleopod 4 1 st pleopod uropod

2nd pleopod

(ventral)

(lateral)

(dorsal) A

Cirolanidae

B

clypeus

mandible

C

D

Sphaeromatidae

maxillule

E

Idoteidae

Asellota

labrum

maxilla

maxilliped

mouthparts

appendix masculina

(ventral) penes

G

Idoteidae pleon

2

3

H

pleopods

PLATE 231 Isopoda. Isopod a n a t o m y in representative groups: A, Cirolanidae; B, Asellota; C, Sphaeromatidae; D, Idoteidae; E, generalized mouthparts; F, penes; G, pleon of Valvifera (ventral view); H, Generalized pleopods (after Van Name 1 9 3 6 ; Menzies and Frankenberg 1 9 6 6 ; Menzies and Glynn 1968).

6. A relatively short abdomen (pleon) composed of six somites (pleonites), at least o n e of which is always fused to the terminal anal plate (telson) to form a pleotelson. 7. Six pairs of biramous pleonal appendages, including five pairs of platelike respiratory/natatory pleopods and a single pair of fanlike or sticklike, uniarticulate (unjointed) uropods. 8. Heart located primarily in the pleon. 9. Biphasic molting (i.e., posterior half of body molts before anterior half). 504

ARTHROPODA

For general isopod morphology, see plate 2 3 1 . All isopods possess one of two fundamental morphologies, being "short-tailed" or "long-tailed" (Brusca and Wilson 1991). In t h e more primitive, short-tailed isopods, the telsonic region is very small, positioning the anus and uropods terminally or subterminally on the pleotelson (Phreatoicidea, Asellota, Microcerberidea, Oniscidea, Calabozoidea). T h e more highly derived long-tailed isopods have t h e telsonic region greatly elongated, thus shifting the anus and uropods to a subterminal position on the pleotelson (Flabellifera, Anthuridea, Gnathiidea, Epicaridea, Valvifera).

Isopods can be sexed in several ways. If oóstegites, or a marsupium, are present, one is obviously examining a female. The openings of the oviducts in females (near the base of the legs on the fifth pereonite) are difficult to observe. If oóstegites are absent, males can be distinguished by the presence of paired penes on the sternum of pereonite 7 (or pleonite 1) or appendices masculinae (sing, appendix masculina) on the endopods of the second pleopods. Absence of penes, appendices masculinae, and oóstegites indicates the specimen is either a nongravid female or a juvenile that has not yet developed secondary sexual features. Isopods are a large, diverse order with 10 named suborders, all but two (Phreatoicidea and Calabozoidea) of which occur in California and Oregon. They are found in all seas and at all depths, in fresh and brackish waters and on land (the Oniscidea). The approximately 10,000 species are more or less equally split between marine and terrestrial/freshwater environments. Several general guides to marine isopods of Pacific North and Middle America have been published. These include: Richardson (1905) (still a valuable reference, although obviously out of date), Schultz (1969), Brusca (1980) and Brusca et al. (2004, keys to common Gulf of California species), Brusca and Iverson (1985, the only summary treatment available for the tropical eastern Pacific region), and Wetzer et al. (1997). Kensley and Schotte (1989) is also a useful reference, especially for keys to higher taxa. Key citations to the original literature are provided in this section, and the history of Pacific isopodology (with a complete bibliography) can be found in Wetzer et al. (1997). The California marine isopod fauna (native and introduced) numbers approximately 200 named species in eight suborders. The keys treat species occurring primarily in the intertidal and supralittoral zones for all of the California and Oregon coasts, plus the commonly encountered fish parasites of the family Cymothoidae. In the sea, isopods compare in ecological importance to the related Amphipoda and Tanaidacea, notably as intermediate links in food chains. They typically predominate (numerically), along with tanaids, bivalves, and polychaetes, in soft bottom sediment samples from continental shelves. On some tropical coasts, isopods may constitute the majority of prey items consumed by rocky-shore fishes. In the Arctic region, they are one of the primary food items of gray whales. Intertidal isopods are predominantly benthic and cryptic, living under rocks, in crevices, empty shells and worm tubes, and among sessile and sedentary organisms, such as algae, sponges, hydroids, ectoprocts, mussels, urchins, barnacles, and ascidians. Some isopods burrow in natural substrates including mud, sand, soft rocks, and driftwood, and some burrowers, such as Limnoria (the gribbles) and Sphaeroma, do extensive damage to pilings and wooden boats. In the tropics, some species of Sphaeroma burrow into mangroves, weakening the prop roots and causing them to break more easily, which typically stimulates the growth of multiple new rootlets, leading to the classic stairstep structure of red mangrove prop roots (Perry and Brusca 1989). Several species are important scavengers on shore wrack or dead animals (e.g., Ligia, Tylos). Cirolanids, corallanids, and tridentellids are voracious carnivores, functioning both as predators and scavengers. Epicarideans are all parasites on other crustaceans, cymothoids are all parasites on fishes, and aegids are "temporary parasites" (or "micropredators") on fishes. Some invertebrate parasites, notably acanthocephalans, use isopods as intermediate hosts. Identification of isopods often requires dissection and microscopic examination of appendages and other structures us-

ing fine-pointed "jewelers" forceps under a binocular dissecting microscope. Dissected parts may be mounted on microscope slides in glycerin or a more permanent medium for observation under a compound microscope.

Key to the Suborders of Isopoda 1.

With five pairs of pereopods (thoracomere 2 entirely fused to cephalon, with its appendages modified as pylopods and functioning as a second pair of maxillipeds; thoracomere 8 reduced, without legs); adult males with mandibles grossly enlarged, forcepslike, projecting in front of head; adult females without mandibles Gnathiidea — With seven pairs of pereopods (thoracomere 2 not fused with cephalon, with one pair of maxillipeds and seven pairs of pereopods); males without projecting, forcepslike mandibles; females with mandibles 2 2. Adults obligate parasites on other crustaceans; bilateral symmetry reduced or lost in females; male a small bilaterally symmetrical symbiont living on the body of the female; antennae (antennae 2) vestigial; antennules (antennae 1) reduced to three or fewer articles; without maxillules (maxillae 1) Epicaridea — Not obligate parasites on other crustaceans; bilateral symmetry retained in both sexes; male not as above; antennae never vestigial; antennules variable; usually with maxillules 3 3. Body cylindrical or tubular in cross-section, but often appearing laterally compressed (amphipodlike) due to ventrally elongated abdominal pleura; with distinct row of filter setae along medial margin of maxilla (maxilla 2); penes located on coxae of male pereopod 7; apex of pleotelson curves dorsally; pleonite 5 elongate, markedly longer than any other pleonites (known only from the southern hemisphere and India) Phreatoicidea —

4. — 5.

— 6.

—

7.

Body variable, but not appearing laterally compressed as above; without row of filter setae along medial margin of maxilla; penes on sternum of male pereonite 7 (or on sternum of pleonite 1); apex of pleotelson does not curve dorsally; pleonite 5 rarely elongate (markedly longer than other pleonites only in Limnoriidae) 4 Terrestrial; antennules vestigial, minute; pleon always of five free pleonites, plus the pleotelson Oniscidea Aquatic; antennules normal, or if reduced not minute; pleon variable, with or without fused pleonites 5 Anus and articulating base of uropods positioned terminally (or subterminally) on pleotelson; uropods styliform 6 Anus and articulating base of uropods positioned at base of pleotelson; uropods flattened 8 With lateral coxal plates; antenna peduncle 5-articulate; maxillipeds without coupling setae; penes of male arise from articulation between pereonite 7 and pleonite 1; mandible without palp; pleopodal exopods broad and opercular to the thick tumescent endopods; female pleopod 1 present Calabozoidea Without lateral coxal plates (pereopodal coxae small); antenna peduncle 6-articulate; maxillipeds with or without coupling setae; penes of male arise on sternum of pereonite 7; mandible with palp; pleopods not as above; female pleopod 1 absent 7 Minute, usually < 3 mm long; long and slender, length about six times width; antenna peduncle without a scale; ISOPODA

505

antennule reduced, peduncle indistinguishable from flagellum; maxilliped without coupling setae on endite; female pleopod 2 biramous; male pleopod 2 endopod not geniculate; interstitial Microcerberidea — Rarely minute, usually > 4 mm long; body not elongate (length less than six times width); antenna peduncle usually with a scale; antennule rarely reduced, peduncle and flagellum distinct; maxilliped almost always with coupling setae on endite; female pleopod 2 uniramous; male pleopod 2 endopod large and geniculate; rarely interstitial Asellota 8. Body elongate, length usually more than six times width; uropodal exopod curving dorsally over pleotelson; coxae of maxillipeds fused to head (i.e., not freely articulating); mandible with lamina dentata in lieu of spine row and lacinia mobilis (lamina dentata, spine row and lacinia mobilis lacking in Paranthuridae); maxillule an elongate stylet with apical hooks or serrate margin; maxilla vestigial and fused with paragnath (or absent) Anthuridea

Four families of Anthuridea are currently recognized, distinguished primarily by characters of the mouthparts and pleon: Hyssuridae, Antheluridae, Anthuridae, Paranthuridae—the latter two occur in California waters.

—

—

Body not markedly elongate, length usually less than four times width; uropodal exopod not curving over pleotelson; coxae of maxillipeds not fused to head; mandible without lamina dentata; maxillule variable; maxilla well developed, never fused with paragnath 9 9. Uropods modified as a pair of ventral opercula covering the entire pleopodal chamber; males with penes arising on sternum of pleonite 1, or on articulation between pereonite 7 and pleonite 1; mandibular molar process a stout, flattened grinding structure Valvifera — Uropods not modified as ventral opercula covering pleopods, but positioned laterally; males with penes arising on sternum of pereonite 7; mandibular molar process usually a thin, bladelike, cutting structure, or absent (flattened only in Sphaeromatidae) Flabellifera

1.

Mouthparts styletlike, adapted for piercing and sucking, forming a conelike structure; mandible usually with smooth incisor, no molar process or lamina dentate; pleonites 1-6 usually with distinct sutures Paranthuridae 2 — Mouthparts adapted for cutting and chewing; mandible usually with molar process, lamina dentate and toothed incisor; all or most pleonites usually fused Anthuridae 4 2. Seven pairs of pereopods; pereonite seven not minute (plate 232D) Paranthura elegans Note: Paranthura japonica

(plate 252E) is a recently introduced

species found in fouling communities in bays and estuaries; see species list.

Six pairs of pereopods; pereonite seven minute, < 2 0 % length of pereonite 6 3 3. Pleon slightly longer than pereonites 6 + 7 (plate 232B) Colanthura bruscai — Pleon slightly shorter than pereonites 6 + 7 Califanthura squamosissima 4. Maxilliped of four articles (at least three free); no pigmentation pattern on pereonites (plate 232A) Cyathura munda — Maxilliped of five articles; pereonites 1-6 each with a rectangular outline of pigment, characteristically discontinuous on each segment, and segment 7 with posterior transverse pigmentation (plate 232C) Mesanthura occidentalis

ASELLOTA ANTHURIDEA

Key general references: Menzies 1951; Menzies and Barnard 1959; Negoescu and Wagele 1984; Poore 1984; Kensley and Schotte 1989; Cadien and Brusca 1993; Wetzer and Brusca 1997. Anthurideans are long, slender, subcylindrical isopods, with a length usually six to 15 times the width. The pereonites are mostly longer than wide (in contrast to most isopods, in which the reverse is true), and the dorsum often bears distinctive ridges, grooves, or chromatophore patterns. Distinct coxal plates are rarely evident. The pleonites are often fused in various combinations, and pleonite 6 usually has its line of fusion with the telson demarcated by a deep dorsal groove. The first antennae are short (except in males of some species), as are the second antennae. The mandibles lack a distinct lacinia mobilis or spine row, instead usually having a dentate lobe or plate (the "lamina dentata"). The outer ramus of the maxillule is a slender stylet with terminal spines; the maxillae are rudimentary. The maxillipeds are more or less fused to the head and lack coupling setae on the endites. Anthurideans are thought to be primarily carnivores, feeding on small invertebrates. Most inhabit littoral or shallow shelf environments, although some deep benthic (and some freshwater) species are also known. Many are known to be protogynous sequential hermaphrodites, and males have not yet been reported for several species. Fewer than 600 species of anthurideans have been named, but many remain undescribed. 506

ARTHROPODA

Key general references: Richardson 1905; Menzies 1951, 1952; Menzies and Barnard 1959; Kussakin 1988; George and Stromberg 1968; Wilson 1994, 1997; Wilson and Wagele 1994. Asellotans are easily recognized by the following combination of features: uropods terminal and styliform; pleonites 4-5, and often pleonite 3, fused to pleotelson, creating an enlarged terminal piece; pleonite 1, 2, or 3 forming an operculum over the more posterior pleopods; male pleopods 2 with specialized copulatory apparatus consisting of an enlarged protopod, a geniculate (kneelike) endopod, and typically a well-muscled exopod; pereonites without coxal plates. The Asellota are one of the most diverse groups of isopods, comprising about 25% of all marine species. They are most successful and diverse in the deep sea. Thirty-eight species of Asellota, in nine families, are known from California waters; 18 (in four families) occur in California's intertidal region. 1.

Eyes on lateral, peduncle-like projections; terminal article (dactylus) of pereopods 2-7 with two claws 2 — Eyes (if present) dorsolateral on head, not pedunculate; dactylus of pereopods 2-7 with two or three claws 3 2. Pleotelson somewhat pear-shaped; uropods greatly reduced, barely visible dorsally Munnidae 4 — Pleotelson broad, shieldlike; uropods short but clearly visible in dorsal view Santiidae Note: Only one species of this family, Santia hirsuta (plate 235A) is known from California.

A1

E

Cyathura munda

C a ecianiropsis psammophila

B

Colanthura bruscai

F

Caecijaera horvathi

C

Mesanthura occidentalis

G1

D

Paranthura elegans

Janiralata daw's/

PLATE 232 Isopoda. Anthuridea: A, Cyathura munda, Al, whole animal, A2, detail of the head in lateral view; B, Colanthura bruscai, pleon; C, Mesanthura occidentalis; D, Paranthura elegans; E-G, Asellota: E, Caecianiropsis psammophila; F, Caecijaera horvathi; G, Janiralata davisi, G l , whole animal, G2, maxilliped (after Menzies 1951A; Menzies and Petit 1956; Menzies and Barnard 1959; Poore 1984; Wetzer and Brusca 1997).

3.

Both pairs of antennae small, flagella lacking or rudimentary; antenna articles of peduncle dilated; uropods short, inserted in subterminal excavations of pleotelson, not extending much beyond its posterior margin, if at all Joeropsididae 7 — Antennae long with multiarticulate flagella (caution: often broken off); antenna articles of peduncle not dilated; uropods well developed Janiridae 8 Note: Iais californica

(plate 252A), a tiny commensal species that

lives on the underside of its host isopod Sphaeroma

quoianum,

is

often c o m m o n and may become disassociated from its host in samples.

4.

— 5.

—

6.

—

7. — 8. — 9.

—

10.

—

11. —

12. — 13.

—

508

Uropods minute, without serrate distal margin; male first pleopods with apices tapering to tip (plate 235E) Uromunna ubiquita Uropods not minute, with serrate distal margin; male first pleopods with apices laterally expanded 5 Uropods without large acute spinelike protuberances on distal margin; dentate suburopodal shelf visible in dorsal view (plate 235C) Munna halei Uropods with large acute spinelike protuberances on distal margin; no dentate suburopodal shelf visible in dorsal view 6 Pleotelson broad (length about 0.8 times width); body stout (length about 1.7 times width) (plate 235D) Munna stephenseni Pleotelson narrow (length about 1.6 times width); body relatively elongate (length about 2.6 times width) (plate 235B) Munna chromatocephala Pleotelson with five to seven spines on each lateral border (plate 234D) Joeropsis dubia dubia Pleotelson with three spines on each lateral border (plate 234E) Joeropsis dubia paucispinis Eyes lacking 9 Eyes present 10 Body not elongate, length less than three times width; not a minute interstitial species (plate 232F) Caecijaera horvathi Body elongate, length about six times width; minute ( < 2 mm long) interstitial species (plate 232E) Caecianiropsis psammophila Propodus (next to last article) of first pereopod with conspicuous serrated margin on proximal third of ventral margin; basal three articles of maxillipedal palp as wide as endite Janiralata 11 Propodus of first pereopod with proximal third of inferior border smooth; maxillipedal palp with second and third articles much wider than endite Ianiropsis 12 Pleotelson with distinct, medially curved, spinelike posterolateral angles (plate 233A) Janiralata occidentalis Pleotelson with posterolateral angles evenly curved, lacking distinct angles or spinelike processes (plate 232G) Janiralata davisi Lateral borders of pleotelson with spinelike serrations 13 Lateral borders of pleotelson spineless (fine setae may be present) 15 Pleotelson with four to seven spinelike serrations on each side; lateral apices of first male pleopod not directed abruptly posteriorly (plate 233B) Ianiropsis analoga Pleotelson with two to three spinelike serrations on each side; lateral apices of first male pleopod directed abruptly posteriorly 14 ARTHROPODA

14. Pleotelson with two spinelike serrations on each side (plate 233D) Ianiropsis epilittoralis — Pleotelson with three spinelike serrations on each side (plate 234C) Ianiropsis tridens 15. Uropods half or less length of pleotelson 16 — Uropods considerably exceeding half pleotelson length . . . 17 16. Pleotelson with distinct posterolateral angles lateral to uropod insertions (plate 233C) Ianiropsis derjugini — Pleotelson lacking posterolateral angles lateral to uropod insertions (plate 234A) Ianiropsis minuta 17. Uropods exceeding length of pleotelson; lateral apices of first male pleopod bifurcate (plate 234B) Ianiropsis montereyensis — Uropods not exceeding pleotelson length; lateral apices of first male pleopod not bifurcate (plate 233E) Ianiropsis kincaidi EPICARIDEA

Key general references: Richardson 1905; Shiino 1964; Markham 1974, 1977. Epicarideans are ectoparasites of other crustaceans (malacostracans, ostracodes, copepods, and cirripeds). Females are usually greatly distorted, being little more than an egg sac in some species. Males are symmetrical but minute and live on the body of the female. Eyes are usually present in males, but reduced or absent in females. The antennules (first antennae) are very reduced, usually of only two or three articles; a 3articulate peduncle is generally apparent only in juvenile stages. The antennae (second antennae) are vestigial in adults. The mouthparts are reduced, forming a suctorial cone with a pair of piercing stylets formed from the mandibles; a mandibular palp is absent. The maxillules and maxillae are reduced or absent. There are no good references for the Epicaridea as a whole, although Strómberg (1971) reviews the embryology (including that of several California species), and Jay (1989) cites several other papers containing general information. The California fauna is poorly known, both taxonomically and biologically. About 700 species of epicarideans have been described worldwide in 11 families. Three of these families are represented in California waters by 16 species, six of which occur in the intertidal region and are included in the key. Species in the family Bopyridae retain complete, or nearly complete, body segmentation, and usually have six or seven pereopods on one side but far fewer on the other. The sides of the pleonites are often produced as large lateral plates (epimeres) that resemble pleopods. Adult bopyrids are parasites either on the abdomen or in the branchial chamber of decapod crustaceans. In branchial parasites, the female attaches ventrally to the host's branchiostegite, inducing a bulge in the host's carapace. Males are much smaller and usually found on the ventral side of the pleon of the female isopod. Females brood many small eggs in an oóstegial brood pouch that hatch as a free-swimming epicaridium stage. The epicaridium attaches to an intermediate host, a calanoid copepod. Once on the copepod, the isopod molts into a microniscus stage and then into the cryptoniscus stage. The cryptoniscus detaches from the copepod, is free-swimming, and eventually attaches to the definitive host. All species are probably sequential hermaphrodites. About 500 species have been described worldwide.

A

Janiralata

D laniropsis

occidentalis

B1

laniropsis

epiiittoralis

E 1 laniropsis

analoga

C

laniropsis

derjugini

kincaidi

Isopoda. Asellota: A, Janiralata occidentalis; B, laniropsis analoga, Bl, whole animal, B2, male first pleopods; C, laniropsis derjugini; D, laniropsis epiiittoralis; E, laniropsis kincaidi, El, whole animal, E2, male first pleopods, E3, detail of the distal part of the male first pleopods (after Menzies 1951A, 1952). PLATE 2 3 3

laniropsis

tridens

D 1 Joeropsis dubia dubia

E

Joeropsis dubia

paucispinis

Isopoda. Asellota: A, laniropsis minuta, Al, whole animal, A2, maxilliped; B, laniropsis montereyensis, Bl, whole animal, B2, male first pleopods, B3, detail of the distal part of the male first pleopods; C, laniropsis tridens; D, Joeropsis dubia dubia, Dl, whole animal, D2, detail of the lateral margin of the pleotelson; E, /oeropsis dubia paucispinis, detail of pleotelson (after Menzies 1951A, 1952). PLATE 2 3 4

A

Santia hirsuta

B1

Munna

chromatocephala

C2

Munna halei

PLATE 235 Isopoda. Asellota: A, Santia hirsuta; B, Munna chromatocephala, Bl, whole animal, B2, uropod, B3, male first pleopods; C, Munna halei, CI, uropod, C2, whole animal; D, Munna stephenseni, Dl, whole animal, D2, uropod; E, Uromunna ubiquita, El, whole animal, E2, male first pleopods, E3, uropod (after Menzies 1951A, 1952).

Species in the family Entoniscidae are internal parasites of crabs and shrimps. Females are usually modified beyond recognition, with the marsupium grossly inflated and in some cases extending dorsally over the head. Males and mancas, however, are less distorted with a flattened body, complete segmentation, and pereopods. Mature females are surrounded by a host response sheath, with an external communication to the environment via a small hole or furrow in the carapace of the hosts. Most are parasitic castrators, and in some cases entoniscids can feminize male hosts. Good references on the biology of this family include: Giard (1887), Giard and Bonnier (1887), Veillet (1945), and Reinhard (1956). The following key is based mainly on adult females. 1.

Female without segmentation, simply an egg sac; antennae and mouthparts absent Hemioniscidae Note: One California species, Hemioniscus balani, parasitic in barnacles of the genera Balanus and

—

2.

Chthamalus.

With more than 3,000 described species, the Flabellifera is the second largest isopod suborder, represented in California by seven families, three of which (Anuropidae, Excorallanidae, Serolidae) have not been reported north of Point Conception. Because of the great diversity of this suborder, it is more convenient to key the families first, and then the species in each family.

Note: One California species, Portunion conformis,

1.

plate 237A, in

—

Female distinctly segmented; pereonites not expanded laterally into thin plates; mouthparts rudimentary; pereopods prehensile, seven present on one side, but all except first may be absent on the other side; parasites of branchial cavity or on pleopods of decapod crustaceans Bopyridae 3 3. Pleon with lateral plates (epimeres or pleural lamellae) elongate, those of female fringed with long, branched processes, those of male without such digitations; in branchial cavity of ghost shrimps of the genus Neotrypaea (plate 23 6B) lone cornuta — Pleon in both sexes with pleural lamellae rudimentary or absent (caution: do not confuse lateral biramous pleopods with pleural lamellae) 4 4. Female pleopods not prominent, relatively short, not noticeable in dorsal view; in branchial chamber of the snapping shrimp Synalpheus lockingtoni and Alpheopsis equidactylus (plate 236A) Bopyriscus calmani — Female pleopods prominent, long, visible in dorsal view 5 5. Pleopods biramous, with narrow branches arising from a peduncle or stem, extending laterally from narrow pleon; among pleopods of the mud shrimp Upogebia pugettensis (plate 236D) Phyllodurus abdominalis Note: Compare to the recently recognized Orthione griffensis (plate 252B), now abundant along the coast in the mud shrimp Upogebia (see species list).

512

Key general references: Stimpson 1857; Richardson 1899,1905, 1909; Holmes and Gay 1909; Hatch 1947; Menzies 1962; Menzies and Barnard 1959; Schultz 1969; Brusca 1981, 1989; Bruce et al. 1982; Bruce 1986, 1990, 1993; Harrison and Ellis 1991; Brusca and Wilson 1991; Brusca et al. 1995; Wetzer and Brusca 1997. Flabellifera comprise a large paraphyletic assemblage of families defined more by the absence of certain features than by any unique attributes. The eyes are usually large and well-developed but are reduced or absent in cave and deep-sea species. The mouthparts are usually robust, adapted for cutting and grinding, or occasionally for piercing. Both the maxillules and maxillae are biramous. The pereopods are usually subsimilar, but in Serolidae, and some Cirolanidae and Sphaeromatidae, the anterior pairs may be subchelate/prehensile. The pleon comprises one to five free segments, plus the pleotelson. The uropods arise laterally, usually forming a distinct tailfan with the pleotelson.

Female with distinct or weak segmentation; not simply an egg sac; antennae and mouthparts present, although may be greatly reduced 2 Body of female without indication ofrigidexoskeleton, seemingly undifferentiated, but body divisions and segmentation present; pereonites expanded laterally into thin plates; maxillipeds are the only recognizable mouthparts; pereopods stubby or absent; endoparasites in body cavity of decapod crustaceans Entoniscidae body cavity of the crab Hemigrapsus spp.

—

FLABELLIFERA

Pleopods biramous, lanceolate, not arising from a peduncle, extending posteriorly from pleon; in branchial chamber of the pelagic galatheid crab Pleuroncodes planipes (plate 236C) Munidion pleuroncodis ARTHROPODA

Key to Families Uropods greatly reduced, with very small, often clawlike exopod; body less than 4 mm long; burrowing in wood or algal holdfasts Limnoriidae — Uropods not greatly reduced; body rarely < 3 mm long; rarely burrowing in wood or algae (a few species of Sphaeromatidae burrow into coastal wood structures, but they are large animals) 2 2. Pleon composed of three or fewer dorsally visible free pleonites, plus the pleotelson 3 — Pleon composed of four or five dorsally visible free pleonites, plus the pleotelson 4 3. Pleon composed of three dorsally visible free (complete) pleonites, plus pleotelson; cephalon fused medially with first pereonite; body strongly depressed and expanded laterally; pereonite 7 tergite incomplete or absent; antennae set very close together; frontal lamina reduced to a small triangular plate visible only by pushing aside antennal bases; pleopods 1-3 small and natatory, basis elongated; pleopods 4-5 large, broadly ovate, suboperculiform Serolidae —

Pleon composed of one or two dorsally visible free (complete) pleonites plus pleotelson; cephalon not fused with first pereonite (except in Ancinus and Bathycopea); body convex dorsally, not strongly depressed; pereonite 7 tergite complete; antennae not set close together; frontal lamina large and distinct; pleopods subequal, of modest size, basis not elongated; pleopods 4-5 ovate but not operculiform Sphaeromatidae 4. All pereopods prehensile (dactyli longer than propodi); antennae reduced, without clear distinction between peduncle and flagellum; maxillipedal palp two-articulate Cymothoidae — At least pereopods 4-7 ambulatory (dactyli not longer than propodi); antennae not as above, with clear distinction between peduncle and flagellum; maxillipedal palp of two to five articles 5

? A

Bobyriscus calmarti

B

lone cornuta

? ^ C

D

Munidion pleuroncodis

Phyllodurus abdominalis

PLATE 236 Isopoda. Epicaridea: A, Bopyriscus caimani; B, Ione cornuta; C, Munidion pleuroncodis; Richardson 1905; Markham 1975; Sassaman et al. 1984).

5.

—

6.

Pereopods 1 - 3 strongly prehensile (dactyli longer than propodi); maxillipeds and maxillules and maxillae with stout, curved, apical setae; lacinia and molar process of mandible reduced or absent; maxilla reduced to a single slender stylet Aegidae Pereopods 1-3 weakly prehensile at best; maxillipeds without stout, curved setae; mandible with or without lacinia and molar process; maxilla not a slender stylet 6 Mandible with distinct lacinia and large bladelike molar process; mandibular incisor generally broad, three-dentate; maxillule lateral (outer) lobe often with several (10-14) stout spines, never styletlike or falcate; maxilla well-developed; pereopods 1 - 3 not prehensile (dactyli not longer than propodi) Cirolanidae

—

3

D, Phyllodurus abdominalis

(after

Mandible with lacinia and molar process greatly reduced, vestigial, or absent; mandibular incisor narrow; maxillule lateral (outer) lobe simple and falcate; maxilla reduced; pereopods 1-3 weakly prehensile or ambulatory Corallanidae

AEGIDAE Aegids are cirolanidlike, with the smooth dorsal surface either vaulted or flattened. The maxillipedal palp is of two, three, or five articles, the terminal ones with stout acute setae ("spines"). The mandible is elongate, with a narrow incisor and reduced or vestigial molar process. Coxal plates of pereonites 2 - 6 are ISOPODA

513

large and distinct. Pereopods 1 - 3 are prehensile (i.e., the dactyli are as long or longer than the propodi and strongly curved); pereopods 4 - 7 are ambulatory. The family Aegidae comprises six genera. All are temporary parasites on marine fishes. Adults engorge themselves with food (presumably blood) from their hosts, then dislodge and sit on the bottom to digest their meal. Nine species, in two genera, have been reported from Pacific North America, six of which inhabit California waters. However, only a single species occurs in the intertidal zone, Rocinela signata (plate 23 7B).

CIROLANIDAE Cirolanids have sleek symmetrical bodies, two to 6.5 times longer than wide, with well-developed coxal plates on pereonites 2 - 7 . The mandible has a broad tridentate incisor and a spinose bladelike molar process. The maxillipedal palp typically is five-articulate, and the articles never have hooked or curved setae or spines. All pereopods are ambulatory, although legs 1 - 3 tend towards a grasping form, with well-developed dactyli. The uropods form a tail fan with the pleotelson. Cirolanids are all carnivores, either predatory or scavenging. A number of species are known to attack sick or weakened fish, or fish trapped in fishing nets, and some are capable of stripping a fish to the bones in a matter of hours. Stepien and Brusca (1985, cited in the species list at Cirolana diminuta) review this phenomenon and describe the behavior from Catalina Island. This large family includes 55 genera. Eight species (in six genera) are known from California waters, six of which occur intertidally. 1.

Antennule peduncle article 1 longer than articles 2 or 3; antennule article 2 arising at right angle to article 1; maxilliped endite barely reaching (or extending barely beyond) first palp article; maxilliped endite without coupling setae; antennae long, extending beyond pereonite 7; lateral margins of pleonite 5 not encompassed by pleonite 4 Eurydice

5.

Pleotelson broadly rounded and crenulate posteriorly; antennule peduncle with articles 2 and 3 subequal in length (plate 238C) Excirolana linguifrons — Pleotelson obtusely rounded and acuminate posteriorly; antennule peduncle with article 3 longer than article 2 (plate 238D) Excirolana chiltoni

CORALLANIDAE Corallanids resemble cirolanids but are even more highly modified as predators. Characteristic features of the family include very large eyes, absence of an endite on the maxilliped, large falcate apical setae on the lateral lobes of the maxillules (often tended by subapical accessory setae), vestigial uniramous maxillae, and frequently a heavily ornamented dorsum beset with setae, spines, tubercles or carinae (especially in males). There are always five free pleonites. The first three pairs of pereopods are often grasping (dactylus as long or longer than the propodus). Corallanidae is a small group, with six genera and about 70 species. The family is largely confined to tropical and subtropical shallow-water marine habitats, although some brackish and freshwater species are known. Many species are common on coral reefs (hence the name). Because they are often found attached to large prey, such as fishes, rays, turtles, or shrimps, they are sometimes called parasites, but they are actually predators. Two species in the large New World genus Excorallana occur in our intertidal region. Both can be collected using night lights over rocky bottoms. E. tricornis occidentalis, at least in Costa Rican waters, has nocturnal mass-migrations into the water column, perhaps preying on other microcrustaceans (Guzman et al. 1988, Bull. Mar. Sci. 43: 77-87). Two species belonging to the closely related family Tridentellidae are easily mistaken for corallanids; Tridentella glutacantha and T. quinicomis both occur in shallow subtidal rocky regions of California's offshore islands (see Delaney and Brusca 1985, J. Crust. Biol. 5: 728-742; Wetzer and Brusca 1997). 1.

Note: One species in California: E. caudata, plate 238B.

—

Antennule peduncle article 2 or 3 longest; antennule article 2 not arising at right angle to article 1; maxilliped endite extending well beyond first palp article, usually to distal margin of second palp article; maxilliped endite with coupling setae; antennae length variable; lateral margins of pleonite 5 variable 2

2.

Antennule peduncle article 2 or 3 longest; clypeus projecting ventrally 3 — Antennule peduncle article 3 always longer than 1 or 2; clypeus short, broad, flat, and sessile, not projecting ventrally Cirolana 4 3. Prominent rostral process, apically spatulate, separating antennules Excirolana 5 — Without prominent rostral process Eurylana Note: One species, E. arcuata, plate 238A.

4.

—

514

Uropodal rami without apical notch; rostrum meets but does not overlap frontal lamina; antennule peduncle articles 1 and 2 not fused (plate 23 7D) Cirolana harfordi Both uropodal rami with apical notch; rostrum overlaps frontal lamina; antennule peduncle articles 1 and 2 fused (plate 23 7C) Cirolana diminuta ARTHROPODA

—

Head of male ornamented with three tubercles; pereonites 4-7 with row of tubercles on posterior margin; pleotelson not densely covered by setae (plate 238E) Excorallana tricornis occidentalis Head of male not ornamented with tubercles; pereonites 4 - 7 without row of tubercles on posterior margin; pleotelson densely covered by setae (plate 238F) Excorallana truncata

CYMOTHOIDAE Cymothoids resemble cirolanids and corallanids but are modified for a parasitic lifestyle—all are fish parasites. The definitive features of the family are that all seven pairs of pereopods are prehensile (with long, strongly recurved dactyli as long as or longer than the propodi) and the maxillipedal endite lacks coupling setae. Overall, the mouth appendages are highly modified for the parasitic lifestyle. The maxillipeds are reduced to small palps of two or three articles, the maxillules are modified as slender uniarticulate stylets lying adjacent to one another to facilitate transfer the host's blood to the mouth, and the maxillae are reduced to small bilobed appendages. All of these mouth appendages bear stout, curved, terminal, or subterminal spinelike setae that serve to hold the buccal region strongly affixed to the flesh of the host fish. All cymothoid species are probably

A

Portunion

conformis

B

Rocinela signata

PLATE 237 Isopoda. Epicaridea: A, Portunion conformis; B-D, Flabellifera: B, Rocinela signata; C, Cirolana diminuta, CI, postmanca, C2, adult male; D, Cirolana harfordi, DI, male, D2, a different male morphotype (after Richardson 1905; after Schiòdte and Meinert; Muscatine 1956; Brusca et al. 1995).

protandric hermaphrodites, first maturing into males and later transforming into females (unless retained in the male stage by the presence of a female already in place on the host fish). Cymothoids are parasites on marine or freshwater fishes, and they are c o m m o n l y found o n sport and commercial fishes, such as mullet, jacks, groupers, flounder, perch, anchovies, and

m a n y others. Although they are n o t intertidal species, they are often seen by sport fishers and researchers, Most species attach either epidermally, in t h e gill chamber, or in the buccal region. However, species in some genera actually burrow b e n e a t h the skin where they live in a pocket or capsule formed within t h e musculature of the host (e.g., Artystone, Riggia, Ichthyoxenus, ISOPODA

515

D

Excirolana

chiltoni

E1

Excorallana tricomis occidentalis

Excorallana

truncata

PLATE 238 Isopoda. Flabellifera: A, Eurylana arcuata; B, Eurydice caudata; C, Excirolana linguifrons, cephalon, pleotelson; D, Excirolana

chiltoni;

E, Excorallana tricomis occidentalis, El, whole animal in dorsal view, E2, whole animal in lateral view; F, Excorallana truncata (after Richardson 1899, 1905, after Hansen; Bruce and Jones 1981; Jansen 1981; Delaney 1982, 1984; Brusca et al. 1995).

Ourozeuktes). Aside from some localized damage, in most cases

Cymothoa exigua, a species that sucks so much blood from its

cymothoids do not appear to create a great hardship for their

host fish's tongue that the tongue atrophies and is destroyed,

hosts. Host-parasite specificity varies between genera, being

but the isopod remains attached to the remaining tongue stub

high in some (e.g., Cymothoa, Idusa, Mothocya) and low in oth-

where the host uses it as a replacement tongue for food manip-

ers (e.g., Anilocra, Nerocila, Livoneca, Elthusa). The only known

ulation (Brusca and Gilligan 1983). An extensive radiation of cy-

case of a parasite functionally replacing a host organ occurs in

mothoid genera and species has taken place in the freshwater

516

ARTHROPODA

rivers of the Amazon Basin, and to a lesser extent central Africa and southeast Asia. Forty-three nominate genera and more than 400 species of cymothoids exist, but the taxonomy of this family is very poorly understood. Seven species, in five genera, are known from California waters. 1.

Posterior margin of cephalon trisinuate; pleon not immersed in pereon 2 — Posterior margin of cephalon not trisinuate; pleon partially immersed in pereon 3 2. Cephalon not immersed in pereonite 1; uropods generally extend beyond posterior border of pleotelson, and clearly visible in dorsal view Nerocila Note: One species in California, N. acuminata, plate 240C.

—

Cephalon somewhat immersed in pereonite 1; uropods barely or not extending beyond posterior border of pleotelson and typically held concealed under the pleotelson (not visible in dorsal view) Enispa Note: One species in California, E. convexa, plate 239C.

3.

Basal articles of antennules not expanded and touching 4 — Basal articles of antennules expanded and touching or nearly touching Ceratothoa 5 4. Antennule longer than antenna Mothocya Note: One species in California, M. rosea (plate 239D).

— Antennule shorter than antenna Elthusa 6 5. Pereopods 4-7 not carinate; posterior margin of pleonite 5 smooth, not trisinuate; labrum with free margin wavy, with wide medial notch (plate 239B) Ceratothoa gilberti — Pereopods 4-7 carinate; posterior margin of pleonite 5 trisinuate (except in occasional males); labrum with free margin broadly excavate, without medial notch (plate 239A) Ceratothoa gaudichaudii 6. Pleotelson in adult female nearly twice as broad as long; eyes medium-size and widely separated; anterior border of head broadly rounded or truncate; antenna of 10-11 articles; juveniles with diffuse dark pigmentation on uropodal exopod and anterolateral areas of pleotelson (plate 240B) Elthusa vulgaris — Pleotelson in adult female about as broad as long; eyes large, close-set medially; anterior border of head strongly produced, apically blunt; antenna of eight to nine articles; juveniles with pigment granules concentrated in melanophores, lacking distinct color pattern (plate 240A) Elthusa califomica

California waters, one of which is an algal borer (L. algarum) and can be most easily found in the holdfasts of large brown algae such as Macrocystis, Egregia, Laminaria, Postelsia, and Nereocystis. The others infest marine woods, such as pier pilings, docks, boats, driftwood, etc. 1.

Incisor process of mandibles simple, lacking rasp or file; algal holdfast borers (plate 240D) Limnoria algarum — Incisor of right mandible with filelike ridges, that of left with rasplike sclerotized plates; wood borers 2 2. Dorsal surface of pleotelson with a median Y-shaped keel at base; lateral and posterior borders of pleotelson smooth (plate 24IB) Limnoria lignorum — Dorsal surface of pleotelson with symmetrically arranged tubercles anteriorly; lateral and posterior borders of pleotelson smooth or tuberculate 3 3. Four anterior tubercles on pleotelson; posterior and lateral margins of pleotelson not tuberculate (plate 241A) Limnoria quadripunctata — Three anterior tubercles on pleotelson; posterior and lateral borders of pleotelson tuberculate (plate 241C) Limnoria tripunctata SEROLIDAE Serolids are quickly recognized by their broadly ovate, very thin, flattened bodies with broadly expanded coxal plates. The head is deeply immersed in the pereon. Some species are quite large (to 80 mm). The mandible lacks a molar process, and the maxilliped lacks coupling setae on the endite. Pereonite 1 is fused dorsally with the cephalon and encompasses it laterally. Pereopod 1 of both sexes and pereopod 2 of most adult males are subchelate, with the dactylus folding back upon an inflated propodus. Serolidae is a cold-water family, primarily distributed in the southern hemisphere. Deep-sea species often have reduced eyes or are blind. They are carnivores, scavengers, or omnivores. Heteroserolis carinata, which ranges form southern California to the Gulf of California, is the only California species (plate 241D). It burrows just under the sediment surface, from the low intertidal zone to about 100 m depth.

SPHAEROMATIDAE

Limnoriids are a cosmopolitan family of wood and algae-boring isopods (the marine gribbles), distinguished by their minute size (4 mm or less in length), wood/algae boring habits, and several unique anatomical features: the head is set off from the pereon and freely rotates, the mandible incisor process lacks teeth and instead forms a projecting rasp-and-file device used to work wood, the mandibular molar process is absent, the basis of the maxillipeds is elongated and waisted, and the uropods are greatly reduced, with a minute often clawlike exopod.

Sphaeromatid isopods can be recognized by their compact, convex bodies, usually capable of rolling into a ball (conglobation); by their pleon which is consolidated into two or three divisions; and by their lateral uropods in which the endopod is rigidly fused to the basal article and the exopod (if present) is movable. In their ability to conglobate, sphaeromatids resemble certain terrestrial isopods called "pillbugs"—a striking example of parallel evolution. Identification of genera and species is often difficult because of marked sexual dimorphism. Hence it is advisable, when making determinations, to have a representative sample including adults of both sexes. Twenty-five species of sphaeromatids, in 10 genera, have been described from California waters, 12 of which occur intertidally and are included in the following key. Some workers place Ancinus, Bathycopea, and Tecticeps in separate families, while others recognize various subfamilies. However, the relationships of the sphaeromatid genera have yet to be analyzed phylogenetically and such taxonomic opinions are based largely on intuition.

More than 70 species, in three genera (Limnoria, Lynseia, Paralimnoria), have been described. Four species are known from

Sphaeromatids are primitive flabelliferans with herbivorous habits. The molar process of the mandible is a broad, ovate

LIMNORIIDAE

ISOPODA

517

A

Ceratothoa

gaudichaudii

C 1 Enispa convexa

B

D3

Ceratothoa

Mothocya

gilberti

rosea

PLATE 2 3 9 Isopoda. Flabellifera: A, Ceratothoa gaudichaudii; B, Ceratothoa gilberti; C, Enispa convexa, C I , whole a n i m a l in dorsal view, C 2 , w h o l e animal in lateral view; D, Mothocya rosea, D l , a n t e n n a 1, D2, a n t e n n a 2, D3, whole animal (after Brusca 1 9 8 1 ; Bruce 1 9 8 6 ) .

grinding structure used to chew algae or other plant material. Smaller species probably feed by scraping diatoms and detritus off sand grains. Paracerceis sculpta, a subtropical species that finds its way north to southern California, is unique in that it is possesses three distinct male morphs (designated alpha, beta, and gamma males). Alpha males are large, with a distinct mor518

ARTHROPODA

phology typical of other members of the genus; beta males mimic females; gamma males mimic juveniles. The advantage of the beta and gamma males is thought to be in allowing them to sneak into the harem, protected by a single alpha male, to inseminate females (see Shuster et al. citations under Paracerceis in species list). In the Sea of Cortez, harems most

A

Elthusa

californica

B

Elthusa

vulgaris

C 1 Nerocila

D

acuminata

Limnoria

algarum

PLATE 240 Isopoda. Flabellifera: A, Elthusa californica; B, Elthusa vulgaris; C, Nerocila acuminata, CI, acuminata form, female, C2, acuminata form, male, C3, aster form, female; D, Limnoria algarum (after Menzies 1957; Brusca 1981).

c o m m o n l y f o r m in calcareous sponges; t h e natural history of

Invertebrates of California) present a color photo. See further notes

California p o p u l a t i o n s of P. sculpta has n o t b e e n studied.

in species list.

Note: A sometimes common sandy beach and surf zone isopod is

1.

P e r e o p o d 1 prehensile; u r o p o d lacking e x o p o d (plate 2 4 I E ) Ancinus

the distinctive Tecticeps convexus, with a broad oval, flattened body, about 15 mm long. Morris, Abbott, and Haderlie (1980, Intertidal

Note: One species in California, A. granulatus. ISOPODA

519

B

A1

Limnoria

D

Limnoria lignorum

quadripunctata

Heteroserolis

carinata

C

Limnoria tripunctata

E

Ancinus

qranulatus

PLATE 241 Isopoda. Flabellifera: A, Limnoria quadripunctata, Al, whole animal, A2, mandible; B, Limnoria lignorum, pleotelson; C, Limnoria tripunctata, pleotelson; D, Heteroserolis carinata-, E, Ancinus granulatus (after Menzies 1957; Trask 1970; Wetzer and Brusca 1997).

— Pereopod 1 ambulatory; uropod with exopod 2 2. Pleopods 4 and 5 lacking pleats Gnorimosphaeroma 3 — Pleopods 4 and 5 with pleats on endopods 4 3. First article of peduncles of right and left antennae touching each other (plate 243B) Gnorimosphaeroma noblei — First article of peduncles of right and left antennae not touching each other (plate 243C) Gnorimosphaeroma oregonense Note: Two additional species of Gnorimosphaeroma occur in our re-

has a narrow, upturned granulated pleotelson; there are two tubercles on pleonite 5, and four tubercles on the anterior portion of the pleotelson; the uropods are smooth and rounded (A. Cohen, J. T. Carlton, and J. Chapman, personal communication).

13. Pleotelson and uropods relatively small; posterior margin of pleotelson rounded (plate 244A) Exosphaeroma inornata — Pleotelson and uropods very large; posterior margin of pleotelson acuminate (plate 243D) Exosphaeroma amplicauda

gion: G. insulare, common intertidally in some areas, such as estuarine reaches of San Francisco Bay, and G. rayi, intertidal in Tomales Bay. In G. insulare (plate 252C1), only the first two pleonites of second (first visible) pleonal division form its lateral margin; in G. oregonense (plate 243C), all three pleonites comprising the second (first visible) pleonal division reach and form its lateral margin. In G. rayi (plate 2S2C2), the basis (first free joint) of pereopod 1 has a tuft of seven to nine setae, and the sternal crest of the ischium (second free joint) has two to three setae; in G. oregonense (plate 2S2C3) the basis of pereopod 1 has only 1 seta, and the ischium has rows of long setae.

4. Pleopod 4 and 5 with branchial pleats on both rami 5 — Pleopod 4 and 5 with branchial pleats on endopods only 6 5. Uropods lamellar in females, endopod reduced and exopod elongate-cylindrical in males; ovigerous females with four pairs of oostegites Paracerceis 7 — Uropods lamellar in both sexes; ovigerous females lacking oostegites 8 6. Uropodal exopod with serrate outer margin Sphaeroma 12 — Uropodal exopod with smooth or lightly crenulate outer margin Exosphaeroma 13 7. Male uropods with spines; female pleotelson stout, with four tubercles (plate 242F) Paracerceis cordata — Male uropods without spines; female pleotelson elongate, with three tubercles (plate 243A) Paracerceis sculpta 8. Frontal margin of head produced as a quadrangular process; first two articles of antennules dilated (plate 242E) Dynamenella dilatata — Frontal margin of head not produced; articles of antennules not dilated 9 9. Uropod rami with crenulate margin (at least in males) (plate 242A) Paradella dianae — Uropod rami without crenulate margin 10 10. Pleotelson with many tubercles (plate 242B) Dynamenella sheareri — Pleotelson without tubercles 11 11. Pleotelson with many ridges; uropod rami of similar length (plate 242C) Dynamenella benedicti — Pleotelson smooth; uropod with exopod (outer ramus) longer than endopod (inner ramus) (plate 242D) Dynamenella glabra 12. Pleotelson with many rows of tubercles, posterior extremity without prominent transverse elevation (plate 244B) Sphaeroma walkeri — Pleotelson with two rows of tubercules, posterior extremity with prominent transverse elevation (plate 244C) Sphaeroma quoianum Note: Pseudosphaeroma

campbellenis

is a recently introduced,

small New Zealand sphaeromatid that may be confused with S. walkeri and S. quoianum. Often light green in color, P. campbellensis

GNATHIIDEA Key general references: Monod 1926; Menzies and Barnard 1959; Menzies 1962; Schultz 1966; Brusca 1989; Cohen and Poore 1994; Wetzer and Brusca 1997. Gnathiids are quickly recognized by the presence of only six free pereonites and five pairs of pereopods, the first pereonite being fused to the cephalon (with its appendages functioning as a second pair of maxillipeds, or pylopods) and the seventh pereonite being greatly reduced and without legs. The pleon is abruptly narrower than the pereon, always with five free pleonites (plus the pleotelson). Adult males have broad flattened heads with grossly enlarged mandibles that project in the front. Females have small narrow heads and no mandibles at all. In both sexes the eyes are well developed and frequently on short processes (ocular lobes). The embryos are incubated internally, distending the entire body cavity and displacing the internal organs. Gnathiids occur from the littoral zone to the deep sea, and they are often numerous in shallow soft-bottom benthic samples. Adults probably do not feed and are often found in association with sponges. Adults are benthic, but the juvenile stage, called "praniza," is a temporary parasite on marine fishes. Praniza are good swimmers, whereas adults have only limited swimming capabilities. Females and juveniles cannot be identified, and the taxonomy of this suborder is based entirely on males. About 10 genera and 125 species, in a single family (Gnathiidae), have been described worldwide. Eight species have been found in California waters, all but G. steveni (plate 244D) being subtidal. Only two species have been reported from north of Point Conception, Gnathia tridens and Caecognathia crenulatifrons, the latter in subtidal waters in Monterey Bay. For a key to all known California species see Wetzer and Brusca (1997).

MICROCERBERIDEA Key general reference: Wagele et al. 1995. Being tiny ( < 2 mm in length) and cryptic, members of this suborder are overlooked by most collectors. Microcerberids resemble anthurid isopods in having an elongate body and subchelate first pereopods. However, they are most closely related to the Asellota, with which they share the terminal styliform uropods and many other features. An asellote species, Caecianiropsis psammophila, also lives interstitially in intertidal sands of central California and shows the same adaptations to this habitat as microcerberids—i.e., elongation, small size, and loss of eyes and pigmentation. Only one species of microcerberid has been reported from California waters, Coxicerberus abbotti, known from the interstitial environment in the Monterey Bay area (plate 244E). ISOPODA

521

E

Dynamenella dilatata

F

Paracerceis cordata

PLATE 242 Isopoda. Flabellifera: A, Paradello dianae; B, Dynamenella shearerì; C, Dynamenella benedicti, pleotelson; D, Dynamenella glabra, pleotelson; E, Dynamenella dilatata; F, Paracerceis cordata (after Richardson 1899; Menzies 1962; George and Stròmberg 1968; Schultz 1969).

VALVIFERA Key general references: Stimpson 1857; Richardson 1905. Valviferans are distinguished by the unique opercular uropods that form hinged doors ("valves") covering the pleopods. Additional features that aid in recognition are the well-developed coxal plates, often partly fused pleonites, absence of mandibular palps (except in the southern hemisphere family Holognathidae), and the penes of males arising 522

ARTHROPODA

from pleonite 1, or on the articulation of pleonite 1 and pereonite 7 (rather than on the thorax, as in all other marine isopods). Three families and 34 species are represented in our waters. Mesidotea entomon, an offshore circum-Arctic species, is reported to occur as far south as Pacific Grove and is the only representative of the Chaetiliidae in California. Twenty-one species in the families Arcturidae and Idoteidae occur in our intertidal region.

A

Paracereis

sculpta

C2

Gnorimosphaeroma

oregonense

B1

Gnorimosphaeroma

D

Exosphaeroma

noblei

amplicauda

P L A T E 243 Isopoda. Flabellifera: A, Paracerceis sculpta; B, Gnorimosphaeroma noblei, Bl, whole animal, B2, frontal view of cephalon; C, Gnorimosphaeroma oregonense, CI, frontal view of cephalon, C2, whole animal; D, Exosphaeroma amplicauda (after Stimpson 1857; Menzies 1954A; Brusca 1980).

1.

Body narrow, subcylindrical; anterior four pereopods unlike posterior three, being smaller, setose, and nonambulatory; head fused with first pereonite, leaving six free pereonites Arcturidae: Idarcturus Note: One intertidal species in California and Oregon, I. hedgpethi, plate 244F.

— 2.

Body dorsoventrally depressed; pereopods subsimilar and ambulatory; seven free pereonites Idoteidae 2 Pleon composed of three complete pleonites and one incomplete pleonite (represented by a pair of lateral suture lines), plus pleotelson Cleantioides Note: One species in California and Oregon, C. occidentalis, plate 244G. ISOPODA

523

A

B

Exosphaeroma inornata

Sphaeroma walken

X

D

Gnathia steveni

E2

Coxicerberus abbotti

F

Idarcturus hedgpethi

"

Cleantioides occidentalis

PLATE 244 Isopoda. Flabellifera: A, Exosphaeroma ¡nomata; B, Sphaeroma walkeri; C, Sphaeroma quoianum, pleotelson; D, Gnathiidea: D, Gnathia steveni; E, Microcerberidea: E, Coxicerberus abbotti, El, antenna 1, E2, whole animal; F-G, Valvifera: F, Idarcturus hedgpethi; G, Cleantioides occidentalis (after Richardson 1905; Menzies 1951A, 1962; Dow 1958; Lang 1960; Brusca and Wallerstein 1979; Kensley and Schotte 1989).

— Pleon with less t h a n three complete pleonites 3 3. Pleon composed of a single segment, with or without incomplete suture lines 4 — Pleon composed of two complete pleonites and one incomplete pleonite Idotea 6 4. Antenna with multiarticulate flagellum; pleon with one pair of incomplete suture lines 5 — Antenna with single clavate flagellar article; pleon usually without suture lines Erichsonella 15 5. Maxillipedal palp of four articles Colidotea 16 — Maxillipedal palp of three articles Synidotea 17 6. Maxillipedal palp of four articles 7 — Maxillipedal palp of five articles 9 7. Pleotelson posterior margin concave (plate 246D) Idotea rufescens — Pleotelson posterior margin not concave 8 8. Pleotelson posterior margin with strong m e d i a n process, triangular in shape and with r o u n d e d apex (plate 246B) Idotea ochotensis — Pleotelson posterior margin without strong median process (plate 247B) Idotea urotoma 9. Eyes transversely (dorsoventrally) elongate; maxilliped with one, two or three coupling setae (plate 246F) Idotea stenops — Eyes not transversely elongate; maxilliped with one coupling seta 10 10. Posterior border of pleotelson strongly concave (plate 246C) Idotea resecata — Posterior border of pleotelson not concave 11 11. Pleonite 1 with acute lateral borders 12 — Pleonite 1 without acute lateral borders 13 12. Eyes reniform; anterior margin of pereonite 1 encompassing cephalon (plate 247A) Idotea wosnesenskii — Eyes rectangular; anterior margin of pereonite 1 n o t encompassing cephalon (plate 246E) Idotea schmitti 13. Pleotelson with median posterior projection 14 — Pleotelson without median posterior projection (plate 245F) Idotea kirchanskii 14. Eyes circular; pleotelson median posterior projection long (plate 245E) Idotea aculeata — Eyes with straight anterior and convex posterior border; pleotelson m e d i a n posterior projection short (plate 246A) I. montereyensis 15. Body not elongated (length about 3 times width) (plate 245 D) Erichsonella pseudoculata — Body elongate (length about 7.4 times width) (plate 245C) Erichsonella crenulata 16. Posterior margin of pleotelson rounded; body relatively stout (length about 2.6 times width); antenna not, or barely, reaching pereonite 2; body dark purple or dark red (fading to bluish-gray in alcohol); commensal on sea urchins (plate 245A) (Strongylocentrotus) Colidotea rostrata — Posterior margin of pleotelson triangular-shaped; body elongate (length about 5.5 times width); antenna reaching pereonite 3 or 4; body brown to brownish-green; n o t commensal on sea urchins (usually in brown algae) (plate 245B) Colidotea findleyi 17. Body smooth; head without preocular horns or other projections (plate 247E) Synidotea harfordi Note: Synidotea laticauda (plate 252D) is a very abundant isopod in fouling communities of San Francisco Bay, living on hydroids o n floats, buoys, and pilings. The frontal margin of the head is transverse or slightly concave with a slight median excavation; in S. harfordi,

the frontal margin of the head is transverse or slightly convex, with no median excavation. In S. laticauda, the pleon is less t h a n onethird longer (in midline) t h a n the greatest width; in S. harfordi, the pleon is at least one-third longer t h a n broad.

— Body with tuberculations, carinae or bumps; head with preocular horns or other processes 18 18. Pereon lacking tubercles (plate 247D) Synidotea consolidata — Pereon with tubercles 19 19. Preocular horns project forward (plate 247G) Synidotea ritteri — Preocular horns project laterally 20 20. Lateral borders of first four pereonites acute; each pereonite with a transverse row of three pointed tubercles (plate 247F) Synidotea pettiboneae — Lateral borders of second, third and f o u r t h pereonites blunt; pereonites with m a n y small tubercles (plate 24 7C) Synidotea berolzheimeri

ONISCIDEA (TERRESTRIAL, MARITIME ISOPODS)

Key general references: Van Name 1936 and 1940, 1942 supplements; Mulaik and Mulaik 1942; Garthwaite et al. 1985, 1992; Garthwaite 1992; Leistikow and Wagele 1999. The Oniscidea (formerly "Oniscoidea") are the only group of crustaceans fully adapted to live o n land. They are distinguished by: extreme reduction (to one to three articles) of the antennules; endopods of male pleopod 1 and/or 2 elongate, styliform, specialized as a copulatory apparatus; and, presence of a complex water-conducting system (Hoese 1981,1982 a, b). In species best adapted to terrestrial life (e.g., Porcellionidae, Armadillidiidae, Armadillidae) the exopods of pleopods 1 - 2 or 1 - 5 bear respiratory structures, called pseudotracheae or "lungs." Terrestrial isopods possess general body morphologies correlated to their ecological strategies and behaviour, and can be grouped in three main categories (Schmalfuss 1984): the runners, with an elongate, slightly convex body and long pereopods; the dingers, with a flat broad body and short strong pereopods; and the rollers, with a highly convex body able to roll up into a ball (pillbugs). With almost 4,000 described species, Oniscidea is t h e largest isopod suborder. They occur in any kind of terrestrial habitat, from littoral to high mountains, from forests to deserts. In our region, 22 species, in 10 families, occur in littoral biotopes, but only species of Ligia, Tylos, Littorophiloscia, the Detonidae, and the Alloniscidae are typical inhabitants of the eulittoral zone. The key and species list include all the strictly littoral oniscid species, some of which have wide distributions or have been introduced to North America, and some of which occur on b o t h coasts. 1.

Uropods ventral, hidden by pleotelson and n o t visible in dorsal view of the animal (plate 248A) Tylidae Tylos punctatus — Uropods terminal, clearly visible in dorsal view 2 2. Flagellum of antenna with more t h a n 10 articles; eye with more t h a n 50 ommatidia Ligiidae 3 — Flagellum of antenna with two to seven articles; eye with < 3 0 ommatidia, or eyes absent 6 3. Pleotelson with posterolateral projections; uropod with insertion of exopod and endopod at the same level Ligia 4

ISOPODA

525

A

Coh'dotea rostrata

B 1 Colidotea findleyi

C3

Erichsonella crenulata

PLATE 245 Isopoda. Valvifera: A, Colidotea rostrata; B, Colidotea findleyi, Bl, whole animal, B2, maxilliped; C, Erichsonella crenulata, CI, dorsal view of cephalon, C2, lateral view of cephalon, C3, whole animal; D, Erichsonella pseudoculata; E, Idotea aculeata; F, Idotea kirchanskii (after Benedict 1898; Stafford 1913; Menzies 1950a; Schultz 1969; Miller and Lee 1970; Brusca and Wallerstein 1977).

—

Pleotelson without posterolateral projections; uropod with insertion of exopod distinctly proximal to that of endopod Ligidium 5

5.

4.

Distance between eyes equal to length of o n e eye; peduncle of uropod several times longer t h a n broad (plate 248B) Ligia occidentalis

—

— 526

Distance between eyes equal to twice length of o n e eye; ARTHROPODA

peduncle of uropod about as broad as long (plate 2 4 8 C ) Ligia pallasii Surface of body smooth and shiny; eye ovoid, far from posterior margin of cephalon; endopod of second male pleopod with rounded apex (plate 2 4 8 D )

Ligidium

gracile

Surface of body rough with sparse scales; eye subtriangular, almost reaching posterior margin of cephalon; endo-

PLATE 246 Isopoda. Valvifera: A, Idotea montereyensis; B, Idotea ochotensis; C, Idotea resecata; D, Motea rufescens; E, Idotea schmitti; F, Idotea stenops, Fl, maxilliped, F2, whole animal (after Richardson 1905; Schultz 1969; Rafi and Laubitz 1990).

A Idotea

D

B Idotea

wosnesenskii

Synidotea consolidata

E

C 2 Synidotea

urotoma

Synidotea harfordi

F

Synidotea pettiboneae

berolzheimeri

G

Synidotea ritteri

PLATE 247 Isopoda. Valvifera: A, Idotea wosnesenskii; B, Idotea urotoma; C, Synidotea berolzheimeri, CI, maxilliped, C2, whole animal; D, Synidotea consolidata; E, Synidotea harfordi; F, Synidotea pettiboneae; G, Synidotea ritteri (after Menzies and Miller 1972; Rafi and Laubitz 1990).

6.

528

pod of second male pleopod with pointed apex (plate 248E) Ligidium latum Flagellum of antenna tapering to a point, with articles distinguishable only in micropreparations. . Trichoniscidae 7 ARTHROPODA

7.

Flagellum of antenna with two to four clearly distinct articles 8 Flagellum of antenna of three minute articles; eye consisting of a single black ommatidium (plate 249A) Haplophthalmus danicus

PLATE 248 Isopoda. Oniscidea: A, Tylos punctatus, A l , lateral view of whole animal, A2, fourth and fifth pleonite and pleotelson; B, Ligia occidentalis; C, Ligia pallasii, C I , cephalon and first pereonite, C2, fifth pleonite, pleotelson, and uropods; D, Ligidium gracile, D l , lateral view of cephalon and first pereonite, D2, fifth pleonite, pleotelson, and uropods, D3, second male pleopod; E, Ligidium latum, El, lateral view of cephalon and first pereonite, E2, second male pleopod.

D1

Armadilloniscus

lindahli

E1

Armadilloniscus

coronacapitalis

P L A T E 2 4 9 Isopoda. Oniscidea: A, Haplophthalmus danicus; B, Brackenridgia heroldi, cephalon and first pereonite; C, Detonella papillicornis; D, Armadilloniscus lindahli, Dl, lateral view of whole animal, D2, dorsal view of cephalon, D3, fourth and fifth pleonite, pleotelson, and uropods; E, Armadilloniscus coronacapitalis, El, female cephalon and first pereonite, E2, male seventh pereopod.

— 8. — 9.

— 10.

— 11.

—

12. — 13.

—

14. — 15.

— 16.

—

17.

— 18.

— 19. — 20.

Flagellum of antenna of six or seven minute articles; eyes lacking (plate 249B) Brackenridgia heroldi Flagellum of antenna with four articles Detonidae 9 Flagellum of antenna with two or three articles 12 Uropods with peduncle subcylindrical, exopod inserted terminally and distinctly protruding from body outline (plate 249C) Detonella papillicomis Uropods with peduncle lamellar, exopod inserted on medial margin and not protruding from body outline 10 Body markedly convex and capable of rolling into a ball; cephalon with median lobe truncate (plate 249D) Armadilloniscus lindahli Body not markedly convex and incapable of rolling into a ball; cephalon with median lobe pointed 11 Penultimate article of peduncle of antenna with spurlike process on lateral margin; dorsal body surface of adult female covered with conspicuous tubercles; seventh male pereopod with a strong spine caudally directed and a rounded lobe on carpus (plate 249E) Armadilloniscus coronacapitalis Penultimate article of peduncle of antenna without spurlike process on lateral margin; dorsal body surface rough with low, rounded tubercles; seventh male pereopod without spine and lobe on carpus (plate 250A) Armadilloniscus holmesi Flagellum of antenna with three articles 13 Flagellum of antenna with two articles 15 Cephalon with cone-shaped lateral lobes protruding frontwards; pleon not abruptly narrower than pereon Alloniscidae Alloniscus 14 Cephalon without cone-shaped lateral lobes; pleon abruptly narrower than pereon (plate 250D) Halophiloscidae Littorophiloscia richardsonae Peduncle of uropod with posterolateral margin produced, rounded (plate 250C) Alloniscus mirabilis Peduncle of uropod with posterolateral margin not produced, oblique (plate 250B) Alloniscus perconvexus Body moderately convex, unable to roll into a ball; uropod subcylindrical, distictly protruding backwards compared with pleotelson tip 16 Body very convex, able to roll into a ball; uropod flattened, reaching pleotelson tip 21 Dorsal surface of body covered with fine but distinct scales; first article of flagellum of antenna distinctly shorter than second Platyarthridae 17 Dorsal surface of body with no distinctly visible scales; first article of flagellum of antenna as long or longer than second Porcellionidae 18 Eyes with about 10 ommatidia; pleotelson tip reaching distal margin of uropodal peduncle (plate 250E) Niambia capensis Eyes lacking; pleotelson much shorter than uropodal peduncle (plate 250F) Platyarthrus aiasensis Cephalon with a V-shaped suprantennal line; pereonite 1 with regularly convex posterior margin (plate 251 A) Porcellionides floria Cephalon with no suprantennal line; pereonite 1 with posterior margin concave at sides Porcellio 19 Pleotelson with a rounded apex (plate 25 IB) Porcellio dilatatus Pleotelson with an acute apex 20 Dorsal surface of body granulated; posterior margin of first pereonite distinctly concave at sides (plate 251C)

Porcellio scaber Dorsal surface of body smooth; posterior margin of first pereonite slightly concave at sides (plate 25 ID) Porcellio laevis 21. Cephalon with a triangular frontal scutellum; eyes with 20-25; posterolateral corner of first pereonite entire; uropod with large flattened exopod filling gap between pleotelson and fifth pleonite (plate 25IE) Armadillidiidae Armadillidium vulgare — Cephalon with no triangular frontal scutellum; eyes with four to eight ommatidia; posterolateral corner of first pereonite cleft; uropod with large flattened peduncle filling gap between pleotelson and fifth pleonite, exopod minute inserted dorsally (plate 251F)

—

Armadillidae Venezillo

microphthalmus

List of Species ANTHURIDEA ANTHURIDAE *Other anthurids may be present in our region; Ernest Iverson noted (1974) a small (2mm) bright orange anthurid in empty spirorbid tubes, with its telson and uropods modified to form an operculum to close the tube, in the Bodega Bay region. Cyathura munda Menzies, 1951. Marin County and south; low intertidal to 132 m; common in kelp holdfasts (e.g., Egregia and Laminaria) and on surfgrass (Phyllospadix). See Wetzer and Brusca 1997. Mesanthura occidentalis Menzies and Barnard, 1959. Point Conception and south; intertidal to 20 m on kelp and rocks. PARANTHURIDAE Califanthura squamosissima (Menzies, 1951). Dillon Beach and south; shallow subtidal to 142 m, muddy or sandy sediments and kelp beds; Macrocystis holdfasts. Colanthura bruscai Poore, 1984. San Clemente and south; intertidal to 27 m. *Paranthura algicola Nunomura, 1978. A questionable species, not distinguishable by its description; possibly P. elegans. Reported by Nunomura (1978) from California, but no specific locality provided. Paranthura elegans Menzies, 1951. Marin County and south; intertidal to 55 m on algal mats, mud bottoms, pier pilings, rocky low intertidal in holdfasts of Laminaria and Macrocystis, among coralline algae, and other habitats. See Wetzer and Brusca 1997. *Paranthura japónica Richardson, 1909. An introduced Asian species found in fouling communities in San Francisco Bay and in marinas in southern California ( J o h n chapman, personal communication). *Paranthura linearis Boone, 1923. A nomen nudum. Reported by Boone from Laguna Beach.

ASELLOTA ASELLIDAE Asellus tomalensis Harford, 1877. Central California and north; shallow subtidal in fresh and brackish water. * = Not in key.

1SOPODA

531

PLATE 250 Isopoda. Oniscidea: A, Armadilloniscus holmesi, Al, cephalon and first pereonite, A2, male seventh pereopod; B, Alloniscus perconvexus, third to fifth pleonite, pleotelson and uropods; C, Alloniscus mirabilis; D, Littorophiloscia richardsonae; E, Niambia capensis; F, Platyarthrus aiasensis, Fl, cephalon and first pereonite, F2, pleon, pleotelson and uropods.

B2

D2

Porcellio

laevis

E3

Porcellio

C2

dilatatus

Armadillidium

vulgare

F3

Porcellio

Venezillo

scaber

microphthalmus

PLATE 251 Isopoda. Oniscidea: A, Porcellionides floria, frontal view of cephalon; B, Porcellio dilatatus, Bl, cephalon and first pereonite, B2, fourth and fifth pleonite, pleotelson, and uropods; C, Porcellio scaber, C I , cephalon and first pereonite, C2, fourth and fifth pleonite, pleotelson, and uropods; D, Porcellio laevis, D l , cephalon and first pereonite, D2, fourth and fifth pleonite, pleotelson, and uropods; E, Armadillidium vulgare, El, lateral view of whole animal, E2, frontal view of cephalon, E3, fifth pleonite, pleotelson, and uropods; F, Venezillo microphthalmus, Fl, lateral view of whole animal, F2, frontal view of cephalon, F3, fifth pleonite, pleotelson, and uropods (F3 after Arcangeli 1932).

B

A

Orthione

griffensis

C1

Gnorimosphaeroma

insulare

lais californica

C2

Gnorimosphaeroma

rayi

Gnorimosphaeroma

oregonense

PLATE 252 Isopoda. A, lais californica; B, Orthione griffensis; CI, Gnorimosphaeroma insulare, C2, Gnorimosphaeroma rayi, pereopod 1 (from Japan); C3, Gnorimosphaeroma oregonense, pereopod 1 (from American Pacific coast); Dl, D2, Synidotea laticauda, male and female; E, Paranthura japonica (A, after Menzies and Barnard 1951; B, from Markham 2004; CI, after Menzies 1954; C2, C3, from Hoestlandt 1975; D, from Richardson 1909.

JANIRIDAE

See Wilson and Wágele 1994, Invert. Taxon. 8: 683-747 (review of family); Kussakin 1962, Trudy Zool. Inst. Akad. Nauk SSSR 30: 17-65 (in Russian; janirids of the seas of U.S.S.R.). Caecianiropsis psammophila Menzies and Pettit, 1956. Tómales Bluff at Tómales Point (Marin County) and Asilomar (Monterey County); interstitial, buried in sand. See Menzies and Pettit 1956, Proc. U.S. Nat. Mus. 106 (3376): 441-446 (description). Caecijaera horvathi Menzies, 1951. Hawaii and southern California; intertidal, living in burrows excavated in wood by the isopod Limnoria. *Iais californica (Richardson, 1904). Introduced from Australia or New Zealand with its host isopod Sphaeroma quoianum; in bays and estuaries. See Menzies and Barnard 1951, Bull. So. Calif. Acad. Sci. 50: 136-151; Rotramel, 1972. Ianiropsis analoga Menzies, 1952. Marin County and north; intertidal under rocks or in Laminaria holdfasts. Hatch (1947) misidentified this species in Washington as the European /. maculosa; Carvacho's (1981) distribution for Janira maculosa (Washington State) is based on Hatch, and therefore incorrect. Ianiropsis derjugini (Gurjanova, 1933) (=Ianiropsis kincaidi derjugini). Monterey County and north; intertidal under rocks covered by algae. See Miller 1968. Ianiropsis epilittoralis Menzies, 1952. Marin County to San Luis Obispo County; on green filamentous algae in high intertidal (Iverson 1974). Ianiropsis kincaidi (Richardson, 1904) (=Ianiropsis pugettensis Hatch, 1947). Monterey County and north; intertidal. Ianiropsis minuta Menzies, 1952. Marin County; intertidal under rocks or sand. Ianiropsis montereyensis Menzies, 1952. Marin to Monterey Counties; intertidal to shallow subtidal, under rocks or in Macrocystis holdfasts. Ianiropsis tridens Menzies, 1952. San Juan Island to Monterey County; northern Chile; intertidal, on algae and occasionally found in sponges. Janiralata davisi Menzies, 1951. Carmel Cove, Monterey County, low intertidal under rocks. Janiralata occidentalis (Walker, 1898). Washington to Orange County; intertidal under rocks. *Janiralata triangulata (Richardson, 1899). Monterey Bay; shallow water. JOEROPSIDIDAE

Joeropsis dubia dubia (Menzies, 1951) formerly Jaeropsis. Dillon Beach, Marin County and south; low intertidal to 100 m; on algal holdfasts, bryozoans, tunicates, hydroids, barnacles and under rocks. See Miller 1968. Joeropsis dubia paucispinis (Menzies, 1951). Marin County; intertidal to 116 m. See Miller 1968. *Joeropsis lobata (Richardson, 1899). Monterey Bay; shallow water. MUNNIDAE

See Kussakin, 1962, Trudy Zool. Inst. Akad. Nauk S.S.S.R. 30: 66-109 (in Russian; munnids of the seas of U.S.S.R.). Munna chromatocephala Menzies, 1952. Central California and north; intertidal on red algae and among incrusting organisms on rocks.

Munna halei Menzies, 1952. Cape Arago (Oregon) to San Luis Obispo; intertidal under rocks, in Macrocystis holdfast, and among spines of the purple sea urchin Strongylocentrotus purpuratus. See Harty 1979, Bull. So. Calif. Acad. Sci., 78: 196-199 (occurrence and behavior on urchins at Cape Arago: when trapped under urchin's spines, the isopod remains still until the spines become erect and the isopod can crawl away; when held by the urchin's pedicellaria, the isopod is eventually freed and moves away apparently unharmed). Munna stephenseni Gurjanova, 1933. Central California and north; intertidal to 18 m. Uromunna ubiquità (Menzies, 1952) (=Munna minuta Hansen in Hatch, 1947). Intertidal to shallow subtidal; reported among colonies of the tube-building worm Owenia at La Jolla by Fager (1964, Science 143: 356-359). PARAMUNNIDAE

*Munnogonium tillerae (Menzies and Barnard, 1959) (=Munnogonium waldronensis George and Stròmberg, 1968; =Munnogonium erratum [Schultz, 1964]). Central to southern California; 5 m-150 m; see Bowman and Schultz 1974, Proc. Biol. Soc. Wash. 87: 265-272 (redescription); Wilson 1997. SANTIIDAE

Santia hirsuta (Menzies, 1951) (=Antias hirsutus). Tomales Bluff at Tomales Point, Marin County; intertidal in rock and sand between coralline and laminarian algal zones.

EPICARIDEA

BOPYRIDAE

*Aporobopyrus muguensis Shiino, 1964. Bodega Bay (Milton Miller) and south; 10 m-12 m; in branchial chamber of porcelain crab Pachycheles rudis. *Aporobopyrus oviformis Shiino, 1934. Seto, Japan and Mugu Pier at Point Mugu; 10 m-12 m; in branchial chamber of porcelain crab Pachycheles pubescens in California. *Argeia pugettensis Dana, 1853 (=Argeia pauperata Stimpson, 1857; =Argeia caimani Bonnier, 1900; =Argeia pingi Yu, 1935). Branchial parasites on crangonid shrimps, 32 m-188 m. See Jay 1989, Amer. Midi. Nat., 121: 68-77 (parasitism on Crangon franciscorum). *Asymmetrione ambodistorta Markham, 1985. Southern California, 3 m infesting the hermit crab Isocheles pilosus. See Markham 1985, Bull. So. Calif. Acad. Sci. 84: 104-108 (description). Bopyriscus caimani (Richardson, 1905) (=Bopyrella macginitiei Shiino, 1964). Southern and central California, intertidal to 9 m on branchial chamber of the snapping shrimp Synalpheus lockingtoni and Alpheopsis equidactylus. See Sassaman et al. 1984, Proc. Biol. Soc. Wash. 97: 645-654. (biology, taxonomy). Ione cornuta Bate, 1864 (=Ione brevicauda Bonier, 1900). San Francisco and north; intertidal to shallow water in branchial chamber of ghost shrimps (on C. longimana in the eastern Pacific and N. japonica in the western Pacific). *Munidion pleuroncodis Markham, 1975. Central California and south; known to infest only the pelagic red galatheid Pleuroncodes planipes, which occurs in California only during warm * = Not in key.

ISOPODA

535

years when the host moves north from the tropical eastern Pacific. Offshore storms occasionally move P. planipes ashore where they are beached. See Markham 1975, Bull. Mar. Sci. 25: 422-441 (systematics); Wetzer and Brusca 1997. *Orthione griffensis Markham, 2004. Abundant on the mud shrimp Upogebia pugettensis in Oregon. See Markham 2004, Proc. Biol. Soc. Wash. 117: 186-198 (description). Phyllodurus abdominalis Stimpson, 1857. Intertidal among pleopods of mud shrimp Upogebia pugettensis (female is posterior to first pair of large pleopods, small male roves; A. Kuris, observations). See Markham 1977, Proc. Biol. Soc. Wash. 90: 813-818 (systematics). Schizobopyrina striata (Nierstrasz and Brender a Brandis, 1929). Shallow water on shrimps Hippolyte californiensis (in San Diego Bay) and on Thor algicola (in Gulf of California). ENTONISCIDAE

Portunion conformis Muscatine, 1956. San Francisco to Marin County; intertidal. An endoparasitic castrator in the crabs Hemigrapsus oregonensis and H. nudus. See Muscatine 1956, J. Wash. Acad. Sci. 46: 122-126; Piltz, 1969, Bull. So. Calif. Acad. Sci. 68: 257-259; Kuris et al. 1980, Parasitology 80: 211-232 (host defensive mechanisms sometimes kill female Portunion); Shields and Kuris 1985, J. Invert. Path. 45: 122-124 (ectopic infections of host). C A B I R O P I D A E (FORMERLY AS C A B I R O P S I D A E )

*Cabirops montereyensis Sassaman, 1985. Monterey Bay. Shallow water on marsupium of the isopod Aporobopyrus muguensis (which in turn lives in the branchial cavity of the porcelain crab Pachycheles). See Sassaman 1988, Proc. Biol. Soc. Wash. 98: 778-789; 1992, Proc. Biol. Soc. Wash. 105: 575-584 (description of mature female and epicaridium larva). *Undescribed cabiropid. An undescribed species occurs in the isopod Tecticeps convexus at Horseshoe Cove at Bodega Head (A. Kuris, unpublished observations). HEMIONISCIDAE

Hemioniscus balani Buchholz, 1866. European species apparently introduced throughout the world; in eastern Pacific from Alaska (Coyle and Mueller 1981, Sarsia 66: 7-18) to Baja California. Parasitic in intertidal barnacles (see Blower and Roughgarden 1988, Oecologia 75: 512-515). This species has also been assigned to Cryptothir, Cryptothiria, and Cryptoniscus.

FLABELLIFERA AEGIDAE

*Aega (Aega) lecontii (Dana, 1854). Central and southern California. Offshore; taken from fish or from soft bottoms. See Brusca 1983, Allan Hancock Fdn. Monogr. Mar. Biol. no. 12, 39 pp. (systematics). Rocinela signata Schiddte and Meinert, 1879 (=Rocine\a aries Schiodte and Meinert, 1879). Los Angeles to Ecuador; also in tropical western Atlantic; intertidal to 68 m; common, taken from fish or from soft bot* = Not in key. 536

ARTHROPODA

toms. See Brusca and France, 1982, Zool. J. Linn. Soc. 106: 231-275 (systematics). CIROLANIDAE

See Brusca and Ninos 1978, Proc. Biol. Soc. Wash. 91: 379-385; key to California species; Bruce and Jones 1981; Brusca et al. 1995. Cirolana diminuta Menzies, 1962. Point Conception and south; intertidal to 50 m; easily confused with the tropical C. parva. C. harfordi var. spongicola Stafford, 1912, is probably this species. C. diminuta attack nearshore fishes in southern California, perhaps attacking fish initially injured by carnivorous ostracodes (Stepien and Brusca 1985, Mar. Ecol. Prog. Ser. 25: 91-105. Cirolana harfordi (Lockington, 1877). Abundant in mussel beds on rocky shores, where they may occur in densities of thousands per square meter; intertidal to shallow subtidal. See Brusca 1966 (salinity and humidity tolerance); Johnson 1976, Mar. Biol. 36: 343-350 (biology, population dynamics); 1976, Mar. Biol. 36: 351-357 (population energetics). Abbott (1987) presents extensive sketches of external and internal anatomy based upon material from Pacific Grove (Monterey Bay). Eurydice caudata Richardson, 1899 (=E. branchuropus Menzies and Barnard, 1959). San Diego and south; intertidal to 160 m. Eurylana arcuata (Hale, 1925) (=Cirolana arcuata). Introduced to San Francisco Bay; occurs in New Zealand, Australia, and west coast of South America; intertidal to shallow subtidal. See Bowman et al. 1981, J. Crustacean Biol. 1: 545-557 (introduction). Excirolana chiltoni (Richardson, 1905) (=£. kincaidi [Hatch, 1947]; =E. vancouverensis [Fee, 1926]; =E. japonica Richardson, 1912). Intertidal on sandy beaches. See Enright 1965, Science 147: 864-867; 1971, J. Comp. Physiol. 75: 332-346; 1972, J. Comp. Physiol. 77: 141-162; 1976, J. Comp. Physiol. 107: 13-37 (all, tidal rhythms); Klapow 1972, Biol. Bull. 143: 568-591 (molting and reproductive cycles); Iverson 1974. Excirolana linguifrons (Richardson, 1899). Monterey Bay to southern California; intertidal on sandy beaches. See Connors et al. 1981, Auk 98: 49-64 (preyed upon by sanderlings, Bodega Bay area). CORALLANIDAE

See Bruce et al. 1982. Excorallana tricomis occidentalis Richardson, 1905. Southern California to Panama; intertidal to 138 m on rocks, sandy beaches, and in mangrove habitats. See Delaney 1993, Bull. So. Calif. Acad. Sci. 92: 64-69 (cuticle). Excorallana truncata (Richardson, 1899) (=£. kathyae Menzies, 1962). Point Conception and south; intertidal to 183 m. See Delaney 1982, J. Crust. Biol. 2: 273-280; 1984, Bull. Mar. Sci. 34: 1-20 (systematics). CYMOTHOIDAE

See Brusca 1981; Brusca and Gilligan 1983; Bruce 1986, 1990. Ceratothoa gaudichaudii (H. Milne Edwards, 1840). Southern California (rare) to Cape Horn and around to southern Patagonia. Found on many species of pelagic fishes. Elthusa californica (Schioedte and Meinert, 1884) (=Livoneca californica; misspelled as Lironeca). On dwarf surfperch (Micrometrus minimus), shiner surfperch (Cymatogaster aggregata),

surf smelt (Hypomesus preitiosus), topsmelt (Atherinops affinis), arrow goby (Clevelandia ios), and California killifish (Fundulus parvipinnis). See Waugh et al. 1989, Bull. So. Calif. Acad. Sci. 88: 33-39 (incidence of infestation on fish in Bodega Harbor). Elthusa vulgaris (Stimpson, 1857) (=Livoneca vulgaris). In gill chambers of a wide variety of fishes. See Brusca, 1978, Occ. Paps. Allan Hancock Fdn. n. ser. 2: 1-19 (biology and systematics). Enispa convexa (Richardson, 1905) (=Livoneca convexa). San Diego and south, but rare in California; a tropical species. Found in gill chambers of Pacific bumper (Chloroscombrus orqueta), pompanos (Trachinotus rhodopus or T. paitensis), and Serraras sp. Mothocya rosea Bruce, 1986. San Diego and south; found in Hyporhampus rosea and H. snyderi. Nerocila acuminata Schioedte and Meinert, 1881 (=Nerocila califomica Schioedte and Meinert, 1881). Southern California and south; parasite of many fish species. See Brusca 1978, Crustaceana 34: 141-154 (biology). LIMNORIIDAE

See Cookson 1991, Mem. Mus. Victoria 52: 137-262 (systematics, including treatments of L. lignorum, L. tripunctata, and L. quadripunctata)-, Menzies 1954, Bull. Mus. Comp. Zool. Harvard 112: 364-388 (reproduction); Menzies 1957, Bull. Mar. Sci. Gulf and Caribbean 7: 101-200 (systematics). Limnoria algarum Menzies, 1957. Oregon to southern California, intertidal to 15 m. In holdfasts of Macrocystis, Egregia, Laminaria, Postelsia, Nereocystis, Sargassum and Pelagophycus. Limnoria lignorum (Rathke, 1799). Temperate and boreal northern hemisphere distribution; south to Point Arena on the Pacific coast; intertidal to 20 m.; wood borer. See Cookson 1991, above. Limnoria quadripunctata Holthuis, 1949. Widespread cool temperate distribution; central to southern California; intertidal to 30 m; wood borer. See Cookson 1991, above. Limnoria tripunctata Menzies, 1951. Temperate and tropical locations around the world; on our coast from at least Oregon south; intertidal to 7 m; wood borer. See Menzies 1951, Bull. So. Calif. Acad. Sci. 50: 86-88; Cookson 1991 (above); Johnson and Menzies 1956, Biol. Bull. 110: 54-68 (migratory behavior); Beckman and Menzies 1960 Bio. Bull. 118: 9-16 (reproductive temperature and geographic range). SEROLIDAE

Heteroserolis carinata (Lockington, 1877) (=Serolis carinata). Southern California and south; intertidal to 98 m. on soft bottoms. See Wetzer and Brusca 1997. SPHAEROMATIDAE

See Harrison and Ellis 1991; Bruce 1993. Ancinus granulatus Holmes and Gay, 1909 (=A. seticomvus Trask, 1970). Santa Barbara and south; intertidal to 10 m. Ancinus and Bathycopea are placed in the family Ancinidae by Bruce (1993) and some other workers. See Trask 1970, Bull. So. Calif. Acad. Sci. 69: 145-149. *Clianella elegans Boone, 1923. Nomen dubium. La Jolla and San Pedro. Dynamene tuberculosa Richardson, 1899. Shallow water. Dynamenella benedicti (Richardson, 1899). Monterey Bay; intertidal.

*Dynamenella cónica Boone, 1923. Species inquirenda. San Francisco to Monterey Bay; intertidal. Dynamenella dilatata (Richardson, 1899). Monterey Bay; intertidal. Dynamenella glabra (Richardson, 1899). Oregon to San Diego; intertidal. Dynamenella sheareri (Hatch, 1947). Intertidal to shallow subtidal. Exosphaeroma amplicauda (Stimpson, 1857). Intertidal under rocks and stones; see Rees 1975, Mar. Biol. 30: 21-25 (habitatcompetition with Gnorimosphaeroma oregonense). *Exosphaeroma aphrodita Boone, 1923. Nomen dubium. La Jolla. Exosphaeroma inornata Dow, 1958 (=E. media George and Stromberg, 1968). Northern California to Los Angeles; intertidal and shallow subtidal in holdfasts of kelp Macrocystis. See Dow 1958, Bull. So. Calif. Acad. Sci. 57: 93-97; Iverson 1974; Iverson 1978, J. Fish. Res. Bd. Can. 35: 1381-1384. Exosphaeroma octoncum (Richardson, 1897). Monterey to Marin County; shallow water. See Iverson 1974. Exosphaeroma rhomburum (Richardson, 1899). Monterey Bay; shallow water. * Gnorimosphaeroma insulare (Van Name, 1940) (=G. oregonensis lutea Menzies, 1954; =G . lutea Menzies, 1954). Fresh and brackish water, in shallow estuaries and lagoons, including Lake Merced on the San Francisco Peninsula. See Menzies 1954 (below); Eriksen 1968 Crustaceana 14: 1-12 (ecology); Riegel 1555, Biui. Bull. 116: 272-254 (osmoregulation) and Í959, Bioi. Bull. 117: 154-162 (physiology, ecology, taxonomy); Hoestlandt 1973, Arch. Zool. Exper. Gen. 114: 3 4 9 - 395, and 1977, Crustaceana 32: 35-54 (taxonomy); Iverson 1974. Gnorimosphaeroma noblei Menzies 1954. Central California; high intertidal under rocks. See Menzies 1954, Amer. Mus. Novitates 1683, 24 pp. (review of Gnorimosphaeroma species); Iverson 1974. Gnorimosphaeroma oregonense (Dana, 1853). Formerly spelled G. oregonensis. San Francisco Bay and north; intertidal to 24 m; brackish to salt water. See Menzies 1954 (above); Riegel 1959 Biol. Bull. 116: 272-284 (osmoregulation), and 1959, Biol. Bull. 117: 154-162 (physiology, ecology, taxonomy); Eriksen 1968, Crustaceana 14: 1-12 (ecology); Hoestlandt 1970, C.R. Acad. Sci. Hebd. Seances Acad. Sci. (D) 270: 2124-2125 (polychromatism); Rees 1975, Mar. Biol. 30: 21-25 (habitat; competition with Exosphaeroma amplicauda); Standing and Beatty 1978, Can. J. Zool. 56: 2004-2014 (humidity behavior and reception); Brook et al. 1994, Biol. Bull. 187: 99-111 (protogynous sex change); Zimmer et al. 2002 Mar. Biol. 140: 1207-1213 (cellulose digestion and phenol oxidation). * Gnorimosphaeroma rayi Hoestlandt, 1969. Japan, eastern Siberia, Hawaii, and Tómales Bay; shallow water; introduced with Japanese oysters planted in Tómales Bay. See Hoestlandt 1969, C.R. Acad. Sci. Paris 268: 325-327; Hoestlandt 1973 (cited above); Hoestlandt 1975, Publ. Seto Mar. Biol. Lab. 22: 31-46 (occurrence on Pacific coast). Paracerceis cordata (Richardson, 1899). Intertidal to shallow subtidal, on pink coralline algae and kelp holdfasts (Lee and Miller 1980). Paracerceis sculpta (Holmes, 1904). Southern California and south. Widely introduced around the world by shipping. Intertidal to shallow subtidal. Males with harems occurring in calcareous sponges. See Miller 1968; Shuster and Wade 1991, Nature 350: 606-610; Shuster 1989, Evolution 43: 1683-1698; Shuster 1992, Behavior 121: 231-258; Shuster and Sassaman * = Not in key.

ISOPODA

537

1997, Nature 388: 373-377 (all reproduction, genetics, in forms of this species); Shuster 1987, J. Crust. Biol. 7: 318-327 (three discrete male morphs); Shuster 1992, J. Exp. Mar. Biol. Ecol. 165: 75-89 (use of artificial sponges as breeding habit). Paradella dianae (Menzies, 1962). Southern California to Bahía de San Quintín; intertidal to shallow subtidal. See Iverson 1974. *Pseuaosphaeroma campbellenis Chilton, 1909. An introduced New Zealand species c o m m o n in fouling communities in brackish water of Coos Bay (Oregon), San Francisco Bay, and other estuaries. Sphaeroma quoianum H. Milne Edwards, 1840 (commonly spelled as S. quoyanum, an unnecessary correction of the original spelling; =S. pentodon Richardson, 1904). Intertidal to shallow subtidal in wood, m u d and soft rock borer. Introduced to western North America in t h e late 1800s o n ships f r o m Australia (see Rotramel 1972; Carlton 1979; Carlton and Iverson 1981). See also Talley et al. 2001, Mar. Biol. 138: 561-573 (habitat utilization and alteration in California salt marshes). Sphaeroma walkeri Stebbing, 1905. A western Pacific and Indian Ocean species introduced to southern California. See Carlton and Iverson 1981, J. Nat. Hist. 15: 31-48 (introduction to California). *Tecticeps convexus Richardson, 1899. Oregon to Point Conception. Intertidal to 9 m; c o m m o n at times on the sandy beaches in t h e intertidal surf zone, as in Sonoma County, where they match in color t h e sediment of the beach they are on. T. convexus has an additional broad range of defensive mechanisms, including the ability to fold in half while protruding its sharp uropods, and, when disturbed, to emit a cucumberlike smell, all suggestive of predation pressure (J. T. Carlton). Placed in the family Tecticipididae by Iverson (1982), Bruce (1993), and other workers. See Iverson 1974.

GNATHIIDEA GNATHIIDAE See Cohen and Poore 1994. Gnathia steveni Menzies, 1962. Redondo Beach to northwestern Baja California; intertidal.

MICROCERBERIDEA MICROCERBERIDAE Coxicerberus abbotti (Lang, 1960) (=Microcerberus abbotti), central California. Interstitial; intertidal. See Lang 1960, Arkiv for Zool. 13: 493-510 (description). Abbott (1987) presents a sketch of a specimen from the sandy beach in front of the Agassiz Laboratory at t h e Hopkins Marine Station in Pacific Grove. VALVIFERA ARCTURIDAE Idarcturus hedgpethi Menzies, 1951. Tómales Bluff at Tómales Point, Marin County; collected by Joel Hedgpeth in low intertidal o n hydroids. * = Not in key.

538

ARTHROPODA

CHAETILIIDAE Mesidotea entomon (Linnaeus, 1767) (=Saduria entomori). Circumpolar, o n our coast south to Pacific Grove. Intertidal in the northern part of its range, to 30 m in t h e south. HOLOGNATHIDAE See Poore 1990. Cleantioides occidentalis (Richardson, 1899). Southern California and south; intertidal to 50 m. See Kensley and Kaufman 1978, Proc. Biol. Soc. Wash. 91: 658-665 (genus description); Brusca and Wallerstein 1979. I DOTE I DAE See Menzies 1950, Wasmann J. Biol. 8: 155-195 (Idotea of northern California); Brusca and Wallerstein 1977; Brusca and Wallerstein 1979, Proc. Biol. Soc. Wash. 92: 253-271 (both, idoteids of t h e Gulf of California); Brusca and Wallerstein 1979, Bull. Biol. Soc. Wash. 3: 67-105 (idoteid zoogeography); Wallerstein and Brusca 1982, J. Biogeogr. 9: 135-190 (fish pred a t i o n a n d role in zoogeography a n d evolution); Brusca 1984, Trans. San Diego Soc. Nat. Hist. 20: 99-134 (phylogeny, evolution, biogeography of idoteids); Rafi and Laubitz 1970 Can. J. Zool. 68: 2649-2687 (idoteids of northeast Pacific); Poore and Lew Ton 1993, Invert. Taxon. 7: 197-278 (idoteids of Australia and New Zealand)). Colidotea findleyi Brusca and Wallerstein, 1977. San Diego and south; intertidal to at least 1 m; c o m m o n on the brown algae Sargassum. See Brusca and Wallerstein 1977; Brusca 1983, Trans. San Diego Soc. Nat. Hist. 20: 69-79 (evolution). Colidotea rostrata (Benedict, 1898). Northern California (rare) and south; commensal of sea urchin Strongylocentrotus. See Brusca 1983 (above); Stebbins 1988 J. Crust. Biol. 8: 539-547 (natural history, behavior); 1988, J. Exp. Mar. Biol. Ecol. 124: 97-113 (urchins as refuge from fish predation); 1989, Mar. Biol. 101: 329-337 (population dynamics and reproductive biology in southern California); Delaney 1993, Bull. So. Calif. Acad. Sci. 92: 64-69 (cuticle). Erichsonella crenulata Menzies, 1950. Southern California (Newport Bay); intertidal to shallow subtidal; on eelgrass Zostera. Erichsonella pseudoculata Boone, 1923 (=Ronalea pseudoculata). Point Conception to the Mexican border. Intertidal to 18 m. See Menzies and Bowman 1956, Proc. U.S. Natl. Mus. 106: 339-343 (redescription). Idotea aculeata (Stafford, 1913) (=Pentidotea aculeata). Intertidal on various habitats, including pink-colored individuals matching Melobesia encrusting o n t h e surfgrass Phyllospadix (D. Carlton, Horseshoe Cove, Bodega Head). Idotea fewkesi Richardson, 1905. Shallow water. Idotea kirchanskii Miller and Lee, 1970. Oregon and south; bright green on the green surfgrass Phyllospadix and like I. aculeata also occasionally m a t c h i n g t h e pink epiphytic alga Melobesia. See Miller and Lee 1970, Proc. Biol. Soc. Wash. 82: 789-798 (description). Idotea metallica Bosc, 1802. A rare tropical species occasionally occurring in southern California and Gulf of California during warm years; pelagic, attached to floating seaweed. Cosmotropical. Idotea montereyensis (Maloney, 1933) (=Pentidotea montereyensis; =Idotea gracillima (Dana) of Richardson, 1905, and Schultz, 1969). C o m m o n on surfgrass Phyllospadix. See Lee 1966, Comp.

Biochem. Physiol. 18: 17-36; 1966, Ecology 47: 930-941; 1972, J. Exp. Mar. Biol. Ecol. 8: 201-215 (all, pigmentation, color change, ecology); Iverson 1974; Lee and Miller 1980. Idotea ochotensis Brandt, 1851. Northern California and north; intertidal to 36 m. Idotea resecata Stimpson, 1857. Intertidal; frequently found living in kelp (e.g., Macrocystis, Egregia) and eelgrass (Zostera). Consumes seeds of the surfgrass Phyllospadix (Holbrook et al. 2000, Mar. Biol. 136: 739-747); see also Menzies and Waidzunas 1948, Bio. Bull. 95: 107-113 (postembryonic growth); Miller 1968; Lee and Gilchrist 1972, J. Exp. Mar. Biol. Ecol. 10: 1-27 (coloration and ecology); Iverson 1974; Brusca and Wallerstein 1977 (description, range); Lee and Miller 1980; Alexander 1988, J. Exp. Biol. 138: 37-49; and Alexander and Chen 1990, J. Crustacean Biol. 10: 406-412 (both, swimming behavior); preyed upon in southern California kelp beds by the labrid fish Oxyjulis californica; when released from regulation by this fish, I. resecata "multiplies rapidly and destroys the kelp canopy" (Bernstein and Jung 1979, Eco. Mono. 49: 335-355). Abbott (1987) presents sketches of internal and external anatomy based upon material from Macrocystis kelp beds in Monterey Bay. Idotea rufescens Fee, 1926. Intertidal to 82 m, on algae. Possibly a synonym of I. resecata. See Iverson 1974; Wetzer and Brusca 1997. Idotea schmitti (Menzies, 1950). (=Pentidotea schmitti; =Pentidotea whitei Stimpson of Richardson, 1905). Intertidal to shallow subtidal. See Iverson 1974. Idotea stenops Benedict, 1898. Intertidal to shallow subtidal. See Miller 1968; Iverson 1974; see Brusca and Wallerstein 1977 (description, range). Abbott (1987) presents sketches of internal and external anatomy based upon material from Point Pinos (Monterey Bay). Idotea urotoma Stimpson, 1864 (=Cleantis heathii Richardson, 1899; =Idotea rectilinea Lockington, 1877). Intertidal to shallow subtidal; see Brusca and Wallerstein 19 77 (description, range). Idotea wosnesenskii Brandt, 1851 (=Idotea hirtipes Dana, 1853; =Idotea oregonensis Dana, 1853). San Francisco and north; one anomalous record from La Paz (Baja California). Intertidal to shallow subtidal. Named for the famous Russian naturalist Ilya G. Voznesenskii. See Brusca 1966 (salinity and humidity tolerance); Miller 1968; Brusca and Wallerstein 1977 (description, range); Alexander 1988, J. Exp. Biol. 138: 37-49; Alexander and Chen 1990, J. Crustacean Biol. 10: 406-412 (both, swimming behavior); Zimmer et al. 2002, Mar. Biol. 140: 1207-1213 (cellulose digestion; cannot oxidize dietary phenolics, despite feeding on seaweeds rich in phenols). Synidotea berolzheimeri Menzies and Miller, 1972. Central California (San Luis Obispo to Sonoma Counties); intertidal, on hydroid Aglaophenia. See Menzies and Miller 1972, Smithsonian Contr. Zool. 102, 33 pp. for review of the genus Synidotea. Synidotea consolidata (Stimpson, 1856) (=Synidotea macginitiei Maloney, 1933). Central California and north; intertidal to 20 m. This species has been confused in the literature with the very similar circumarctic Synidotea bicuspida (Owen 1839). Synidotea harfordi Benedict, 1897. Oregon and south; introduced to Japan. Intertidal to shallow subtidal. See Brusca and Wallerstein (1979). *Synidotea laticauda Benedict, 1897. Abundant in fouling communities on floats and buoys in San Francisco Bay and also in Willapa Bay, Washington. Poore (1996, J. Crust. Biol. 16: * = Not in key.

384-394) retained the name S. laticauda, while Chapman and Carlton (1991, J. Crust. Biol. 11: 386-400; 1994, J. Crust. Biol. 14: 700-714) indicate that this species is introduced and a synonym of the Japanese Synidotea laevidorsalis (Miers, 1881). See also Miller 1968. Synidotea pettiboneae Hatch, 1947. Central California and north; intertidal on hydroids and bryozoans. Synidotea ritteri Richardson, 1904. Alaska (Coyle and Mueller 1981, Sarsia 66: 7-18) to north of San Francisco; intertidal.

ONISCIDEA

See Miller (1938) and Brusca (1966) for aspects of biology and ecology of maritime isopods of the San Francisco Bay and Dillon Beach areas, respectively. ARMADILLIDAE

Venezillo microphthalmias central California.

(Arcangeli, 1932). Southern and

ARMADILLIDIIDAE

Armadillidium vulgare (Latreille, 1804). Cosmopolitan species of Mediterranean origin. LIGIIDAE

Ligia occidentalis Dana, 1853. Oregon and south on rocky shores. See Armitage 1960, Crustaceana 1: 193-207 (chromatophores); Wilson 1970, Bio. Bull. 138: 96-108 (osmoregulation); Lee and Miller 1980. Ligia pallasii Brandt, 1833. Santa Cruz and north; rocky shores on open coast. Principal food is encrusting diatoms, insect larvae, algae, and "occasional members of the same species" (Carefoot 1973, Mar. Biol. 18: 228-236). See also Wilson 1970, Bio. Bull. 138: 96-108 (osmoregulation); Carefoot 1973, Mar. Biol. 18: 302-311 (growth, reproduction, life cycle), and 1979, Crustaceana 36: 209-214 (habitat of young); Lee and Miller 1980; Zimmer et al. 2001, Mar. Biol. 138: 955-963 (possesses high numbers of microbial symbionts in hepatopancreatic caeca, which contribute to digestive processes); Zimmer et al. 2002, Mar. Biol. 140: 1207-1213 (cellulose digestion and phenol oxidation). Ligidium gracile (Dana, 1856). Riparian. Ligidium latum Jackson, 1923. San Francisco Bay area to Santa Barbara County; riparian. PHILOSCIIDAE

Littorophiloscia richardsonae (Holmes and Gay, 1909). Littoral species common in marshes, along bays and estuaries. See Taiti and Ferrara 1986, J. Nat. Hist. 20: 1 3 4 7 - 1 3 8 0 (systematics). PLATYARTHRIDAE

Niambia capensis (Dollfus, 1895) (=Porcellio littorina Miller, 1936). Introduced from southern Africa; supralittoral and riparian. See Miller 1936. Univ. Calif. Publ. Zool. 41: 165-172 (descriptions). ISOPODA

539

Platyarthrus aiasensis Legrand, 1953. Introduced; western Mediterranean/Atlantic; known in the United States from southern California and Texas. A myrmecophile (sharing the nests of ants). PORCELLIONIDAE Porcellio dilatatus Brandt, 1 8 3 3 (=Porcellio spinicomis occidentalis Miller, 1936). Introduced from Europe. See Miller 1936, Univ. Calif. Publ. Zool. 41: 1 6 5 - 1 7 2 (descriptions). Porcellio laevis Latreille, 1804. A cosmopolitan introduced species of Mediterranean origin. Synanthropic. See Miller 1936, Univ. Calif. Publ. Zool. 41: 1 6 5 - 1 7 2 (description). Porcellio scaber Latreille, 1 8 0 4 (=Porcellio scaber americanus Arcangeli, 1932). A cosmopolitan species of European origin. See Miller 1936, Univ. Calif. Publ. Zool. 41: 1 6 5 - 1 7 2 (descriptions). Porcellionides floria Garthwaite and Sassaman, 1985. Southern and western United States and Baja California; very similar to the cosmopolitan synanthropic Porcellionides pruinosus (Brandt, 1833), which is present in the United States but does not seem to occur on the Pacific coast (Garthwaite and Sassaman 1985, J. Crust. Biol. 5: 5 3 9 - 5 5 5 ) . ALLONISCIDAE See Menzies 1950, Proc. Calif. Acad. Sci. (4), 26: 4 6 7 - 4 8 1 , on California Armadilloniscus; Schultz 1972, Proc. Biol. Soc. Wash. 84: 4 7 7 - 4 8 8 (systematics); Garthwaite et al. 1992. Alloniscus mirabilis (Stuxberg, 1875) (=Alloniscus cornutus Budde-Lund, 1885). San Mateo County to Magdalena Bay; littoral halophilic species c o m m o n on sandy beaches above hightide line, where it borrows in sand under driftwood. See Schultz 1984, Crustaceana 47; 1 4 9 - 1 6 7 (systematics). Alloniscus perconvexus Dana, 1856. A littoral halophilic species c o m m o n on sandy beaches above high-tide line, where it borrows in sand under driftwood. See Lee and Miller 1980; Schultz 1984 (above). DETONIDAE Armadilloniscus coronacapitalis Menzies, 1950. Marin County to San Miguel and Anacapa Islands. A littoral halophilic species. Armadilloniscus holmesi Arcangeli, 1 9 3 3 (=Actoniscus tuberculatus Holmes and Gay, 1909, a preoccupied name). A littoral halophilic species found in marshes, bays, and estuaries under rocks and driftwood. Armadilloniscus lindahli (Richardson, 1905). Marin County (Tomales Bay) and south; a littoral halophilic species. Schultz (1972, Proc. Biol. Soc. Wash. 84: 4 7 7 - 4 8 8 ) notes that this species is unique among West Coast Armadilloniscus in being capable of rolling into a ball like a pillbug. Detonella papillicornis (Richardson, 1 9 0 4 ) . San Francisco Bay and north; a littoral halophilic species c o m m o n under rocks above high tide line. See Garthwaite 1988, Bull. So. Calif. Acad. Sci. 87: 4 6 - 4 7 (occurrence in Bolinas Lagoon, California). TRICHONISCIDAE Brackenridgia heroldi (Arcangeli, 1932). Central and southern California. Haplophthalmus 540

danicus Budde-Lund, 1885. Cosmopolitan.

ARTHROPODA

TYLIDAE Tylos punctatus Holmes and Gay, 1909. Southern California and south; a littoral halophilic species restricted to sandy beaches where it burrows above the most recent high-tide line during the day and is active on surface at night (Hays 1977, Pac. Sci. 31: 1 6 5 - 1 8 6 ) . See also Hamner et al. 1968, Anim. Behav. 16: 4 0 5 - 4 0 9 (orientation), and 1969, Ecology 50: 4 4 2 - 4 5 3 (behavior, life history); Schultz 1970, Crustaceana 19: 2 9 7 - 3 0 5 (systematics); Hayes 1974, Ecology 55: 8 3 8 - 8 4 7 , and 1977, Pac. Sci. 31: 1 6 5 - 1 8 6 (ecology); Holanov and Hendrickson 1980, J. Exp. Mar. Biol. Ecol. 46: 8 1 - 8 8 (burrowing).

References Abbott, D. P. 1987. Observing marine invertebrates. Drawings from the laboratory. G. H. Hilgard, ed. Stanford, CA: Stanford University Press, 380 pp. Arcangeli, A. 1932. Isopodi terrestri raccolti dal Prof. Silvestri nel NordAmerica. Boll. Lab. Zool. gen. agr. Portici 26: 121-141. Bruce, N. L. 1986. Revision of the isopod crustacean genus Mothocya Costa, in Hope, 1851 (Cymothoidae: Flabellifera), parasitic on marine fishes. J. Nat. Hist. 20: 1089-1192. Bruce, N. L. 1990. The genera Catoessa, Elthusa, Enispa, Ichthyoxenus, Idusa, Livoneca and Norileca n. gen. (Isopoda, Cymothoidae), crustacean parasites of marine fishes, with descriptions of eastern Australian species. Rec. Australian Mus. 42: 247-300. Bruce, N. L. 1993. Two new genera of marine isopod crustaceans (Flabellifera: Sphaeromatidae) from southern Australia, with a reappraisal of the Sphaeromatidae. Invertebrate Taxon. 7: 151-171. Bruce, N. L., and D. A.Jones. 1981. The systematics and ecology of some cirolanid isopods from southern Japan. J. Nat. Hist. 15: 67-85. Bruce, N. L., R. C. Brusca, and P. M. Delaney. 1982. The status of the isopod families Corallanidae Hansen, 1890 and Excorallanidae Stebbing, 1904 (Flabellifera). J. Crustacean Biol. 2: 464-468. Brusca, G. J. 1966. Studies on the salinity and humidity tolerance of five species of isopods in a transition from marine to terrestrial life. Bull. So. Calif. Acad. Sci. 65: 146-154. Brusca, R. C. 1980. Common intertidal invertebrates of the Gulf of California. 2nd ed. Tucson, AZ: Univ. Arizona Press. Brusca, R. C. 1981. A monograph on the Isopoda Cymothoidae (Crustacea) of the Eastern Pacific. Zool. J. Linn. Soc. 73: 117-199. Brusca, R. C. 1989. Provisional keys to the genera Cirolana, Gnathia, and Limnoria known from California waters. SCAMIT [Southern California Association of Marine Invertebrate Taxonomists] Newsletter 8: 17-21. Brusca, R. C., and M. R. Gilligan. 1983. Tongue replacement in a marine fish (Lutjanusguttatus) by a parasitic isopod (Crustacea: Isopoda). Copeia 3: 813-816. Brusca, R. C., and E. W. Iverson. 1985. A guide to the marine isopod Crustacea of Pacific Costa Rica. Rev. Biol. Trop. 33 (Suppl. 1): 1-77. Brusca, R. C., E. Kimrey, and W. Moore. 2004. Invertebrates [of the Northern Gulf of California], Pp. 35-107. In Seashore guide to the northern Gulf of California. R. C. Brusca, E. Kimrey, and W. Moore, eds. Tuscon, AZ: Arizona-Sonora Desert Museum. Brusca, R. C., and M. Ninos. 1978. The status of Cirolana califomiensis Schultz and Cirolana deminuta Menzies and George, with a key to the California species of Cirolana (Isopoda: Cirolanidae). Proc. Biol. Soc. Wash. 91: 379-385. Brusca, R. C., and B. R. Wallerstein. 1977. The marine isopod Crustacea of the Gulf of California. I. Family Idoteidae. Amer. Mus. Novitates 2634: 1-17. Brusca, R. C., and B. R. Wallerstein. 1979. The marine isopod crustaceans of the Gulf of California. II. Idoteidae. New genus, new species, new records, and comments on the morphology, taxonomy and evolution within the family. Proc. Biol. Soc. Wash. 92: 253-271. Brusca, R. C., and G. D. F. Wilson. 1991. A phylogenetic analysis of the Isopoda with some classificatory recommendations. Mem. Queensland Mus. 31: 143-204. Brusca, R. C., R. Wetzer, and S. France. 1995. Cirolanidae (Crustacea; Isopoda; Flabellifera) of the tropical eastern Pacific. Proc. San Diego Nat. Hist. Soc., No. 30, 96 pp. Cadien, D., and R. C. Brusca. 1993. Anthuridean isopods (Crustacea) of California and the temperate northeast Pacific. SCAMIT [Southern

California Association of Marine Invertebrate Taxonomists] Newsletter 12: 1-26. Carlton, J. T. 1979. Introduced invertebrates of San Francisco Bay. Pp. 427^444. In San Francisco Bay: the urbanized estuary. T.J. Conomos, ed. San Francisco: California Academy of Sciences. Carvacho, A. 1981. Le genre ¡anira Leach, avec description d ' u n e nouvelle espèce (Isopoda, Aseliota). Crustaceana 41: 131-142. Cohen, B. J., and G. C. B. Poore. 1994. Phylogeny and biogeography of the Gnathiidae (Crustacea: Isopoda) with description of new genera and species, most from southeastern Australia. Mem. Mus. Victoria 54: 271-397. Garthwaite, R. 1992. Oniscidea (Isopoda) of the San Francisco Bay Area. Proc. Calif. Acad. Sei. 47: 303-328. Garthwaite, R., F. G. Höchberg, and C. Sassaman. 1985. The occurrence and distribution of terrestrial isopods (Oniscoidea) o n Santa Cruz Island with preliminary data for the other California islands. Bull. So. Calif. Acad. Sei. 84: 23-37. Garthwaite, R., R. Lawson, and S. Taiti. 1992. Morphological and genetic relationships a m o n g four species of Armadilloniscus Uljanin, 1875 (Isopoda: Oniscidea: Scyphacidae). J. Nat. Hist. 26: 327-338. Giard, A. 1887. Fragments biologiques. VII. Sur les Danalia, genre de Cryptonisciens parasites des Sacculines. Bull. Biol. Fr. Belgique (2) 18:47-53. Giard, A., and J. Bonnier. 1887. Contributions a l'etude des bopyriens. Trav. Inst. Zool. Lille Lab. Mar. Wimereux 5: 1-272. George, R. Y., and J. O. Strömberg. 1968. Some new species and new records of marine isopods from San Juan Archipelago, Washington, U.S.A. Crustaceana 14: 225-254. Harrison, K., and J. P. Ellis. 1991. The genera of the Sphaeromatidae (Crustacea: Isopoda). A key and distributional list. Invert. Taxon. 5: 915-952. Hatch, M. H. 1947. The Chelifera and Isopoda of Washington and adjacent regions. Univ. Wash. Publ. Biol. 10: 155-274. Hoese, B. 1981. Morphologie u n d Funktion des Wasserleitungssystems der terrestrischen Isopoden (Crustacea, Isopoda, Oniscoidea). Zoomorphology 98: 135-167. Hoese, B. 1982a. Der Ligia-Typ des Wasserleitungssystems bei den terrestrischen Isopoden u n d seine Entwicklung in der Familie Ligiidae (Crustacea, Isopoda, Oniscoidea). Zool. Jb. (Anat.) 108: 225-261. Hoese, B. 1982b. Morphologie u n d Evolution der Lungen bei den terrestrischen Isopoden (Crustacea, Isopoda, Oniscoidea). Zool. Jb. (Anat.) 197: 396-422. Holmes, S., and M. E. Gay. 1909. Four new species of isopods from the coast of California. Proc. U. S. Nat. Mus. 36: 375-379. Iverson, E. W. 1974. Range extensions for some California marine isopod crustaceans. Bull. Soc. Calif. Acad. Sei. 73: 164-169. Iverson, E. 1982. Revision of the isopod family Sphaeromatidae (Crustaccea: Isopoda: Flabellifera) I. Subfamily names with diagnoses and key. Journal of Crustacean Biology 2: 248-254. Jay C. V. 1989. Prevalence, size and fecundity of the parasitic isopod Argeia pugettensis on its host shrimp Crangon francisorum. American Midland Naturalist 121: 68-77. Kensley, B., and R. C. Brusca (eds). 2001. Isopod systematics and evolution. Crustacean Issues 13, A. A. Balkema, Rotterdam, 365 pp. Kensley, B., and M. Schotte. 1989. Guide to marine isopod crustaceans of the Caribbean. Washington, D.C.: Smithsonian Institution Press, 308 pp. Kussakin, O. G. 1979. Marine and brackish isopods (Isopoda) of cold and temperate waters of the northern hemisphere. Volume 1. Suborder Flabellifera. (In Russian.) Opred. Faune S.S.S.R. Akad. Nauk 122: 1-470. Kussakin, O. G. 1982. Marine and brackish isopods (Isopoda) of cold and temperate waters of the northern hemisphere. Volume 2. Suborder Anthuridea, Microcerberidea, Valvifera, Tyloidea. (In Russian.) Opred. Faune S.S.S.R. Akad. Nauk 131, 461 pp. Kussakin, O . G . 1988. Marine and brackish isopods (Isopoda) of cold and temperate waters of the northern hemisphere. Volume 3. Suborder Asellota. Part 1. Families Janiridae, Santiidae, Dendrotionidae, M u n n i d a e , Paramunnidae, H a p l o m u n n i d a e , Mesosignidae, Haploniscidae, Mictosomatidae, Ischnomesidae. (In Russian.) Opred. Faune S.S.S.R. 152, 500 pp. Lee, W. L., and M. A. Miller. 1980. Isopoda and Tanaidacea: the isopods and allies, pp. 536-558. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds. Stanford, CA: Stanford University Press, 690 pp. Leistikow, A., and J. W. Wägele. 1999. Checklist of the terrestrial isopods of the new world (Crustacea, Isopoda, Oniscidea). Revta Bras. Zool. 16: 1-72.

Markham, J. C. 1974. Parasitic bopyrid isopods of the amphi-American genus Stegophryxus Thompson with the description of a new species from California. Bull. So. Calif. Acad. Sci. 73: 33-41. Markham, J. C. 1977. Description of a new western Atlantic species of Argeia Dana with a proposed new subfamily for this and related genera (Crustacea: Isopoda: Bopyridae). Zoologische Mededelingen 52: 107-123. Menzies, R.J. 1951. New marine isopods, chiefly from Northern California, with notes on related forms. Proc. U.S. Nat. Mus. 101: 105-156. Menzies, R. J. 1952. Some marine asellote isopods from Northern California, with descriptions of nine new species. Proc. U.S. Nat. Mus. 102: 117-159. Menzies, R. J. 1962. The marine isopod fauna of Bahia de San Quintin, Ba|a California, Mexico. Pac. Nat. 3: 337-348. Menzies, R. J., and J. L. Barnard. 1959. Marine Isopoda o n coastal shelf bottoms of Southern California: systematics and ecology. Pac. Nat. 1: 3-35. Menzies, R. J., and D. Frankenberg. 1966. Handbook o n the c o m m o n marine isopod Crustacea of Georgia. Univ. Georgia Press, Athens, 93 pp. Menzies, R. J., and P. W. Glynn. 1968. The c o m m o n marine isopod Crustacea of Puerto Rico: a handbook for marine biologists. Stud. Fauna Curacao Other Caribb. Is. 27 (104): 1-133. Miller, M. A. 1938. Comparative ecological studies of the terrestrial isopod Crustacea of t h e San Francisco Bay region. Univ. Calif. Publ. Zool. 43: 113-142. Miller, M. A. 1968. Isopoda and Tanaidacea from buoys in coastal waters of the continental United States, Hawaii, and the Bahamas (Crustacea). Proc. U.S. Nat. Mus. 125: 1-53. Monod, T. 1926. Les Gnathiidae. Essai monographique (morphologie, biologie, systématique). Mem. Soc. Sci. Nat. Maroc. 12: 1-667. Mulaik, S., and D. Mulaik. 1942. New species and records of American terrestrial isopods. Bull. Univ. Utah 32: 1-23. Negoescu, I., and J. W. Wàgele. 1984. World list of the anthuridean isopods (Crustacea, Isopoda, Anthuridea). Trav. Mus. Hist. Nat. "GR Antipa" XXV: 99-146. Perry, D. M., and R. C. Brusca. 1989. Effects of the root-boring isopod Sphaeroma peruvianum on red mangrove forests. Mar. Ecol. Prog. Ser. 57: 287-292. Poore, G. C. B. 1984. Colanthura, Califanthura, Cruranthura and Cruregens, related genera of the Paranthuridae (Crustacea: Isopoda). J. Nat. Hist. 18: 697-715. Poore, G. C. B. 1990. The Holognathidae (Crustacea: Isopoda: Valvifera) expanded and redefined o n the basis of body-plan. Invert. Taxon. 4: 55-80. Reinhard, E. G. 1956. Parasitological reviews. Parasitic castration of Crustacea. Exp. Parasit. 5: 79-107. Richardson, H. R. 1899. Key to the isopods of the Pacific coast of North America, with descriptions of twenty-two new species. Proc. U.S. Nat. Mus. 21: 815-869. Richardson, H. 1905. A monograph on the isopods of North America. Bull. U.S. Nat. Mus. 54: 727 pp. Richardson, H. 1909. Isopods collected in the northwest Pacific by the U.S. Bureau of Fisheries Steamer "Albatross" in 1906. Proc. U.S. Nat. Mus. 37: 75-129. Rotramel, G. 1972. lais californica and Sphaeroma quoyanum, two symbiotic isopods introduced to California (Isopoda, Janiridae and Sphaeromatidae). Crustaceana, Suppl. 3: 193-197. Schmalfuss, H. 1984. Eco-morphological strategies in terrestrial isopods. Symp. zool. Soc. Lond. 53: 49-63. Schultz, G. A. 1966. Marine isopods of the submarine canyons of the southern California shelf. Allan Hancock Pac. Exp. 27: 1-56. Schultz, G. A. 1969. How to know the marine isopod crustaceans. Dubuque: W. C. Brown, 359 pp. Shiino, S. M. 1964. On three bopyrid isopods from California. Rept. Fac. Fish. Pref. Univ. Mie 5: 19-25. Stafford, B. E. 1913. Studies in Laguna Beach Isopoda, IIB. J. Ent. Zool. 5: 182-188. Stimpson, W. 1857. The Crustacea and Echinodermata of the Pacific shores of North America. Boston J. Nat. Hist. 6: 503-513. Strômberg, J. O. 1971. Contribution to t h e embryology of bopyrid isopods with special reference to Bopyroides, Hemiarthrus, and Pseudione (Isopoda, Epicaridea). Sarsia 47: 1-46. Van Name, W. G. 1936. The American land and fresh-water isopod Crustacea. Bull. Amer. Mus. Nat. Hist. 71: 1-535 (and Supplements, 1940, 77: 109-142 and 1942, 80: 299-329).

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541

Veillet, A. 1 9 4 5 . Recherches sur le parasitisme des crabes et des galathees par les Rhizocephales et les Epicarides. Ann. Inst. Oceanogr. Monaco, 22: 1 9 3 - 3 4 1 . Wagele, J. W., N. J. Voelz and J. Vaun McArthur. 1 9 9 5 . Older than the Atlantic Ocean: discovery of a fresh-water Microcerberus (Isopoda) in North America and erection of Coxicerberus, new genus. J. Crustacean Biol. 15: 7 3 3 - 7 4 5 . Wetzer, R„ H. G. Kuck, P. Baez, R. C. Brusca, and L. M. Jurkevics. 1991. Catalog of the Isopod Crustacea type collection of the Natural History Museum of Los Angeles County. Nat. Hist. Mus. Los Angeles Co., Tech. Rpt. No. 3: 1 - 5 9 . Wetzer, R., and R. C. Brusca. 1 9 9 7 . The Order Isopoda. Descriptions of the Species of the Suborders Anthuridea, Epicaridea, Flabellifera, Gnathiidea and Valvifera, pp. 9 - 5 8 . In: Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. Vol. 11. The Crustacea, Part 2: Isopoda, Cumacea and Tanaidacea. J.A. Blake and P. H. Scott, eds. Santa Barbara: Santa Barbara Museum Natural History. Wetzer, R„ R. C. Brusca, and G. D. F. Wilson. 1 9 9 7 . The Order Isopoda. Introduction to the Marine Isopoda, pp. 1 - 8 . In: Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. Vol. 11. The Crustacea, Part 2: Isopoda, Cumacea and Tanaidacea. J. A. Blake and P. H. Scott, eds. Santa Barbara: Santa Barbara Museum of Natural History. Wilson, G. D. F. 1994. A phylogenetic analysis of the isopod family Janiridae (Crustacea). Invert. Taxon. 8: 7 4 9 - 7 6 6 . Wilson, G. D. F. 1 9 9 7 . The suborder Asellota, pp. 5 9 - 1 2 0 . In: Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western santa barbara channel. Vol. 11. The Crustacea, Part 2: Isopoda, Cumacea and Tanaidacea. J. A. Blake and P. H. Scott, eds. Santa Barbara: Santa Barbara Museum Natural History. Wilson, G. D. F. and J. = W Wagele. 1 9 9 4 . A systematic review of the family Janiridae (Isopoda, Asellota). Invertebrate T o x o n o m y 8. 683-747.

Tanaidacea ANDREW N. COHEN (Plate 253)

Tanaids are small, mostly marine creatures that look like tiny lobsters with elongate bodies a few millimeters in length and conspicuous claws that they hold in front of their heads. Some species are typically found on hydroids, bryozoans, coralline algae, barnacles, or other epibenthic organisms, and sometimes in fouling communities on floats or pilings, while other species occur on mud. Most live either in tunnels or in mucous tubes cemented together from particles of detritus, where they often appear with their head and claws poking out. Some members of the family Pagurapseudidae live coiled inside tiny snail shells with their claws protruding, like minute hermit crabs. The tanaid body is subcylindrical or flattened dorsoventrally and is divided into three sections (plate 253A): a CÉPHALOTHORAX (a small carapace consisting of the cephalon fused with the first two thoracic segments), which typically bears a pair of compound eyes, two pairs of antennae, mouth parts (including paired mandibles, first and second maxillae, and maxillipeds), and a pair of clawed appendages (CHELIPEDS); a PEREON consisting of six segments or PEREONITES (thoracic segments 3-8), each of which bears a pair of legs (PEREOPODS); and a short abdomen or PLEON, with two to three free segments ( P L E O N I T E S ) , plus a terminal PLEOTELSON (the telson fused with the 6th pleonite). The pleon usually bears a series of up to five pairs of flattened, two-branched PLEOPODS and a pair of caudal appendages called UROPODS. Tanaids differ from isopods in having six rather than seven pereonites, at least one jointed uropod branch, and (with few exceptions) a pair of pincers or true chelae on the chelipeds, where these are simple or subchelate in isopods. 542

ARTHROPODA

The young are brooded in the female's brood pouch (MARSUPIUM), and emerge as epibenthic juveniles called MANCAS. The marsupium is formed on the underside of the pereon from thin plates (O6STEGITES) that project from the basal segments of one or more pairs of legs. The sexes are often dissimilar, and in some species different types of males may develop either from mancas or secondarily from females. Males of highly dimorphic species can generally be distinguished from females by their more strongly developed chelipeds, often bearing large and sometimes grotesque chelae; longer first antennae with more flagellar segments, which bear sensory setae (AESTHETASCS); larger eyes; and in some genera, fused or vestigial mouth parts. Lang (1956) divided the tanaids into two suborders, the Monokonophora with a single, small genital cone (the penial process at the end of the sperm duct) between the last pair of legs, and the Dikonophora with two. Sieg (1980) proposed an arrangement with three suborders, the Apseudomorpha (corresponding to the Monokonophora), the Tanaidomorpha, and the Neotanaidomorpha (together corresponding to the Dikonophora), which is followed here. Only the Apseudomorpha and Tanaidomorpha are represented by species in this key.

ACKNOWLEDGMENTS

My thanks to Richard Heard, Don Cadien, and Jim Carlton for their very helpful comments on this section.

Key to Tanaidacea 1.

First antenna with two-branched flagellum (plate 253B2); pleopods sometimes lacking; mandible with three-articled palp (plate 253H1); marsupium in females formed by four pairs of oostegites; not tube dwellers Apseudomorpha 2 — First antenna with unbranched flagellum; mandible without palp (plate 253H2); pleopods always present; marsupium in females formed by one or four pairs of oostegite; tube dwellers Tanaidomorpha 3 2. Five pleonites plus pleotelson; pleon coiled or asymmetrical; pereopods cylindrical; first pereopod more than twice the length of pereopods 2-5; lives in tiny snail shells Pagurotanais sp. — Two free pleonites (pleonites 3-5 fused with pleotelson) plus a sharply triangular pleotelson with three dorsal swellings, each bearing a few spines; pleon straight and symmetrical; pereopods somewhat flattened and stout; first pereopod little longer than pereopods 2 - 5 (plate 253B) Synapseudes intumescens Five pleonites plus pleotelson; five pairs of pleopods; four pairs of oostegites; uropods two-branched, though the outer branch may be inconspicuous; usually found on mud (plate 253A, 253G) Leptochelia sp. — Three to five pleonites plus pleotelson; three pairs of pleopods (one may be rudimentary); one pair of oostegites modified into ovisacs on the fifth pair of pereopods; uropods unbranched; usually found on hard substrates Tanaidae 4 4. Three pleonites plus pleotelson; two functional pairs and one rudimentary pair of pleopods (plate 253C) Pancolus californiensis 3.

nlonn

cephalo-

cheliped '

1st antenna

PLATE 253 A, Leptochelia sp., male, specimen from New England, from Richardson, 1905b (from Harger), as L. savignyi; Bl, Synapseudes intumescens, from Menzies, 1949; B2, flagellum of 1st antenna, from Miller, 1968; C, Pancolus califomiensis, modified after Richardson, 1905a, to show three pleonites; D, Sinelobus sp., damaged male, from Miller, 1968 (as Tanais sp.); E, Anatanais pseudonormani, from Sieg and Winn, 1981; F, Zeuxo normani, from Miller, 1968; G, Leptochelia sp., G l , female, specimen from New England, from Richardson, 1905b (from Harger), as L. savignyi; G2, uropod, from Holdich and Jones, 1983; HI, Apseudomorpha mandible, with 3-articled palp; H2, Tanaidomorpha mandible, without palp, from Sieg and Winn, 1979; I, 1st antenna, II, of Anatanais pseudonormani, from Sieg and Winn, 1981; 12, of Zeuxo normani, f r o m Sieg, 1980; J, uropod, J l , of Zeuxo normani; J2, of Zeuxo paranormani, from Sieg and Winn, 1981; K, Zeuxo normani, Kl, coxa of 1st pereopod; K2, distal end of carpus of 2nd pereopod, lateral view; Zeuxo paranormani, K3, coxa of 1st pereopod; K4, distal end of carpus of 2nd pereopod, lateral view, from Sieg and Winn, 1981 (figures from Sieg and Winn [19/9, 1981] used with permission of the Biological Society of Washington; figure from Holdich and Jones [1983] used with permission of Cambridge University Press).

—

Four pleonites plus pleotelson; three pairs of functional pleopods on pleonites 1-3; complete transverse dorsal rows of setae on first two to three pleonites; male cephalon strongly narrowed toward anterior (plate 253D) Sinelobus sp. — Five pleonites plus pleotelson; three pairs of functional pleopods on pleonites 1-3 5 5. First article of the first antenna twice the length of the second article (plate 253E, 25311) Anatanais pseudonormani — First article of the first antenna two and a half to three times the length of the second article (plate 25312) 6 6. Adult uropods with six articles (plate 253J1); coxa of first pereopod with longer protuberance (plate 253K1); distal end of carpus of second pereopod with four lateral and two medial spines (plate 253K2, 253E) Zeuxo normani — Adult uropods with five articles (plate 253J2); coxa of first pereopod with shorter protuberance (plate 253K3); distal end of carpus of second pereopod with three lateral and two medial spines (plate 253K4) Zeuxo paranormani

List of Species APSEUDOMORPHA PAGURAPSEUDIDAE Pagurotanais sp. (=Pagurapseudes of previous west coast literature). Pagurotanais species, which are adapted for occupying snail shells in the manner of hermit crabs, have rarely been reported in the northeastern Pacific. Menzies (1953) described P. laevis from kelp holdfasts in 4 - 6 m off Santa Catalina Island, and from 91-93 m off Guadalupe Island, Mexico; Howard (1952) noted a species (identified as Pagurapseudes sp. by Menzies) living in a caecid snail shell in Concepcion Bay, Baja, California. Lee and Miller (1980) reported females of an undescribed species, similar to but not P. laevis, at Pacific Grove in Monterey Bay "occupying small snail shells among holdfasts of red algae, low intertidal zone on rocky shores protected from strong surf"; apparently the same species was collected from red algae in the lower intertidal at Hopkins Marine Station in 1967 "in shells of Barleeia and other gastropods" and illustrated in Abbott (1987). METAPSEUDIDAE Synapseudes intumescens Menzies, 1949. Fairly common on exposed rocky shores in the low intertidal from Sonoma County to Guadalupe Island, Mexico, occasionally down to 66 m. Reported on a variety of substrates including the holdfasts and lower blades of brown and red algae, arborescent bryozoans, tunicates, the dorsal surface of the seastar Patiria, abalone shells, in Mytilus beds, and on and under rocks (Menzies 1949, 1953; Lee and Miller 1980; Abbott 1987).

13 m in Scorpio Harbor on Santa Cruz Island), but included here so it may be watched for over a broader area. Pancolus californiensis Richardson, 1905. Habitats include the sand held underneath cushionlike clumps of Cladophora in the high intertidal and the holdfasts of sea palms (Postelsia) in the low intertidal, from central to southern California; records in the Columbia River estuary and Puget Sound require confirmation. Richardson (1905a, b) described and illustrated this species as having two pleonites, but Lang (1950, 1961) re-examined the type material and provided photographs that clearly show three pleonites. Sinelobus sp. (=Tanais sp. of previous editions). Introduced species in fouling in bays and estuaries. Although Sieg (1980) assigned this species to 5. stanfordi (Richardson, 1901) (=Tanais stanfordi) based on an illustration of a damaged specimen, it is apparently not that species. S. stanfordi has two dorsal, separated, curved rows of setae on each of the first two pleonites, rather than continuous transverse rows. Zeuxo normani (Richardson, 1905) (=Anatanais normani, = Tanais normani). On bryozoans, hydroids, and red (especially coralline) algae, from British Columbia to southern California, and Japan (Hatch 1947; Miller 1968; Sieg 1980; Sieg and Winn 1981). Zeuxo paranormani Sieg, 1980. Sieg (1980) determined that part of Richardson's Zeuxo normani type material consisted of this very similar species. Reported in Humboldt Bay, Monterey Bay, and southern California. LEPTOCHELIIDAE Leptochelia spp. Usually white, sometimes greenish or tinged with orange, abundant on mudflats and among algae in pools. Leptochelia species, all under the name Leptochelia dubia (Krayer, 1842), which was first described from Brazil, have been reported from sandy intertidal flats in Puget Sound (where they prey on sand dollar larvae; Highsmith 1983, Ecology 63: 329-337; see also Highsmith 1983, Ecology 64: 719-726, sex reversal and fighting behavior in Puget Sound), from deep water (to nearly 600 m) off southern California (Dojiri and Sieg 1997), and from bay mud and occasionally in fouling communities elsewhere. These doubtless represent more than one species, possibly including both native and introduced taxa. Globally, the name L. dubia has been variously restricted to tropical-subtropical populations around the world (as reviewed by Miller 1968) or used for all temperate to tropical populations of this species group (Sieg 1986). The name Leptochelia savignyi (Kreyer, 1842), has been used as both a junior and a senior synonym of L. dubia; if the two are the same, L. savignyi is the "older" name, with page priority.

LEPTOGNATHIIDAE There are a few unconfirmed reports in shallow water in central California of the usually deepwater genus Leptognathia. However, the Leptognathiidae has been revised (Larsen and Wilson 2002), and it is unclear to which genus or family these records should now be referred.

TANAIDOMORPHA TANAIDAE Anatanais pseudonormani Sieg, 1980. See Sieg and Winn 1981. A sublittoral southern California species (as shallow as 544

ARTHROPODA

References Abbott, D. P. 1 9 8 7 . Observing marine invertebrates. Drawings f r o m t h e laboratory. Edited by Galen Howard Hilgard. Stanford University Press, 3 8 0 pp.

Dojiri, M., and J. Sieg, 1 9 9 7 . The Tanaidacea, pp. 1 8 1 - 2 7 8 . In: J. A. Blake and P. H. Scott, Taxonomic atlas of the benthic fauna of the Santa Maria Basin and western Santa Barbara Channel. 11. The Crustacea. Part 2 The Isopoda, Cumacea and Tanaidacea. Santa Barbara Museum of Natural History, Santa Barbara, California. Hatch, M. H. 1 9 4 7 . The Chelifera and Isopoda of W a s h i n g t o n and adjacent regions. Univ. Wash. Publ. Biol. 10: 1 5 5 - 2 7 4 . Holdich, D. M., and J. A. Jones. 1 9 8 3 . Tanaids: keys and notes for the identification of the species. New York: Cambridge University Press. Howard, A. D. 1 9 5 2 . Molluscan shells occupied by tanaids. Nautilus 65: 74-75. Lang, K. 1950. The genus Pancolus Richardson and some remarks o n Paratanais euelpis Barnard (Tanaidacea). Arkiv. for Zool. 1: 3 5 7 - 3 6 0 . Lang, K. 1 9 5 6 . Neotanaidae nov. fam., with some remarks on the phytogeny of the Tanaidacea. Arkiv. for Zool. 9: 4 6 9 - 4 7 5 . Lang, K. 1 9 6 1 . Further notes o n Pancolus califomiensis Richardson. Arkiv. for Zool. 13: 5 7 3 - 5 7 7 . Larsen, K. and G. D. F. Wilson. 2 0 0 2 . Tanaidacean phylogeny, the first step: the superfamily Paratanaidoidea. J. Zool. Syst. Evol. Res. 40: 2 0 5 - 2 2 2 . Lee, W. L., and M. A. Miller. 1 9 8 0 . Isopoda and Tanaidacea: the isopods and allies. In Intertidal invertebrates of California, pp. 5 3 6 - 5 5 8 . R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds. pp. 5 3 6 - 5 5 8 . Stanford, CA: Stanford University Press, 6 9 0 pp. Menzies, R. J. 1 9 4 9 . A new species of Apseudid crustacean of the genus Synapseudes from northern California (Tanaidacea). Proc. U.S. Natl. Mus. 99: 5 0 9 - 5 1 5 . Menzies, R. J. 1 9 5 3 . The Apseudid Chelifera of the eastern tropical and north temperate Pacific Ocean. Bull. Mus. Comp. Zool. 107: 4 4 3 - 4 9 6 . Miller, M. A. 1 9 4 0 . The isopod Crustacea of the Hawaiian Islands (Chelifera and Valvifera). Occ. Pap. Bernice P. Bishop Mus. 15, no. 26, pp. 299-321. Miller, M. A. 1 9 6 8 . Isopoda and Tanaidacea from buoys in coastal waters of the continental United States, Hawaii, and the Bahamas (Crustacea). Proc. U.S. Natl. Mus. 125: 1 - 5 3 . Richardson, H. 1905a. Descriptions of a new genus of Isopoda belonging to the family Tanaidae and of a new species of Tanais, both from Monterey Bay, California. Proc. U.S. Natl. Mus. 2 8 : 3 6 7 - 3 7 0 . Richardson, H. 1905b. A monograph on the isopods of North America. Washington, D.C. Smithsonian Institution, 727 pp. Sieg, J. 1 9 8 0 . Taxonomische Monographie der Tanaidae Dana, 1 8 4 9 (Crustacea: Tanaidacea). Abhandlungen Senckenbergische Naturforschende Gesellschaft 5 3 7 : 1 - 2 6 7 . Sieg, J. 1986. Distribution of the Tanaidacea: Synopsis of the known data and suggestions o n possible distribution patterns, pp. 1 6 5 - 1 9 3 . In: Crustacean Issues, vol. 4, Crustacean Biogeography, F. R. Schram, ed., Balkema, Rotterdam, The Netherlands. Sieg, J., and R. N. W i n n . 1 9 7 9 . Keys to suborders and families of Tanaidacea (Crustacea). Proc. Biol. Soc. Wash. 9 1 : 8 4 0 - 8 4 6 . Sieg, J., and R. N. Winn. 1 9 8 1 . The Tanaidae (Crustacea; Tanaidacea) of California, with a key to the world genera. Proc. Biol. Soc. Wash. 9 4 : 315-343.

stranded medusae or salps. The Gammaridea (scuds, landhoppers, and beachhoppers) (plate 254E) are the most abundant and familiar amphipods. They occur in pelagic and benthic habitats of fresh, brackish, and marine waters, the supralittoral fringe of the seashore, and in a few damp terrestrial habitats and are difficult to overlook. The wormlike, 2mm-long interstitial Ingofiellidea (plate 254D) has not been reported from the eastern Pacific, but they may slip through standard sieves and their interstitial habitats are poorly sampled.

Key to Amphipoda 1.

—

2. — 3.

— 4.

—

Gills not exceeding three pairs, female oostegites not exceeding two pairs; pleon and urosome (abdomen) vestigial and pereonite 1 fused to head 2 Gills and oostegites exceeding three pairs, abdomen and abdominal appendages well developed; head and pereonite 1 separate 3 Body segments tubular, legs with moderate hooks, free living (plate 254A) Caprellidae Body segments loosely separated, legs powerful with sharp hooks, parasites of cetaceans (plate 254B) Cyamidae Urosome with only two segments; palps of maxillipeds absent; eyes usually cover most of head but can be tiny; entirely pelagic (plate 254C) Hyperiidea Urosome with three segments; palps of maxillipeds present 4 Pleopods leaflike, vestigial, or absent; movable compound claw of gnathopods formed of articles 6 and 7 together; body vermiform; without coxal and epimeral plates; entirely interstitial (unreported from the northeast Pacific) (plate 254D) Ingolfiellidea Pleopods well developed, with few exceptions; dactyls of gnathopods formed by article 7 alone (plate 254E) Gammaridea

Gammaridea JOHN W. CHAPMAN (Plates 255-304)

The Amphipoda have been divided into the suborders Gammaridea, Caprellidea, Cyamidea, Hyperiidea and Ingolfiellidea (Schram 1986, Crustacea. Oxford University Press, New York). However, Myers and Lowry (2003) regard the caprellids, or skeleton shrimps, and the cyamids, or whale lice, as families Caprellidae and Cyamidae. These distinctive groups are covered in separate sections in this manual, for ease of recognition and identification.

The ubiquitous and abundant gammaridean amphipods are critically important in marine and estuarine shallow-water ecosystems of the northeast Pacific and warrant reliable, workable guides to the species. The numerical abundances and species and life-history diversities of the Gammaridea exceed all other eucaridan or peracaridan orders. Gammaridean amphipods are one of the most common aquatic taxa. The taxonomy and systematics of marine eastern Pacific species have greatly advanced since 1975, but many undescribed species occur in the region and little more than the names of most described species are known. The lack of research is disproportionate to these species' importance in ecosystems that are of great interest to humans.

The Caprellidae (plate 254A) occur on solid surfaces and are strictly marine or estuarine. The Cyamidae are ectoparasites of cetaceans and are occasionally found on beached whales and dolphins (plate 254B). The Hyperiidea (plate 254C) are parasites and commensals of marine macrozooplankton and are exclusively pelagic. Hyperiids are occasionally discovered free swimming intertidally or in shallow-water plankton tows, or are found attached beneath or embedded in the bells of

G a m m a r i d e a n a m p h i p o d s are critical food sources of whales, fish, and birds, (Moore et al. 2003, McCurdy et al. 2005, Schneider and Harrington 1981) and are highly sensitive to environmental alterations (Conlan 1994, Zajac et al. 2003). All amphipods care for their offspring for extended periods (Jones 1971, Shillaker and Moore 1987). Some change sex (Lowry and Stoddart 1986); others attract, hold, and defend mates (Borowskyl983, 1984, 1985; Conlan 1989, 1995a) and

Amphipoda (Plate 254)

AMPHIPODA:

GAMMARIDEA

545

Caprellidae

Eps = Epistome UL = Upper lip LL= Lower lip Md = Mandible Mx 1 = Maxilla 1 MX2 = Maxilla 2 Mxp = Maxilliped

J-lyperiidea

"

Ingolfiellidea

Subchelate

PLATE 254 Amphipoda. A, Caprellidae—Caprella mutica; B, Cyamidae—Cyamus scammoni; C, Hyperiidea—Hyperoche medusarum (Miiller, 1776) in situ; D, Ingolfiellidea—Ingolfiella fuscina Dojiri and Seig, 1987; E, Gammaridea—generalized body; F, G, generalized upper lip; H, generalized mandible; I, generalized head; J, generalized lower lip; K, generalized maxilla 1; L, generalized maxilla 2; M, Polycheria mandible; N, generalized maxilliped; O, uropod 1, Paragrubia uncinata; P, telson, Eohaustorius; Q, telson, Batea lobata; R, telson, Parallorchestes leblondi; S, telson, Stenothoe estacola; T, telson, Paracorophium sp.; U, gnathopod 1, Aoroides secundus; V, gnathopod 2, Ericthonius brasiliensis; W, gnathopod 1, Americhelidium shoemakeri; X, gnathopod 2, Americhelidium rectipalmum; Y, gnathopod 1, Stenothoe valida (figures modified from: Barnard 1953,1962c, 1965, 1975; Barnard and Karaman 1991a, 1991b; Bousfield 1973; Bousfield and Chevrier 1996; Bousfield and Hendrycks 2002; Bousfield and Kendall 1994; Doiji and Sieg 1987, Flores and Brusca 1975; Gurjanova 1938; Margolis et al. 2000; Todd Miller, personal communication; and Platovoet et al. 1995).

territories (Connell 1963). Some use chemicals for defense (Hay et al. 1987, Hay et al. 1990) or are repelled by defensive chemicals (Hay et al. 1988, 1990; Cronin and Hay 1996a, 1996b). Some species undergo risky long-distance migrations (Chess 1979, Mills 1967, Watkin 1941), and others exploit, imitate, parasitize, eat (Crane 1969, Cartwright and Behrens 1980, Goddard, Skogsberg, and Vansell 1928), displace, or attack other invertebrates and fish (Bousfield 1987, Wilhelm and Schindler 1999); burrow in wood (Barnard 1955c) or macroalgae (Conlan and Chess 1992); or alter sediment dynamics in estuaries (Olafsson and Persson 1986). Lysianassid amphipods are adapted for engorgement and are among the most important carrion feeders in the sea (Dahl 1979, Thurston 1990). Some amphipods die of unknown diseases (Pelletier and Chapman 1996), which they may introduce with them by humans to new areas (Slothouber Galbreath et al. 2004). Genus-level variation within most families occurs in geographical patterns that correspond with the Cretaceous continental divisions. However, these evolutionary patterns have been and continue to be obscured by human introductions of shallow-water amphipods among continents. One in 10 of the eastern Pacific shallow-water species treated herein are likely introductions. Morphologies for stridulation (to make harsh sounds) occur among Isaeidae, Melitidae, and perhaps Phoxocephalidae and are likely adaptations for attracting mates. Their sounds have not been recorded and their adaptive values have not been resolved. Most amphipod species are beautiful (flamboyant) in color and form, but color pictures of live amphipods are seldom published and only a few are posted on the internet. All coastal marine and estuarine gammaridean amphipod families, genera, and species from the Columbia River to Point Conception reported from < 1 0 m depths are included in the keys or listed. A few species known only from depths > 1 0 m or slightly north or south of the region are listed and indicated by asterisks. These latter species are recognized from limited taxonomical or geographical information and thus, although not clearly within the geographical region, cannot be reliably discounted. Few of these latter species are included in the keys. The first edition of Light's Manual (Light 1941) covered 47 gammaridean species; the second edition Barnard (1954d) covered approximately 61, and the third edition (Barnard 1975) included 141 species. This section includes 351 species. The exponential increase in species (including nearly half of the species discovered or resolved since the 1970s) is due largely to the contributions of Bousfield, Conlan, Hendrycks, and coworkers at the Canadian Museum of Nature. The many species and additional character variations and types of taxonomic characters that Bousfield and his colleagues discovered reveal the paramount importance of distinguishing interspecific and intraspecific variation. The taxonomic outlines for this section rely extensively on their contributions. General treatments of gammaridean amphipod taxonomy and systematics also include Barnard and Barnard (1983a, b), Barnard and Karaman (1991a, b), Bellan-Santini (1999), Bousfield (2001), Myers and Lowry (2003), Serejo (2004) and Staude (1997). Additional guides to amphipod taxonomic literature of the eastern Pacific include bibliographies (SCAMIT 2001) and Internet postings, such as the "Amphipod Newsletter." Although intended to be comprehensive within the region, these keys are not reliable outside of their specified geographic,

bathymétrie, or ecological boundaries. Barnard's (1975) emphasis on durable and external morphology is followed with "natural" dichotomies sacrificed when artificial distinctions are more apparent, where family, genus, or species relationships remain poorly resolved, where difficult dissections or magnifications of greater than 40x can be avoided, or where characters are fragile or difficult to observe or to define. Occasional notes in the species lists are to assist with identifications, indicate pitfalls, or provoke interest. The Gammaridea (plate 254E, center) (legged order) have a clearly defined CEPHALON (HEAD), a thorax or PEREON of seven freely articulated segments, (PEREONITES = PE,_7), a six-segmented ABDOMEN (PLEON) of three (PLEONITES = PL!_ 3 ) (PLEOSOME) a n d three (UROSOMITES = UR,_ 3 ) (UROSOME) and a TELSON ( = T ) . T h e

TELSON is a flap over the anus attached to pleonite 6 (urosomite 3). Most gammarideans are laterally flattened. Each pleonite has a pair of PLEOPODS (swimmerets). The pleopods are complex and seldom illustrated. The lower lateral edges of the pleonites that extend below the body are EPIMERA (=EP,_ 3 ). The urosomites of the UROSOME each bear rigid, lateral, posterior projecting UROPODS (=U ] _ 3 ). The uropods usually consist of a basal PEDUNCLE and one or two distal RAMI. The appendages of the head (plate 254E, 2541 center left) are, in order from anterior to posterior: ANTENNA 1, ANTENNA 2 (=AT!_ 2 ) (plate 254E, center left), UPPER LIP (UL) (plate 254F, 254G, bottom left), MANDIBLE (MD) (plate 254H, 254M), LOWER LIP (LL) (plate 254J), MAXILLA 1 (MX,) (plate 254K), MAXILLA 2 (MX2) (plate 254L), and the MAXILLIPED (MXP) (plate 25 4N). ANTENNA I (plate 254E, center left) is composed of a threearticle peduncle and a FLAGELLUM of variable article numbers. An ACCESSORY FLAGELLUM extends from the distal medial surface of the third peduncle article and is prominent on many species and families but is also minute (requiring high magnification to observe) or absent in other species and families. ANTENNA 2 (plate 254E, center left) consists of five peduncular articles and a flagellum of variable article numbers. The morphologies of the peduncle articles and the flagellum and the distributions and morphologies of their spines and sensory organs (calceoli) are important taxonomic characters (Steele and Steele 1993, Bousfield 2001). Count peduncle articles from the fifth backward because articles 1-3 are usually more difficult to distinguish than the difference between peduncle and flagellum. The EPISTOME (EPS) (plate 254F, bottom left) is a cephalic sclerite attached to of the anterior upper lip and usually fused to the upper lip when it is large. The epistome is taxonomically important mainly in Phoxocephalidae and Lysianassidae. However, the epistome varies greatly in other families and perhaps the most spectacular is the noselike extension of Proboscinotus loquax (plate 256B) for which this species is named. The UPPER LIP (plate 254F, 254G, bottom left) is variable among species and families but seldom used for taxonomic purposes unless it has a well-developed epistome. Najnidae and Pleustidae have asymmetrical upper lips. The MANDIBLE (plate 254H, 254M) has a MOLAR (plate 254M), which can be large and triturative, reduced, or vestigial and without a grinding surface. The molar often bears a large pinnate seta (illustrated in plate 254M). The apex of the mandible is the INCISOR (plate 254M), which usually projects as a series of teeth. Above the incisor is the LACINIA MOBILIS (plate 254M), a spinelike movable appendage of the medial mandibular edge AMPHIPODA:

GAMMARIDEA

547

that consists of variable numbers of individual or fused articulated spines (see E. Dahl and R. T. Hessler, 1982, Zool. J. Linnean Soc. 74:133-146 on origin, function and phytogeny). The lacinia mobilis (plate 254M) varies laterally in Phoxocephalidae and Pleustidae and is used for species distinctions among pleustids (Bousfield and Hendrycks 1994a, 1994b; Hendrycks and Bousfield 2004). A row of accessory spines usually occur above the lacinia mobilis (plate 254M). The mandible also usually bears a triarticulate PALP (plate 254H, 2541). The mandibular palp is sometimes only one or two articles and is lacking in Dogielinotidae, Eophliantidae, Hyalidae, Hyalellidae, Najnidae, Phliantidae and Talitridae and variably present in Dexaminidae and Synopiidae. The LOWER LIP (plate 254J) lies behind the mandibles and in front of the first pair of maxillae. The tower lip can be difficult to remove without damage, (see instructions for dissection below) but is a particularly important character for distinguishing ampithoid and pleustid species and genera and for distinguishing eusirids from pleustids. The MAXILLA 1 (plate 254K) have an inner and an outer plate and a palp of two or more articles. The inner plate is not closely contiguous with the outer plate and can be overlooked or lost during dissection when it remains partially attached to the lower lip. The outer plate bears heavy distal spines. The palp is occasionally reduced to one article or is absent. The MAXILLA 2 (plate 254L) are two simple, setose plates and lack a palp. The MAXILLIPED (plate 254N) usually covers the other mouth parts from below and is therefore usually removed first in mouth part dissections. The maxillipeds are fused at the base and appear as a single branched appendage. Each branch has an inner and an outer plate and a palp that is usually composed of four articles. The palp is occasionally reduced to three articles (absent in hyperiids), and the plates are often severely reduced in size. The distal palp article is usually pointed and referred to as a dactyl. The amphipod ROSTRUM (plate 2541) is variable and can extend over or between the first antennae, or it can be greatly reduced or absent. Some amphipods are blind. Most have lateral eyes of one to hundreds of ommatidia. The ocular lobe (plate 2541) of many Gammaroidea, including Hadzioidea, Eusiroidea, and Corophioidea, extends over the second antenna and usually forms a ventral antennal sinus notch. Oedicerotidae and Synopiidae ommatidia merge dorsally into a single eye. Argissidae eyes each consist of four lenticular facets and Ampeliscidae eyes consist of two corneal lenses. Most uropods (=u 1 _ i ) (plate 254E, right; 2540) are composed of a PEDUNCLE and one or two RAMI (plate 2540). The inner and outer rami are labelled in illustrations as R, and R„ respectively, or simply "," and " 0 ." The rami vary from bare or spinose stubs, to short ornamented appendages with fine teeth and denticles, to tubular, to long and spinose, lanceolate (spear-shaped), and to foliose (leaf-shaped). Many species have a large peduncular tooth extending between the rami (plate 2540) of the first or second uropods or other large spines that are important taxonomic characters. Most rami are of a single article, but on uropod 3, outer rami of two articles are characteristic of Lysianassidae, Liljeborgiidae, Gammaridae, Hadzioidea, Melitidae, and Stenothoidae. General TELSON (=T) morphologies (plate 254P-254T, bottom center) are, respectively: INDISTINCT (plate 254P), LAMINAR CLEFT (plate 254Q), FLESHY CLEFT (plate 254R), LAMINAR UN-

CLEFT (plate 254S), and FLESHY UNCLEFT (plate 254T). Fleshy 548

ARTHROPODA

and laminar telsons range greatly in form between CLEFT (split into two lobes) and UNCLEFT (fused into a single piece), LAMINAR telsons are dorsoventrally thin (flattened). Some laminar telsons (Pleustidae) have a ventral keel that creates a thickened appearance from a lateral view even though the edges and apex are laminar. Fleshy telsons are at least one-third as thick as they are wide or long. The tonguelike telsons of some Stenothoidae (plate 254S) seem to fall in between, but they are mostly longer and wider than thick. Haustoriidae telsons (plate 254P) are referred to as indistinct because the widely separated lobes are not clearly fleshy or laminar. "Amphipod" means "double feet." The amphipod thorax (PEREON) (plate 254E, center) bears seven pairs of walking legs (PEREOPODS = P ^ ) . Naming systems for amphipod legs (pereopods) vary. The first two pereopods are adapted primarily for feeding, defense, cleaning, and reproductive activities. Evolution of gnathopod morphology for feeding, mating, and defense is unlikely to have occurred in response to the same selection processes as pereopods 3-7, which are used for attachment, mobility, and nest or tube construction. The refere n c e to p e r e o p o d s 1 a n d 2 as GNATHOPODS (=G]_ 2 ) a n d

continuing the sequence with PEREOPODS 3-7 (=P3_7) is used here (plate 254E, center; plate 254U-254Y). However, reference to all walking legs as pereopods 1-7 is also correct. Beware of amphipod descriptions previous to the 1980s that commonly refer to gnathopods 1 and 2 and then to pereopods 2-7 as pereopods 1, 2, 3, 4, and 5. Each pereopod has seven ARTICLES (= A J _7) (plate 254E, center) ("joint" is an inappropriate term). These seven articles are, respectively,

t h e COXA, BASIS,

ISCHIUM, MERUS,

CARPUS,

PROPODUS, a n d DACTYL (plate 254E, center). The COXAE (=CX!_ 7 )

(plate 254E, center) is pereopod article 1 and often expands from its attachment point on the body downward to cover remaining parts of the pereopod. The coxae are normally the most conspicuous articles of the pereopods. Reference to the coxae and dactyls and then to article numbers 2-6, rather than MERUS-PROPODUS, is common usage, but exceptions are numerous in this key and elsewhere when descriptions require fine details or distinctions. Details of the prehensile gnathopod morphology are critical in amphipod taxonomy, MEROCHELATE (plate 254U, tower right) refers to the condition in which articles 5 (carpus), 6 (propodus), and 7 (dactyl), respectively, fold around the merus (article 4) to become prehensile, CARPOCHELATE (plate 254V) refers to the condition in which articles 6 (propodus) and 7 (dactyl) fold around the carpus (article 5) to become prehensile. The posterior edge of gnathopod article 6 that is overlapped by the dactyl is commonly referred to as a HAND or PALM, CHELATE (plate 254W) refers to the dactyl (article 7) closing onto an extended finger of the palm at >90°. TRANSVERSE (plate 254X) applies to pereopods and gnathopods on which the dactyl closes against a palm at a 90° angle, SUBCHELATE (plate 254Y) is the condition where the dactyl closes against the palm at less than a 90° angle, SIMPLE refers to the condition in which the dactyl does not fold onto article 6 and is thus not prehensile. Thus, most pereopods (P 3 . 7 ) (plate 254E, center) are simple. Sexual differences are distinct in many species, with males bearing enlarged, heavily prehensile gnathopods; extra large, long, and densely setose antennae; large and densely setose uropod 3; powerful pleopods; and, occasionally, large eyes. However, many species have few external sexual differences. Mature males have a minute pair of PENIAL PROCESSES (penes) that hang ventrally from the pereonite 7 between the coxae. Penes often bear tiny spines that are difficult to see and, after

the seventh pereopods are removed, can be confused with broken ends of tendons. The penes can also be confused with gills (plate 255MM), which are attached to the coxae and vary greatly in shape and size among amphipod families. Among appendages of the pereopods, if they break off easily, they are probably gills. Breeding females bear up to six laminate brood plates (OOSTEGITES) (plate 255MM, 255NN) in the space between the bases of coxae 2 and 5. The oostegites form a pericardium (marsupium or brood chamber) that encases the eggs and for which peracaridans are named. The oostegites are attached to the coxae medially and can be confused with the gills but are clearly distinguished by their long, interleaving, pinnate setae on mature females.

COLLECTION AND

DISSECTION

The great diversity and superficially similar morphologies of gammaridean amphipods could make their taxonomy appear difficult, but they don't. Sharp forceps, sometimes probes tipped with insect pins or fine sewing needles, a stereomicroscope with magnifications ranging between 6x and 40x, patience, and interest to learn the simple anatomy, follow instructions, and learn from mistakes are all that is needed to identify amphipods. Dissections of mouth parts under high magnification can appear daunting, but preparation is more important than skill. The top half of 50-mm petri dishes are good containers for dissections. Glass is preferable. Detach the base of transmitting stereoscopes that do not have hand rests or otherwise provide a platform level with the specimens that will allow palms to rest on a surface and stabilize both hands for the fine manipulations that are needed. Replace or cover clear glass microscope stages with black or dark blue covers to prevent transmitted light and maximize reflected light. Adjust the light source to maximize unobstructed illumination of the specimen without reflection from overlying liquid surface. A compound microscope with 100x-l,000X magnifications (and transmitted light) is necessary to observe tiny appendages or fine anatomical characters. Prepare mounts of these characters under the stereoscope using the equipment above. Tiny parts are easy to lose. A slide placed off center on the petri dish with a centered drop of glycerin will allow continuous observation of the transfer of dissected parts directly from the dissecting dish into the glycerin drop. Begin with numerous large, mature, unbroken specimens of a single species bearing both pairs of antennae, all three pairs of uropods, a telson, both pairs of gnathopods, and at least the first three articles of all other legs. Previously identified species, if available, limit the need for guessing at the conditions of difficult-to-find or -observe characters. Readily identifiable gammaridean amphipods that are easy to find include beach hoppers (Talitridae) of open coastal beaches; the large green Ampithoidae of docks and floats in bays and estuaries, and Corophiidae and Aoridae of estuary mudflats and fouling communities are usually large enough for observations of basic morphology and anatomy under low magnification. Amphipods occur nearly everywhere that permanent water occurs, and they are easy to find by washing aquatic sediments or plants on a 0.5 mm or 1.0 mm mesh sieve or in a section of plastic window screening or by sweeping with a dip net. Spread the washed material in a shallow pan and sort out the animals using light forceps or plastic eyedropper (pipette).

Freezing kills painlessly and does not ruin amphipods for later use if they are preserved in 70% alcohol within a few hours. Suitable preservation for morphological analyses includes fixing the animals in 10% formalin for a few days before permanent storage in 70% alcohol. Preserve the specimens directly in alcohol if they are to be used for molecular genetics analyses. For dissection, immerse a specimen in 70% alcohol that is sufficiently deep for manipulations using forceps without distorting the liquid surface directly over the specimen. The best light is usually by reflection from the sides of the specimen rather than transmitted from beneath. Two lamps from different angles are better than one. Cool fiber optics lamps are better than direct, hot light from tungsten lamps. Examine coxa 1 to determine whether it is significantly smaller than or hidden by coxa 2, or nearly as large as coxa 2 and freely visible. Tilt and rotate the amphipod and adjust the light(s) to provide maximum lateral illumination and contrast of plate and segment edges for these observations. Count the coxae to ensure that all seven are being observed. Manipulate the telson to determine its fleshy or laminar condition. A laminar telson is freely articulate at its base. Remove the urosome and mount it dorsal side up on a depression slide filled with glycerin overlain with a coverslip. Note whether the urosome consists of three separate segments or has one or two fused segments. The rami of uropod 3 are often lost during preservation. Check the mounted urosome and count the rami of the uropods (usually three pairs). Damaged uropods are especially common among Iphimediidae, Megaluropidae, Oedicerotidae, Pleustidae, Eusiroidea, and a few genera of the Podoceridae. Some Gammaridae and Hyalidae have extremely short or inconspicuous inner rami. Remove uropod 3 if necessary and mount it on slide for observation under lOOx magnification or more. A sclerotic socket usually remains to mark the presence of a ramus that has been lost. S P I N E S and SETAE are the ends of a range of homologous structures. Setae are highly flexible and can be bent in the middle without breaking. Spines are thickened setae that are less flexible and can break when bent. Subtle differences in the placement and arrangement of spines and setae are becoming critical characteristics for distinguishing species in many families. Whether the distal spines of uropod 1 are apicomedial (between the rami) or apicolateral (lateral to the rami), for example, are critical taxonomic characters for distinguishing genera of Phoxocephalidae. Examine antenna 1 for the presence of an accessory flagellum on the distal medial corner of peduncle article 3 and its condition, if it is present. If an accessory flagellum is not obvious, tiny accessory flagella are readily observed by mounting antenna 1 in glycerin on a slide with a bit of clay or a few grains of sand under a thin coverslip. The sand or clay on the slide allow movement of the coverslip, which can be used to roll appendages to suitable angles for observation. The glycerin slide mounts also work for other small appendages requiring high magnification observations. Make a slide for each appendage. Hold the body with a dissecting pin or forceps and remove pereopod 5, including the coxa, by grasping deeply into the basal musculature with forceps. Place the pereopod on a drop of glycerin with the outside up. Add the coverslip. Repeat this process for pereopods 4 and 3 and for gnathopods 2 and 1 in order. Remove and mount the urosome. Label the slides as they are produced using a grease pencil or tape labels.

AMPHIPODA:

GAMMARIDEA

549

Study the slide of the urosome (telson and urosomites 1-3) and note whether the urosomites are fused, the proportionate lengths of the urosomites, the numbers of uropods, the number of rami on the uropods, the relative lengths of the uropods, and the lengths of the rami relative to the peduncles of the uropods. Examine the general condition of gnathopods 1 and 2. Proceed in the key as far as is possible with these observations. Make additional slides as needed, or fully dissect the amphipod into its component parts. (About 20 slides are required to mount each major character of a specimen.) Observations on the head and EPIMERA (the ventral, lateral, posterior sides of the pleonites) can be difficult using a stereomicroscope. Remove the pleopods for a clearer view of the epimera. Closely observe the head, noting the general outline, the shape of the ocular lobe and any anterior or ventral incisions before removing the antennae or any mouth parts. Test the amphipod for shrinkage in glycerin before mounting parts in critical dissections. Use a slow-drip method for an hour to replace the alcohol preservative with glycerin if the amphipod develops significant "frost," or air bubbles. Hyalidae are especially sensitive to glycerin. Spear the head with a needle or clutch it dorsally with forceps in a dish of alcohol to remove mouth parts. Right-handers should hold the left side down with the left forceps or needle and point the mouth parts toward 12 o'clock. Mouth parts are easy to dissect from back to front. Grab the maxilliped across its base with the right forceps to pull it off. Mount it in a drop of glycerin with the curved posterior side upward and without separating the lobes or palps. Follow this procedure to remove and mount maxilla 1 and 2. The mandibles are heavily scleroticized, solidly attached, or somewhat twisted, can be difficult to remove. If possible, note the presence or absence of the mandibular palps before dissecting the mandibles because they are easily lost during dissection. Use extreme care not to grab the mandible near the molar, incisor, or palp because these characters are readily shattered or broken away. Rotate the mandible outward with slight pressure of the forceps to identify the medial molar before grasping heavily. Remove the mandible by grabbing deeply into and tearing out the fleshy and flexible tissue immediately behind it and place it in a puddle of glycerin on a slide. This mass will often include the right and left maxilla 1 and lower lip attached together. Tease away the lower lip, leaving the inner plates of the maxillae attached to their outer plates. Separate and mount the maxillae 1 in glycerin under a coverslip. Mount each mandible in glycerin with sand grains under a coverslip. The sand will allow the mandibles to be rolled over and properly oriented for observation. Label the left and right mandibles. A clear view of the epistome is possible from the lateral front of the head. Pull the first and second antennae forward and up. The epistome reaches forward beyond the mouth part bundle and can be extended into a significant tooth, spike, or cusp. Care is needed not to confuse the EPISTOMAL SPIKE with the MANDIBULAR PALPS; the latter are flexible and setose whereas the epistomal spike is solid, smooth, and fixed. An epistomal spike may also be confused with the lateral EXCRETORY SPOUTS or ENSIFORM PROCESSES projecting from the ventral side of the second antennae peduncle article 2 of phoxocephalids.

tered in the illustrated keys into similar groups where whole body pictures of each genus are attempted. "Flipping" can be a good way to quickly search among taxa, and the plates are ordered, in part, for this purpose. Use keys forward and backward from known species to test or "verify" identifications (and the key). Read the ecology, natural history, and identification notes in the species lists for more hints on their identities. Most anatomical characters referred to in the keys are clustered in the illustrations of plate 254 to allow quick access to explanations of morphologies referred to in the keys. Mark or copy plate 254 for continuous reference to anatomical notes. First identifications should begin with large mature specimens in good condition, free of debris or damaged appendages. Return to a mature specimen of the opposite sex or the sex appropriate for the particular key to check critical characters. Test identifications further by reference to any additional relevant literature. Keys interpret nature from incomplete knowledge. Even the best keys can be wrong, incomplete, or unclear. Many northeast Pacific amphipod species remain to be identified or fully described. New species continue to be introduced. Identifications of species using a single key can provide only a first level of confidence. Specific identifications are increasingly reliable as they are based on increasing numbers of characters and include more biogeographic, ecological, and natural history information. Comparisons with original taxonomic descriptions or with type specimens provide increasingly confident identifications. Character distinctions should also account for variations due to size, reproductive development, and age. Specific differences are nearly all based on adult morphologies and often on only one sex. The opposite sex often is too poorly described for specific distinctions. Groups emphasizing males usually provide a lower proportion of specimens suitable for identifications. Species are keyed out twice in some cases when sexual characters are critical in the taxonomy and where sexual dimorphism is known.

TABULAR KEY TO FAMILIES

In addition to flaws in the keys, damaged specimens (from gut contents in particular) often lack critical anatomical features, preventing progress directly through dichotomous keys. The gammaridean families and suborders are therefore distinguished additionally in a tabular key and followed by notes on distinctive external and readily observed internal characters. The auxiliary information on the shapes of heads, gnathopods, telsons, and third uropods (and quick-to-observe internal characters) are useful for identifying families "at a glance," or to test questionable endpoints. Gammaridean families and suborders are arranged in Table 5 by telson shape and condition, then by the number and shapes of the rami of uropod 3, and then by external similarity. Use the tabular key and notes to check the dichotomous keys (and vice versa) and broaden searches for family placements of specimens missing critical morphological characters. The following notes, in order of family or suborder, include salient characters that would not readily fit in the tabular key.

TAXONOMIC NOTES BY FAMILY AND SUPERFAMILY AIDS TO IDENTIFICATION

Characters referred to in the keys are usually illustrated in the introduction, family key, or keys to species. Families are clus550

ARTHROPODA

AMPELISCIDAE tiny eyes when present, two separated dorsal frontal lenses when present, massive head, pleated gills, build pocket-shaped silt tubes.

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40x (plate 257U-257W); telsons deeply cleft or evenly rounded and with few or n o prominent distal setae or spines (plate 257X, 257Y) 35 33. Pereopods 6 and 7 similar in length and form, ventral cephalic margin extended (see arrow; plate 25 7N) entirely marine Urothoidae (plate 288) — Pereopod 7 different in form and at least 40% shorter t h a n pereopod 6 (plate 256M); ventral cephalic margin reduced (see arrows; plates 256M, 25 7Z) 34 34. Rostrum extended and visorlike (plate 256M, 256Y) entirely marine or high-salinity estuary Phoxocephalidae (plates 289-292) — Rostrum minute; entirely freshwater or low-salinity estuary (plate 25 7Z) Pontoporeiidae (plate 293) 35. Telson evenly rounded (plate 257X) or emarginate (plate 255J) 36 — Telson deeply cleft (plate 25 7Y) Eusiroidea (Pontogeneiidae) (plates 296-297) 36. Ventral antennal sinus without a notch (plate 257W); upper lip ventrally bilobed (plate 257AA, 257BB); lower lip with inwardly tilting pillow shaped inner and outer lobes 556

ARTHROPODA

—

37.

—

38. — 39.

—

(except for Anomalosymtes coxalis) (plate 257CC) and with short mandibular extensions (arrows, plate 257DD, 257EE) Pleustidae (plates 294-295) Ventral a n t e n n a l sinus with a n o t c h (plate 256N); lower lip ventrally convex (plate 257FF); i n n e r a n d outer lobes of lower lip n o t pillow shaped a n d bearing large extensions of t h e outer lobes (plate 257GG, 257HH) Eusiroidea (Calliopidae) (plates 296-297) Pereopods 5 - 7 dactyls small and straight (plate 257Q); uropod 3 rami sharply pointed distally, nearly equal in length and lined with single thick spines (plate 25 711, 257JJ); molar reduced (plate 257KK) Liljeborgiidae (plate 298) Pereopods 5 - 7 dactyls stout and slightly curved (plate 25 7R); uropod 3 rami with thick spines in clusters or inner ramus greatly reduced (plate 257LL-257NN); molar prominent (plate 2 5 7 0 0 , 257PP) 38 Urosome with dorsal clusters of large stout spines or setae (plate 257QQ) Gammaroidea (plate 299) Urosome dorsum bare (plate 25 7P) or variously toothed (plate 257RR) but without clusters of spines 39 Head with an inferior antennal sinus (plate 257R, 257SS, 257TT); accessory flagellum of three or more segments (plate 257R) Hadzioidea (plates 300-301) Head lacking inferior antennal sinus and accessory flagellum of two segments (plate 257UU) Crangonyctidae (plate 302)

LISTS OF G A M M A R I D E A S P E C I E S BY FAMILY

Species lists include author, notes, species lengths and d e p t h ranges. Species lengths are a crude index of size based o n the distance from t h e distal end of t h e head to t h e posterior edge of the telson and are usually of the largest specimens reported. Species preceded by an asterisk are not in the key or are out of t h e range of t h e region.

EOPHILANTIDAE

Eophliantidae are kelp burrowers of the eastern Pacific and southern hemisphere. This rare, antlike species is t h e only member of the family with a fused telson. Urosomites 2 and 3 are also fused. Reproductive individuals are u n k n o w n . The n a m e Lignophliantis indicates an eophliantid with lignin in its gut (Barnard 1969a: 104). KEY TO EOPHILIANTIDAE

1.

Tiny tubular body, lacking accessory flagellum, with sparse body setae and spines and pereonites lacking a ventral flange (plate 258A); mandible lacking palp or molar (plate 258B); uropod 3 consisting of a peduncle only (plate 255H) Lignophliantis pyrifera

LIST OF SPECIES

Lignophliantis pyrifera Barnard, 1969a. Bores into haptera of the kelp Macrocystis pyrifera. A lack of records is likely due to low probability of retention on standard 0.5 m m mesh collecting sieves normally used and the difficulty of recognizing such a small, unusual amphipod in nearshore algae samples; 1.4 m m ; intertidal—3 m.

Pontoporeiidae CC

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Crangonyctidae

PLATE 257 Family Key. A, coxae 1-4, Elasmopus antennatus; B, head, C, telson, D, mandible, Argissa hamatipes; E, head, F, urosome, G, mandibular palp, H, molar, Gibberosus myersi; I, antenna 1, Macronassa pariter; J, antenna 1, Ocosingo borlus; K, gnathopod 2, Macronassa macromer; L, gnathopod 2, Pleusirus secorrus; M, gnathopod 2, Urothoe varvarini; N, body, Urothoe marina; O, antenna 2, Grandifoxus grandis; P, pereopod 5, Grandifoxus grandis; Q, body, Listriella diffusa; R, body, Elasmopus antennatus; S, telson, Anisogammarus pugettensis; T, telson, Crangonyx pseudogracilis; U, accessory flagellimi, Oligochinus lighti; V, antenna 1 and accessory flagellum, Anomalosymtes coxalis; W, body, Kamptopleustes coquillus; X, telson, Chromopleustes lineatus; Y, telson, Pontogeneia rostrata; Z, head, Monoporeia affinis; AA, upper lip, Anomalosymtes coxalis; BB, upper lip, Chromopleustes lineatus; CC, lower lip, Anomalosymtes coxalis; DD, upper lip, Holopleustes aequipes; EE, lower lip, Chromopleustes lineatus; FF, upper lip, Oligochinus lighti; GG, lower lip, Accedomoera vagor; HH, lower lip, Paracalliopiella pratti; II, female uropod 3, Listriella diffusa; JJ, male uropod 3, Listriella diffusa; KK, mandible, Listriella metanica; LL, uropod 3, Crangonyx pseudogracilis; MM, uropod 3, Melita nitida; NN, uropod 3, Elasmopus antennatus; OO, mandible, Maera similis; PP, mandible, Megamoera dentata; QQ, urosome, Gammarus daiberi; RR, urosome, Desdimelita microdentata; SS, head, Melita nitida; TT, head, Maera jerrica; UU, head, Crangonyx pseudogracilis (figures modified from: Barnard 1954a, 1959a, 1959b,1960a, 1962b, 1969a, 1969b, 1979a; Bousfield 1958b, 1973; Bousfield and Hendrycks 1995b; Gurjanova 1953; Hendrycks and Bousfield 2004; Jarrett and Bousfield 1996; Krapp-Schickel andjarrett 2000; Lincoln 1979; McKinney 1980; Segerstrale 1937; and Thomas and Barnard 1986).

Lignophliantis pyrifera

Pariphinotus escabrosus

Pariphinotus

PLATE 2 5 8 Eophliantidae and Phliantidae. A, B, Lignophliantis pyrifera; C, E, Pariphinotus escabrosus; D, Pariphinotus from: Pariphinotus escabrosus, Pariphinotus seclusus of: Barnard 1969a, 1979a, and Shoemaker 1933).

PHLIANTIDAE

2.

Phliantidae look more like isopods than amphipods, with their simple or barely subchelate gnathopods, square rostrum, dorsoventrally flattened calcified body, short antennae, splayed coxae, and the lack of a third uropod.

— 3.

KEY TO PHLIANTIDAE

1.

Body broad, dorsoventrally flattened (plate 258C, sex not known); mandibule lacking palp and molar (plate 258D); coxae splayed (plate 258C, 2S8E); rostrum square and distally annulated (plate 255W) Pariphinotus escabrosus

— 4.

—

5.

LIST OF SPECIES

Pariphinotus escabrosus (Barnard, 1962b) (=Heterophlias). Moderately abundant under rock substrata, in kelp Macrocystis holdfasts, rare in surfgrass Phyllospadix. P. escabrosus was initially misidentified as Pariphinotus seclusus Shoemaker, 1933, from the Dry Tortugas, Florida, which does not occur in the Pacific; 3.8 mm; intertidal—16 m. PODOCERIDAE

Podoceridae have an extended urosomite 1, minute or absent uropod 3, and fleshy, entire telsons. The delicate antennae, pereopods, and pleopods of preserved specimens are usually missing. Some species are brilliantly pigmented and occur in highly visible locations (Goddard 1984). An unidentified Podocerus of Oregon (probably in the P. "cristatus" group) appears to be a Batesian mimic of Flabellina trilineata (Goddard 1984, Shells and Sea Life 16: 220-222). The particularly long urosomite 1 of males may be an adaptation for their powerful pleopods, which are used for pelagic swimming in search of mates (Conlan 1991, Hydrobiologia 223: 255-282). The broad geographic ranges of many podocerids are likely due to human introductions or to poorly resolved species definitions. KEY TO PODOCERIDAE

1.

Urosomites 1-3 separate and antenna 1 shorter than antenna 2 (plate 259A, 259B); uropod 3 minute (plate 259B) 2 — Urosomites 2 and 3 fused (plate 259C); antenna 1 as long or longer than antenna 2, uropod 3 absent (plate 259D) 4 558

ARTHROPODA

—

6.

—

seclusus

seclusus

(figures modified

Pleonites with raised carina (plate 259E) Podocerus "cristatus" Pleonites without raised carina (plate 259B) 3 Male gnathopod 2 article 4 extended forward (plate 259F) Podocerus spongicolus Male gnathopod 2 article 4 not greatly extended forward (plate 259G) Podocerus brasiliensis Pereopods 3 and 4 article 2 expanded and pereopods 5-7 lengths 1 . 4 times width of article 2 (plate 262A, 262N, 2620) 6 Male gnathopod 1 article 5 with anterior setae bundles and article 5 and article 2 widths nearly equal (plate 262P, 262Q) 8 Gnathopod 1, anterior and lateral edges of article 2 densely setose and hind margin of article 2 bare (plate 262A) Aoroides columbiae Gnathopod 1, anterior and lateral edges of article 2 sparsely setose and posterior edge of article 2 with setae (plate 262N, 2 6 2 0 ) 7 Gnathopod 1, anterior edge of article 3 with sparse setae (plate 262N) Aoroides spinosus Gnathopod 1, anterior edge of article 3 with dense setae (plate 2 6 2 0 ) Aoroides exilis Gnathopod 1, article 5 anterior margin densely setose (plate 262Q), thick spines of inner edge of inner plate of maxilliped nearly smooth (plate 262R) Aoroides inermis Gnathopod 1, article 5 anterior margin sparsely setose (plate 262P), thick spines of inner edge of inner plate of maxilliped serrate (plate 262S) Aoroides intermedia Male gnathopod 1 subchelate (plate 262D, 262T) Bemlos concavus Male gnathopod 1 carpochelate (plate 262C) 10 Article 2 of male gnathopods 1 and 2 not expanded (plate 262U) Paramicrodeutopus schmitti Article 2 of male gnathopods 1 and 2 both expanded (plate 262C, 262V) Microdeutopus gryllotalpa

floats and docks of central San Francisco Bay and southern California harbors; 3.5 mm; intertidal—2 m. Aoroides spinosus Conlan and Bousfield, 1982b. Low intertidal and subtidal; on various substrata, but especially with algae and among debris; not known south of Coos Bay; 7 mm; intertidal—45 m. Bemlos concavus (Stout, 1913). Stony bottoms, surf exposed bedrock, Phyllospadix, kelp, Corallina; 6 mm; intertidal—3 m. Columbaora cyclocoxa Conlan and Bousfield, 1982b. Under boulders and among Laminaria on exposed algal-covered rocky beaches; 7 mm; intertidal—10 m. Microdeutopus gryllotalpa Costa, 1853. Introduced, a wellknown western Atlantic and Mediterranean species of shallow estuaries found on the intertidal mud flats of Humboldt Bay since the 1980s (Boyd et al. 2002); 10 mm; to 150 m in Atlantic. Paramicrodeutopus schmitti (Shoemaker, 1942). Rocky surfwashed beaches among Phyllospadix and red algae; 5 mm; intertidal—43 m. LIST OF SPECIES

Paracorophium sp. An introduced intertidal mudflat species of northern Humboldt Bay, possibly from South America, included here because of its biramous uropod 3, collected and illustrated by Todd Miller; 4 mm; intertidal—2 m. ISAEIDAE

Isaeidae are entirely marine suspension feeders that build tubes or occupy empty shells and occur at a wide depth range. Male gnathopod 1 is smaller than gnathopod 2. Photis males bear conspicuous stridulation ridges on the lateral face of gnathopod article 2 and medial ventral edge of coxa 2. Rostrum short or absent, eyes small or large, ocular lobe prominent and pointed. Pereopod 7 longer than pereopod 6. The common loss of pereopods and antennae in preservation can greatly complicate identifications. Urosome articles are separate except for Chevalia. Uropod 3 is biramous and the telson is entire. The taxonomy is reliable for males only. KEY TO ISAEIDAE

1. —

LIST OF SPECIES

2.

Aoroides columbiae Walker, 1898. Abundant in subtidal fouling communities of rocks, pilings and floats; 6 mm; intertidal— > 1 0 0 m. Aoroides exilis Conlan and Bousfield, 1982b. Among algae and sponges under stones and on sand and gravel beaches of open coasts and protected waters; 6 mm; intertidal— 50 m. Aoroides inermis Conlan and Bousfield, 1982b. High-salinity sand and rock surfaces of exposed and protected waters; 6.5 mm; intertidal—148 m. Aoroides intermedia Conlan and Bousfield, 1982b. 6 mm; intertidal—63 m. Aoroides secundus Gurjanova, 1938. An Asian species introduced probably by ships to the Pacific coast where it occurs on

—

562

ARTHROPODA

3. —

4.

—

Uropod 3 inner ramus less than half as long as outer ramus and scale- or platelike (plate 263A, 263B) 2 Uropod 3 inner ramus more than half as long as outer ramus (plate 263C) 5 Gnathopod 2 article 5 of males less than one-third as large as article 6 (plate 263D) 3 Gnathopod 2 article 5 of males more than half as large as article 6 (plate 263E) 4 Antenna 1, accessory flagellum a tiny nub (plate 263F) (view at lOOx); coxa 3 deeper than pereonite 3 (plate 263G) 8 Antenna 1, accessory flagellum multiarticulated, and coxa 3 shallower than pereonite 3 (plate 263D); large teeth on palm of male gnathopod 2 vary from three to five (adults lose inner ramus of uropod 3) Cheiriphotis megacheles Gnathopod 2 article 5 broader than article 6 (plate 263E); gnathopods 1 and 2 palms transverse and greatly overlapped by dactyls (plate 263H, 2631) Cheirimedeia zotea Gnathopod 2 article 5 and 6 approximately equal in width (plate 263J); gnathopods 1 and 2 palms oblique and not

P. bifurcata

P. macinerneyi

PLATE 263 Isaeidae. J, K, L, Cheirimedeia macrocarpa; A, E, H, I, Cheirimedeia zotea; D, Cheiriphotis megacheles; M, Chevalia aviculae; O, Gammaropsis thompsoni; Q, R, Photis bifurcata; G, Photis brevipes; B, F, Photis conchicola; S, Photis macinerneyi; C, N, Protomedeia articulata; P, Protomedeia prudens (figures modified from Barnard 1962a; and Conlan 1983).

greatly overlapped by dactyls (plate 263K, 263L) Cheirimedeia macrocarpa 5. Urosomites 1 and 2 coalesced and pereopod 5-7 with heavy gripping dactyl (plate 263M) Chevalia aviculae — Urosomites 1 and 2 separate, accessory flagellum of two or more articles, usually conspicuous (plate 263N) 6 6. Antenna 1 article 3 shorter than article 1, pereopods 3 and 4 anterior margins of articles 2 and 4 strongly setose, male ocular lobes distally rounded (plate 263N) 7 — Antenna 1 article 3 as long as article 1 or longer, pereopods 3 and 4 anterior margins of articles 2 and 4 weakly setose, ocular lobes distally pointed (plate 2 6 3 0 ) 13 7. Gnathopods 1 and 2 palms more than half as long as dactyls and coxa 1 without a posterior tooth (plate

263N) Protomedeia articulata Gnathopods 1 and 2 palms less than half as long as dactyls and coxa 1 with a posterior tooth (plate 263P) Protomedeia prudens 8. Gnathopod 2 with two teeth defining the palm process of article 6 (plate 263Q); gnathopod 1 article 5 nearly three times as long as wide (plate 263R) Photis bifurcata — Gnathopod 2 with a single tooth defining the palmer process of article 6 and gnathopod 1 article 5 less than twice as long as wide (plate 263S) 9 9. Gnathopod 1 article 5 posterior margin short, less than onethird the length of the anterior margin (plate 263S) Photis macinerneyi —

AMPHIPODA: GAMMARIDEA

563

P

G. martesia

PLATE 264 Isaeidae. E, J, M, Gammaropsis barnardi; I, Gammaropsis effrena; K, L, Gammaropsis mamola; N-P, Gammaropsis martesia; F, Gammaropsis shoemakeri; H, Gammaropsis spinosa; D, G, Gammaropsis thompsoni; A, Photis califomica; B, Photis conchicola; C, Photis lacia (figures modified from Barnard 1959b, 1962a, 1969a; Conlan 1983; Kudrajaskov and Tzvetkova 1975; and Shoemaker 1942).

—

10. — 11. — 12.

— 13.

— 564

Gnathopod 1 article 5 posterior margin extended, more than one-third the length of the anterior margin (plate 263G) 10 Palmar excavation deeply rounded (plates 263G, 264A) 11 Palmar excavation sharply incised (plate 264B) 12 Inner margin of gnathopod 2 dactyl without a large protrusion (plate 264A) Photis califomica Inner margin of gnathopod 2 dactyl with a large protrusion (plate 263G) Photis brevipes Dactyl of gnathopod 2 extending past the defining palmar tooth of article 6 (plate 264B); lives in small snail shells attached by mucus to algae on rocky coasts Photis conchicola Dactyl of gnathopod 2 not extending past the defining palmar tooth of article 6 (plate 264C) Photis lacia Urosome of males dorsally cusped (plate 264D); coxa 7 greatly expanded posteriorly, pereopods 3 and 4 articles 4 and 5 subequal (plate 2 6 3 0 ) 14 Urosome of both sexes dorsally smooth, pereopod 7 coxa ARTHROPODA

14.

—

15.

—

16.

—

short, pereopods 3 and 4 articles 5 half to three-quarters the length of article 4 (plate 264E) 15 Male gnathopod 1 posterior distal corner of article 2 expanded and densely covered with setae (plate 264F) Gammaropsis shoemakeri Gnathopod 1 posterior distal corner of article 2 unexpanded and without dense cover of setae (plate 264G) Gammaropsis thompsoni Gnathopod 2 (both sexes) posterior margin of gnathopod 2 article 5 more than one-third the length of article 6 (plate 264H, 2641) 16 Gnathopod 2 (both sexes) posterior margin of gnathopod 2 article 5 less than one-fifth the length of article 6 (plate 264E, 264J) 18 Male coxa 2 posteriorly straight or only slightly concave (plate 264H, 2641); pereopod 3 anteriodistal article 2 not expanded 17 Male coxa 2 posteriorly lobed (plate 264K); pereopod 3 anteriodistal article 2 expanded (plate 264L) Gammaropsis mamola

17. Antenna 1 article 1 twice as thick as article 2, accessory flagellum tiny and of two articles, articles 2 and 4 of pereopod 5 normal, head pigmented, ocular lobes rounded (plate 2641) Gammaropsis effrena — Antenna 1 article 1 only slightly thicker than article 2, accessory flagellum prominent and of three articles, pereopod 5 articles 2 and 4 of thick, article 4 posterior lined with spines, head unpigmented, ocular lobes pointed (plate 264H) Gammaropsis spinosa 18. Male pereopod 5 article 2 posterior ventral edge deeply notched (plate 264M); gnathopod 2 article 6 half as wide as long (plate 264J); accessory flagellum a microscopic button (not shown) (plate 264E) Gammaropsis barnardi — Male pereopod 5 article 2 posterior ventral edge evenly rounded (plate 264N); gnathopod 2 article 6 two-thirds as wide as long (plate 2640); accessory flagellum as long as the first article of the flagellum (plate 264P) Gammaropsis martesia LIST OF SPECIES

Cheiñmedeia macrocarpa Bulytscheva, 1952. In brackish to full marine waters on semiprotected sand flats; possibly introduced; 5 mm; intertidal. Cheirimedeia zotea (Barnard, 1962) (=Protomedeia zotea). In mixed mud and sand, sediments; 5 mm; intertidal—113 m. Cheiriphotis megacheles (Giles, 1885). Abundant among Phyllospadix and Silvetia and under rocks in California; also reported widely from the warmer Pacific and Indian Oceans. Cryptogenic, possible species complex; 3 mm; intertidal—16 m. Chevalia aviculae (Walker, 1898). Reported also in the Indian Ocean, South Africa, and the Caribbean Sea; cryptogenic; soft benthos; 4 mm; intertidal—35 m. Gammaropsis bamardi (Kudriaschov and Tzvetkova, 1975) (=Podoceropsis bamardi). In mixed rock sediments and sand; 5 mm; intertidal—17 m. Gammaropsis effrena (Barnard, 1964). Among Phyllospadix, algae, and polychaete tubes in rocky areas; 3.7 mm; intertidal. Gammaropsis mamola (Barnard, 1962). Among algae holdfasts and on hard surfaces including submerged logs. 4 mm; 3 m-25 m. Gammaropsis martesia (Barnard, 1964a). Among Phyllospadix, tunicates, and sponges; 3 mm; intertidal—84 m. Gammaropsis shoemakeri Conlan, 1983. Among kelp and hydroids; 5.5 mm; intertidal—27 m. Gammaropsis spinosa (Shoemaker, 1942). Among algae, sponges, and polychaete tubes; 3.5 mm; intertidal—27 m. Gammaropsis thompsoni (Walker, 1898). Among encrusting animals and in algal holdfasts; 11.5 mm; intertidal—27 m. Photis bifurcata Barnard, 1962. Usually on soft sediments; 4 mm; low water—109 m. Photis brevipes Shoemaker, 1942. In various sediments but especially sand; 7 mm; low water—289 m. Photis califomica Stout, 1913. Among Phyllospadix and on open coast rocky shores; 6 mm; low intertidal—147 m. Photis conchicola Alderman, 1936. On rocky beaches with algae and surfgrass, often paguridlike, living in empty gastropod shell; 5.5 mm; intertidal—42 m. Photis lacia Barnard, 1962a. In sandy sediments of exposed coasts; 3.3 mm; low intertidal—40 m. Photis macinemeyi Conlan, 1983. Sandy substrates of exposed and protected marine coasts; 4.3 mm; low intertidal—40 m. Protomedeia articulata Barnard, 1962. In soft sediments; 8 mm; low intertidal to deep subtidal

Protomedeia prudens Barnard, 1966. In soft sediments; 7.5 mm; intertidal—400 m. AMPITHOIDAE

Ampithoidae are herbivores that build nests of algae or burrow into kelp stipes and commonly attain the same color as the algae they inhabit. The third uropods and rami are short, with two (occasionally one) distinctive stout hook spines on the outer ramus. Taxonomy emphasizes males. KEY TO AMPITHOIDAE

1.

—

2.

—

3.

— 4.

—

5.

—

6.

—

7.

—

Pereopods 3 and 4 article 2 strongly inflated, width more than three-fourths of the width of the coxa (plate 265A); gnathopod 1 palm transverse (plate 265B) 9 Pereopods 3 and 4 article 2 width less than one-half of the width of the coxa (plate 265C); gnathopod 1 palm subchelate (plate 265D) 2 Antenna 1 accessory flagellum multiarticulated (plate 265C); uropods 1 and 2 with distal ventral spinose process projecting below the rami (plate 265E) Paragrubia uncinata Antenna 1 accessory flagellum vestigial or absent (plate 265F); uropods 1 and 2 with distal ventral spinose process small or absent (plate 265G) 3 Gnathopod 1 posterior lobe of article 5 long, more than 40% of the length of the entire article (plate 265F, 265H) 4 Gnathopod 1 posterior lobe of article 5 short, < 4 0 % of the length of the entire article (plate 2651) 6 Antenna 2 peduncle 5 and flagellum with dense plumose setae (plate 265H); male gnathopod 1 article 5 shorter than article 6 (plate 265H); male gnathopod 2 palm slightly oblique (plate 265J); epimeron 3 hind margin evenly rounded (plate 265K) Ampithoe plumulosa Antenna 2 lacking dense plumose setae, gnathopod 1 article 5 as long or longer than article 6, male gnathopod 2 palm transverse or produced forward (plate 265F); epimeron 3 posterior ventral corner with intersecting ridge and angular or slightly notched (plate 265F) 5 Male gnathopod 2 palm produced forward (plate 265F); epimeron 3 posterior ventral corner with small notch at the end of the intersecting ridge (plate 265F); lower lip lobes widely separated (plate 265L) Ampithoe lacertosa Male gnathopod 2 palm transverse and bearing square tooth (plate 265M); epimeron 3 posterior ventral comer without a notch at the end of the intersecting ridge (plate 265N); lower lip lobes separated by narrow gap (plate 2650) Ampithoe valida Apex of telson with two enlarged, lobed "rabbit ear" folds (plate 265P); pereopod 5 article 5 less than half as long as article 6 (plate 265S) Ampithoe aptos Apex of telson with two minute lateral knobs (plate 265R); pereopod 5 article 5 more than half as long as article 6 (plate 265Q) 7 Male gnathopod 2 palm sharply incised to form a large pointed tooth (plate 266A); antenna 2 slightly shorter than antenna 1 (plate 266A); antenna 2 setose and with flagellum shorter than combined articles 4 and 5 (plate 266A) Ampithoe sectimanus Male gnathopod 2 palm roundly incised to form short, blunt tooth (plate 266B); antenna 2 longer than antenna 1 (plate 266B), antenna 2 weakly setose and with flagellum AMPHIPODA:

GAMMARIDEA

565

A. plumulosa PLATE 2 6 5 Ampithoidae. I, P, S, Ampithoe aptos; F, L, Ampithoe lacertosa; G, H, J, K, Ampithoe plumulosa; Q, Ampithoe sectimanus; R, Ampithoe simulans; M - O , Ampithoe valida; C-E, Paragrubia uncinate; A, B, Peramphithoe humeralis (figures modified from Barnard 1952b, 1965, 1 9 6 9 a ; Conlan and Bousfield 1 9 8 2 a ; and Shoemaker 1938a).

8.

—

9. — 10.

— 11.

—

566

as long as peduncular articles 4 and 5 (plate 266B) 8 Male gnathopod 1 articles 2 anterior edge lined with plumose setae (plate 266B); mandibular palp article 3 distal seta row marked by angle at inner proximal margin (plate 266C); epimeron 3 posterior ventral corner evenly rounded (plate 266D) Ampithoe dalli Male gnathopod 1 article 2 anterior edge bare (plate 266E); mandibular palp article 3 distal seta row rounding evenly into inner proximal margin (plate 266F); epimeron 3 posterior ventral corner notched (plate 266G) Ampithoe simulans Male gnathopod 2 article 6 less than twice as thick as gnathopod 1 article 6 (plates 265A, 266H, 2661) 10 Male gnathopod 2 article 6 more than twice as thick as gnathopod 1 article 6 (plate 266J-266L) 12 Antenna 2 flagellum proximal articles fused into one article longer than wide (plate 2661) Peramphithoe stypotrupetes Antenna 2 flagellum proximal articles separate and not longer than wide (plate 265A) 11 Pereopod 7 more than 1.5 times as long as pereopod 6 (plate 265A); gnathopod 2 (both sexes) palm transverse; and article 5 equal to or longer than article 6 (plate 266M) Peramphithoe humeralis Pereopod 7 less than 1.2 times length of pereopod 6; and gnathopod 2 (both sexes) palm oblique with article 5 length less than article 6 (plate 266H) Peramphithoe mea ARTHROPODA

12. Male gnathopod 2 palm well defined, extending about half the length of posterior edge of article 6 (plate 266K); antenna 2 article 5 shorter than article 4 (plate 266N) Peramphithoe lindbergi — Male gnathopod 2 palm poorly defined and extending more than half length of article 6; antenna 2 article 4 length approximately equal to article 5 (plate 266L) 13 13. Lower lip lateral and medial lobes projecting equally (plate 2660); antenna 2 flagellum article 1 nearly 2 times longer than more distal articles (plate 266L) Peramphithoe plea — Lower lip lateral lobes projecting further than medial lobes (plate 266P); antenna 2 flagellum article 1 less than two times wider than more distal articles (plate 266Q) Peramphithoe tea LIST OF SPECIES

Ampithoe aptos (Barnard, 1969) (=Pleonexes aptos). Algal covered bottoms where it is scarce; 7 mm; intertidal. *Ampithoe corallina Stout, 1913. Southern California; possible nomen nudum. Ampithoe dalli Shoemaker, 1938. Boreal, south to Cape Arago on exposed and protected beaches, in tide pools, under rocks and log fouling organisms, in 10-34%o salinity. Females ovigerous March to August; 20 mm; intertidal—10 m. * = Not in key.

,.Peramphithoe plea K

P. lindbergi

^

n ^ g2 MP

humeralis

PLATE 266 Ampithoidae. B, C, D, Ampithoe dalli; A, Ampithoe sectimanus; E-G, Ampithoe simulans; M, Peramphithoe humeralis; J, K, N, Peramphithoe lindbergi; H, Peramphithoe mea; L, O, Peramphithoe plea; I, Peramphithoe stypotrupetes; P, Q, Peramphithoe tea (figures modified from Barnard 1952b, 1965; Conlan and Bousfield 1982a; Conlan and Chess 1992; and Shoemaker 1938a).

Ampithoe lacertosa (Bate, 1858). Among algae, gravel, or woody debris and on pilings and floats of estuaries; also protected open coasts; heavily speckled with diffuse spots. See Heller 1968, MSc thesis, Univ. Washington 132 pp. (biology and development); 24 mm; intertidal—11 m. *Ampithoe longimana (Smith, 1873). North Atlantic, introduced to southern California, may receive protection from predators by accumulating toxins from algae it ingests (Hay et al. 1990, Ecology 71: 733-743); 10 mm; intertidal—10 m. Ampithoe plumulosa Shoemaker, 1938. Eastern Pacific and western Atlantic; common on algae and Mytilus beds; origins unclear, a likely introduction or misidentified elsewhere in the world; 16 mm; intertidal—IS m. *Ampithoe pollex Kunkel, 1910. Northeast Pacific records unclear due to poor description of type populations; possibly introduced to southern California; 5.5 mm; intertidal. *Ampithoe ramondi Audoin, 1828. Cosmopolitan at latitudes

hedgpethi

B C. kelleri

c

C. kelleri

PLATE 2 8 3 S t e g o c e p h a l o i d e a . E, F, H, J , Coboldus

hedgpethi;

C. hedgpethi

I. rickettsi c• hedgpethi

C. hedgpethi A - C , Cryptodius

kelleri;

D, G, I, Iphimedia

rickettsi

(figures m o d i f i e d f r o m : B a r n a r d

1969a and Moore 1992).

PLATE 2 8 4 Argissidae. A - C , Argissa hamatipes

(figures m o d i -

fied f r o m B a r n a r d 1 9 6 9 b a n d H i r a y a m a 1 9 8 3 ) .

Argissa hamatipes

C A. hamatipes

ARGISSIDAE

Argissidae of this region include a single cosmopolitan species distinguished by the combination of long coxae 1 and 4, feeble gnathopods, telson deeply cleft and posteriorly expanded pereopod 7 article 2. Eyes (when present) consist of four visual elements. The Pacific species is unlikely to be the same as A. hamatipes of the North Atlantic. The unusual coxa of Argissidae may allow upside-down burrowing and feeding similar to Megaluropidae, which Argissidae resemble.

the upside down position; the long, flexible pereopods 5-7 can quickly dig into well-sorted sediments leaving only a hole at the sand surface that is maintained by the legs and leaf like uropods (Barnard et al., 1988, Crustaceana Suppl. 13: 234-244). Terminal pelagic males have large eyes and antenna 2 with long flagellum and setal tufts on the peduncle, a "distinctive" gnathopod 2 and large pleon. KEY TO

MEGALUROPIDAE

1.

KEY TO ARGISSIDAE

1.

Eye of four visual elements, coxa 4 longer than coxa 3, female urosomite 1 evenly rounded (plate 284A); male urosomite 1 with a large tooth (plate 284B); gnathopod 2 simple (plate 284C) Argissa hamatipes

LIST OF SPECIES

Argissa hamatipes (Norman, 1869). Cosmopolitan in mud, sand and rock benthos. A likely complex of species of which there are shallow and deep-water members. Males of eastern Pacific populations have carina on dorsal urosomites 1-3 (no illustrations published); 4.5 mm; 4 m-1,096 m. MEGALUROPIDAE

Megaluropidae feed upside down at the sand episurface. Their unusual coxae allow dorsal extension of pereopods 3-4 from

Gnathopod 2 article 4 distally produced (plate 285A, 285B); male rostrum short and ocular lobe of head bearing a sharp angle (plate 285C); accessory flagellum of two articles (plate 285D) 2 — Gnathopod 2 article 4 not distally produced (plate 285E); male rostrum long, ocular lobe lacking sharp angle, accessory flagellum of one article (plate 285F) Resupinus 2. Epimeron 3 posteriorly serrate (plate 285A, 285G) Gibberosus myersi — Epimeron 3 posteriorly smooth (plate 285H) Gibberosus devaneyi LIST OF SPECIES

*Resupinus sp. Shallow-water tropical genus (Thomas and Barnard 1986) included for reference due to complex geography and taxonomy of Gibberosus. Gibberosus myersi (McKinney, 1980) (=Megaluropus longimerus Barnard 1962b). Cryptogenic: in Atlantic from Caribbean to * = Not in key.

AMPHIPODA:

GAMMARIDEA

587

H

6. devaneyi

PLATE 285 Megaluropidae. H, Gibberosus devaneyi; A-D, G, Gibberosus myersi; E, F, Resupinus (figures modified from Barnard 1962b; McKinney 1980; Thomas and Barnard 1986).

North Carolina and in the eastern Pacific from Peru to British Columbia; not likely to be a single species; eastern Pacific forms on sand bottoms, among Phyllospadix and Silvetia, and occasionally among Anthopleura elegantissima; 4 mm; intertidal—27 m. *Gibberosus devaneyi Thomas and Barnard 1986. La Jolla and south but may occur in the southern end of our region; 2 - 3 mm; intertidal sand beaches.

4. — 5. — 6.

LYSIANASSOIDEA Lysianassoidea (Aristidae, Lysianassidae, Opisidae, Uristidae) are predators, scavengers, commensals, and parasites (Dahl, 1979; Conlan 1994). The mitten-shaped article 6 and long article 3 of gnathopod 2 and stubby article 1 of antenna 2 are distinctive characteristics of the infraorder. Telsons of lysianassids range from flat and deeply cleft to entire and stubby.

—

7. —

KEY TO LYSIANASSOIDEA

1.

Uropod 3 consisting of peduncle only (plate 286A); pereopod 7 article 2 greatly expanded (plate 286B); body may be covered with scales and fuzz; one to three pleonites plus the first urosomite forming erect peaks (plate 286B); or body smooth, with only the third pleonite forming peaks (plate 286C) (secondary phase male) Ocosingo borlus

—

Uropod 3 with two rami (plate 286D); body not as above 2 2. Gnathopod 1 chelate (plate 286E) 3 — Gnathopod 1 simple (plate 286F), or subchelate, or parachelate (plate 286G), maximum extension of thumb not beyond dactyl hinge 4 3. Gnathopod 1 inner margins of dactyl and palm nearly parallel (plate 286E, 286H); telson entire (plate 2861); eye usually present Prachynella lodo — Dactyl and palm of gnathopod 1 outlining a circular gap * = Not in key.

588

ARTHROPODA

8.

—

9.

—

10.

with the dactyl and thumb touching only at the tips (plate 286J); telson deeply cleft (plate 286K), eyes always present Opisa tridentata Telson entire (plate 286L) 5 Telson cleft (plate 286M) 10 Telson distally concave (plate 286L) 6 Telson distally convex (plate 286N) 8 Female antenna 1 article 3 half as long as wide and epistome not extending past upper lip (plate 2860); outer ramus of uropod 3 of two prominent articles (plate 286P) Dissiminassa dissimilis Female antenna 1 article 3 less than one-third as long as wide (plate 286Q); and epistome extending past upper lip (plate 286R); outer ramus of uropod 3 with a minute distal article (plate 286S) 7 Female third pleonal epimeron a quadrate plate (plate 286T) Aruga holmesi Female third pleonal epimeron posteriorly concave (plate 286U) Aruga oculata Posterior edge of telson with two stout spines (plate 286N); outer ramus of uropod 3 of two articles (plate 286V); gnathopod 1 palm transverse 7 (plate 286G) Orchomenella recondita Posterior edge of telson without stout spines (plate 286W, 286X); uropod 3 outer ramus of a single article (plate 286Y); gnathopod 1 simple (plate 286Z) 9 Uropod 3 inner ramus over half as large as outer ramus (plate 286Y); anterior cephalic lobe and posterior margins of pereopod 7 crenulate (plate 286AA); mandibular molar large (plate 286BB) Macronassa macromera Uropod 3 inner ramus < 3 0 % as large as outer ramus (plate 286CC); anterior cephalic lobe and posterior margins of pereopod 7 smooth (plate 286DD, 286EE); mandibular molar small and fuzzy (plate 286FF) Macronassa pariter Ventral posterior of pleonal epimeron 3 faintly or strongly hooked (plate 287A, 287B); mandibular palp even with molar (plate 287C) 14

macromera AA Macronassa macromera

CCA

M. pariter

EE M. pariter

pariter

PLATE 286 Lysianassoidea. Q, R, T, Aruga holmesi; S, U, Aruga oculata; F, L, O, P, Dissiminassa dissimilis; M, Lepidepecreum serraculum; W, Y, AA, BB, Macronassa macromera; X, Z, CC-FF, Macronassa pariter; G, N, V, Orchomenella recondita; A-C, Ocosingo borlus; ], K, Opisa tridentata; D, E, H, I, Prachynella lodo (figures modified from Barnard 1955a, 1964b, 1967c, 1969a; Bousfield 1987; Dalkey 1998; Shoemaker 1942; and Stasek 1958). Ventral posterior of third pleonal epimeron square, rounded, n o t hooked (plate 2 8 7D); mandibular palp proximal to molar (plates 286BB, 286FF, 287E) 11 11 Urosomite 1 dorsally carinate, overlapping urosomite 2 (plate 2 8 7 D ) 12 Urosomite 1 rounded, not overlapping urosomite 2 (plate 2 8 7F) Orchomene minutus 12 Dorsal pereonites and pleonites rounded (plate 2 8 7 D ) ; anterior extension of antenna 1 article 1 over article 2 slight (plate 2 8 7 G ) 13 —

Dorsal pereonites and pleonites carinate or sharply extending posteriorly (plate 287H); large projection on dorsal antenna 1, article 1 (plate 2 8 7 1 ) . . . . Lepidepecreum gurjanovae

13. Third pleonal epimeron extension acuminate (plate 287J) Orchomene pacifica —

Third pleonal epimeron square (plate 2 8 7 D ) Lepidepecreum

serraculum

14. Coxa 1 tapering distally, smaller and partially hidden by coxa 2 (plate 287K); uropod 3 outer ramus article 2 narrower

—

than article 1 (plate 287L) Aristias velerortis Coxa 1 not tapering distally, of similar size and not obscured by coxa 2 and uropod 3 outer ramus article 2 expanding evenly to width of 1 (plate 287A) 15

15. Coxa 1 anterior concave (plate 287A); and upper lip greatly extending beyond the epistome (not shown) 16 —

Coxa 1 anterior c o n v e x (plate 2 8 7 M ) ; upper lip not extending to or extending only slightly beyond the epistome (plate 2 8 7N) 17

16. Epimeron 2 ventral posterior corner square (plate 2 8 7 0 ) ; uropod 2 weakly constricted (not shown), outer ramus with enlarged spines (plate 287P); possibly a new species Anonyx cf. lilljeborgi —

Epimeron 2 ventral posterior corner produced into a sharp tooth (plate 287Q); uropod 2 distal rami with small spines (plate 287R) Anonyx cf. nugax

17. Pereopod 7 longer t h a n pereopod 6 (plate 2 8 7 M ) —

Psammonyx longimerus Pereopod 7 shorter than pereopod 6 (plate 287S) 18 AMPHIPODA: GAMMARIDEA

589

H. columbianus

]TW. wecomus

Wecomedon wecomus

PLATE 287 Lysianassoidea. A, O, P, Anonyx lill/eborgi; C, Q, R, Anonyx nugax; B, K, L, Aristias veleronis; S, T, Hippomedon columbianus; H, I, Lepidepecreum gurjanovae; D, E, G, Lepidepecreum serraculum• F, Orchomene minutus; J, Orchomene pacifica; M, Psammonyx longimerus; N, U, V, Wecomedon wecomus (figures modified from Barnard 1964c, 1971; Bousfield 1973; Dalkey 1998; Hurley 1963; Jarrett and Bousfield 1982; Lincoln 1979; and Steel and Brunei 1968).

18. Antenna 1 flagellum article 1 more than half as long as peduncle article 1 (plate 287S); tips of telson pointed and bearing one to two spines (plate 28 7T) Hippomedon columbianus — Antenna 1 flagellum article 1 less than half as long as article 1 (plate 287U); tips of telson blunt and bearing two or more spines (plate 287V) Wecomedon wecomus LIST OF SPECIES ARISTIDAE

Aristias veleronis Hurley, 1963. A likely commensal with brachiopods, sponges, and ascidians. Possible synonym of A. pacificus Schellenberg, 1936; Aristias sp. A (1985, SCAMIT 590

ARTHROPODA

Newsletter 3[10]) in the sponge Staurocalyptus may also be this species; 6 mm; intertidal—18 m.

LYSIANASSIDAE

A ruga holmesi Barnard, 1955a. Soft sediment; Washington, California, Gulf of Mexico, Western Florida; perhaps two species, one in each ocean; 11.5 mm; intertidal—183 m. Aruga oculata Holmes, 1908. Most common in shallow soft benthos of California; 15 mm; 1 m-457 m. Dissiminassa dissimilis (Stout, 1913) (=Lysianassa dissimilis). Tomales Bay and south among Macrocystis holdfasts, Aplidium sp., loose rocks, Phyllospadix and coralline algae; 6 mm; intertidal—73 m.

PLATE 288 Urothoidae. A, B, D-F, Urothoe elegans; C, G-J, Urothoe varvarini (figures modified from Gurjanova 1953; Lincoln 1979; and Sars 1895).

Hippomedon columbianus Jarrett and Bousfield, 1982. Soft benthos, epimeral notch not apparent in specimens < 3 mm; 4.8 mm; 4 m-320 m. Lepidepecreum gurjanovae Hurley, 1963. Sex of ¡Illustrated specimen not given. Three forms occur (1) in Carmel and Goleta, 0 m-3 m, (2) in southern California shelf, 15 m-135 m, and (3) from southern California to British Columbia, being the typical 3-mm form described by Hurley, 1963 (see Barnard 1969a: 175); intertidal-1,720 m; tiny (to 3 mm). Lepidepecreum serraculum Dalkey, 1998. A shallow-water species of the L. gurjanovae—complex, fine sandy silt to coarse red sand off open coasts; also in harbors; 3 mm at Mexico-United States border ranging to 6 mm in Canada; intertidal—150 m. Macronassa macromera (Shoemaker, 1916) (=Lysianassa macromera). Abundant in high-energy intertidal environments among Egregia holdfasts and Anthopleura elegantissima; 5 mm. Macronassa pariter (Barnard, 1969a) (=Lysianassapariter). Among sponges and tunicates, Cayucos and south; 5.7 mm; intertidal. Ocosingo borlus Barnard, 1964c (=Fresnillo fimbriatus [Barnard, 1969]). A sequential hermaphrodite; the secondary phase male was renamed F. fimbriatus (see Lowry and Stoddart 1983, 1986); 2 mm; intertidal—180 m. Orchomene minutus (Kroyer, 1846). A boreal species found south to Oregon and south to the Gulf of St. Lawrence in the Atlantic; 11 mm; intertidal—547 m. Orchomene pacifica (Gurjanova, 1938). Japan Sea, coastal shelf of southern California; 5 mm; 3 m-421 m. Orchomenella recóndita (Stasek, 1958) (=Allogaussia recóndita; = Orchomene recóndita). Commensal in the gut of the sea anemone Anthopleura elegantissima, Oregon to Santa Cruz Island; intertidal; with global warming, should be watched for north of Oregon; 4 mm. See De Broyer and Vader 1990; Beaufortia 41: 31-38 (biology). Prachynella lodo Barnard, 1964b. A southern species found as far north as Monterey Bay; also reported from Sea of Japan; 5.8 mm; 10 m-439 m. Psammonyx longimerus Jarrett and Bousfield, 1982. Sandy sediments; 14 mm; intertidal—200 m. Wecomedon wecomus (Barnard, 1971). Soft sandy sediments; 13 mm; intertidal—100 m.

OPISIDAE

Opisa tridentata Hurley, 1963. Fish gill parasite; 8 mm; 17 m-183 m. URISTIDAE

Anonyx cf. lilljeborgi Boeck, 1871b. Soft sediments; another boreal species assumed to occur from the Gulf of Alaska to Mexico on our coast (southern populations should be reexamined), and from Nova Scotia to Delaware in the Atlantic, but perhaps representing a species complex; 11 mm; intertidal— 1,015 m. Anonyx cf. nugax (Phipps, 1774). Panboreal, south to California, perhaps representing a species complex but also perhaps misreported; up to 42 mm; 4 m-1,184 m.

UROTHOIDAE

Urothoidae of our region are probably undescribed but have been variously assigned to Urothoe varvarini and U. elegans. Urothoids live in fine subtidal sediments over a large depth range and are likely meiofaunal predators. Although reported mostly from deep water, this obscure, low-density group could be overlooked in shallow marine benthic habitats. The description and illustrations here are composites from previous reports in which specimens from the region were compared with Sars' (1895) and Lincoln's (1979) illustrations of U. elegans and with Gurjanova's (1953) illustrations of U. varvarini.

KEY TO UROTHOIDAE

1.

Large dactyls on pereopods 5-7; pereopod 7 article 2 oval (plate 288A); prominent mandibular palp and molar (plate 288B); weak rostrum, broad ventral extensions of the head and prominent accessory flagellum (plate 288A, 288C-D); small subchelate gnathopods (plate 25 7L); spinose fossorial pereopods 5 (plate 288F, 288G) and AMPHIPODA:

GAMMARIDEA

591

B

HeterophoxusG£ndjfoxus .t oculatus / nranriic

D \

v J K s ^ G. granais

=

^

_ _

_ _

„

G

^

Rhepoxynius stenodes

N

R. sp. L

R. sp. D

G. longirostris

heterocuspidatus

PLATE 2 8 9 Phoxocephalidae. A, Foxiphalus obtusidens; C - E , K, L, Grandifoxus grandis; M, N, Grandifoxus longirostris-, I, J , Grandifoxus sp.; B, Heterophoxus oculatus; H, Metharpinia coronodoi (expanded tip of outer ramus); AA, Rhepoxynius fatigans; V - X , Rhepoxynius bamardi; O, R - U , Rhepoxynius bicuspidatus; P, Rhepoxynius daboius; CC, Rhepoxynius heterocuspidatus; Z, Rhepoxynius sp. D; BB, Rhepoxynius sp. L; F, G, Rhepoxynius stenodes; Q, Rhepoxynius variatus; Y, Rhepoxynius vigitegus (figures modified from Barnard 1960a, 1 9 7 1 , 1980a, 1 9 8 0 b ; Barnard and Barnard 1982a;, Coyle 1 9 8 2 ; Gurjanova 1 9 3 8 ; and Jarrett and Bousfield 1994a).

antenna 2 (plate 288H); straight rami of uropods 1 and 2 (plate 288A); laminar telson cleft to the base (plate 2881), and biramous uropod 3 (plate 288J) Urothoe sp. LIST OF SPECIES

*Urothoe elegans Bate 1857. Cited in the eastern Pacific but not clearly present; mud benthos; 6 mm; shallow subtidal— shelf depths. *Urothoe varvarini Gurjanova 1953. Rare in mud benthic samples; 5 mm; 5 m-1,292 m.

PHOXOCEPHALIDAE

Phoxocephalidae, "spiny heads," are the most diverse and abundant sand- and mud-burrowing marine crustaceans of the 1 mm-10 mm range in coastal soft bottoms after ostracodes (Barnard 1960a). Phoxocephalidae variously resemble Dogielonotidae, Haustoriidae, Urothoidae, Gammaridae, and Pontoporeiidae, but are distinguished readily from these taxa by their shieldlike pointed rostrums. Sexual dimorphism occurs in eye development, uropod 3, gnathopods, and antennae. Phoxocephalid taxonomy is reliable only for females and rests on * = Not in key. 592

ARTHROPODA

untested assumptions of the invariance of characters. Phoxocephalidae are predators of meiofauna and invertebrate larvae (Oliver et al. 1982, Mar. Ecol. Prog. Ser. 7: 179-184; Oakden 1984, J. Crust. Biol. 4: 233-247). They live a year or more (Kemp et al., 1985, J. Crust. Biol. 5: 449-464) and are used extensively in aquatic toxicology due to their great sensitivity to pollutants (Robinson et al. 1988, Environ. Tox. Chem. 7: 953-959). KEY TO PHOXOCEPALIDAE

1.

Rostrum unconstricted, lateral edges straight or slightly convex (plate 289A, 289B) 22 Rostrum constricted, lateral edges concave (plate 289C) 2 2. Epimera 1 and 2 posterior edges with numerous long setae (plate 289D); telson with distal and medial dorsal spines (plate 289E) 3 — Epimera 1 and 2 without posterior setae (plate 289F); telson with only distal spines (plate 289G) 6 3. Uropods 1 and 2 with tiny, subapical supernumerary spines on one or more rami and with subapical spines poorly developed (plate 289H); examine this character under a minimum of 50x magnification Metharpinia spp. — Uropods 1 and 2 without tiny, subapical supernumerary spines on any rami and subapical ramal spines well developed (plate 2891, 289J) 4

R. stenodes heterocuspidatus

Mandibulophoxus gilesi

Y , z Heterophoxus R, fatigans R- fatigans

gn 1

R \ BB daboius ' G Rhepoxyhius daboius

PLATE 290 Phoxocephalidae. EE, Heterophoxus sp. 1; CC, DD, Mandibulophoxus gilesi; M, P, R, Rhepoxynius abronius; AA, BB, Rhepoxynius daboius; W-Z, Rhepoxynius fatigans; A, G, L, Rhepoxynius heterocuspidatus; K, Rhepoxynius homocuspidatus; U, V, Rhepoxynius lucubrans; N, M, Rhepoxynius menziesi; D, J, Rhepoxynius pallidus; B, C, H, Rhepoxynius stenodes; E, F, I, Rhepoxynius tridentatus; S, T, Rhepoxynius variatus (figures modified from Barnard 1954a, 1957c, 1960a; and Barnard and Barnard 1982a).

4.

Coxae 1 - 3 with distinct posterioventral tooth (plate 289K); uropod 1 inner distal peduncle lacking large displaced spine (plate 289L) 5

—

C o x a e 1 - 3 posteriorly rounded (plate 2 8 9 M ) ; uropod 3 with large distal medial spine (plate 289N)

5.

Uropods 1 and 2

—

Uropods 1 and thick, rhomboid (not illustrated)

Grandifoxus longirostris outer ramus spines small (plate 2 8 9 L ) . . . . Grandifoxus grandis 2 (U 2 not illustrated) outer ramus spines (plate 289J); coxae 1 setae narrowly spread Grandifoxus sp. J

9. —

ends (plate 289V, 2 8 9 W ) ; telson with long distal setae (plate 2 8 9 X ) Rhepoxynius bamardi Urosome dorsal surface smooth, without a t o o t h (plate 289A) 10 Urosome dorsal surface bearing conspicuous anteriorly reverting t o o t h (plate 289Y) Rhepoxynius vigitegus

10. Urosome with lateral spine row (plate 289Z) —

Rhepoxynius sp. D Urosome bare, without lateral spine row (plate 289A)

6.

Pereopod 7 article 2 posterior edge with two p r o m i n e n t spurs (plate 2 8 9 0 ) 7

11 11. Epistome rounded, lacking anterior cusp 12 — Epistome anterior cusp pointed (long or short) (plate 289AA) 17

—

Pereopod 7 article 2 posterior edge with three or more large spurs (plate 289P) 9

12. Pereopod 7, article 2 posterior edge with six or more small teeth (plate 289BB) 16

7.

Epistome prominent and pointed (plate 2 8 9 Q ) (R- sp. A n o t illustrated but similar to R. variatus)

—

Rhepoxynius sp. A Epistome blunt, inconspicuous (plate 289R) 8 Female gnathopods 1 and 2 article 6 anterior and posterior edges parallel at distal end (plate 289S, 289T); telson with

13. Female uropod 3 inner ramus more t h a n two-thirds length of outer ramus (plate 290A, 290B); pereopod 7 article 2 posterior edge with more t h a n three teeth (plates 2 8 9 C C , 290C) 14

short distal setae (plate 2 8 9 U )

—

— 8.

—

Rhepoxynius bicuspidatus Female gnathopods 1 and 2 article 6 expanding at distal

Pereopod 7, article 2 posterior with five or less prominent teeth (plate 2 8 9 C C ) 13

Female uropod 3 inner ramus length one-half or less of outer ramus (plate 290D, 290E); pereopod 7 article 2 with three large posterior teeth (plate 290F) 15 AMPHIPODA: GAMMARIDEA

593

V\T

F. golfensis

Paraphoxus sp. 1 Foxiphalús

obtusidens

x( F. golfensis

PLATE 291 Phoxocephalidae. B, Cephalophoxoides homilis; P, Eyakia robusta; O, U, W, X, Foxiphalus golfensis; T, Foxiphalus obtusidens; A, Heterophoxus; F, G, Heterophoxus affinis; H, I, Heterophoxus conlanae; J, Heterophoxus ellisi; C, D, Heterophoxus oculatus (original drawing incomplete); E, K, Heterophoxus sp. 1; N, Q, V, Majoxiphalus major; M, Metaphoxus frequens; L, Parametaphoxus quaylei; R, S, Paraphoxus sp. 1 (figures modified from Barnard 1960a; Holmes 1908; and Jarrett and Bousfield 1994b).

14. Pereopod 7 article 2 with four to five asymmetrical posterior serrations on article 2 (plate 289CC); female rostrum broad, with base greater than one-half of the head width (plate 290G) Rhepoxynius heterocuspidatus — Pereopod 7 article 2 with four symmetrical posterior teeth (plate 290C); rostrum narrow, with base less than one-third of the head width (plate 290H) Rhepoxynius stenodes 15. Female uropod 3 inner ramus length one-third of outer ramus (plate 290E); male telson medial setae long (plate 2901) Rhepoxynius tridentatus — Female uropod 3 inner ramus length one-half of outer ramus (plate 290D); male telson medial setae short (plate 290J) Rhepoxynius pallidus 16. Antenna 1, article 2 lateral marginal setae extending to apex (plate 290K) Rhepoxynius homocuspidatus — Antenna 1, article 2 lateral marginal setae extending less than one-third of the distance to the apex (plate 290L) (illustrations of R. sp. L not published; R. heterocuspidatus is Rhepoxynius sp. L a similar example) 17. Epistome cusp long, extending >1.5 times the width of its base (plate 290M) 18 — Epistome cusp short, extending approximately equal to width of its base (plate 289AA) 20 594

ARTHROPODA

18. Female uropod 1 peduncle with large displaced dorsomedial spine (plate 290N); pereopod 7 article 2 with eight small posterior teeth (plate 2900) Rhepoxynius menziesi — Female uropod 1 peduncle without large displaced dorsomedial spine (plate 290P); pereopod 7 article 2 with less than eight posterior teeth 19 19. Female uropod 3 inner ramus length greater than one-half of the outer ramus (plate 290Q); pereopod 7 article 2 with five to six posterior teeth (plate 290R) Rhepoxynius abronius — Female uropod 3 inner ramus length less than one-half of the outer ramus (plate 290S); pereopod 7 article 2 with three to five (usually four) variably sized teeth lining posterior edge (plate 290T) Rhepoxynius variatus 20. Female uropod 3 inner ramus length about one-half of the outer ramus length (plate 290U); eyes large (plate 290V) Rhepoxynius lucubrans — Female uropod 3 inner ramus length less than onethird of the outer ramus (plate 290W); eyes small (plate 290X) 21 21. Gnathopod 1 article 6 narrow (plate 290Y); pereopod 7 article 2 ventral edge slightly beveled, not straight (plate 290Z) Rhepoxynius fatigans

—

22.

—

23. — 24.

—

25.

—

26.

—

27.

— 28.

—

29.

— 30.

—

31.

—

32.

Gnathopod 1 article 6 broad (plate 290AA); pereopod 7 article 2 ventral edge straight (plate 290BB) Rhepoxynius daboius Pigmented eyes absent (plate 290CC) (check also Heterophoxus oculatus if antenna 2 ensiform process is longer than wide); pereopod 5 article 2 slightly concave and expanding distally (plate 290DD) Mandibulophoxus gilesi Pigmented eyes present (plate 290EE); pereopod 5 article 2 convex and parallel-sided or slightly narrowing distally 23 Antenna 2 with ensiform process longer than wide (plate 291 A) 24 Antenna 2 ensiform process absent or wider than long (plate 29IB) 28 Epimeron 3 tooth weakly upturned or straight (plate 291C); pereopod 6, article 6 with posterior setae (plate 25 29 ID) Epimeron 3 tooth strongly upturned (plate 291E, 291F); pereopod 6, article 6 without posterior setae (plate 291G) 27 Pleonite 3 with more than 14 ventral, plumose setae and posterioventral tooth as thick at the base as length (plate 291C) Heterophoxus oculatus Pleonite 3 with less than 14 ventral, plumose setae and with posterioventral tooth longer than thick (plate 291H) 26 Pereopod 6 article 6 posterior edge lined with doubly or triply inserted setae (plate 2911); female pereopod 7 with small coxal gill Heterophoxus conlanae Pereopod 6 article 6 posterior edge lined with singly inserted setae (plate 291J); female pereopod 7 lacking coxal gill Heterophoxus ellisi Pereopod 6 article 5 posterior margin with three setae pairs plus a single seta and article 6 with one mid-posterior seta (plate 29IK) Heterophoxus sp. 1 Pereopod 6 articles 5 and 6 with posterior setae only on extreme distal ends (plate 291G) Heterophoxus affinis Female gnathopod 1 article 5 attachment to article 6 constricted (plate 291L); pereopod 5, article 4 deeper than wide (plate 291M) 40 Female gnathopod 1 article 5 attachment to article 6 normal, unconstricted (plate 291N); pereopod 5, article 4 wider than deep (plate 29 lO) 29 Epimeron 3 with large posterioventral tooth and an oblique row of facial setae (plate 29IP) Eyakia robusta Epimeron 3 posterioventrally square or rounded and without an oblique row of facial setae (plate 291Q) 30 Pereopod 6 dactyl long and thin (plate 291R); antenna 2, articles 4 and 5 without facial spine clusters (plate 29IS) Paraphoxus sp. 1 Pereopod 6 dactyl shorter and relatively stout (plate 29 IT); antenna 2, articles 4 and 5 with facial spine clusters (plate 291U) 31 Epimeron 3 posterior edge lined with 20 or more setae (plate 291Q); mandibular palp second article swollen (plate 291V) Majoxiphalus major Epimeron 3 posterior edge lined with 15 or less setae (plate 291W); mandibular palp article 2 linear with parallel sides (plate 29IX) 32 Uropod 1 peduncle with large displaced lateral or medial distal spine (plate 292A) (variable in Eobrolgus, plate 292L) 34

—

33.

— 34. — 35. — 36. — 37.

— 38.

—

39.

—

40.

—

41.

—

42.

—

Uropod 1 peduncle without large displaced lateral or medial distal spine (plate 292B) (variable in Eobrolgus, plate 292L) 33 Pereopod 7 article 2 ventral edge slightly crenulated and lined with long setae (plate 292C) Foxiphalus golfensis Pereopod 7 article 2 ventral edge smooth and without long setae (plate 292D) Foxiphalus falciformis Epistome produced (plate 292E) 35 Epistome unproduced (plate 292F, 292G) 36 Epistome cusp longer than width of base (plate 292H, 2921) Foxiphalus similis Epistome length no greater than width of base (plate 292E) Foxiphalus cognatus Telson lobes with dorsolateral spines (plate 292J) 37 Telson lobes without dorsolateral spines (plate 292K) 38 Uropod 1 inner ramus apical nail flexible, articulate (flex the inner distal nail with a fine needle to make this observation) (plate 292A, right arrow) Foxiphalus obtusidens Uropod 1 inner ramus apical nail immersed, rigid (plate 292M) Foxiphalus xiximeus Female rostrum lateral edges straight or slightly concave (plate 292N); two stout distal spines on the inner maxilliped palp (plate 2 9 2 0 ) Foxiphalus aleuti Female rostrum lateral edges slightly convex (plate 292P); one stout distal spine on the inner maxilliped palp (plate 292Q) 39 Epimeron 3 bearing one to two ventral setae (plate 292R); outer plate of maxilla 1 with 11 spines (incompletely illustrated) (plate 292S) Eobrolgus chumashi Epimeron 3 bearing a single ventral seta (plate 292T); outer plate of maxilla 1 with nine spines (not illustrated) . . . . Eobrolgus spinosus Gnathopods 1 and 2 sixth articles similar in shape and length (plate 292U, 292V); mandibular molar triturative (plate 292W) Cephalophoxoides homilis Gnathopod 1 article 6 longer than gnathopod 2 article 6 (plate 292X, 292Y); mandibular molar weak, nontriturative (plate 292Z) 41 Gnathopod 1 palm not extending beyond anterior distal corner and posterior article 5 of gnathopods 1 and 2 overlapped by articles 6 and 4 (plate 292X, 292Y) Metaphoxus frequens Gnathopod 2 weakly chelate, palm extending beyond anterior distal corner, and posterior lobe of article 5 of gnathopod 1 free of articles 6 and 4 (plate 292AA, 292BB) 42 Pereopod 5 coxa extending less than 40% of article 2 length (plate 292CC); pereopod 6 article 2 ventral posterior corner extended and rounded (plate 292CC) Parametaphoxus quaylei Pereopod 5 coxa extending more than 50% of article 2 length(plate 292DD); pereopod 6 article 2 posterior ventral corner square (plate 292EE) Parametaphoxus sp.

LIST OF SPECIES

Cephalophoxoides homilis (Barnard 1960a) (=Phoxocephalus homilis). Intertidal eelgrass beds (Dean and Jewitt 2001, Ecol. Appl. 11: 1456-1471) and soft benthos; 4.3 mm; intertidal— 250 m. Eobrolgus chumashi Barnard and Barnard, 1981. Marine, estuary, muddy sands; body (plate 25 6M). Eobrolgus are not AMPHIPODA:

GAMMARIDEA

595

PLATE 292 Phoxocephalidae. U-W, Cephalophoxoides homilis; R, S, Eobrolgus chumashi; L, P, T, Eobrolgus spinosus; N, O, Foxiphalus aleuti; E, Foxiphalus cognatus (epistomes); D, Foxiphalus falciformis; B, C, Q, Foxiphalus golfensis (distal inner plate); E, F, G (epistomes); A, F, G, J, Foxiphalus obtusidens; H, I, Foxiphalus similis; M, Foxiphalus xiximeus; K, Majoxiphalus major; X-Z, Metaphoxus frequens; CC, Parametaphoxus quaylei; AA, BB, DD, EE, Parametaphoxus sp. (figures modified from Alderman 1936; Barnard 1960a, 1964a; Barnard and Barnard 1982a, 1982b; Chapman, personal communication; and Jarrett and Bousfield 1994a, 1994b).

distinguished morphologically from Foxiphalus falciformis; 4.5 mm; intertidal—11 m. Eobrolgus spinosus (Holmes, 1903). A possible introduction from the Northwest Atlantic; "study on hybridization [with E. chumashi] is warranted" (Barnard and Barnard, 1981). Displaced uropod 1 spine on uropod 1 variably present. Estuarine, muddy sand; 4 mm; intertidal. Eyakia robusta. (Homes, 1908). Associated with brittle stars, occasional surface swimmer of neritic zone; Alaska population is possibly a different species (Jarrett and Bousfield 1994a Amphipacifica 1: 89); 6.5 mm-15 mm; intertidal—320 m. Foxiphalus aleuti Barnard and Barnard, 1982b. In sand; 9 mm; subtidal—110 m. Foxiphalus cognatus (Barnard, 1960). In coarse shell and sand; 5 mm; intertidal—324 m. Foxiphalus falciformis Jarrett and Bousfield, 1994a. Fine marine sands; doubtfully distinguished from Eobrolgus and F. golfensis by pereopod 7 and minute differences in mandibles; 8 mm; intertidal. 596

ARTHROPODA

Foxiphalus golfensis Barnard and Barnard, 1982b. Oregon and south; 9.1 mm; intertidal—91 m. Foxiphalus obtusidens (Alderman, 1936). Common in sand tide pools; 5.5 mm-15 mm; intertidal—210 m. Foxiphalus similis (Barnard, 1960a). Surf-protected fine sands; 5 mm; sublittoral—324 m. Foxiphalus xiximeus Barnard and Barnard, 1982. May not be distinct from F. obtusidens; medium surf-exposed beaches in sand; 8 mm; low intertidal—20 m. Grandifoxus granáis (Stimpson, 1856) (=Paraphoxus milleri). Often in reduced salinities; 9.5 mm-14 mm; intertidal. Grandifoxus longirostris (Gurjanova, 1938). In sand, largely subtidal; 8 mm; 10 m-90 m. Grandifoxus sp. Barnard 1980a. Pacific Grove, from a "senile" incompletely described 14.6 mm male, may not be distinct from G. granáis; intertidal sands. Heterophoxus affinis (Holmes, 1908). In fine sand to mud, the deep-water populations may include Heterophoxus sp. 1

of Jarrett and Bousfield 1994b; 9 mm; shallow subtidal to 600+ m. Heterophoxus conlanae Jarrett and Bousfield, 1994b. Not clearly distinguished from H. oculatus; 8 mm; intertidal— 40 m. Heterophoxus eltisi Jarrett and Bousfield 1994b. Fine sands and mud; 7 mm; intertidal—155 m. Heterophoxus oculatus (Holmes, 1908). In fine sands, eye loss occurs in deeper populations and is not accompanied by other character differences (Cadien 2002, SCAMIT 21 [2]: 7); 9 mm; 10 m-120 m. Heterophoxus sp. 1 Jarrett and Bousfield 1994b. Southern California, not clearly distinguished from H. affinis; fine sediments; 7 mm; 90 m-360 m. Majoxiphalus major (Barnard, 1960a). Majoxiphalus is poorly distinguished from Foxiphalus; differences may be size- or agerelated; 6.5 mm-17.5 mm; intertidal—91 m. Mandibulophoxus gilesi Barnard, 1957c. Fine sands; 6 mm; shallow subtidal—14 m. Metaphoxus frequens Barnard, 1960a. Fine sands and muddy sand; 3.5 mm; intertidal—496 m. *Metharpinia coronadoi Barnard, 1980a. Southern California, posterioventral corner of pleonite 3 produced into a large hook, muddy sand; 7 mm; 18 m-43 m. *Metharpinia jonesi (Barnard, 1963). Southern, pleonite 3 without posterioventral hook; 3.8 mm; intertidal—18 m. *Parametaphoxus sp. Chapman (undescribed). Southern California and south; 3.5 mm; intertidal—170 m. *Parametaphoxus quaylei Jarrett and Bousfield 1994b. Fine sand and mud, Washington and north; 2.8 mm; 25 m-100 m. Parametaphoxus sp. Chapman and P. quaylei may occur in our region. *Paraphoxus spp. Barnard 1960a. Shallow water Paraphoxus reported north and south of the region in mixed sediments and mud but not confirmed in the region (Barnard 1979b); 3 mm-5 mm; shallow subtidal to 2,800 m. Rhepoxynius abronius (Barnard, 1960a). Abundant inshore and subtidally at the high salinity mouths of estuaries, mostly in surf-protected localities, in sand to below 50 m. An important species for toxicity bioassays (Ambrose 1984, J. Exp. Mar. Biol. Ecol. 80: 67-75 (behavior); DeWitt et al. 1988, Mar. Envir. Res. 25: 99-124 (sediment features, toxicity); Swartz 1986, Mar. Envir. Res. 18: 133-153 (toxicity); 5.5 mm; shallow subtidal— 90 m. *Rhepoxynius bamardi Jarrett and Bousfield 1994a. Sand habitats, a possible synonym of R. bicuspidatus; 4 mm; intertidal— 59 m. Rhepoxynius bicuspidatus (Barnard, 1960a). Fine sand and sandy mud, a low proportion of specimens of this species has three spurs on article 2 of one or both seventh pereopods; 4.5 mm; 8 m-475 m. *Rhepoxytiius boreovariatus Jarrett and Bousfield 1994a. Northern; 4.5 mm; intertidal—40 m. Rhepoxynius daboius (Barnard, 1960a). Sandy mud, a probable synonym of R. fatigans; 4 mm; intertidal—813 m. Rhepoxynius fatigans (Barnard, 1960a). Sandy mud; 4 mm; intertidal—330 m. *Rhepoxynius heterocuspidatus (Barnard, 1960a). 4.8 mm, intertidal—146 m. This species, Rhrepoxynius sp. C, R. stenodes and the following three species occur south of this region. *Rhepoxynius homocuspidatus (Barnard and Barnard, 1982a). 3.5 mm; intertidal—64 m. *Rhepoxynius lucubrans (Barnard, 1960a). 5.3 mm; intertidal—91 m.

*Rhepoxynius menziesi (Barnard and Barnard, 1982a). 7 mm; intertidal—22 m. *Rhepoxynius pallidus (Barnard, 1960). British Columbia and Washington; possible synonym of R. tridentatus ; 6 mm; intertidal—40 m. Rhepoxynius sp. A SCAMIT, 1987. Sand benthos; length not known; < 2 0 m. *Rhepoxynius sp. C Barnard and Barnard 1982a. Sand; 4.3 mm; intertidal—15 m. *Rhepoxynius sp. D Barnard and Barnard 1982a. Southern California, a possible morph of R. menziesi; 8 mm; intertidal— 27 m. Rhepoxynius sp. L Barnard and Barnard 1982a. Dillon Beach, fine sand; epistome is assumed to be rounded since it combines "characters of both R. heterocuspidatus and R. homocuspidatus" (Barnard and Barnard 1982a); a lack of illustrations of the epistome and antenna 1 leave the placement of this species uncertain; 5.7 mm; intertidal—2 m. *Rhepoxynius stenodes (Barnard, 1960a). Muddy sand; 3.5 mm; 2 m-374 m. Rhepoxynius tridentatus (Barnard, 1954a). Mud and sand; 5 mm, intertidal—89 m. Rhepoxynius variatus (Barnard, 1960a). Muddy sands; number and relative sizes of teeth on posterior pereopod 7 are variable; 5 mm; intertidal—89 m. Rhepoxynius vigitegus (Barnard, 1971). Sandy mud; 4.5 mm; shallow subtidal to 30 m. PONTOPOREIIDAE Pontoporeiidae are represented in the eastern Pacific by Diporeia erythrophthalma and Monoporeia sp. (see species list below). The figures are of Monoporeia affinis for identifying the genus. American pontoporeiids were long assumed to be "glacial marine relicts" dispersed over North America and Eurasia during the Pleistocene deglaciation by marine inundations of coastal regions that trapped brackish water species in freshening ponds and then forced them inland (e.g., Segerstrale 1976, Dadswell 1974). However molecular (Váinolá and Varvio 1989) and morphological data (Bousfield 1989) indicate that speciation among these "relicts" has occurred, a pattern expected from long isolation among distant populations rather than recent arrivals. Pontoporeiidae mate pelagically (Bousfield 1989), and male antennae can be twice as long as their bodies. Pontoporeiidae differ from Gammaridae by lacking pereopod 7 coxal gills, from Phoxocephalidae by lacking a rostrum, and from Urothoidae by dissimilar pereopods 6 and 7.

KEY T O P O N T O P O R E I I D A E

1.

Urosome evenly rounded, lateral head lobe slightly acute, eyes dark, prominent accessory flagellum (plate 293A); gnathopod 1 article 5 posterior edge length greater than half the anterior article length (plate 293B); gnathopod 2 article 6 narrowest distally and with pinnate distal setae (plate 293C); coxa 5 lobes ventral projection equal (plate 293D); sternal gills on pereonites 2-5 (arrows) (plate 293A, 293E); telson as wide as long cleft two-thirds of its length (plate 293F) and; uropod 3 outer ramus with a tiny distal nail (plate 293G) Monoporeia sp. * = Not in key.

AMPHIPODA:

GAMMARIDEA

597

CxE

C Monoporeia sp.

B Monoporeia sp. /

D Monoporeia

F ' i/r

7

r

Monoporeia sp.

E Monoporeia sp.

w

3 G

Monoporeia sp.

PLATE 293 Pontoporeiidae. A-G, Monoporeia sp. (figures modified from Bousfield 1989). L I S T OF S P E C I E S

and a n t e n n a 1 article 1 with anterior ventral or dorsal projections (except for Heteropleustes setosus) (plate 2 9 4 G ) . .

*Diporeia erythrophthalma (Waldron 1953). Named for its red eyes, known only from freshwater Lake Washington and the only other pontoporeiid of the eastern Pacific; 5 m m ; 0 m - 5 0 m. Monoporeia sp. Restricted to the low-salinity benthos of the lower Columbia River where it is common, and from a single male collected in August 2 0 0 4 from low-salinity benthos of Yaquina Bay, Oregon. Cryptogenic (historical occurrence in the region unclear, but unknown elsewhere); 8 mm; intertidal—20 m.

18 Rostrum massive, extending beyond a n t e n n a 1 peduncle article 1, dorsal p l e o n i t e s l - 3 weakly or strongly carinate (plate 294A) 4 Rostrum moderate or indistinct, extending less than length of antenna 1 peduncle article 1 and dorsal pereonites 1 - 4 4.

PLEUSTIDAE Pleustidae are commensals, egg predators, and microparasites of other invertebrates and are c o m m o n in fouling c o m m u n i ties. T h e left mandible morphology is used for t a x o n o m y because t h e right lacinia mobilis is greatly reduced or missing in m a n y species. Thorlaksonius may be Batesian mimics of snails, while the bright colors of Chromopleustes may be for warning or Mullerian mimicry. Males have relatively larger gnathopods and smaller, narrower bodies, but sexual dimorphism is weak. The distinctive and beautiful pigmentation of pleustids is lost in preservation. The loss of pigment and the emphasis placed o n the left mandible morphology to define species increases the difficulty of distinguishing pleustids of the region. Genera and species erected without complete notes o n t h e presence or absence of the mandibular molar are doubtful; in particular, all characters proposed to distinguish Gnathopleustes, Incisocalliope, and Trachypleustes vary uniformly among the taxa or with size and thus do not yet reveal significant differences.

5.

7.

8.

2.

—

Gnathopods 1 and 2 article 5 distally produced and narrowly attached to article 6, eusiridlike and pereopod 3 and 4 dactyls less t h a n one-third of the length of article 6 and simple (plate 2 9 4 D ) Pleusirus secorrus

10. Gnathopods 1 and 2 article 6 width about equal to of posterior margin length (plate 294L)

Mandibular molar fully developed, triturative (plate 294F); * = Not in key.

598

Pereopods 3 - 7 dactyls less than one-third t h e length of article 6 (plate 2 9 4 N ) and distally notched (plate 294C), coxa

Gnathopods 1 and 2 article 5 distally truncate and broadly attached to article 6 (plate 294A, 294B); pereopods 3 and 4 dactyls more than one-third of the length of article 6 and simple (plate 294A) or short and notched (plate 2 9 4 C ) . . . 2

Mandibular molar reduced, nontriturative (plate 294E), antenna 1 article 1 without anterior projections (plate 294A) 3

—

Thorlaksonius depressus

Coxa 7 posteriorly pointed bluntly and laterally ridged (plate 294J) Thorlaksonius subcarinatus Coxa 5 with large lateral ridge and pointed behind (plate 294H) Thorlaksonius borealis Coxa 5 with reduced lateral ridge and obtuse behind (plate 294K) Thorlaksonius grandirostris Antenna 1 and 2 length less t h a n one-third of t h e total body length; gnathopods 1 and 2 article 6 palms shorter t h a n posterior margin (plate 294L) 9 Antennae 1 and 2 and more t h a n one-third of t h e total body length (not shown); gnathopods 1 and 2 palms equal to or longer t h a n article 6 posterior margin (plate 2 9 4 M ) 11

9.

—

Coxa 7 not laterally ridged or sharply pointed posteriorly (plate 294A) Thorlaksonius brevirostris Coxa 7 laterally ridged or sharply pointed posteriorly (plate 2941) 6 Coxa 7 posteriorly pointed but not laterally ridged (plate

2941)

KEY TO P L E U S T I D A E

1.

smooth, not carinate or ridged (plate 2 9 4 D ) 8 Rostrum apex strongly deflexed (80°-90°) with nearly straight lower margin (plate 294A) 5 Rostrum apex at < 8 0 ° angle to dorsum, lower margin convex (plate 294H) 7

ARTHROPODA

1 smaller than coxa 2 (plate 294N)

Dactylopleustes echinoides

Pereopods 3 - 7 dactyls more than one-third of the length of article 6 and unnotched; coxa 1 approximately equal to coxa 2 (plate 294L) 10

Micropleustes nautilus

—

Gnathopods 1 and 2 article 6 width about 6 0 % of posterior margin length (plate 2 9 4 0 ) Micropleustes nautiloides

11. Pereopod 4 article 6 swollen and lined posteriorly with large stout spines (plate 294P)

Commensipleustes commensalis

PLATE 294 Pleustidae. F, Anomalosymtes coxalis; P, Commensipleustes commensalis; C, N, Dactylopleustes echinoides; M, ¡ncisocalliope derihavini• G, Kamptopleustes coquillus; O, Micropleustes nautiloides; L, Miaopleustes nautilus; D, Pleusirus secorrus; E, H, Thorlaksonius borealis; A, B, Thorlaksonius brevirostris; I, Thorlaksonius depressus; K, Thorlaksonius grandirostris; J, Thorlaksonius subcarinatus (figures modified from Alderman 1936; Barnard 1969a; Bousfield and Hendrycks 1994b, 1995b; Hendrycks and Bousfield 2004; and Shoemaker 1952).

lacina mobilis

•incisor

Q

H. aequipes

R

A. coxalis

W

T

A. coxalis

K. coquillus Kamptopleustes coquillus

PLATE 295 Pleustidae. O, R-T, Anomalosymtes coxalis; B, D, Chromopleustes ¡meatus; E, Chromopleustes oculatus; K, Gnathopleustes pachychaetus; H, I, L, Gnathopleustes pugettensis; A, C, G, Gnathopleustes serratus; P, U, Heteropleustes setosus; N, Q, Holopleustes aequipes; F, [ncisocalliope derzhavini; V, W, Kamptopleustes coquillus; J, M, Trachypleustes trevori (figures modified from Barnard 1971; Chapman 1988; Bousfield and Hendrycks 1995b; and Hendrycks and Bousfield 2004).

—

12. — 13. —14. — 15. — 16. — 17.

— 18. — 19.

—

20.

—

Pereopod 4 article 6 of uniform width and lined posteriorly with long setae or short spines but not stout large stout spines (plate 295A) 12 Lacinia mobilis of left mandible with 17-50 teeth (plate 295B), live specimens brilliantly pigmented 13 Lacinia mobilis of left mandible with 10 or less teeth (plate 295C), live pigmentation unknown 14 Male gnathopod 2 article 5 less than half the length of article 6 (plate 295D) Chromopleustes lineatus Male and female gnathopod 2 article 5 more than half as long as article 6 (plate 295E) Chromopleustes oculatus Anterior edge of eye convex (oval), protected bays and estuaries (plate 295F) Incisocalliope derzhavini Anterior edge of eye concave or flat (bean-shaped), marine (plate 295A) 15 Gnathopod dactyls serrate (plate 295G) Gnathopleustes serratus Gnathopod dactyls smooth (plate 295H) 16 Antenna 2 flagellum sparsely setose (plate 2951, 295J) 17 Antenna 2 flagellum densely setose (plate 295K) Gnathopleustes pachychaetus Telson posterior edge truncate and with lateral setae set into tiny notches (plate 295L) Gnathopleustes pugettensis Telson posterior evenly rounded and without distal notches (plate 295M) Trachypleustes trevori Pleon epimera 3 posterior ventral corner blunt or rounded, not produced (plate 295N, 2 9 5 0 ) 19 Epimera 3 posterior ventral corner sharply acute (plate 295P) 20 Coxa 4 nearly as wide as long, ocular lobe rounded or obtuse, and anterior of antenna 1 article 1 blunt or bluntly produced (plate 295N); telson distally rounded (plate 295Q) Holopleustes aequipes Coxa 4 nearly twice as deep as long (plate 295R), antenna 1 peduncle dorsal anterior article 1 and ocular lobe both sharply produced (plate 295S); telson distally blunt or notched (plate 295T) (note ventral keel) Anomalosymtes coxalis Antenna 1 article 1 bearing an acute dorsal projection and ocular lobe evenly rounded (plate 295P); lower lip with acute medial process (plate 295U) Heteropleustes setosus Antenna 1 article 1 bearing an acute ventral projection (plate 295V); ocular lobes acute (plate 25 7W, 295V); medial junction of lower lip flat (plate 295W) Kamptopleustes coquillus

L I S T OF S P E C I E S

Anomalosymtes coxalis Hendrycks and Bousfield 2004. Natural history and ecology unknown. Lack of a ventral antenna 2 sinus in common with Pleustidae, but the lower lip lacks pillowshaped inner lobes and resembles Eusiroidea. Mandibular palp present and molar triturative; 3 mm; shallow subtidal—25 m. Chromopleustes (=Parapleustes) lineatus (Bousfield, 1985). A commensal and possible egg predator of echinoderms in rocky habitats. Four to five bright yellow and brown longitudinal body stripes (Bousfield, 1985, Rotunda 18: 30-36); 9 mm; shallow subtidal—17 m. Chromopleustes (=Parapleustes) oculatus (Holmes, 1908) (=Parapleustes oculatus). Predator of the sea cucumber Cucumaria miniata (Chen and Norton, 2005, Abstracts, Estuarine

Research Federation Annual Meeting, Norfolk, VA), and also associated with the brittle star Amphiodia urtica (Barnard and Given, 1960, Pac. Nat. 1: 46). Not clearly distinguished from Heteropleustes setosus or Pleusymptes pacifica-, 11 mm; intertidal— 2 m or more. Commensipleustes (=Parapleustes) commensalis (Shoemaker, 1952). Commensal and possible lobster egg predator. Bousfield and Hendrycks (1995a) give northern records on sponges, indicating plasticity in the species or taxonomic complications; 5.5 mm; intertidal—50 m. Dactylopleustes echinoides Bousfield and Hendrycks 1995b. Commensal or egg predator of sea urchins; 3.3 mm; intertidal— 2 m.

Gnathopleustes pachychaetus Bousfield and Hendrycks, 1995b. Rocky intertidal (to 2 m) among algae; 7 mm. Gnathopleustes pugettensis (Dana, 1853) (=Parapleustes pugettensis). Rocky and soft benthos. See also Trachypleustes trevori; 6 mm; intertidal—140 m. Gnathopleustes serratus Bousfield and Hendrycks 1995b. Under intertidal boulders, associated with sessile invertebrates; 10 mm. Heteropleustes setosus Hendrycks and Bousfield 2004. Associated with sponges; 6.7 mm; intertidal. Holopleustes aequipes Hendrycks and Bousfield 2004. Opencoast sand and algae; 3.3 mm; intertidal—2 m. *Incisocalliope bairdi Hendrycks and Bousfield 2004 (=Parapleustes bairdi of Barnard, 1956). Soft benthos, probably associated with hydroids or bryozoans; could be misidentified Gnathopleustes; 5.5 mm; intertidal—140 m. Incisocalliope derzhavini (Gurjanova, 1938) (=Parapleustes derzhavini). Introduced Asian species in protected bays, harbors and estuaries; may include I. newportensis; 4 mm; shallow subtidal—2 m. *Incisocalliope newportensis Barnard 1959c (=Parapleustes newportensis). Bays and estuaries among fouling organisms of floats and pilings and of doubtful distinction from I. derzhavini; 5 mm; intertidal—2 m. Kamptopleustes coquillus (Barnard, 1971) (=Pleusymptes coquillus). Whole body illustration plate 25 7W; on mud and sandy mud; 3.8 mm; 3 m-200 m. Micropleustes nautiloides Bousfield and Hendrycks, 1995b (=Parapleustes nautiloides). In coralline algae and Phyllospadix mats; 2.9 mm; intertidal. Micropleustes nautilus (Barnard, 1969a) (=Parapleustes nautilus). In exposed rocky shore algal mats, sponges and among Phyllospadix; 3.4 mm; intertidal—3 m. Pleusirus secorrus Barnard, 1969a. Low intertidal and subtidal cobbles; 3.8 mm; intertidal—25 m. *Pleusymptes subglaber Barnard and Given 1960 (=Sympleustes subglaber). Recorded from San Clemente sublittoral, but the unknown condition of the P. subglaber mandibular molar and distal ventral extension of antenna 1 article prevent confidence in its distinction from species of either Chromopleustes or other Pleusymptes; 4 mm; 9 m or less to 110 m. Thorlaksonius borealis Bousfield and Hendrycks, 1994b. Occurring in offshore fouling communities of hard substrate; 11 mm; intertidal—10 m. Thorlaksonius brevirostris Bousfield and Hendrycks, 1994b. Among algae on rocks; 7 mm; intertidal—35 m. Thorlaksonius depressus (Alderman, 1936) (=Pleustes depressus). Among algae on rocks and among Phyllospadix. Mimics snails (Carter and Behrens, 1980, Veliger 22: 376-377); 8.5 mm; intertidal—4 m. * = Not in key.

AMPHIPODA:

GAMMARIDEA

601

P rostrata

X

P. inermis Y

P. rostrata

P. rostrata

R inermis

P. intermedia

PLATE 296 Eusiroidea. S, Accedomoera vagor; B, K, L, M, Batea lobata; I, Calliopius pacifìcus; H, Oligochinus lighti; C, Paramoera bousfieldi; W, X, Pontogeneia inermis; T, Paramoera mohri; J, O, R, Pontogeneia intermedia; N, P, Q, V, Y, Z, Pontogeneia rostrata; D, E, Rhachotropis bamardi; G, Rhachotropis inflata; A, F, Rhachotropis oculata (figures modified from Barnard 1952b, 1964c, 1969a, 1971, 1979; Bousfield 1973; Bousfield and Hendrycks 1995a, 1997; Sars 1895; Shoemaker 1926; and Staude 1995).

Thorlaksonius grandirostris Bousfield and Hendrycks, 1994b. On rocks with seagrass, probably mimics a snail; 6 mm; intertidal—2 m. *Thorlaksonius platypus (Barnard and Given, 1960) (=Pleustes platypa). Pt. Conception and south; but not clearly distinct from the more northern T. grandirostris. On various macrophytes. Imitates a snail (Crane 1969, Veliger 12: 200; Field 1974. Pacific Science 28: 439-447); 8.5 mm; 3 m-100 m. Thorlaksonius subcarinatus Bousfield and Hendrycks, 1994b. On rocks and algae; 9.5 mm; intertidal—25 m. Trachypleustes trevori Bousfield and Hendrycks, 1995b. Associated with sponges and tunicates under rocks of exposed coasts. Distinction from Gnathopleustes pugettensis is mainly the smaller gnathopods which are described largely from males; 5 mm; intertidal. EUSIROIDEA Eusiroidea (Bateidae, Calliopiidae, Eusiridae, Pontogeneiidae) include a broad range of morphological diversity (which is particularly apparent in the shapes of telsons—laminar cleft or entire—and in the absolute and relative sizes of first and second gnathopods), which makes this group difficult to distinguish * = Not in key. 602

ARTHROPODA

from other families. The Bateidae, with vestigial gnathopod 1 and coxa 1 obscured by coxa 2, are among the most extreme of gnathopod morphotypes. Accessory flagellum either a tiny button or absent. Rostrum variable, urosomites separate, third uropod biramous. Eusiroidea are free living, with well-developed molars and mandibular palps. Pontogeneia and Paramoera occasionally swarm in intertidal pools and eusirids are extremely abundant in hard bottom nearshore marine communities.

KEY T O E U S I R O I D E A

1.

Gnathopods powerful and subchelate with dactyls reaching more than two-thirds of the length of article 6, dorsal urosomites 1 and 2 and posterior ventral epimeron 3 toothed, dactyls of pereopods 10-20 times as long as broad (plate 296A) 2 — Gnathopod 1 vestigial, (plate 296B), or normally subchelate (plate 296C); if dactyl present, not reaching onehalf of the length of article 6 (plate 296C) 4 2. Urosomite 1 dorsally toothed, epimeron 2 nearly square (plate 296D); distal notch of telson small (plate 296E) Rhachotropis barnardi — Urosomite 1 not dorsally toothed (plate 296A); epimeron 2 produced or rounded; telson cleft more than one-third of its length (plate 296F) 3

Paracalliopiella pratti

Calliopius pacificus

z

C. pacificus

PLATE 297 Eusiroidea. E-G, Accedomoem melanophthalma; A, B, H, Accedotnoera vagor; V, AA, Calliopius carinatus; W-Z, Calliopius pacificus; Q, Oligochinus lighti; R-U, Paracalliopiella pratti; I, Paramoera bouspeldi; J, L, M, Paramoera Columbiana; K, N, P, Paramoera mohri; C, D, Paramoera serrata; O, Paramoera suchaneki (figures modified from Barnard 1952b, 1969a; Bousfield 1958a; Bousfield and Hendrycks 1997; Gurjanova 1938; and Staude 1995).

3.

Posterior ventral epimeron 2 acute (plate 296A) Rhachotropis oculata — Posterior ventral epimeron 2 rounded (plate 296G) Rhachotropis inflata 4. Telson entire, distally concave (plate 296H); or convex (plate 2961) but not cleft 15 — Telson deeply cleft (plate 296J) 5 5. Gnathopod 1 reduced to two articles (plate 296B); head without a ventral antenna 2 sinus (plate 296K); mandibular palp article 2 with distal expansion for dense distal setae group (plate 296L); pereopod 5 article 2 parallel sided and distally expanded (plate 296M) Batea lobata

—

Gnathopod 1 of 7 normal articles (plate 296N); head with ventral antennal sinus (plate 2960); mandibular palp article 2 without distal expansion for dense distal group of long setae (plate 296P); pereopod 5 article 2 expanded and thickest in the middle (plate 296Q) 6 6. Antenna 1 without an accessory flagellum (plate 296R) (examine this character under more than 50x) 7 — Antenna 1 with a tiny uniarticulate accessory flagellum (plate 296S, 296T) (examine character under more than 50x) 9 7. Rostrum reaching no more than one-fourth of the length of antenna 1 article 1 (plate 2960); posterior extension of AMPHIPODA: GAMMARIDEA

603

—

8.

—

9. — 10.

—

11.

—

12.

—

13. — 14. — 15.

—

16.

—

17.

—

604

epimeron 3 slight (plate 296U) Pontogeneia intermedia Rostrum reaching more than one-third of the length of antenna 1 article 1 (plate 296V); posterior extension of epimeron 3 prominent (plate 296W) 8 Apices of telson rounded (plate 296X); posterior margin of epimeron 3 strongly convex and with obtuse ventral corner (plate 296W) Pontogeneia inermis Apices of telson angled (plate 296Y); posterior margins of epimeron 3 with moderate convex posterior edge and weak ventral tooth (plate 296Z) Pontogeneia rostrata Rostrum prominent (plate 297A); inner plate of maxilla 2 with one medial spine (plate 297B) 10 Rostrum indistinct or absent (plate 297C); inner plate of maxilla 2 with multiple medial spines (plate 297D) 11 Antenna 1, peduncular article 3 with ventral distal tooth (plate 29 7E); epimeron 3 posterior edge greatly expanded beyond ventral corner (plate 29 7F); ventral antennal sinus evenly rounded (plate 297G) Accedomoera melanophthalma Antenna 1, peduncular article 3 without a ventral distal tooth (plate 296S); epimeron 3 posterior edge only slightly expanded beyond ventral corner (plate 297H); ventral antennal lobe notched (plate 29 7A) Accedomoera vagor Deep cleft separating ocular lobe and second antenna sinus and female gnathopod 2 article 5 shorter than or equal to article 6 (plate 297C) 12 Shallow cleft separating ocular lobe and antenna 2 sinus and female gnathopod 2 article 5 as long as article 6 (plate 2971) Paramoera bousfieldi Anterioventral region of head below the antennal notch extending nearly even with the ocular lobe and posterior edges of pereopod 7 article 2 strongly serrate (plate 297C) Paramoera serrata Anterioventral region of head posterior to ocular lobe (plate 29 7J); posterior edges of pereopod 7 article 2 weakly serrate (plate 297K) or smooth (plate 297L) 13 Male gnathopod 2 palm one-half of the length of article 6 and subchelate (plate 29 7M) Paramoera columbiana Male gnathopod 2 palm less than one-third of the length of article 6 and oblique (plate 297N) 14 Female uropod 2 outer ramus equal to or longer than inner ramus (plate 2 9 7 0 ) Paramoera suchaneki Female uropod 2 outer ramus shorter than inner ramus (plate 29 7P) Paramoera mohri Telson, posteriorly concave (plate 296H); pleonal epimeron 3, posteriorly serrate and with ventral spines (plate 297Q) Oligochinus lighti Telson, posteriorly convex and evenly rounded (plates 2961, 297R); epimeron 3, without serrations (plate 297S) 16 Pleonite 3 posteriorly rounded (plate 297S); antenna 1 article 3 without ventromedial extension (plate 29 7T); lacinia mobilis of mandible greatly extended (plate 297U) Paracalliopiella pratti Pleonite 3 posterior ventrally square and with a minute tooth (plate 297V); antenna 1 article 3 ventromedially extended (plate 29 7W); lacinia mobilis of mandible normal (plate 29 7X) 17 Dorsal pereonites 5-7 and pleonites 1 and 2 not carinate (plate 29 7Y); pleon plate 2 with facial setae in two to three submarginal rows (plate 29 7Z) Calliopius pacificus Dorsal pereonites 5-7 and pleonites 1 and 2 carinate (plate 297V); pleon plate 2 with facial setae in five to seven submarginal rows (plate 297AA) Calliopius carinatus ARTHROPODA

LIST OF SPECIES

BATEIDAE

Batea lobata Shoemaker, 1926. Inshore sand and mud bottoms and pier pilings; 6 mm; intertidal—8 m. CALLIOPIIDAE

Calliopius carinatus Bousfield and Hendrycks, 1997. Common in surf-swash zone, mainly along rocky shores, marine to mesohaline inshore waters; 9 mm; intertidal. Calliopius pacificus Bousfield and Hendrycks, 1997. Dominant in inshore waters of bays and estuaries, apparently moderately euryhaline, among submerged plants and algae and on floats; 15 mm; intertidal to shallow depths. Oligochinus lighti Barnard, 1969a. In the cobble-Si/vetiaPhyllospadix zone; among the most abundant amphipods in Mastocarpus papillatus and Endocladia muricata of high and middle intertidal where they feed on epiphytic algae; see Johnson 1975, pp. 559-587 in Gates and Schmerl, eds., Perspectives of biophysical ecology, Springer Verlag (ecology); named in honor of the founder of this book, Sol Felty Light, 1886-1947; 11.5 mm. Paracalliopiella pratti (Barnard 1954a). Low intertidal and subtidal on algae, mixed sediment, and seagrass. Known only from Alaska, Puget Sound, and Fossil Point in Coos Bay, Oregon, the latter collected from the introduced Japanese seaweed Sargassum muticum; 5 mm; intertidal—2 m. EUSIRIDAE

Rhachotropis barnardi Bousfield and Hendrycks 1995a. Deep subtidal on fine sediment and probably also pelagic; abundance in shallow waters unclear; 4 mm; 17 m-350 m. Rhachotropis inflata (Sars, G. O., 1883). On fine sediments and pelagic, circum-Arctic; occurrence in shallow waters possible; 8 mm; 10 m-154 m. Rhachotropis oculata (Hansen, 1888). Pan-arctic, swimming, planktivorous; south to southern California; occurrence in shallow waters unclear; 10 mm; 18 m-274 m. PONTOGENEIIDAE

Accedomoera melanophthalma (Gurjanova, 1938). On mixed algae and sediments of boreal western Pacific to California, but Eastern Pacific occurrences poorly documented; 8 mm; intertidal—80 m. Accedomoera vagor Barnard, 1969a. On algae in exposed rocky areas; 7.5 mm, intertidal—2 m. Paramoera bousfieldi Staude, 1986. Gravel of brackish, stream mouths or intertidal freshwater seeps; 4.5 mm. Paramoera columbiana Bousfield, 1958. Estuary, in gravel and other mixed sediments; 11 mm; intertidal. Paramoera mohri Barnard, 1952b. Marine rocky open coasts; 6.5 mm, intertidal—10 m. Paramoera serrata Staude, 1995. Marine, sand, and mixed sediments; 6 mm; low intertidal. Paramoera suchaneki Staude, 1986. Marine, gravel, cobble and mussel beds; 13 mm; intertidal. Pontogeneia inermis (Kroyer, 1838). Pan boreal in northern hemisphere, eastern Pacific identification uncertain; mixed sediments, possible echinoderm and coelenterate commensal

A

Listriella diffusa F L. geminata

PLATE 298 Liljeborgiidae. C-F, Liljeborgiageminata;

A-B, Listriella diffusa (figures modified from Barnard 1959a, 1969a).

and also common in nocturnal plankton samples; 4.5 mm; intertidal—220 m. Pontogeneia intermedia Gurjanova, 1938. Intertidal and shallow subtidal on algae and various rocky sediments occurring also Japan and eastern Russia; 7.5 mm; intertidal. Pontogeneia rostrata Gurjanova, 1938. On algae and mixed sediments; 6.5 mm; shallow subtidal and low intertidal. *Pontogeneia sp. A shallow subtidal undescribed purple species that occurs among Strongylocentrotus purpuratus spines (Harty 1979, p. 198, concerning observations at Cape Arago, Oregon, in: Bull. So. Calif. Acad. Sci. 78: 196-199); 7 mm; shallow subtidal. LILJEBORGIIDAE

Liljeborgiidae have tiny rostrums, short antenna 2 relative to antenna 1, prominent accessory flagellum, poorly developed mandibular molars (plate 257KK), large gnathopods, and distally notched, laminar telsons that are cleft to the base. Pigmentation of many Listriella remains partially intact in preservation. Liljeborgiidae are likely commensals in tubes and burrows of large subtidal invertebrates, including polychaetes and echiuroids. KEY TO LILJEBORGIIDAE

Gnathopods and often body pigmented urosome smooth and accessory flagellum of two articles (plates 25 7Q, 298A); gnathopod 2 article 5 posterior lobe not extending behind article 6 and dactyl posterior edges minutely serrate or smooth (plate 298B) Listriella diffusa — Gnathopods and body not pigmented, gnathopod 2 article 5 posterior lobe extending behind article 6 and dactyls deeply serrate (plate 298C); accessory flagellum multiarticulate (plate 298D); pleonites 1 and 2 minutely toothed dorsally (plate 298E); uropod 1 peduncle with long lateral spines (plate 298F) Liljeborgia ? geminata

uropods 1 and 2 (plate 298F) are characteristic of this species; 8.7 mm; 1 m - 7 0 m. *Listriella albina Barnard 1959a. Oregon to Baja California, a shallow warm-water species in its southern range and found at great depths in its northern range (Barnard 1971); 7.5 mm; 16 m-721 m. Listriella diffusa Barnard 1959a. Shallow subtidal to 23 m in sandy sediments, possibly a commensal with large tube building polychaetes. Additional species of Listriella reported from southern California (Barnard 1959a) are expected in our region. Whole female body illustration plate 257Q. The toothlike structures on the inner lobes of the lower lip (functions unknown) occur also in Melitidae; 3.5 mm; 3 m-172 m. *Listriella goleta Barnard 1959a. Oregon to Baja California, a shallow warm-water species in its southern range found at great depths in its northern range; 3.5 mm, 16 m-721 m. GAMMAROIDEA

Gammaroidea (Anisogammaridae and Gammaridae) are freeliving, benthic, and epibenthic omnivores and zooplankton predators that range widely in shallow marine shores, estuaries, tidal creeks, and low-elevation rivers and lakes. Sexual dimorphism is weak. Whether native Gammaridae occur in the region is unclear.

1.

LIST OF SPECIES

*Liljeborgia geminata Barnard 1969a. Of a poorly distinguished species complex (Barnard 1969a) occurring in the Atlantic and Pacific Oceans; on floats and pilings of southern California harbors and shallow coastal waters in rhizomes of Macrocystis pyrifera. Multiple long spines on peduncles of

KEY TO GAMMAROIDEA

1.

Male gnathopod palms nearly transverse, lined with thick peg spines and gnathopod dactyls thick (plate 299A299C); gills with accessory lobes (plate 299D) 2 — Gnathopod palms oblique, lined with simple spines and dactyls slender (plate 299E); gills normal, without accessory lobes (plate 299F) 6 2. Urosomite 2 with prominent median tooth (plate 299G); uropod 3 inner ramus > 6 0 % length of outer ramus (plate 299H) Anisogammarus pugettensis — Urosomite 2 without prominent median tooth (plate 299A, 2991); uropod 3 inner ramus less than 30% length of outer ramus (plate 299J) 3 3. Pleon segments dorsum bare (plate 299A) or with a few tiny setae (plate 2991) Eogammarus confervicolus * = Not in key. AMPHIPODA: GAMMARIDEA

605

R. ramellus PLATE 2 9 9 G a m m a r o i d e a . G, H, Anisogammarus pugettensis; A-D, I, J, Eogammarus confervicolus; F, M, N, Gammarus daiberi; E, O, P, Gammarus lacustris; K, Ramellogammarus oregonensis; L, Ramellogammarus ramellus (figures modified from Barnard 1 9 5 4 a ; Bousfield 1 9 5 8 b , 1 9 7 3 , 1 9 7 9 ; Shoemaker 1 9 4 4 , 1 9 6 4 ; and Weckel 1 9 0 7 ) .

—

Pleon segments (one or more) with numerous, conspicuous, dorsal spines or setae (plate 299K, 299L) 4 4. Pleonite 3 with few or no setae and numerous stout spines (plate 299K) 5 — Pleonite 3 with numerous long setae and few stout spines (plate 299L) Ramellogammarus ramellus 5. Pleonites 1-3 with few setae and stout spines anterior to posterior pleonite margins (plate 299K) Ramellogammarus oregonensis — Pleonites 1-3 with few setae and stout spines only on posterior edges Ramellogammarus spp. 6. Telson with two lateral bundles of prominent spines and seta (plate 299M); inner ramus extending to distal end of the first article of the outer ramus article 1 (plate 299N) Gammarus daiberi — Telson with one or no lateral spine bundles and few seta (plate 2990); inner ramus not reaching distal end of the first article of the outer ramus article 1 (plate 299P) Gammarus lacustris 606

ARTHROPODA

L I S T OF S P E C I E S ANISOGAMMARIDAE

Anisogammarus pugettensis (Dana, 1853). Marshes and lowsalinity estuaries; high tolerance of low oxygen (Waldichuck and Bousfield 1962, J. Fish. Res. Bd. Canada 19: 1163-1165); 17 mm; subtidal to intertidal. Eogammarus confervicolus (Stimpson, 1856) (=£. oclairi Bousfield, 1979). Estuarine, intertidal, and subtidal; various substrata but especially associated with sedges, eelgrass, algae, and wood chips; calceoli (plate 299A) are chemosensory organs of ecological and taxonomic interest (Stanhope et al. 1992, J. Chem. Ecol.18: 1871-1887); 19 mm; subtidal to intertidal. The major character separating E. oclairi and E. confervicolus (two distal telson lobe spines instead of one) is size dependent: E. oclairi are large (19 mm) E. confervicolus, and are thus synonyms. *Eogammarus oclairi Bousfield 1979. See E. confervicolus. * = Not in key.

*Ramellogammarus columbianus Bousfield and Morino, 1992. Freshwater, occurring in pebble and stone bottoms in moss or woody detritus often at the mouths of medium-size streams flowing into protected bays; 13 mm; intertidal. *Ramellogammarus littoralis Bousfield and Morino, 1992. Freshwater, occurring in pebble and stone bottoms in moss or woody detritus often at the mouths of medium-size streams flowing into protected bays; 9.5 mm; intertidal. Ramellogammarus oregonensis (Shoemaker 1944) (=Anisogammarus oregonensis, Eogammarus oregonensis). Known only from extreme low salinities and freshwater of Big Creek and mouth of D River, Lincoln County, Oregon, and Siltcoos River, Lane County, Oregon; 10 mm; subtidal to intertidal. Ramellogammarus ramellus (Weckel, 1907) (=Gammarus ramellus, Anisogammarus ramellus and Eogammarus ramellus). Low-salinity and freshwater marshes and stream mouths among coarse sand, stones, and wood debris, a morphologically variable, poorly described species or species complex; 13 mm; subtidal to intertidal. Ramellogammarus spp. Several freshwater species from aquatic plants, coarse gravel and benthos of the lower Columbia River and coastal river mouths in up to 2% salinities (Bousfield and Morino 1992, Cont. Nat. Sci. 17: 1-22) GAMMARIDAE

Gammarus daiberi Bousfield 1969. Ballast water introduction from eastern North America to 0 - 1 5 % salinity areas of San Francisco Bay and Delta, benthic and semipelagic; 12.5 mm; subtidal to intertidal. *Gammarus tigrinus Sexton 1939. A benthic and pelagic species, introduced to the North Sea from eastern North America with ballast water, a likely invader of the intertidal Pacific coast and estuaries; referred to in Europe as a "scourge" due to its likely replacement of native gammaroid species (see Dielman and Pinkster 1977, Bull. Zool. Mus. Univ. Amsterdam 6: 21-29; Pinkster et al. 1977, Crustaceana Suppl. 4: 91-105); morphology and ecology are similar to G. daiberi, 1-25% salinity; 14 mm; low intertidal to shallow subtidal. *Gammarus lacustris (Sars, 1863). Filamentous algae in weed and rush margins of hard-water lakes and ponds of American Pacific coastal alpine, rare in tidal waters of rivers, West Coast distribution and taxonomy unclear and may be present along the Pacific coast south of 45° N (Barnard and Barnard 1983: 81); important zooplankton predator in lakes (Wilhelm and Schindler 1999, Can. J. Fish. Aquat. Sci. 56:1401-1408); 15 mm; intertidal river mouths, low elevation lakes and streams.

KEY TO HADZIOIDEA

1. — 2.

— 3. — 4. — 5.

—

6.

—

7.

—

8.

—

9.

—

HADZIOIDEA

10.

Hadzioidea (Hadziidae and Melitidae) occur in marine and estuarine benthic fouling communities. The Hadzioidea have large accessory flagella, short antenna 2 relative to antenna 1, waxy cuticles and greater lateral body compression than most Gammaridea. The only Hadziidae of the region is marine. Estuarine Melitidae may overlap with Crangonyctidae in low-salinity environments. The diversity of secondary sex characters in Melitidae, ranging from the enormous male gnathopods of Dulichia, probably adapted for competition for females, to the stridulating anatomy in Melita perhaps to attract males, indicate broad variation in mating behaviors in the family.

— 11.

* = Not in key.

— 12.

—

Uropod 3 inner ramus less than a fifth as long as the outer ramus (plate 300A) 2 Rami of uropod 3 similar in length (plate 300B) 12 Male and female gnathopod 2 article 6 equal to or smaller than article 5 and coxa 2-3 longer than deep (plate 300C) Netamelita cortada Male and female gnathopod 2 article 6 larger than article 5 and coxa 2-3 deeper than long (plate 300D) 3 Pleosome segments 1-3 with a central dorsal tooth plus accessory lateral teeth (plate 300E) 4 Pleosome segments 1-3 without dorsal teeth (plate 300D) or with only dorsal lateral teeth (plate 300F) 6 Male gnathopod 2 article 6 immense and chelate (plate 300G) Dulichiella spinosa Male gnathopod 2 large but subchelate and not immense (plate 300H) 5 Gnathopod 2 dactyl distally blunt and without dense anterior setae (plate 300H); dorsal pleonite 1 with multiple lateral teeth (plate 3001) Megamoera subtener Gnathopod 2 dactyl distally pointed and covered anteriorly with setae (plate 300J); pleonite 1 with single lateral teeth (plate 300E) Megamoera dentata Male gnathopod 1 article 6 and dactyl highly modified (plate 300K); distinct from simple female dactyl (plate 300L) 7 Male gnathopod 1 article 6 and dactyl normally subchelate, not modified or distinct from simple dactyl of female (plate 300M) 10 Urosomite 1 posterior edge with a distinct dorsal medial tooth (plate 300D); condition of female coxa 5 not reported Melita sulca Urosomite 1 posterior edge without a medial tooth (plate 300F, 300N); female coxa 5 ventrally extended (plate 3000) 8 Urosomite 3 dorsally bare and pleonal epimeron 3 of both sexes weakly toothed or square (plate 300N) Melita nitida Urosomite 2 with dorsal lateral teeth (plate 300F, 300P); posterior edge of pleonal epimeron 3 of both sexes sharply toothed (plate 300Q, 300R) 9 Urosomite 2 with widely separate pairs of dorsal lateral teeth (plate 300P); male gnathopod 1 dactyl overlapped by article 6 less than half its length (plate 300S) Melita oregonensis Urosomite 2 with only two closely spaced dorsolateral teeth (plate 300F); male gnathopod 1 dactyl overlapped more than half by article 6 (plate 300K) Melita rylovae Urosomite 1 with 3-5 dorsal lateral teeth (plate 301A). . . Desdimelita californica Urosomite 1 with a single dorsal tooth (plate 301C) 11 Pereopods 5-7 dactyl lengths greater than 4 times width (plate 301C) Desdimelita desdichada Pereopods 5-7 dactyls lengths < 3 times width (plate 301D) Desdimelita microdentata Pleon epimeron 3 with multiple irregular posterior teeth (plate 300T); mandibular palp article 3 less than one third of the length of article 2 (plate 300V) Ceradocus spinicauda Pleon epimeron 3 rounded (plate 300U) or with one ventral posterior tooth (plate 3010); mandibular palp article 3 greater than two thirds of the length of article 2 (plate 301F) 13 AMPHIPODA:

GAMMARIDEA

607

o Melita nitida

M. oregonensis

C. spinicauda

PLATE 300 Hadzioidea. B, T, V, Ceradocus spinicauda; M, Desdimelita califomica; G, Dulichiella spinosa; U, Elasmopus mutatus; E, J, Megamoera dentata; H, I, Megamoera subtener, N, O, Melita nitida; P-S, Melita oregonensis; A, F, K, L, Melita rylovae; D, Melita sulca; C, Netamelita cortada (figures modified from Barnard 1954a, 1962b, 1969a, 1970; C h a p m a n 1988; Jarrett and Bousfield 1996; Krapp-Schickel a n d j a r r e t t 2000; and Yamato 1987, 1988).

T

M. jerrica

Maera similis

M. similis

PLATE 301 Hadzioidea. A, B, Desdimelita califomica; C, Desdimelita desdichada; D, Desdimelita microdentata; E, G, Elasmopus antennatus; H, K, Elasmopus mutatus; L-P, Elasmopus rapax; I, J, Elasmopus serricatus; F, R-T, Maera jerrica; U, V, Maera similis; Q, Quadrimaera vigota (figures modified from Barnard 1954a, 1959b, 1962b, 1969b, 1979a and Krapp-Schickel and Jarrett 2000).

13. Mandibular palp article 3 falcate and with dense comblike setae (plate 301E) 14 — Mandibular palp ordinary and sparsely setose (plate 301F) 17 14. Male gnathopod palm without defining proximal processes (plate 301G) (examine from lateral and medial. These processes are nearly transparent and can be obscured by dense setae) Elasmopus antennatus — Male gnathopod palm with defining proximal processes (plate 301H) 15 15. Telson distally truncate and spinose (plate 3011); posterior pereopod 5 deeply serrated (plate 301J) Elasmopus serricatus

— Telson less spinose, distally incised and with medial extensions of the lobes (plate 301K-301M); posterior pereopod 5 weakly serrate (plate 301N) 16 16. Third pleonal epimera posterior ventrally rounded (plate 300U); male gnathopod 2 article 6 proximal palmar tooth reduced and palm bearing few setae (plate 301H); medial lobe of telson bluntly acute (plate 301K) Elasmopus mutatus — Third pleonal epimera posterior ventrally square or with a small tooth (plate 3010); male gnathopod 2 with a defining hinge process at the proximal medial corner of article 6; palm (plate 30IP) with dense setae (plate 3010, 301P) Elasmopus rapax AMPHIPODA: GAMMARIDEA

609

17. Male gnathopod 2 nearly transverse, 80-90° angle of article 6 distal posterior corner (plate 301Q) Quadrimaera vigota — Male and female gnathopod 2 subchelate, with palm angle >100° (plate 30IR, 301S) 18 18. Telson distal spines less than one-third of the telson length (plate 301T); coxa 1 anterior acute (plate 301R) Maera jerrica — Telson distal spines greater than one-half of the telson length (plate 301U); coxa 1 anterior rounded (plate 301V) Maera similis LIST OF SPECIES HADZIIDAE

Netamelita cortada Barnard, 1962b. Tunicate colonies at base of Phyllospadix beds; 3.5 mm; intertidal—20 m. MELITIDAE

Ceradocus spinicauda (Holmes, 1908). Intertidal algae among cobbles; 12 mm; 3 m-218 m. Desdimelita califomica (Alderman, 1936). Among cobbles to fine sediments; 10 mm; intertidal—10 m. Desdimelita desdichada (Barnard, 1962b) (=Melita desdichada). Soft sediments; 9 mm; 10 m-108 m. Desdimelita microdentata Jarrett and Bousfield, 1996.11 mm; 1 m-35 m. Dulichiella spinosa Stout, 1912 (=Melita appendiculata). A rocky intertidal semitropical species reported north of Pt. Conception only once (Bousfield and Jarrett 1996, Amphipacifica 2[2]: 13); not clearly distinct from tropicopolitan Dulichiella appendiculata (Say, 1818); 4.5 mm; intertidal—3 m. Elasmopus antennatus (Stout, 1913). Distinguished from E. mutatus by its acute rather than round posterior epimeron 3 (plate 25 7R); among Phyllospadix and algae bottoms; 10.5 mm; intertidal—18 m. Elasmopus mutatus Barnard, 1962b. Open rocky coast among algae turf. Allometric distinctions between E. mutatus and the larger E. rapax are unclear; 7.5 mm; intertidal. Elasmopus rapax Costa, 1853. Cosmopolitan in latitudes below 45° and restricted to enclosed bays. Introduced in California. Variation in telson morphology with size is apparent in male telsons of 7.5 mm E. mutatus (plate 301K) and 8 mm and 11 m m £ . rapax (plate 301L, 301M); to 11 mm; intertidal— 100 m. Elasmopus serricatus Barnard, 1969b. Among Egregia, Phyllospadix and coralline algae. Poorly distinguished from southern Californian Elasmopus holgurus Barnard, 1962b. 8 mm; intertidal. *Maera grossimana (Montagu, 1808). The northeast Pacific record of this North Atlantic species (Bousfield 2001) is uncertain; 10 mm. Maera jerrica Krapp-Schickel and Jarrett, 2000 (=Maera inaequipes Barnard, 1954a). Among intertidal algae and in soft offshore sediments; 14 mm; intertidal—135 m. Maera similis Stout, 1913. Soft benthos of estuaries and coastal waters. 9 mm, intertidal—221 m. Megamoera dentata (Kroyer, 1842). Cosmopolitan in Arctic to cold temperate northern hemisphere oceans, on rocky and sedimentary bottoms; to 28 mm; intertidal—672 m. * = Not in key.

610

ARTHROPODA

Megamoera subtener (Stimpson, 1864) In coarse gravel and shell, under stones and kelp; 12 mm; intertidal—10 m. Melita nitida Smith, 1874. Estuarine, abundant among algae and hydroids. Introduced probably from the northwest Atlantic, but also indistinguishable from the Asian Melita setiflagellata Yamato 1987 and therefore may be introduced to or from Asia. See Borowsky et al. 1997, J. Exp. Mar. Biol. Ecol. 214: 85-95 (reproductive morphology and physiology in polluted estuarine sediments); 12 mm; intertidal—10 m. Melita oregonensis Barnard, 1954a. Rocky shores; 12 mm, intertidal. Melita sulca (Stout, 1913). Condition of female coxa 5 not described. Harbors and among cobbles and algae holdfasts of open coasts; 12 mm; intertidal—101 m. Melita rylovae Bulycheva, 1955. Introduced to San Francisco Bay from Asia and also found in ballast water samples collected in Australia where it is also introduced (Williams et al. 1996, Est. Coastal Shelf Sci. 26: 409-420); in fouling communities of docks and floats; 7.5 mm; 1 m-10 m. Quadrimaera vigota (Barnard, 1969a) (=Maera vigota). Abundant under cobbles, on sponges and tunicates and rarely on algal holdfasts; dark pink; 8.5 mm; intertidal. CRANGONYCTIDAE Crangonyctidae have two segment accessory flagella (plate 257UU) with small terminal articles, dorsally smooth urosomes and lack a ventral antenna sinus. They are distinguished from the Hadzioidea also by having pereopod 6 longer than pereopod 7. Sexual dimorphism is reduced. As crangonyctids, Crangonyx pseudogracilis and C. floridanus share a biramous uropod 3 with reduced inner ramus (plate 302A) singly inserted spine rows on lateral article 6 of gnathopods 1 and 2 (plate 302B, 302C), eyes, and above ground occurrence; but morphological distinctions between the two species are not clear, with pleon tooth development and ventral comb setae of the male uropod 2 outer ramus being variable and of uncertain significance. The low-salinity occurrences of Crangonyx pseudogracilis and C. floridanus are unique among the almost exclusively freshwater Crangonyctidae. KEY T O

CRANGONYCTIDAE

1.

Pleon epimera teeth reduced (plate 302D); male uropod 2 outer ramus slightly decurved and lined ventrally with tiny comb spines (plate 302E) Crangonyx pseudogracilis — Pleon epimera teeth large (plate 302F); male uropod 2 outer ramus straight and lined ventrally with large comb spines (plate 302G) Crangonyx floridanus LIST OF SPECIES

Crangonyx floridanus Bousfield, 1963. Endemic to sloughs, swamps, caves, and ponds along the U.S. Gulf Coast and possibly introduced to San Francisco Bay. The specific identity of C. floridanus in the San Francisco Bay Delta (Toft et al. 2002) is unclear since the associated illustration in the report is of a previously published figure of Crangonyx forbesi (Hubricht and Mackin 1940); 6 mm; intertidal—10 m. Crangonyx pseudogracilis Bousfield, 1958. Occurring in aquatic vegetation in still or slow flowing, organically polluted, low salinity waters. Introduced to western North America and Japan (Zhang 1997) and Europe, where it spread secondarily from Great Britain to Ireland possibly in aquarium

C. pseudogracilis PLATE 3 0 2 Crangonyctidae. F, G, Crangonyx

C. floridanus floridanus;

A-E, Crangonyx

plants (Costello 1993, Crustaceana 65: 287-299). Whether C. floridanus or C. pseudogracilis occur in San Francisco Bay should be more than an academic concern. Crangonyx pseudogracilis is declining in some areas of its native central and eastern North American range in the presence of invading introduced species (Beckett et al. 1997). In contrast, native European amphipod populations decline in the presence of the invading C. pseudogracilis which are largely unaffected by native parasites (MacNeil et al. 2003). However, the microsporidian parasite Fibrillanosema crangonycis of C. pseudogracilis appears to be transmitted with the host in invasion events and then vertically transmitted to native European amphipod hosts (Slothouber Galbeath et al. 2004). Vertical transmission combined with host sex ratio distortion may enhance host invasion success through increased rates of population growth and declines of potential native competitors (MacNeil et al. 2003). C. pseudogracilis also occurs in Oregon (Bousfield 1961b) and southern California (Bottoroff et al. 2003); 5 mm; intertidal—10 m. TALITRIDAE EDWARD L. BOUSFIELD

Talitrids comprise mainly beach hoppers, common at night on damp sand beaches, where they feed upon seaweeds cast up by the tide. Fresh beach wrack may contain purely aquatic amphipods, but their death is rapid in the air, whereas beach hoppers survive well out of water. Because the patterns and colors by which they may be identified in life are lost in preservatives, a morphological key to the Talitridae precedes a key to Megalorchestia based largely on color (Bowers 1963). Although entirely terrestrial talitrids (land hoppers) are not native to our area, the student and professional zoologist will encounter southern hemisphere species introduced in urban and agriculture environments in California. Abundant, for example, under Eucalyptus and other leaf litter in Golden Gate Park (and other parks) in the City of San Francisco is the introduced Australian leafhopper Arcitalitrus sylvaticus (Haswell, 1880). KEY TO TALITRIDAE GENERA

From Bousfield 1982. 1. Male gnathopod 1 simple, article 6 more than twice as long as wide (plate 303A1, 303C3, 303F1, 303H1); pere-

pseudogracilis

(figures modified from Bousfield 1958b, 1963, 1973).

opods and uropods stout, with large spines; pleopod peduncles laterally spinose (plate 303A2); burrowers Megalorchestia — Male gnathopod 1 transverse, article 6 less than twice as long as wide (plate 303B1, 303E1); appendages slender, with small spines; pleopod peduncles with few or no lateral spines (plate 303B2); under debris or rocks 2 2. Male antenna 2 thick (plate 303E6) and sexual dimorphism is strong; male gnathopod 2 dactyl sinuate (plate 303E2) Transorchestia — Male antenna 2 slender (plate 303B1, 303G1) and sexual dimorphism is weak; male gnathopod 2 dactyl evenly curved (plate 303B1) 3 3. Uropod 1 with distolateral spine (plate 303G2); telson longer than broad, with single dorsolateral spines (plate 303G3); female gnathopod 1 articles 5 and 6 posteriorly swollen, dactyl not exceeding palm (303G4); brood plate setae simple (i.e., plate 255MM) Paciforchestia — Uropod 1 lacking distolateral spine (plate 303B1, 303E4); telson broader than long, with groups of dorsal and marginal spines (plate 303B3); female gnathopod 1 segments 5 and 6 not swollen posteriorly and dactyl slightly exceeding palm (plate 303B4); brood plate setae hook-tipped (i.e., plate 255NN) Traskorchestia KEY TO TALITRIDAE

1.

Male gnathopod 1 transverse, dactyl not or barely overlapping palm (plate 303B1, 303E1, 303G4); pereopod 7 longer than 6 (plate 303B1); uropod 3, ramus narrowing distally and shorter than peduncle (plate 303E3) 2 — Male and female gnathopod 1 simple (both sexes), dactyl strong, heavy (fossorial) (plate 303A1, 303C3, 303D1, 303F1, 303H1); pereopod 6 longer than 7 (plate 303A1); uropod 3 ramus distally broad and as long as peduncle (plate 303C1) 4 2. Pereopods 3 and 4 slender, article 5 about equal to article 6 length and width (plate 303E5); male gnathopod 2 palm slightly concave and dactyl sinuate (plate 303E2); male antenna 2 peduncle thick (plate 303E6) Transorchestia enigmatica — Pereopods 3 and 4 article 5 shorter and thicker than segment 6 (303B1); male gnathopod 2 palm evenly convex, AMPHIPODA:

GAMMARIDEA

611

PLATE 303 Talitridae. H, Megalorchestia benedirti; A, Megalorchestia californiana; D, Megalorchestia pugettensis; F, Megalorchestia corniculata; C, Megalorchestia californiana; G, Paciforchestia klawei; E, Transorchestia enigmatica; B, Traskorchestia traskiana (figures modified from: Bousfield 1961a; Bousfield 1982, Nat. Mus. Canada, Pubi. Biol. Oceangr. 11, 73 p.; Bousfield and Carlton 1967. Bull. Sth. Calif. Acad. Sci. 66: 277-283).

dactyl evenly curved and male antenna 2 peduncle relatively short and thin (plate 303B1) 3 3. Pleopods weak, rami 4-6 segmented; male gnathopod 1 article 4 lacking posterior translucent process ("blister")... Traskorchestia georgiana — Pleopods strong, rami 7 - 1 0 segmented (plate 303B2); male gnathopod 1 article 4 with small, posterior, translucent process (plate 303B1, arrow) Traskorchestia traskiana 4. Uropod 2, inner and outer margins of outer ramus bearing spines (plate 303D2); flagellum of male antenna 2 as long or longer than peduncle (plate 303A1) 5 — Uropod 2, only outer margin of outer ramus bearing spines (plate 303H2); flagellum of antenna 2 shorter than pe612

ARTHROPODA

duncle (plate 303H1) 6 Posterior margins of pleonites with numerous small spines (plate 303F3); female gnathopod 1 article 5 with posterior translucent process ("blister"); pleopod rami less than one half of the peduncle length Megalorchestia califomiana — Posterior margins of pleonites without spines; female gnathopod 1 without translucent process on article 5 (plate 303D1, arrow); pleopod rami half to three fourths as long as peduncles Megalorchestia columbiana 6. Telson with shallow distal notch (plate 303C2); anteroventral margin of pleonite 1 with 1-7 spines; male gnathopod 1 article 6 with posterior distal expansion (plate 303C3, arrow) Megalorchestia pugettensis 5.

PLATE 3 0 4 Talitridae. Color patterns of Megalorchestia: dorsal and lateral views; paired figures show extent of pattern variation. A, M. californiana; B, M. comiculata; C, M. Columbiana; D, M. benedicti; E, M. pugettensis (figures after Bowers 1963, Pac. Sci. 17:315-320).

—

Telson without distal notch (entire) (plate 303F2, 303H3); anteroventral margin of pleonite 1 without spines; male gnathopod 1 article 6 without posterior distal expansion (plate 303F1, 303H1, arrows) 7 7. Posterior pleonite edges with 10 or more small spines (plate 303F2); male gnathopod 2 shallowly concave (plate 303F4) Megalorchestia comiculata — Posterior pleonite edges with five or less spines; male gnathopod 2 deeply incised (plate 303H1, arrow) Megalorchestia benedicti A FIELD (COLOR-PATTERN) KEY TO MEGALORCHESTIA DARL E. BOWERS (Plate 304)

1. Mature Megalorchestia 2 — Megalorchestia immature or not distinguished in couplets 2a through 4a below 5

2. Antenna 2 when folded reaching back to or past middle of body; flagellum longer than peduncle 3 — Antenna 2 when folded not reaching middle of body; flagellum shorter than peduncle 4 3. Color of antennae 2 rosy red Megalorchestia californiana — Color of antennae 2 bluish white Megalorchestia columbiana 4. Color of antennae 2 usually salmon pink Megalorchestia comiculata Color of antennae 2 otherwise 5 5 . Dorsal pigment pattern containing "butterfly" design 6 Dorsal pigment pattern containing T-shaped figures; the _ lower limb of the T may be faint or missing 8 6. Mid-dorsal line absent; "butterfly" spots are flattened Megalorchestia columbiana — Mid-dorsal line present 7 AMPHIPODA:

GAMMARIDEA

613

7.

No markings on third pleonite; sides of body relatively free of pigment marks Megalorchestia californiana — Markings on third pleonite; sides of body blotched in checkerboard pattern Megalorchestia benedicti 8. Two diffuse spots on lateral pereonites 5-7 Megalorchestia comiculata — Three discrete spots on lateral pereonites 5-7 Megalorchestia pugettensis LIST OF SPECIES EDWARD L. BOUSFIELD

Species of Megalorchestia were formerly Orchestoidea, and species of Paciforchestia, Transorchestia, and Traskorchestia were formerly in Orchestia. Megalorchestia benedicti (Shoemaker, 1930). Common on fine-sand beaches with M. californiana; 8 mm. Megalorchestia californiana (Brand, 1851). Large and common, high up on wide, exposed beaches of fine sand; digs burrows of elliptical cross-section. May have parasitic mites (see note under M. comiculata); 23 mm. Megalorchestia columbiana (Bousfield, 1958). On coarse-sand beaches with little seaweed. See Bowers 1964, Ecology 45: 677-696 (ecology); 22 mm. Megalorchestia comiculata (Stout, 1913). Large and common, on steep, protected beaches with coarse sand and considerable seaweed; burrow nearly circular in cross-section. May be infested on their ventral surface with parasitic mites. See Craig 1971, Anim. Behav. 19: 368-374 and 1973, Anim. Behav. 21: 699-706 (lunar orientation); Craig 1973, Mar. Biol. 23: 101-109 (ecology). See Bowers 1964, Ecology 45: 677-696 (ecology); 21 mm. *Megalorchestia minor (Bousfield, 1957). A southern species occurring north to San Simeon, just north of Point Conception, on surf-exposed flat sand beaches; see Bousfield, 1982; 15 mm. Megalorchestia pugettensis (Dana, 1853). Under debris on coarse-sand beaches with little seaweed; 17 mm. *Paciforchestia klawei (Bousfield, 1961). Known from British Columbia and from southern and Baja California; to be expected within our range. Under debris on protected coarsesand and pebble beaches; 14.5 mm. Transorchestia enigmatica Bousfield and Carlton, 1967. Described as a new species from the estuarine Lake Merritt, in Oakland, in San Francisco Bay, this amphipod is a member of the T. chiliensis species group, known from Chile and New Zealand (although the enigmatica clade remains unknown from either region). It was introduced in solid ballast from the southern hemisphere, perhaps by sailing ships carrying lumber from California to Valparaiso or Iquique, and returning in ballast, which was known to then be dumped into the Oakland Estuary near Lake Merritt. Under debris on sandy beaches; 15 mm. Traskorchestia georgiana (Bousfield, 1958). In the drift line of protected stony and pebbly beaches, on sand with windrows of Zostera and Sargassum and usually co-occurring with T. traskiana. Possibly sexually dimorphic uropod 1; 13.5 mm. Traskorchestia traskiana (Stimpson, 1857). On rocky beaches, occasionally on sandy beaches with algae; under debris and boards in salt marshes. See Page, 1979, Crustaceana 37: 247-252 (antennal growth); Busath, 1980, pp. 395^101 in Power ed, The California Islands Santa Barbara Mus. Natl. Hist, (genetics); Koch 1980, Crustaceana 57: 295-303 (behavior); Koch 1990, Crustaceana 59: 35-52 (population biology); 17 mm. * = Not in key.

614

ARTHROPODA

ACKNOWLEDGMENTS

Many improvements were provided by SCAMIT (Southern California Association of Marine Invertebrate Taxonomists) members, E. L. Bousfield, K. E. Conlan and E. A. Hendrycks (Canadian Museum of Nature), D. Cadien, S. McCormick, D. Pasko, and W. C. Fields. Assistance was provided by Amy Chapman and Carol Cole. Nicole Rudel assembled many plates. L. Weber and G. Boehlert allowed space at the OSU, HMSC. J. Webster, J. Mullens and S. Gilmont, Guin library, located difficult references. V. Gertseva translated Russian texts. The Gammaridea section is dedicated to J. Laurens Barnard, author of the two previous versions (Barnard 1954d. 1975), a patient, generous mentor and an inspiration to every amphipod taxonomist (Bousfield and Staude 1994, Thomas 1992, Rothman 1993). REFERENCES Alderman, A. L. 1 9 3 6 . Some new and little known amphipods of California. University of California Publications in Zoology 4 1 : 5 3 - 7 4 . Barnard, J. L. 1 9 5 0 . The occurrence of Chelura terebrans Philippi in Los Angeles and San Francisco Harbors. Bulletin of the Southern California Academy of Science. 4 9 : 9 0 - 9 7 . Barnard, J. L. 1 9 5 2 . Some Amphipoda from central California. Wasm a n n Journal of Biology 10: 9 - 3 6 . Barnard, J. L. 1953. On two new amphipod records from Los Angeles Harbor. Bulletin of the Southern California Academy of Science 52: 8 3 - 8 7 . Barnard, J. L. 1954a. Marine Amphipoda of Oregon. Oregon State Monographs 8: 1 - 1 0 3 . Barnard, J. L. 1954b. Amphipoda of the family Ampeliscidae collected in the eastern Pacific Ocean by the Velero III and Velero IV, Allan Hancock Pacific Expeditions 18: 1 - 1 3 7 . Barnard, J. L. 1 9 5 4 c . A new species of Microjassa (Amphipoda) from Los Angeles Harbor. Bulletin of the Southern California Academy of Science 53: 1 2 7 - 1 3 0 . Barnard, J. L. 1954d. Amphipoda, pp. 1 5 5 - 1 6 7 in R. I. Smith et al., (eds.) Intertidal Invertebrates of the Central California Coast. University of California Press, Berkeley, 4 4 6 pp. Barnard, J. L. 1955a. Notes o n the amphipod genus Aruga with the description of a new species. Bulletin of the Southern California Acade m y of Science 5 4 : 9 7 - 1 0 3 . Barnard, J. L. 1955b. Two new spongicolous amphipods (Crustacea) from California. Pacific Science 9: 2 6 - 3 0 . Barnard, J. L. 1 9 5 6 . Two rare amphipods from California with notes o n the genus Atylus. Bulletin of the Southern California Academy of Science 5 5 : 3 5 ^ 4 3 . Barnard, J. L. 1957a. A new genus of haustoriid amphipod from the northeastern Pacific Ocean and the southern distribution of Urothoe varvarini Gurjanova. Bulletin of the Southern California Academy of Sciences 56: 8 1 - 8 4 . Barnard, J. L. 1957b. A new genus of dexaminid amphipod (marine Crustacea) from California. Bulletin of the Southern California Academy of Sciences 56: 1 3 0 - 1 3 2 . Barnard, J. L. 1 9 5 7 c . A new genus of phoxocephalid Amphipoda (Crustacea) from Africa, India, and California. Annals and the Magazine of Natural History 10: 4 3 2 - 4 3 8 . Barnard, J. L. 1 9 5 8 . Revisionary notes o n the Phoxocephalidae (Amphipoda), with a key to the genera. Pacific Science 12: 1 4 6 - 1 5 1 . Barnard, J. L. 1 9 5 9 a . Liljeborgiid amphipods of southern California coastal bottoms, with a revision of the family. Pacific Naturalist 1 : 1 2 - 2 8 . Barnard, J. L. 1959b. Part II. Estuarine Amphipoda, pp. 1 3 - 6 9 , In Ecology of Amphipoda and Polychaeta of Newport Bay, California. J. L. Barnard and D . J . Reish, eds. Allan Hancock Foundation Publications Occasional Papers 21, 1 0 6 pp. Barnard, J. L. 1960a. The amphipod family Phoxocephalidae in the eastern Pacific Ocean, with analyses of other species and notes for a revision of the family. Allan Hancock Pacific Expeditions 18: 1 7 5 - 3 7 5 . Barnard, J. L. 1960b. New bathyal and sublittoral ampeliscid amphipods from California, with an illustrated key to Ampelisca. Pacific Naturalist 1: 1 - 3 6 . Barnard, J. L. 1962a. Benthic marine Amphipoda of southern California: Families Aoridae, Photidae, Ischyroceridae, Corophiidae, Podoceridae. Pacific Naturalist 3: 1 - 7 2 .

Barnard, J. L. 1962b. Benthic marine Amphipoda of southern California: Families Tironidae to Gammaridae. Pacific Naturalist 3: 7 3 - 1 1 5 . Barnard, J. L. 1962c. Benthic marine Amphipoda of southern California: Families Amphilochidae, Leucothoidae, Stenothoidae, Argissidae, Hyalidae. Pacific Naturalist 3: 1 1 6 - 1 6 3 . Barnard, J. L. 1962d. Benthic marine Amphipoda of southern California: Family Oedicerotidae. Pacific Naturalist 3: 3 5 1 - 3 7 1 . Barnard, J. L. 1962e. A new species of sand-burrowing marine Amphipoda from California. Bulletin of the Southern California Academy of Science 61: 2 4 9 - 2 5 2 . Barnard, J. L. 1964a. Deep-sea Amphipoda (Crustacea) collected by the R/V Vema in the eastern Pacific Ocean and the Caribbean and Mediterranean Seas. Bulletin of the American Museum of Natural History 127: 3 - 4 6 . Barnard, J. L. 1964b. Los anfipodos bentonicos marinos de la costa occidental de Baja California. Revista de la Sociedad Mexicana Historia Natural 24: 2 0 5 - 2 7 4 . Barnard, J. L. 1964c. Marine Amphipoda of Bahia de San Quintin, Baja California. Pacific Naturalist 4: 5 5 - 1 3 9 . Barnard, J. L. 1965. Marine Amphipoda of the family Ampithoidae from southern California. Proceedings of the U.S. National Museum 118: 1-46. Barnard, J. L. 1966. Benthic Amphipoda of Monterey Bay, California. Proceedings of the U.S. National Museum 119: 1 - 4 1 . Barnard, J . L. 1967a. New and old dogielinotid marine Amphipoda. Crustaceana 13: 2 8 1 - 2 9 1 . Barnard, J. L. 1967b. New species and records of Pacific Ampeliscidae (Crustacea: Amphipoda). Proceedings of the U.S. National Museum 121: 1 - 2 0 . Barnard, J. L. 1967c. Bathyal and abyssal gammaridean Amphipoda of Cedros Trench, Baja California. United States National Museum Bulletin 260, 204 pp. Barnard, J. L. 1969a. Gammaridean Amphipoda of the rocky intertidal of California: Monterey Bay to La Jolla. Bulletin of the U.S. National Museum 258: 1 - 2 3 0 . Barnard, J. L. 1969b. The families and genera of marine gammaridean Amphipoda. Bulletin of the U.S. National Museum 271: 1 - 5 3 5 . Barnard, J. L. 1970. Sublittoral Gammaridea (Amphipoda) of the Hawaiian Islands. Smithsonian Contributions to Zoology 34: 1 - 2 8 6 . Barnard, J. L. 1971. Gammaridean Amphipoda from a deep-sea transect off Oregon. Smithsonian Contributions to Zoology 61: 1 - 8 6 . Barnard, J. L. 1972a. Gammaridean Amphipoda of Australia, Part I. Smithsonian Contributions to Zoology 103: 1 - 3 3 3 . Barnard, J. L. 1972b. A review of the family Synipiidae (=Tironidae), mainly distributed in the deep sea (Crustacea: Amphipoda). Smithsonian Contributions to Zoology 124: 1 - 1 9 4 . Barnard, J. L. 1972c. The marine fauna of New Zealand: Algae-living littoral Gammaridea (Crustacea, Amphipoda). New Zealand Oceanographic Institute Memoirs 62: 1 - 2 1 6 . Barnard, J. L. 1975. Crustacea, Amphipoda: Gammaridea, pp. 313-366. In Light's manual: intertidal invertebrates of the Central California Coast. R. I. Smith and J. T. Carlton, eds. University of California Press, Berkeley. Barnard, J. L. 1977. A new species of Synchelidium (Crustacea, Amphipoda) from sand beaches in California. Proceedings of the Biological Society of Washington 90: 8 7 7 - 8 8 3 . Barnard, J. L. 1979a. Littoral gammaridean Amphipoda from the Gulf of California and the Galapagos Islands. Smithsonian Contributions to Zoology 271: 1 - 1 4 9 . Barnard, J. L. 1979b. Revision of American species of the marine amphipod genus Paraphoxus (Gammaridea: Phoxocephalidae). Proceedings of the Biological Society of Washington 92: 3 6 8 - 3 7 9 . Barnard, J. L. 1980a. The genus Grandifoxus (Crustacea: Amphipoda: Phoxocephalidae) from the northeastern Pacific Ocean. Proceedings of the Biological Society of Washington 93: 4 9 0 - 5 1 4 . Barnard, J. L. 1980b. Revision of Metharpina and Microphoxus (marine phoxocephalid Amphipoda of the Americas). Proceedings of the Biological Society of Washington 93: 1 0 4 - 1 3 5 . Barnard, J. L., and C. M. Barnard. 1981. The amphipod genera, Eobrolgus and Eyakia (Crustacea: Phoxocephalidae) in the Pacific Ocean. Proceedings of the Biological Society of Washington 94: 2 9 5 - 3 1 3 . Barnard, J. L., and C. M. Barnard. 1982a. The genus Rhepoxynius (Crustacea: Amphipoda: Phoxocephalidae) in American Seas. Smithsonian Contributions to Zoology 357, 149 pp. Barnard, J. L., and C. M. Barnard. 1982b. Revision of Foxiphalus and Eobrolgus (Crustacea: Amphipoda: Phoxocephalidae) from American oceans. Smithsonian Contributions to Zoology 372: 1 - 3 5 .

Barnard, J. L., and C. M. Barnard. 1983a. Freshwater Amphipoda of the World I. Evolutionary Patterns 1. Hayfield Associates, Mt. Vernon, VA, pp. 1 - 3 5 9 . Barnard, J. L., and C. M. Barnard. 1983b. Freshwater Amphipoda of the World II. Handbook and Bibliography, 2, Hayfield Associates, Mt. Vernon, VA, pp. 3 5 9 - 8 3 0 . Barnard, J. L., and R. R. Given. 1960. Common pleustid amphipods of southern California, with a projected revision of the family. Pacific Naturalist 1: 37^18. Barnard, J. L., and G. S. Karaman. 1990a. The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Part 1, Records of the Australian Museum 13: 1 - 4 1 7 . Barnard, J. L., and G. S. Karaman. 1990b. The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Part 2. Records of the Australian Museum 13: 4 1 9 - 8 6 6 . Beckett, D. C., P. A. Lewis, and J. H. Green. 1997. Where have all the Crangonyx gone? The disappearance of the amphipod Crangonyx pseudogracilis, and subsequent appearance of Gammarus nr. fasciatus, in the Ohio River. American Midland Naturalist 139: 2 0 1 - 2 0 9 . Bellan-Santini, D. 1999. Ordre des Amphipodes (Amphipoda Latreille, 1816). In: Bacescu, M. et al. Treatise on zoology: anatomy, systematics, biology: 7. Crustaceans: 3A. Peracarida. Mémoires de l'Institut océanographique, Monaco 19: 9 3 - 1 7 6 . Boeck, A. 1872. Bidrag til Californiens Amphipodefauna. Forhandlinger i Videnskskabs -Selskabet i Christiana, 1871, 2 2 pp. Borowsky, B. 1983. Reproductive behavior of three tube-building peracarid crustaceans: the amphipods Jassa falcata and Ampithoe valida and the tanaid Tanais cavolinii. Marine Biology 77: 2 5 7 - 2 6 3 . Borowsky, B. 1984. The use of males' gnathopods during precopulation in some gammaridean Amphipoda. Crustaceana 47: 2 4 5 - 2 5 0 . Borowsky, B. 1985. Differences in reproductive behavior between two male morphs of the amphipod crustacean Jassa falcata Montagu. Physiological Zoology 58: 4 9 7 - 5 0 2 . Bosworth, W. S. 1973. Three new species of Eohaustorius (Amphipoda, Haustoriidae) from the Oregon coast. Crustaceana 25: 2 5 3 - 2 6 0 . Bottoroff, R. L., B. A. Hamill, and W. I. Hamill. 2003. Records of the exotic freshwater amphipod, Crangonyx pseudogracilis, in San Luis Obispo County, California. California Fish and Game 89: 1 9 7 - 2 0 0 . Bousfield, E. L. 1957. Notes on the amphipod genus Orchestoidea on the Pacific Coast of North America. Bulletin of the Southern California Academy of Science 56: 1 1 9 - 1 2 9 . Bousfield, E. L. 1958a. Distributional ecology of the terrestrial Talitridae (Crustacea: Amphipoda) of Canada. Proceedings of the 10th International Congress of Entomology 1: 8 8 3 - 8 9 8 . Bousfield, E. L. 1958b. Fresh-water amphipod crustaceans of glaciated North America. Canadian Field Naturalist 72: 5 5 - 1 1 3 . Bousfield, E. L. 1961a. New records of beach hoppers (Crustacea: Amphipoda) from the coast of California. National Museum of Canada Bulletin 172, Contributions to Zoology, 1959: 1 - 1 2 . Bousfield, E. L. 1961b. New records of fresh-water amphipod crustaceans from Oregon. National Museum of Canada, Natural History Papers, 12: 1 - 7 . Bousfield, E. L. 1963. New freshwater amphipod crustaceans from Florida. National Museum of Canada, Natural History Papers 1 8 : 1 - 9 . Bousfield, E. L. 1969. New records of Gammarus (Crustacea: Amphipoda) from the middle Atlantic region. Chesapeake Science 10: 1 - 1 7 . Bousfield, E. L. 1973. Shallow-water gammaridean Amphipoda of New England. Cornell University Press, Ithaca, NY, 3 1 2 pp. Bousfield, E. L. 1979. The amphipod superfamily Gammaroidea in the northeastern Pacific region: Systematics and distributional ecology. Bulletin of the Biological Society of Washington 3: 2 9 7 - 3 5 7 . Bousfield, E. L. 1987. Amphipod parasites of fishes of Canada. Canadian Bulletin of Fisheries and Aquatic Sciences 217: 1 - 3 7 . Bousfield, E. L. 1989. Revised morphological relationships within the amphipod genera Pontoporeia and Gammaracanthus and t h e "glacial relict" significance of their postglacial distributions. Canadian Journal of Fisheries and Aquatic Sciences 46: 1 7 1 4 - 1 7 2 5 . Bousfield, E. L. 2 0 0 1 . An updated commentary on phyletic classification of the amphipod Crustacea and its application to the North American fauna. Amphipacifica 3(1): 4 9 - 1 1 9 . Bousfield, E. L., and A. Chevrier. 1996. The amphipod family Oedicerotidae on the Pacific coast of North America. Part 1. The Monoculodes and Synchelidium generic complexes: Systematics and distributional ecology. Amphipacifica 2(2): 7 5 - 1 4 8 . Bousfield, E. L., and E. A. Hendrycks. 1994a. A revision of family Pleustidae (Crustacea: Amphipoda: Leucothoidea) Part I. Systematics and

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Hay, M. E., J. E. Duffy, a n d W. Fenical. 1990. Host-plant specialization decreases p r e d a t i o n o n a m a r i n e a m p h i p o d : a n herbivore in plant's clothing. Ecology 71: 733-743. Hay, M. E., J. E. Duffy, W. Fenical, a n d K. Gustafson. 1988. Chemical d e f e n s e in t h e seaweed Dictyopteris delicatula: differential effects against reef fishes a n d a m p h i p o d s . Marine Ecology Progress Series 48: 185-192. Hendrycks, E. A., a n d E. L. Bousfield. 2001. The a m p h i p o d genus Allorchestes in t h e N o r t h Pacific region: systematics a n d distributional ecology. Amphipacifica 3(2): 3 - 3 8 . Hendrycks, E. A., a n d E. L. Bousfield. 2004. The a m p h i p o d family Pleustidae (mainly subfamilies Mesopleustinae, Neopleustinae, Pleusymtinae, a n d Stenopleustinae) f r o m t h e Pacific coast of N o r t h America: systematics a n d distributional ecology. Amphipacifica 3(4): 45-113. Hirayama, A. 1983. 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The A m p h i p o d a collected by t h e U.S. Bureau of Fisheries steamer "Albatross" off t h e west coast of N o r t h America, in 1903 a n d 1904, w i t h descriptions of a n e w family a n d several n e w genera a n d species. Proceedings of t h e U.S. National M u s e u m 35: 489-543. Hoover, P. M., a n d E. L. Bousfield. 2001. The a m p h i p o d superfamily Leuc o t h o i d e a o n t h e Pacific coast of N o r t h America: Family Amphilochidae: systematics a n d distributional ecology. Amphipacifica 3(1): 3 - 2 8 . Hubricht, L., a n d J. G. Mackin. 1940. Descriptions of n i n e n e w species of fresh-water a m p h i p o d crustaceans w i t h notes a n d n e w localities for o t h e r species. American Midland Naturalist 23: 187-218. Hurley, D. E. 1963. A m p h i p o d s of t h e family Lysianassidae f r o m t h e west coast of N o r t h a n d Central America. Allan Hancock F o u n d a t i o n Publications Occasional Paper 25: 1 - 1 6 0 . Imbach, M. C. 1967. G a m m a r i d e a n A m p h i p o d a f r o m t h e South C h i n a Sea. Naga Report 4: 39-167. Jarrett, N. E., a n d E. L. Bousfield. 1982. Studies o n t h e a m p h i p o d family Lysianassidae in t h e Northeastern Pacific region. Hippomedoti: a n d related genera. National M u s e u m of Natural Sciences (Ottawa). Publications in Biological O c e a n o g r a p h y 10: 103-128. Jarrett, N. E., a n d E. L. Bousfield. 1994a. The a m p h i p o d superfamily P h o x o c e p h a l o i d e a o n t h e Pacific coast of N o r t h America. Family P h o x o c e p h a l i d a e . Part 1. M e t h a r p i n i i n a e , n e w subfamily. Amphipacifica 1: 58-140. Jarrett, N. E., a n d E. L. Bousfield. 1994b. The a m p h i p o d superfamily Phoxocephaloidea o n t h e Pacific Coast of N o r t h America. Family P h o x o c e p h a l i d a e . Part II. Subfamilies P o n t h a r p i n i i n a e , Brolginae, Phoxocephalinae, a n d Harpiniinae. Systematics a n d distributional ecology. Amphipacifica 1(2): 71-150. Jarrett, N. E., a n d E. L. Bousfield. 1996. The a m p h i p o d superfamily Hadzioidea o n t h e Pacific Coast of N o r t h America: Family Melitidae. Part I. The Melita group: systematics a n d distribution ecology. Amphipacifica 2(2): 3 - 7 4 . Krapp-Schickel, T., a n d N. Jarrett. 2000. The a m p h i p o d family Melitidae o n t h e Pacific coast of N o r t h America. Part II. The Maera-Ceradocus complex. Amphipacifica 2(4): 23-61. Kudrjaschov, V. A., a n d N. L. Tzvetkova. 1975. New a n d rare species off A m p h i p o d a ( G a m m a r i d e a ) f r o m t h e coastal waters of t h e South Sakhalin. Zoologicheskii Zhurnal 54: 1306-1315 (in Russian). Laubitz, D. R. 1977. A revision of t h e genera Dulichia Kroyer a n d Paradulichia Boeck (Amphipoda, Podoceridae). C a n a d i a n Journal of Zoology 55: 942-982. Light, S. F. 1941. A m p h i p o d a , pp. 93-104, in S. F. Light, Laboratory a n d Field Text in Invertebrate Zoology, Associated Students Store, University of California, Berkeley, 232 pp. Lincoln, R. J. 1979. British m a r i n e A m p h i p o d a : G a m m a r i d e a . British M u s e u m (Natural History), London, 658 pp. Lowry, J. K., a n d H. E. Stoddart. 1983. The shallow-water g a m m a r i d e a n A m p h i p o d a of t h e subantarctic islands of New Zealand a n d Australia: Lysianassoid. Journal of t h e Royal Society of New Zealand 13:279-394.

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Application of antibiotics to cultures of t h e g a m m a r i d e a n a m p h i p o d Corophium spinicome Stimpson, 1857. J o u r n a l of Crustacean Biology 16: 2 9 1 - 2 9 4 . Roney, J. D. 1990. A n e w species of m a r i n e a m p h i p o d (Gammaridea: Ampeliscidae) f r o m t h e sublittoral of s o u t h e r n California. Bulletin of t h e S o u t h e r n California Academy of Sciences 89: 124-129. R o t h m a n , P. L. 1993. New families, genera a n d species of a m p h i p o d crustaceans described by J. L. Barnard (1928-1991). J o u r n a l of Natural History 27: 743-780. Sars, G. O. 1895. A m p h i p o d a , An account of t h e Crustacea of Norway w i t h s h o r t descriptions a n d figures of all t h e species, 711 pp. Schneider, D. C., a n d B. A. Harrington. 1981. Timing of shorebird migration in relation t o prey depletion. Auk 98: 801-811. Segerstrale, S. G. 1937. Susien uber die Bodentierwelt in sudfinnlandisc h e n kustengewassern III. 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GAMMARIDEA

617

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ARTHROPODA

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CAPRELLIDAE LES WATLING AND JAMES T. CARLTON (Plates 305-311) Caprellids, or "skeleton shrimp," are remarkable crustaceans in which one can easily invest many hours of profitable observation, watching their feeding behavior, inter- or intraspecific interactions, and sheer gymnastics, as they cling and climb, often perfectly camouflaged, on hydroids, bryozoans, or other substrates. Much remains to be learned about their biology, ecology, and distribution along the Pacific coast, and some relatively c o m m o n intertidal species remain known from hardly more than their original descriptions. Especially overlooked—or mistaken for juveniles—are those species that are only a few millimeters in length as adults. The patient student working with living substrates, a comfortable chair, and a good microscope will be richly rewarded.

Caprellids, often looking somewhat skeletonlike because of their elongated segments and thus sticklike nature, differ from other amphipods in their overall body shape and the strong reduction of abdominal somites (plate 305). In many species, legs 3 and 4 may also be reduced to a minute article or two, such that only coxal gills are present. The body is usually slender and cylindrical, and the head is generally completely or partly fused with the first pereonite. As a result, the head appears to possess an additional pair of appendages behind the maxillipeds, but these are actually the first pair of gnathopods. The mouth appendages are typical for amphipods in general, but the mandible may be modified through reduction of the palp. All the legs of caprellids, unless reduced, are modified for clinging or grasping. There are generally two pairs of coxal gills, on pereopods 3 and 4, but occasionally a gill is present on pereopod 2 or absent from pereopod 4. Oostegites, or brood plates, are present in mature females on pereopods 3 and 4 only. When present the oostegites may obscure the presence of minute legs or gills, so those specimens need to be examined carefully. The abdomen is always reduced and generally consists of one or two somites bearing very reduced appendages or simple lobes. In a few cases the details of these lobes can be important in determining the identity of a specimen. Until the revision of caprellid families by Laubitz (1993), the taxonomy of caprellids had remained virtually unchanged since the early seminal work of Mayer (1882, 1890, 1903). McCain (1970) and Vassilenko (1974) proposed slightly different familial arrangements for the caprellids. However, the characters used were basically those established by Mayer along with the addition of some mandibular features. Laubitz (1993) reduced in significance a few of Mayer's characters, incorporated McCain's mandible features, and added characters from maxilla 1 and the lower lip. While Laubitz (1993) states that her familial divisions are "both preliminary and speculative," they augment those established by Vassilenko (1974). Laubitz (1993) and Takeuchi (1999), however, suggested that caprellids, as presently constituted, are polyphyletic, perhaps originating twice from different gammarid ancestors. Myers and Lowry (2003) conducted a detailed phylogenetic analysis of all corophiidean amphipods, with caprellids included. They showed that caprellids were, as has been suspected for a long time, merely highly modified members of the suborder Corophiidea and did not constitute a separate suborder of amphipods. We have chosen to adopt the Myers and Lowry (2003) arrangement of families and subfamilies that resulted from their phylogenetic analysis in preference to the higher level schemes of Vassilenko, Laubitz, or Takeuchi. Caprellids are dingers, and so can be found on almost any substratum that is erect above the bottom, including parts of other invertebrates. For the most part, caprellids use their mandibles to scrape microalgae from the surface of the substratum to which they cling. In other cases, they may feed on particles suspended in the water or, rarely, are predaceous (e.g., Caine 1980). Collecting of caprellids is made somewhat easy by their tendency to aggregate on certain substrates. Rarely does a hydroid or bryozoan colony produce just one specimen. In Japanese and eastern American waters, caprellids have been observed to engage in extended parental care in which the young are either carried on the female's appendages or always in close proximity to the female (Aoki and Kikuchi 1991; Thiel 1997). Similar examples may be found in littoral California and Oregon waters with careful collecting and observing.

The following key is for species found in littoral to shallow waters only and works best for males (which are often much more elongate than females), although an attempt has been made to keep the key as gender-neutral as possible. When keying out caprellids, care must be taken to not let your attention be drawn to certain obvious features, such as body spines and tubercles. Unless explicitly noted, body spination or tuberculation can be a quite variable character and may not be very useful for species discrimination. To facilitate identification with a dissection microscope, other very useful characters, such as those of the mouth appendages or the abdomen, which require higher magnification, have not been used in this key, but should be consulted in the primary literature. Guides to the Californian and Oregonian caprellid fauna include Laubitz (1970), Martin (1977), and Marelli (1981). Jessen (1969) is an excellent source of habitat and general ecological information on many Pacific coast species. Given the number of introduced caprellids now present in the bays and estuaries of the American Pacific coast, including Caprella drepanochir, C. equilibra, C. mutica, C. penantis, and C. scaura, further species, especially harbor-dwelling Asian taxa, should be expected. The monographs of Ishitaro Arimoto (1976) and Stella Vassilenko (1974) should be consulted in this regard, as well as more recent summaries and papers, such as those by Takeuchi (1999) and Guerra-Garcia and Takeuchi (2003). Deeper-water caprellids can be identified using Laubitz (1970) and Watling (1995). ACKNOWLEDGMENTS

We are very grateful to Marvin Peterson Jessen (formerly with Grand View College, Des Moines, Iowa) for providing us with and allowing us to use the original artwork from his unpublished PhD dissertation. We thank Suzanna Stoike for bringing Jessen's dissertation to our attention.

KEY TO CAPRELLIDS

In part from Martin 1977. 1. — 2. — 3. — 4. — 5.

—

6.

Pereonites 3 and 4 with minute, rudimentary pereopods; mandible with palp 2 Pereonites 3 and 4 bearing only gills, and oostegites in females; mandible without palp 7 Pereonite 5 with rudimentary pereopods (plate 306B) Mayerella banksia Pereonite 5 leg similar to legs on pereonites 6 and 7 3 4 Gills present on pereonites 3 and 4 Gills present on pereonite 2 as well as on pereonites 3 and 4 6 Antenna 2 without swimming setae; head with spine or knob (plate 306A) Deutella californica Antenna 2 with swimming setae; head smooth 5 Pereonites 3 and 4 with median lateral projections over the gills; antenna 2 flagellum slender with long swimming setae; pereopods 5-7 articles slender (plate 306D) Tritella pilimana Pereonites 3 and 4 without median lateral projection over the gills; antenna 2 flagellum stout with short setae; pereopods 5-7 articles stout (plate 306C) Tritella laevis Abdomen five-segmented and with uropods (does not look like typical caprellid); pereonites 5 and 6 short and stout (plate 310A) Cercops compactus AMPHIPODA:

GAMMARIDEA:

CAPRELLIDAE

619

CAPRELLID M O R P H O L O G Y

pereonite I

first antenna

cephalon

pereonite 4

PLATE 305 Basic morphology of a caprellid amphipod (from McCain 1968). first maxilla penes

setal row

molar

second maxilla mandible

— 7.

A b d o m e n minute; pereonites 5 and 6 l o n g and slender

8.

Head w i t h paired dorsal spines or tubercles

(plate 310B)

—

Head w i t h 1 anteriorly directed or dorsal spine or w i t h o u t

Perotripus brevis

Body short, compact, stout; antenna 1 peduncle articles not much longer than wide (plate 307A)

spine 9.

1 peduncle articles much longer than wide 620

307B)

Body m a y be shortened, but not excessively stout; antenna

ARTHROPODA

8

—

11

Head spines appear m o r e as small tubercles; g n a t h o p o d 2 merus anteroventral

Caprella greenleyi —

9

corner s m o o t h l y rounded

(plate

Caprella ferrea

Head spines sharp, directed anteriorly; g n a t h o p o d 2 merus

PLATE 306 A, Deutella californica, A2, antenna 2; B, Mayerella banksia, Bl, antenna 1-2; C, Tritella laevis, CI, antenna 1-2; D, Tritella pilimana, Dl, antenna 1-2; drawings not to scale; (from Laubitz 1970).

C

Tritella laevis

D1 D

Tritella pilimana

anteroventral corner with stout spinelike seta or produced into spinous projection 10 10. Male antenna 1 peduncle articles very setose and stout, flagellum with fewer than 20 articles; pereonites 3 and 4 in both sexes with several pairs of spines (plate 307C) Caprella kennerlyi — Male antenna 1 peduncle elongate and not heavily setose, flagellum with at least 21 articles; pereonites 3 and 4 in male smooth, in female with few pairs of spines (plate 307D) Caprella anomala 11. Head smooth, without anteriorly directed spine, or with

minute dorsal spine 12 — Head with one large, anteriorly-directed spine 17 12. Pereonites 3, 4, and 5 in males with several to many sharp spines (plate 310C1); note that females may have spines on anterior pereonites, including on cephalon (plate 310C2) Caprella mutica — Pereonites 3, 4, and 5 in males with no spines, or few blunt spines 13 13. Pereonites 5-7 in males with one or two small blunt spines (plate 310D); spines may be extend forward onto cephalon in some males; females may be much spinier, with spines AMPHIPODA: GAMMARIDEA: CAPRELLIDAE

621

B Caprella ferrea

GN2

9

A Caprella greenleyi

C Caprella kennerlyi

D Caprella anomala P L A T E 307 A, Caprella greenleyi; B, Caprella ferrea; C, Caprella kennerlyi; D, Caprella anomala; drawings not to scale; A1 = antenna 1, A2 = antenna 2, GN1 = gnathopod 1, GN2 = gnathopod 2 (A, from McCain 1969; rest, Laubitz 1970).

also on all pereonites and onto cephalon Caprella alaskana — Pereonites 5 - 7 without middorsal blunt spines 14 14. Antenna 1 flagellum shorter than peduncle article 3 (plate 308A) Caprella équilibra — Antenna 1 flagellum as long as or longer than peduncle article 3 15 622

ARTHROPODA

15. Gills on male nearly circular, on females broadly rounded (plate 310E) Caprella drepanochir — Gills on males and females elongate 16 16. Male gnathopod 2 with large "thumblike" extension on palm of propodus (plate 311A) Caprella laeviuscula — Male gnathopod 2 propodus elongate and with two-thirds of palmar margin concave (plate 308B) Caprella mendax

B

Capretta mendax

PLATE 3 0 8 A, Caprella equilibra; B, Caprella mendax; C, Caprella brevirostris; D, Caprella verrucosa; drawings not to scale; P7 = pereopod 7 (A, McCain 1968; B, D, from Laubitz 1970; C, from Mayer 1903).

17. Propodus of pereopods lacking heavy, "grasping" setae (plate 308C) Caprella brevirostris — Propodus of pereopods with grasping setae 18 18. Body tubercles large, wide at base and at tips (plate 308D) Caprella verrucosa — Body tubercles may be numerous but are low and narrow sharply toward tips or body tubercles absent 19 19. Head spine originating from dorsal margin of head 20

—

Head spine originating from anterior margin of head 24 20. Head spine long and narrow, anteriorly curving, head otherwise smooth 21 — Head with small tubercles and dorsally directed spine with wide base 23 21. Pereonite 5 with one dorsal spine in subadult and adult male; antenna 1 with 18-20 flagellar articles; adult male gnathopod AMPHIPODA: GAMMARIDA: CAPRELLIDAE

623

A

B

Caprella

Caprella

californica

pilipalma

C

D

Caprella

Caprella pilipalma

head

natalensis

E

Caprella

incisa

PLATE 309 A, Caprella californica; B, Caprella pilipalma; C, Caprella pilipalma head; D, Caprella natalensis; E, Caprella incisa; drawings and photos not to scale (A, D, E, from Laubitz 1970; B, photograph by L. Watling).

2 covered with feathery setae (plate 309A) Caprella californica — Pereonite 5 with two dorsal spines in subadult and adult male 22 22. Adult and subadult male with posterior middorsal process on pereonite 4 (plate 31 IB) Caprella scaur a 624

ARTHROPODA

—

Adult and subadult males pereonite 4 dorsally smooth (plate 311C) Caprella simia 23. Antenna 1 with dense setation; body with large, raised spination (plate 31 ID) Caprella pustulata — Antenna 1 without significant setation; body with low, small tubercles (plate 309B-309C) Caprella pilipalma

PLATE 31 o A, Cercops compactus, male; B, Perotripus brevis, female; C, Caprella mutica, CI, male (California); C2, female (California); D, Caprella alaskana, subadult male; E, Caprella drepanochir, male; scale bars = 1 mm (A, B, from Jessen 1969; CI, from Marelli 1981; C2, from Martin 1977; D, E, Laubitz 1970).

PLATE 311 A, Caprella laeviuscula, male; B, Caprella scaura, male (from California); C, Caprella simia, adult male (from Japan); D, Caprella pustulata, male; E, Caprella penantis, males: El, from Florida, E2, from Cape Cod, Massachusetts, E3, from Prince Edward Island, Canada, to show variation in robustness; scale bars = 1 mm (A, from Laubitz 1970; B, from Marelli 1981; C, from Arimoto 1976; D, Jessen 1969; E, from Laubitz 1972).

24. Body with tuberculations on all pereonites; boundary between head and pereonite 1 marked with groove and ridge on anterior margin of pereonite 1 (plate 309E) Caprella incisa — Body with tuberculations o n posterior pereonites; boundary between head and pereonite 1 marked with simple or faint groove 25 25. Pereonite 5 usually shorter t h a n pereonite 6 plus 7 (plate 31 IE; see also discussion in species list) Caprella penantis — Pereonite 5 usually longer t h a n pereonite 6 plus 7 (plate 309D; see also discussion in species list) Caprella natalensis

Caprella ferrea Mayer, 1903 (=Metacaprella ferrea). Intertidal on algae, hydroids, bryozoans, sabellid tubes, and other substrates. Martin (1977) noted that specimens from northern California "differed from Laubitz's (1970) description in that peduncular segments 2 and 3 of antenna 1 were heavily setose." *Caprella gracilior Mayer, 1903. Keyed out in t h e previous edition of this manual, but a generally sublittoral and deeperwater species (in Monterey Bay, for example, in depths of more t h a n 1,700 m). McCain and Steinberg (1970) record it from Tómales Bay, but this may have a transcription error f r o m Dougherty and Steinberg (1953), where n o such record is noted. See Caine 1978, Biol. Bull. 155: 288-296 (observations o n the seastar Luidia foliata, Puget Sound)

LIST OF SPECIES

Caprella greenleyi McCain, 1969. Originally taken o n t h e seastar Henricia in Boiler Bay, Oregon, but a rare habitat (McCain 1969; Martin 1977); o n coralline algae and bryozoans. See Martin (1977) for supplemental description and plates; a small species, ranging as adults from 1.5 m - 3 . 6 m m in length. Caprella incisa Mayer, 1903. On hydroids (such as Aglaophenia and campanulariids), bryozoans, coralline algae, and kelp holdfasts. Caprella kennerlyi (Stimpson, 1864) (=Metacaprella kennerlyi). C o m m o n all along coast on open shores, intertidal and subtidal, o n m a n y substrates, and to be expected in marine fouling communities, having been first described from t h e bottom of a revenue cutter at Port Townsend, Washington. Jensen (1969) noted that it was "particularly unnoticeable o n Plumularia lagenifera, where t h e caprellid body resembles closely a hydrocladium branching f r o m t h e main axis of t h e hydroid." Ricketts et al. (1985) describe this species as "prettily pinkbanded." See Martin 1977 (habitat diversity); Caine 1978, Biol. Bull. 155: 288-296 (observations o n behavior, Puget Sound).

CAPRELLIDAE CAPRELLINAE

Caprella alaskana Mayer, 1903. San Francisco Bay (Marelli, 1981) and north, intertidal on bryozoans and sabellid worm tubes. *Caprella andreae Mayer, 1890. A high-seas pelagic species f o u n d o n drifting objects; recorded in the North Pacific and should be looked for o n oceanic debris washed ashore in t h e Pacific Northwest. Illustrated in McCain (1968). Caprella angusta. See Caprella natalensis. Caprella anomala (Mayer, 1903) (=Metacaprella anomala). Intertidal on hydroids; sublittoral to 100 m. Mori (1999) argued for the submergence of the genus Metacaprella into Caprella; it is retained, however, as a full genus by Myers and Lowry (2003). Caprella brevirostris Mayer, 1903. On hydroids, algae, and abalone shells; see Martin (1977) for redescription and additional figures. Caprella californica Stimpson, 1856. In bays (on algae, eelgrass, and hydroids) and on outer coast o n coralline algae; sublittoral in kelp beds. See Keith 1969, Crustaceana 16:119-124 (omnivorous diet); Keith 1971, Pac. Sci. 25:387-394 (substrate preference: prefers bryozoan Bugula neritina over algae Ulva and Polysiphonia). *Caprella carina Mayer, 1903. Jessen (1969) reported this boreal species washed ashore o n a sandy beach near Coos Bay. Illustrated in Laubitz (1972). Caprella drepanochir Mayer, 1890. Largely k n o w n f r o m Asian and subarctic Alaskan waters, and also occurring t h r o u g h o u t Coos Bay, Oregon, in fouling communities (Rudy and Rudy 1985; S. Stoike, field collections, 2005), to where it was probably introduced in ship fouling f r o m Japan; to be looked for in other bays and harbors along the coast. Caprella equilibra Say, 1818. Originally described from South Carolina, and said to occur in many habitats world-over. Often c o m m o n along the coast in intertidal and shallow waters on hydroids, bryozoans, and ascidians, on wharf pilings and marina floats. Part of its distribution is doubtless due to transport in ship fouling: Mayer (1903) records a specimen from Hong Kong collected "off ships bottoms," and several specimens from ships and buoys in the Atlantic. C. equilibra is also reported from 100 m-145 m off southern California (Watling 1995). This species may consist of both a harbor- and bay-dwelling taxon that has been distributed globally in ship-fouling, as well as cryptic species (that may be distinguishable only genetically) that occur o n the open rocky shore, or in the deep sea. Martin (1977) reports that intersex individuals occur in San Francisco Bay. See Keith 1969, Crustaceana 16: 119-124 (omnivorous diet); Keith 1971, Pac. Sci. 25: 387-394 (substrate preference). * = N o t i n key.

Caprella laeviuscula Mayer, 1903. On m a n y substrates (hydroids, bryozoans, compound ascidians, algae, eelgrass); Martin (1977) notes the occasional presence on the animals of hydroids and the epiphytic diatom Isthmia. See Caine 1980, Mar. Biol. 56: 327-335 (ecology, Puget Sound); 1991, J. Crust. Biol. 11: 56-63 (reproductive behavior and sexual dimorphism, Puget Sound). Caprella mendax Mayer, 1903. Predominately sublittoral throughout range but may extend into shallower water; close to C. equilibra, and still listed as a synonym of this species by some workers (Stoddart and Lowry 2003). Caprella mutica Schurin, 1935 (=Caprella acanthogaster humboldtiensis Martin, 1977, described from Humboldt Bay; =Caprella macho Platvoet, de Bruyne, and Meyling, 1995, from the Netherlands, in b o t h cases based u p o n n o n n a t i v e populations). A distinctive Asian species introduced to t h e Pacific coast with shipping or oysters, and often very abundant o n hydroids in fouling communities o n floats and pilings. See Marelli (1981) for synonymy and detailed description. Caprella natalensis Mayer, 1903 (=Caprella angusta in Dougherty and Steinberg, 1953, and in Laubitz, 1970, not of Mayer, 1903; =Caprella uniforma LaFollette, 1915). Aprobable global species complex, this morphospecies is recorded from m a n y habitats worldwide. O n California and Oregon shores, intertidal o n hydroids, algae, the surfgrass Phyllospadix, bryozoans, and so forth, as well as in deeper southern California waters (Watling 1995). Caprella penantis Leach, 1814. In her Atlantic monograph, Laubitz (1972) reported the "true C. penantis" from Monterey Bay (but without specific location, habitat, or date of collection). J o h n McCain, in the previous edition of this manual (1975), speculated that Monterey Bay "may be the northern limit of C. penantis and t h e southern of C. natalensis" (but t h e AMPHIPODA:

GAMMARIDA:

CAPRELLIDAE

627

latter was subsequently reported from deeper water off southern California by Watling [1995]). C. penantis is widely known throughout the Atlantic basin, with scattered records through the Pacific Ocean, and may represent an introduction to the California coast. C. penantis and C. natalensis "are very similar in general appearance" (Laubitz 1972); in addition to differences noted in the key between the species in the ratio of the length of pereonite segments, Laubitz illustrates differences in the propodus palm of gnathopod 2 and in the abdomen of males and females of both species. She also notes that C. penantis "tends to be stouter than C. natalensis and, particularly in mature specimens, to have very obvious pleural development not present in C. natalensis"; the Monterey Bay material reported by Laubitz showed "the typical stout body and strong pleural development... and [were] obviously more setose than C. natalensis, particularly the adult males." C. penantis is wellknown to vary considerably in overall morphology and robustness; Laubitz (1972) illustrated a latitudinal gradient in stoutness along the Atlantic coast of North America (plate 311E, herein). See Bynum (1980, Est. Coastal Mar. Sci. 10: 225-237) and Caine, 1989, Crustaceana 9: 425-431) relative to the relationship of robustness to degree of wave exposure. *Caprella pilidigitata Laubitz, 1970. Intertidal and subtidal in British Columbia and occurring in deeper waters in southern California (Watling 1995). To be looked for in intertidal and shallow waters along the intervening coast. Laubitz (1970) noted that C. pilidigitata is similar to C. mendax and C. equilibra; it is distinguished from C. mendax by a setose gnathopod 2 dactylus (it is not setose in mendax) and by the absence of a lateral spine at the base of gnathopod 2 (there is a small lateral spine in this position in mendax); it is distinguished from C. equilibra by the absence of spines on the sides of pereonites 3, 4, and 5 (present in C. equilibra); in addition, pereonite 4 is longer than pereonite 5 in C. pilidigitata, but equal to or less than the length of pereonite 5 in C. equilibra. Illustrated in Laubitz (1970). Caprella pilipalma Dougherty and Steinberg, 1953. Monterey Peninsula; to be looked for elsewhere. This species has never been illustrated and needs a thorough «description. Dougherty and Steinberg (1953) noted that C. natalensis, C. incisa, C. verrucosa, and C. pilipalma may all occur together on the same hydroids. Caprella pustulata Laubitz, 1970. A northern species occurring at least as far south as the Coos Bay, Oregon, region, and first noted there by Jessen (1969). See also Martin (1977). On hydroids, bryozoans, and sabellid worm tubes. Caprella scaura Templeton, 1836. A possible species complex reminiscent of C. equilibra and C. natalensis; first described from the Indian Ocean, and since reported widely from the Atlantic and Pacific (McCain 1968; Foster et al. 2004). May owe part of its global distribution to shipping. Introduced to the California coast; known from San Francisco Bay and Elkhorn Slough (Marelli 1981). In fouling communities (see Ren and Zhang 1996). Caprella simia Mayer, 1903. A Japanese species introduced to southern California harbors (Cohen et al. 2005; identification by John Chapman). To be watched for in central California and perhaps further north as well. Caprella uniforma. Keyed out in the previous edition; see C. natalensis. Caprella verrucosa Boeck, 1871. On open coast and in bays, on hydroids, bryozoans, coralline algae. See Marelli (1981) for morphological variations. Deutella califomica Mayer, 1890. Open rocky shore and on pilings of marine wharfs such as at Monterey, on many substrates; also deeper water off southern California (Watling 1995). See 628

ARTHROPODA

Martin 1977 (habitat diversity); Caine, 1980, Mar. Biol. 56: 327-335 (ecology, Puget Sound). Mayerella banksia Laubitz, 1970. Primarily sublittoral; see Laubitz 1970 and Watling 1995. Tritella laevis Mayer, 1903. Intertidal on many substrates (hydroids, algae, bryozoans, coralline algae [e.g., Odonthalia], sponges); reported at 88 m in Monterey Bay. Tritella pilimana Mayer, 1890. Widely occurring on open intertidal coast on many substrates, in bays on eelgrass with hydroids, subtidally on crabpots from 9 m and in deeper water to 145 m off southern California. Martin (1977) reports that intersex specimens exist. *Tritella tenuissima Dougherty and Steinberg, 1953. Keyed out in previous edition, but a species of deeper offshore waters of central and southern California. McCain (1968) noted that this species "should probably be transferred to Triliropus" based on lack of swimming setae on antenna 2 and because pereopod 5 is inserted near the midlength on pereonite 5. PARACERCOPINAE

Cercops compactus Laubitz, 1970. Open rocky shore, on alga Plocamium, coralline algae, bryozoans, hydroids. A small species, reaching 3.8 mm in length. PHTISICINAE

Perotripus brevis (LaFollette, 1915). Intertidal on hydroids and other substrates on open coast; also known from the sublittoral in southern California (Watling 1995). A small species, under 5 mm (Martin's [1977] largest male was 2.7 mm). See Caine, 1978, Biol. Bull. 155: 2 8 8 - 2 9 6 (on tubes of Phyllochaetopterus prolifica in very low intertidal, Puget Sound; harpacticoid copepods are major prey). REFERENCES Aoki, M., and T. Kikuchi. 1991. Two types of maternal care for juveniles observed in Caprella monoceros Mayer, 1890 and Caprella decipiens Mayer, 1890 (Amphipoda: Caprellidae). Hydrobiologia 223: 2 2 9 - 2 3 7 . Arimoto, I. 1976. Taxonomic studies of caprellids (Crustacea, Amphipoda, Caprellidae) found in the Japanese and adjacent waters. Seto Marine Biological Laboratory, Special Publications III, 2 2 9 pp. Caine, E.A. 1980. Ecology of two littoral species of caprellid amphipods (Crustacea) from Washington, USA. Marine Biology 56: 3 2 7 - 3 3 5 . Cohen, A. N., L. H. Harris, B. L. Bingham, J. T. Carlton, J. W. Chapman, C. C. Lambert, G. Lambert, J. C. Ljubenkov, S. N. Murray, L. C. Rao, K. Reardon, and E. Schwindt. 2005. Rapid Assessment Survey for exotic organisms in southern California bays and harbors, and abundance in port and non-port areas. Biological Invasions 7: 9 9 5 - 1 0 0 2 . Dougherty, E. C., and J. E. Steinberg. 1953. Notes on the skeleton shrimps (Crustacea: Caprellidae) of California. Proceedings of the Biological Society of Washington 66: 3 9 - 5 0 . Foster, J. M., R. W. Heard, and D. M. Knott. 2004. Northern range extensions for Caprella scaura Templeton, 1836 (Crustacea: Amphipoda: Caprellidae) on the Florida Gulf coast and in South Carolina. Gulf and Caribbean Research 16: 6 5 - 6 9 . Guerra-Garcia, J. M., and I. Takeuchi. 2003. The Caprellidea (Malacostraca: Amphipoda) from Mirs Bay, Hong Kong, with the description of a new genus and two new species. Journal of Crustacean Biology 23: 1 5 4 - 1 6 8 . (Caprella hirayamai, new species, similar to Caprella califomica and C. scaura). Jensen, M. P. 1969. The ecology and taxonomy of the Caprellidae (Order: Amphipoda; Suborder: Caprellidea) of the Coos Bay, Oregon, area. PhD dissertation, Department of Entomology, University of Minnesota, 2 4 8 pp. * = Not in key.

LaFollette, R. 1915. Caprellidae from Laguna Beach. Part II. Journal of Entomology and Zoology, Pomona College, California 7: 5 5 - 6 3 . Laubitz, D. R. 1970. Studies on the Caprellidae (Crustacea, Amphipoda) of the American North Pacific. National Museum of Natural Sciences, Canada, Publications in Biological Oceanography, No. 1, pp. 1 - 8 9 . Laubitz, D. R. 1972. The Caprellidae (Crustacea, Amphipoda) of Atlantic and Arctic Canada. Natl. Mus. Can. Pubis. Biol. Ocean. No. 4, 8 2 pp. Laubitz, D.R. 1993. Caprellidea (Crustacea: Amphipoda): towards a new synthesis. Journal of Natural History 27: 9 6 5 - 9 7 6 . Marelli, D. C. 1981. New records for Caprellidae in California. Proc. Biol. Soc. Wash. 94: 6 5 4 - 6 6 2 . Martin, D. M. 1977. A survey of the family Caprellidae (Crustacea, Amphipoda) from selected sites along the northern California coast. Bull. So. Calif. Acad. Sei. 76: 1 4 6 - 1 6 7 . Mayer, P. 1882. Die Caprelliden des Golfes von Neapel und der angrenzenden Meeres-Abschnitte. Ein Monographie. Fauna und Flora des Golfes von Neapel 6: 1 - 2 0 1 . Mayer, P. 1890. Die Caprelliden des Golfes von Neapel. Nachtrag zur Monographie derselben. Fauna und Flora des Golfes von Neapel 17: 1 - 1 5 7 . Mayer, P. 1903. Die Caprellidae der Siboga-Expedition. Siboga Expedition 34: 1 - 1 6 0 . McCain, J. C. 1968. The Caprellidae (Crustacea: Amphipoda) of the western North Atlantic. Bulletin of the United States National Museum 278: 1 - 1 4 7 . McCain, J. C. 1969. A new species of caprellid (Crustacea: Amphipoda) from Oregon. Proceedings of the Biological Society of Washington 82: 5 0 7 - 5 1 0 . McCain, J. C. 1970. Familial taxa within the Caprellidae (Crustacea: Amphipoda). Proceedings of the Biological Society of Washington 82: 837-842. McCain, J. C., and J. E. Steinberg. 1970. Crustaceorum Catalogus. Part 2. Amphipoda I, Caprellidea I, Fam. Caprellidae. Dr. W. Junk N. V., Den Haag, Netherlands, 78 pp. Mori, A. 1999. Caprella kuroshio, a new species (Crustacea: Amphipoda: Caprellidae), with a redescription of Caprella cicur Mayer, 1903, and an evaluation of the genus Metacaprella Mayer, 1903. Proc. Biol. Soc. Wash. 112: 7 2 2 - 7 3 8 . Myers, A. A., and J. K. Lowry. 2 0 0 3 . A phylogeny and new classification of the Corophiidea Leach, 1814 (Amphipoda). Journal of Crustacean Biology 23: 4 4 3 - 4 8 5 . Ren, X., and Ch. Zhang. 1996. (Fouling Amphipoda (Crustacea) from Dayawan, Guangdong province, China (South China Sea). Institute of Oceanology (China Academy of Sciences) 1: 5 8 - 7 8 (in Chinese). Ricketts, E. F., J. Calvin, J . W. Hedgpeth, and D.W. Phillips. 1 9 8 5 . Between Pacific Tides. 5th ed. Stanford, CA: Stanford University Press. Rudy, P., and L. Rudy. 1985. Oregon estuarine invertebrates. Supplement. On deposit in the Library, University of Oregon Institute of Marine Biology, Charleston, Oregon. Stoddart, H. E., and J . K. Lowry. 2003. Zoological catalogue of Australia. Crustacea: Malacostraca: Peracarida: Amphipoda, Cumacea, Mysidacea. Volume 19.2B. Victoria, Australia: CSIRO Publishing. Takeuchi, I. 1999. Checklist and bibliography of the Caprellidae (Crustacea, Amphipoda) from Japanese waters. Otsuchi Marine Science 24, 5-17. Thiel, M. 1997. Another caprellid amphipod with extended parental care: Aeginina longicomis. Journal of Crustacean Biology 17: 2 7 5 - 2 7 8 . Vassilenko, S. V. 1974. Caprellids (skeleton shrimps) of the seas of the USSR and adjacent waters. Opredeleliteli po Faune SSSR 107: 1 - 2 8 7 . [In Russian] Watling, L. 1995. The Suborder Caprellidea. Taxonomic Atlas of the Benthic Fauna of t h e Santa Maria Basin and Western Santa Barbara Channel. Volume 12, Part 3, pp. 2 2 3 - 2 4 0 . Santa Barbara, CA: Special Publications of the Santa Barbara Museum of Natural History.

CYAMIDAE J O E L W. MARTIN A N D TODD A. HANEY (Plate 312)

The family Cyamidae is a relatively species-poor group of crustaceans, all of which live in obligate symbiotic association with marine cetaceans (Laubitz 1982; Martin and Heyning 1999; Haney 1999). There are seven genera and 28 species (Martin and Heyning 1999; Margolis et al. 2000). Of those species of

A

PLATE 312 Ventral aspects of two male cyamids from the gray whale:

A, Cyamus ceti; B, Cyamus scammoni (Haney, original).

cetaceans that most often harbor cyamids, the gray whale (£schrichtius robustus) is by far the most likely to strand on California beaches, with the humpback whale (Megaptera novaeangliae) a distant second (J. Heyning, personal communication). Three species of cyamids are known from gray whales: Cyamus scammoni Dall, 1872; Cyamus kessleri Brandt, 1872; and Cyamus ceti (Linnaeus, 1758). Cyamus scammoni is the most commonly encountered species and is immediately distinguished from other cyamids by the branched and tightly coiled gills (plate 312). Cyamus scammoni is also the largest of all cyamids, with males and females reaching body lengths of 27 mm and 16 mm, respectively (Leung 1976). Cyamus scammoni and C. ceti usually attach to the head region of their gray whale host, where as C. kessleri typically is found near the anus and genital valves. The second species, Cyamus kessleri, was redescribed by Hurley and Mohr (1957). This species can also be relatively large (up to 21 mm). It is most easily recognized by its narrow body and elongate, uniramous gills. Cyamus ceti, which is also known to be associated with the bowhead whale (Balaena mysticetus), is smaller and apparently less abundant than the other two species in collections from the gray whale. From humpback whales, Martin and Heyning (1999) list only two cyamid species: Cyamus boopis Liitken, 1870, and Cyamus erraticus Roussel de Vauzeme, 1834. It is possible that the two published records of Cyamus erraticus from the humpback whale can be referred to Cyamus boopis, given the similar appearances of individuals of these two species. On both gray and humpback whales, respectively, cyamids are commonly found associated with the parasitic barnacles Cryptolepas rachianecti and Conchoderma auritum. They are otherwise typically restricted to sites on the host animal such as folds of skin, scars, and unhealed wounds, presumably where they are protected from the water currents. In addition to gill morphology and location, cuticular processes (spines) and morphology of the mouthparts are important taxonomic characters in this family. The above species can be reliably identified without dissection; Leung's (1967) key is particularly helpful. Few other cyamids have been reported from the coast of California and Oregon. Leung (1965) reported an unidentified species of Cyamus from Baird's beaked whale (.Berardius bairdii) from San Francisco Bay and the Farallon Islands. Only two other species have been recorded from California: Isocyamus kogiae Sedlak-Weinstein, 1992, from the pygmy sperm whale (Kogia breviceps) (Martin and Heyning 1999), and Syncyamus aequus Lincoln and Hurley, 1981, from the striped dolphin (Stenella coeruleoalba) (Haney et al. 2004). See Martin and Heyning (1999) for a list of known cyamids and their cetacean hosts. AMPHIPODA: GAMMARIDA:

CAPRELLIDAE

629

This section was partially supported by NSF PEET grant DEB 9978193 to J. Martin and D. Jacobs.

REFERENCES Haney, T. A. 1 9 9 9 . A phylogenetic analysis of the whale-lice (Amphipoda: Cyamidae). University of Charleston, South Carolina, MS thesis, 3 6 2 pp. Haney, T. A., O. De Almeida, and M. S. S. Reis. 2 0 0 4 . A new species of cyamid (Crustacea: Amphipoda) from a stranded cetacean in southern Bahia, Brazil. Bulletin of Marine Science 75: 4 0 9 - 4 2 1 . Hurley, D. E., and J. L. Mohr. 1 9 5 7 . On whale-lice (Amphipoda: Cyamidae) from the California gray whale, Eschrichtius glaucas. Journal of Parasitology 4 3 : 3 5 2 - 3 5 7 . Laubitz, D. R. 1982. Caprellidea. pp. 2 9 2 - 2 9 3 . In Synopsis and classification of living organisms. S. P. Parker, ed. New York: McGraw-Hill, Inc. Leung, Y.-M. 1 9 6 5 . A collection of whale-lice (Cyamidae, Amphipoda). Bulletin of the Southern California Academy of Sciences 6 4 : 1 3 2 - 1 4 3 . Leung, Y.-M. 1 9 6 7 . An illustrated key to the species of whale-lice (Amphipoda, Cyamidae), ectoparasites of Cetacea, with a guide to the literature. Crustaceana 12: 2 7 9 - 2 9 1 . Leung, Y. -M. 1976. Life cycle of Cyamus scammoni (Amphipoda, Cyamidae), ectoparasite of gray whale, with a remark on the associated species. Scientific Reports of the Whales Research Institute 2 8 : 1 5 3 - 1 6 0 . Margolis, L., T. E. McDonald, and E. L. Bousfield. 2 0 0 0 . The whale-lice (Amphipoda: Cyamidae) of the northeastern Pacific region. Amphipacifica 2: 6 3 - 1 1 7 . Martin, J. W., a n d j . E. Heyning. 1999. First record of Isocyamus kogiae Sedlak-Weinstein, 1 9 9 2 (Crustacea, Amphipoda, Cyamidae) from the eastern Pacific, with comments on morphological characters, a key to the genera of the Cyamidae, and a checklist of the cyamids and their hosts. Bulletin of the Southern California Academy of Sciences 9 8 : 2 6 - 3 8 .

Hyperiidea BERTHA E. LAVANIEGOS

Hyperiids are amphipods adapted to pelagic life. Their abundance tends to be low relative to other planktonic crustaceans such as copepods or euphausiids. Hyperiids can be distinguished by the morphology of mouth parts and limbs. Some hyperiids have large compound eyes or inflated bodies; others are elongate or have long antennae. Most hyperiid amphipods live as parasitoids in association with gelatinous zooplankton hosts. Cutting-edge chelae are characteristic of hyperiid species associated with gelatinous organisms such as salps, hydromedusae, siphonophores, and ctenophores. They use these chelae to penetrate the gelatinous tissue of the host. Phronima produce barrellike houses from the bodies of salps, or from large nectophores of siphonophores such as Rosacea cymbiformis. In some regions of the California Current, aggregations of hyperiid amphipods can play an important role in food webs. For example, Vibilia australis has been found as a significant prey item in stomachs of the chinook (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) (Schabetsberger et al. 2003). Hyperiids reproduce sexually, but the proportion of females is higher than males. Males of many rare species remain unknown. Despite low abundances, the group is diverse. Up to 80 species have been recorded off southern California (Lavaniegos and Ohman 1999) and about 60 species off central California (Lavaniegos and Ohman, unpublished). The species most frequently found in central California are Primno brevidens, Themisto pacifica (=Parathemisto pacifica), Vibilia armata, Paraphronima gracilis, Tryphana malmi, Phronimopsis spinifera, and Phronima sedentaria. Abundant summer species off the Oregon coast include Themisto pacifica, Paraphronima gracilis, Streetsia challenged, Tryphana malmi, Hyperia medusarum, Primno macropa, and Hyperoche medusarum (Lorz and Pearcy 1975). A figure of 630

ARTHROPODA

the later species is included in the introductory plate to amphipods (plate 254C). The most complete identification key of hyperiid amphipods is provided by Vinogradov et al. (1996). Brusca (1981) provides a key to hyperiids along our coast. REFERENCES Brusca, G. J. 1 9 8 1 . Annotated keys to the Hyperiidea (Crustacea: Amphipoda) of North American coastal waters. Allan Hancock Foundation, Technical Report 5, 1 - 7 6 . Lavaniegos B. E., and M. D. O h m a n . 1999. Hyperiid amphipods as indicators of climate change in the California Current, pp. 4 8 9 - 5 0 9 . In Crustaceans and the biodiversity crisis. Vol. I. F. R. Schram, J. C. v o n Vaupel Klein, eds.. Brill, Leiden. Lorz H. V. and Pearcy W. G. 1 9 7 5 . Distribution of hyperiid amphipods off the Oregon coast. J. Fish. Res. Board Can. 3 2 : 1 4 4 8 - 1 4 4 7 . Schabetsberger R., C. A. Morgan, R. D. Brodeur, C. L. Potts, W. T. Peterson, and R. L. Emmett, 2 0 0 3 . Prey selectivity and diel feeding chronology of juvenile chinook (Oncorhynchus tshawytscha) and c o h o (O. kisutch) salmon in the Columbia River plume. Fisheries Oceanography 12: 5 2 3 - 5 4 0 . Vinogradov, M. E., A. F. Volkov, and T. N. Semenova. 1 9 9 6 . Hyperiid amphipods of the world oceans. Science Publishers Inc., New Delhi, 6 3 2 pp.

Stomatopoda ROY L. CALDWELL (Plate 313)

The only living representatives of the Hoplocarida are the stomatopods, an order of marine predators characterized by a pair of greatly enlarged second maxillipeds, or raptorial appendages, used to capture and process prey. These appendages are analogous to the predatory front legs of the praying mantis. This gives the group their common name of "mantis shrimp." Functionally, stomatopods can be divided into two groups— spearers and smashers—depending on the type of raptorial appendage they possess (Caldwell and Dingle 1976). Spearers have a thin dactylus armed with two or more spines that are used to impale relatively unarmored prey such as shrimp and fish. In smashers, the heel of the dactylus is enlarged and heavily calcified. This weapon is used as a powerful hammer to smash the shells of armored prey such as snails and crabs. There are more than 450 species of stomatopods, the great majority of which occur in tropical and subtropical shallow coastal seas. However, four species of stomatopod have been recorded from Californian waters including two, Hemisquilla califomiensis and Pseudosquillopsis marmorata, that may occasionally be found in our range. List of Species Hemisquilla califomiensis Stephenson, 1967 (=H. ensigera califomiensis, elevated to specific rank by Ahyong, 2001; =H. stylifera of the older California literature). The largest of all smashers, this colorful mantis shrimp can reach 30 cm in length. Adults exhibit an overall yellow-brown body color; telson and distal segments of raptorial appendages greenish yellow to bright yellow; distal segments of antennules, maxillipeds, walking legs and pleopods blue; distal segment of uropods deep blue with red setae fringe, antennal scales bluish at base brownish yellow distally with pink setae; adult males have red polarized patches on their carapace. Postlarvae recruit from the plankton at under 35 mm and burrow in soft

vertical burrows in sandy bottoms at a depth of 5 m - 2 3 m. Maximum reported size is 41 mm. It can be recognized by its small eyes with the subglobular cornea set obliquely on the stalk. The midband consists of six rows of ommatidia. The raptorial claw dactylus is armed with 1 0 - 1 4 teeth. Schmittiuspolitus Manning, 1972. A small spearer found from Monterey Bay to Punta Abreojos, Mexico, at depths of 12 m 185 m, adults reach a maximum size is 60 mm. It can be recognized by its bilobed eye with the midband consisting of two rows of ommatidia. The raptorial claw dactylus is armed with four teeth. PLATE 313 Stomatopoda. Juvenile of Pseudosquilliopsis marmorata, Monterey, California (drawn from life by Christine Huffard).

sediments. Hemisquilla californiensis has been recorded at depths from 4 m to more than 100 m, but it typically is found at 7 m - 2 0 m (Hendrickx and Salgado-Barragan 1989). Burrows are simple blind tunnels that extend into the substrate at an angle. A large adult will have a burrow nearly 2 m long and 8 c m - 1 0 cm in diameter. Males may decorate the entrance to their burrow with shells and stones; the burrow entrances of females are unadorned. Adults may forage away from their burrow during the day and can travel 50 m or more, occasionally moving into the low rocky intertidal to collect prey (Basch and Engle 1989). When disturbed, individuals may emit a low frequency hum produced by vibrating the carapace. Breeding occurs in the spring when large numbers of males may be captured in trawls. MacGinitie and MacGinitie (1968) report a single haul of more than 2 0 0 males taken at 2 0 m off Ventura County. Occasionally such catches are sold commercially and appear in local seafood markets. The strike of this species can inflict serious injury and care should be taken when handling adults. Hemisquilla californiensis can be recognized by the subglobular cornea of the eye set obliquely on the stalk. The midband of the eyes is made up of six rows of ommatidia. The raptorial claw dactylus is unarmed. Hemisquilla californiensis is found from Point Conception south to Golfo de Chirique, Panama. During El Nino years, larvae have been reported as far north as Monterey Bay. Pseudosquillopsis marmorata Lockington, 1877 (referred to as Pseudosquilla lessonii in Schmitt 1940, and Ricketts and Calvin 1968). This is the one spearing stomatopod likely to be encountered in the low intertidal. Postlarvae recruit at 25 m m - 2 9 m m (Manning 1969), and adults may reach 145 m m . The body is a mottled burnt orange to brown and in adults, the distal segments of the uropods are deep pink with purple setae. The telson also has a purple caste and the setae of the antennal scales and pleopods rose purple. Little is known of the biology of this species, but adults construct burrows, often under the edges of rocks. Postlarvae and juveniles may occupy cavities in rubble. Pseudosquillopsis marmorata can be recognized by the cornea of the eye being bilobed with the midband consisting of three rows of ommatidia. The raptorial claw dactylus is armed with two teeth. Pseudosquillopsis marmorata is normally found from south of Point Conception down the Mexican coast and in the Galapagos Islands. Individuals may occasionally recruit further north. A juvenile has been collected from rubble at 6 m off Monastery Beach in Monterey Bay (plate 313), and a 124 m m adult female was taken from a commercial oyster bed in Tomales Bay. Nannosquilla anomala Manning, 1967. This is a small spearer that has been reported from San Clemente Island living in

References Ahyong, S. T. 2001. Revision of the Australian Stomatopod Crustacea. Records of the Australian Museum, Supplement 26; 1 - 3 2 6 . Basch, L. V., and J. M. Engle. 1989. Aspects of the ecology and behavior of the stomatopod Hemisquilla ensigera californiensis (Gonodactyloidea: Hemisquillidae). Biology of Stomatopods. E. A. Ferrerò (ed.) Selected Symposia and Monographs U.A. I. 3, Mucchi, Modena, pp. 199-212. Caldwell, R. L., and H. Dingle. 1976. Stomatopods. Sci. Amer. 234: 80-89. Hendrickx, M. E., and J. Salgado-Barragan. 1989. Ecology and fishery of stomatopods in the Gulf of California, Mexico.). Biology of Stomatopods. E. A. Ferrerò, ed. Selected Symposia and Monographs U.A. I. 3, Mucchi, Modena, pp. 2 4 1 - 2 4 9 . MacGinitie, G. E. and N. MacGinitie. 1968. Natural history of marine animals. Second Edition. McGraw-Hill Book Co., New York, 523 pp. Manning, R. 1967. Nannosquilla anomala, a new stomatopod crustacean from California. Proc. Biol. Soc. Wash. 80: 1 4 7 - 1 5 0 . Manning, R. 1969. The postlarvae and juvenile stages of two species of Pseudosquillopsis (Crustacea, Stomatopoda) from the Eastern Pacific region. Proc. Biol. Soc. Wash. 82: 5 2 5 - 3 7 . Manning, R. 1972. Notes on some stomatopod crustaceans from Peru. Proc. Biol. Soc. Wash. 85: 2 9 7 - 3 0 8 . Ricketts, E. F., and J. Calvin. 1968. Between Pacific tides. 4th ed. Revised by J. W. Hedgpeth. Stanford, CA: Stanford University Press, 614 pp. Schmitt, W. 1940. The stomatopods of the west coast of America based on collections made by the Allan Hancock Expeditions, 1 9 3 3 - 1 9 3 8 . Allan Hancock Pacific Exped. 5: 1 2 9 - 2 2 5 . Stephenson, W. 1967. A comparison of Australian and American specimens of Hemisquilla ensigera (Owen, 1832) (Crustacea: Stomatopoda). Proc. U.S. Nat. Mus. 120: 1 - 1 8 .

Eucarida Euphausiacea L A N G D O N QUETIN A N D R O B I N ROSS

Euphausiids are shrimplike but have biramous thoracic and abdominal appendages, and all thoracic appendages are of a similar form. Decapods, in contrast, have the first three thoracic appendages greatly reduced in size and modified as maxillipeds. In euphausiids, the carapace does not cover the branched gills whereas in decapods the gills are enclosed in branchial chambers. All euphausiids are marine and planktonic, generally less than 35 m m in total length, and have swimming abilities that allow control of both horizontal and vertical location under some conditions. The word euphausia is derived from the Greek words eu- for good and true and -phausia for shining or light-emitting, because bioluminescence is common to this order. In many parts of the world's oceans, euphausiids are an important food for baleen whales, fish, seals, and seabirds. The term "krill" has become synonymous with euphausiids. Norwegian whalers first used krill to describe the swarming "little fish" (euphausiids) in whale feeding grounds (Brinton et al. 1999). EUCARIDA:

EUPHAUSIACEA

631

Of the 32 species whose distributions include the northern Californian and Oregonian coast, three are abundant enough in the nearshore California Current System (CCS) to merit mention; all three serve as an important food source for fish, birds, and whales (Brinton et al. 1999). In the CCS, the frequently cooccurring Euphausia pacifica Hansen, 1911, and Nyctiphanes simplex Hansen, 1911, have large round eyes and lack a rostrum. Although E. pacifica can be larger (adults are 11 m m - 2 5 m m vs. 8 m m - 1 6 m m for N. simplex), the presence of a leaflet o n the first segment of the first antenna of N. simplex is a distinguishing characteristic. E. pacifica is the primary cool-water species in the CCS, whereas N. simplex is a subtropical coastal species that can dominate the communities in southern parts of the CCS. T h e third species, Thysandessa spinifera Holmes, 1900, a neritic species that is most abundant at nearshore stations, also has a large, essentially round eye, but the rostrum is long, very acute and reaches past the eye. T h e adults are 16 m m - 2 5 m m in the CCS. T. spinifera ranges from the southeastern Bering Sea to as far as mid-Baja California during particularly cool springtimes (Brinton et al. 1999). This euphausiid is often infected by a dajid isopod parasitic castrator. Regional distribution and abundance of several of these euphausiids appear to be tied to the ENSO cycle. For example, N. simplex has been reported as far north as 46°N (Brodeur 1986) during an extreme warming ENSO episode. T h e low abundance of T. spinifera off Oregon during El Niño may be due to a reversal of the shelf current, moving the adults off shore (Feinberg and Peterson 2 0 0 3 ) . Daytime surface swarms have been observed in all three species. Swarms of T. spinifera have been observed from San Diego north to Oregon, including Monterey, San Francisco, and Tómales Bays (Brinton et al. 1999), and swarms of E. pacifica have been observed off Monterey. Although records of surface swarms of N. simplex are primarily from the southern parts of its range in the Gulf of California (Gendron 1992), such swarms may occur throughout its range, which extends into the Monterey/San Francisco/Tomales Bay region during warming episodes. Mauchline and Fisher (1969) provide an older, but still useful, summary of euphausiid biology and ecology. REFERENCES Brinton, E., M. D. Ohman, A. W. Townsend, M. D. Knight, and A. L. Bridgeman. 1 9 9 9 . Euphausiids of the World Ocean. World Biodiversity Database. CD-ROM Series. Springer-Verlag, UNESCO. Brodeur, R. D. 1 9 8 6 . Northward displacement of the euphausiid Nyctiphanes simplex Hansen to Oregon and Washington waters following the El Niño event of 1 9 8 2 - 1 9 8 3 . Journal of Crustacean Biology 6: 6 8 6 - 6 9 2 . Feinberg, L. R., and W. T. Peterson. 2 0 0 3 . Variability in duration and intensity of euphausiid spawning off central Oregon, 1 9 9 6 - 2 0 0 1 . Progress in Oceanography 5 7 : 3 6 3 - 3 7 9 . Gendron, D. 1 9 9 2 . Population structure of daytime surface swarms of Nyctiphanes simplex (Crustacea: Euphausiacea) in the Gulf of California, Mexico. Marine Ecology Progress Series 8 7 : 1 - 6 . Mauchline, J., and L. R. Fisher. 1 9 6 9 . The biology of euphausiids. Advances in Marine Biology 7: 1^154.

Decapoda (Plates 3 1 4 - 3 2 6 )

Members of this large and diverse order have five pairs of thoracic limbs, developed for walking, grasping, or swimming, and three pairs of maxillipeds. Decapods include t h e familiar 632

ARTHROPODA

shrimps, prawns, lobsters, crayfishes, and crabs, as well as others less familiar; the group is diverse and presently divided into a number of suborders and infraorders: Suborder Dendrobranchiata: primitive prawns; n o local intertidal species Suborder Pleocyemata Infraorder Caridea: shrimps a n d prawns Infraorder Palinura: spiny lobsters a n d slipper lobsters, n o local intertidal species Infraorder Astacidea: lobsters a n d crayfish, locally represented o n l y b y freshwater species Infraorder Brachyura: true crabs Infraorder Thalassinidea: m u d a n d ghost shrimps Infraorder Anomura: diverse forms, including: Superfamily Paguroidea: h e r m i t crabs a n d s t o n e crabs Superfamily Galatheoidea: porcelain crabs a n d pelagic galatheids ("red crabs") Superfamily Hippoidea: sand crabs Of these, t h e Caridea, Thalassinidea, Anomura, and Brachyura are treated in detail below.

BIOLOGY A R M A N D M. KURIS A N D PATRICIA S. SADEGHIAN

Decapod crustaceans are relatively large and sturdy, well suited for field observations and study of living or freshly killed specimens. Recognition of life-history features will provide m a n y clues for physiological, ecological, and behavioral discoveries. This section provides a protocol for efficient observation of crustacean field biology. Details of life history have n o t been recorded for most of our local species. Thus the primary int e n t i o n of this protocol is not to describe well-known features, but to direct attention to topics where interesting discoveries may be made.

SEXING All local species of decapods attach their eggs to the pleopods of the female for embryonic development. These OVIGEROUS FEMALES provide the quickest means for sexual determination, but not all females breed at the same time or in all seasons. The Caridea are only weakly sexually dimorphic; o n e must look for the presence (males) or absence (females) of an APPENDIX MASCULINA o n the second pair of pleopods (plate 315C1, 315C2). Brachyura are markedly sexually dimorphic. Males have relatively large chelae and narrow, often triangular a b d o m e n s (plate 315A1); first and second pleopods are specialized for copulation (plate 3 1 5 E 1 , 315E2); third and fourth pleopods are absent. Females have wide, flaplike a b d o m e n s (plate 3 1 5 A 3 - 3 1 5 A 5 ) and four pairs of pleopods with long setae for egg a t t a c h m e n t . Anomura have a variety of sexually dimorphic features. In general, males have fewer pairs of relatively small, slender, or inflexible pleopods. Local female hermit crabs (Pagurus) have four pairs of pleopods, males have three (plate 315F1, 315F2). Stone crabs (Hapalogaster, Oedignathus) are quickly sexed, as only females show signs of segmentation o n the left side of

rostrum

first antenna (antennule)

abdomen

antennal ( spine scale [biade

chelate hand palm flagellum A

GENERALIZED CARIDEAN

frontal area orbital area

anterolateral 1 teeth 8

hepatic area branchial area

gastric area

intestinal area

posterolateral margin cardiac area B

PLATE 314 Caridea, Brachyura. A, Generalized caridean, carapace region: CI, frontal; C2, gastric; C3, cardiac; C4, orbital; C5, antennal; C6, hepatic; C7, branchial; B, dorsal view of brachyuran carapace (outline of Cancer magister); C, anteroventral view of brachyuran (all modified after Schmitt).

first abdominal segment

DORSAL VIEW OF BRACHYURAN

antenna

first antenna (antennule) epistome

suborbital region subhepatic region ^

renal opening of third (outer) maxilliped

epimeral suture pterygostomial region

exognath

endognath

b u c c a | cavity

C ANTEROVENTRAL VIEW OF BRACHYURAN

their soft, asymmetrical abdomens. Female porcelain crabs (.Petrolisthes) have two pairs of pleopods; males have one (plate 3 1 5 G 1 , 3 1 5 G 2 ) . Sand crab (Emerita) females have three pairs of pleopods; males have none. Ghost and m u d shrimp (Neotrypaea and Upogebia) males also have fewer and/or smaller and more slender pleopods than do females (plate 315H, 3151). The function of these appendages remains to be studied. However, Neotrypaea is most easily sexed by noting the presence of the large major chela of the males, often twice as long as the minor chela; in females, the major chela exceeds the minor by < 5 0 % in length. Size is a n o t h e r sexually dimorphic feature. Adult female sand crabs (Emerita) and most pea crabs (Pinnixa, Fabia) are m u c h larger than males. Most female shrimp are also larger, but the size ranges of the sexes often overlap. Sizes are similar for b o t h sexes of hermit crabs. In most of t h e remaining Brachyura, Thalassinidea, and Anomura, males are larger than

females, again with considerable overlap. These patterns probably reflect differences in mating systems.

MATURATION Upon reaching sexual maturity, most if n o t all decapods undergo a MOLT OF PUBERTY to attain their adult morphology. This is most easily seen in female brachyurans, in w h i c h t h e width of t h e a b d o m e n relative to o t h e r parts of t h e crab greatly increases at t h e molt of puberty (plate 3 1 5 A 4 , 3 1 5 A 5 ) . In all decapods, more subtle changes in t h e relative size o f t h e chelae, a b d o m i n a l width, presence of setae o n pleopods and the abdominal margin, and shape of the genital opening can usually be detected in at least one sex. Relative growth techniques (Teissier 1960, Hartnoll 1985, Vogel 1988, Clayton 1 9 9 0 ) are very useful in maturation studies. The relative size of EUCARIDA: DECAPODA

633

A 1 normal c f

PLATE 315 Caridea, Brachyura, Anomura. A, Abdominal shape and chela length of Hemigrapsus oregonensis in various stages of maturation and parasitism by the entoniscid isopod parasitic castrator Portunion conformis; all crabs 10.3 mm-10.8 mm carapace width: Al, normal male, A2, male feminized by Portunion, A3, Juvenile female, A4, prepuberty female, A5, adult female; B, H. oregonensis, as labeled (redrawn from Joel Hedgpeth by E. Reid); C-I, sexual dimorphism of decapod pleopods, sex and number as labeled: C, Crangon: CI, left, posterior face, C2, 50 mm total length; D, Pachygrapsus: D l , 20 mm carapace width, left, anterior face, D2, D3, left, posterior face; E, Cancer: 150 mm carapace width, left, anterior face; F, Pagurus: left, Fl, 8 mm carapace length; G, Petrolisthes: left, anterior face, Gl, 15 mm carapace length; H, Neotrypaea: HI, posterior face, H2, 100 mm total length, anterior face; I, Upogebia: posterior face, 12, 100 mm total length (A, by Emily Reid, except A4, drawn by Dottie McLaren; rest from A. Kuris, drawn by E. Reid).

A 3 juvenile $

A 2 feminized c f

dactyl

manus (hand or palm) • carpus y f (wrist)

ambulatory legs 3 B

Hemigrapsus oregonensis

A 5 adult

9

exopod appendix masculina

1cm

endopod 9

2nd

c f 2nd

Cl

C2

Crangon franciscorum

Cf 1 st

c f 2nd

E1

E2

Cancer antennarius

Pachygrapsus crassipes

4mm

9

2nd c f

Gl Pagurus hirsutiusculus

G2

Petrolisthes cinctipes

claws is also an aid t o recognition of social systems. Males w i t h

Upogebia pugettensis

Neotrypaea californiensis

ily be seen through the transparent cuticle of most shrimps.

particularly large claws are generally dominant, and males of

Corresponding observations can also be made o n typically

different sizes and claw d e v e l o p m e n t m a y adopt very different

opaque crabs by l o o k i n g through the

behavioral reproductive strategies (Kuris et al. 1987).

MEMBRANES connecting the ventral surfaces of thorax and ab-

A related p h e n o m e n o n

is the acquisition of

BREEDING

flexible

ARTHRODIAL

d o m e n . Ovarian color varies as does egg color, being red (Puget-

DRESS prior to oviposition in m a n y shrimp and possibly other

tia),

decapods.

their

orange (Emerita), or magenta (Petrolisthes). As the ovary matures

pleopods at the preceding molt. Shorter setae appear at molts

and grows, pigmentation becomes more intense. Pigments in

preceding nonovigerous instars.

the yolk are complexed w i t h vitellogenin proteins.

Female

shrimp

acquire

longer

setae o n

purple (Pachygrapsus), b r o w n ( F a b i a ) , green

(Crangon),

Relative size of the ripening ovary m a y be judged by its relation t o certain morphological markers, such as sutures sepaREPRODUCTION

rating

abdominal

segments.

Recently

laid

eggs

lie

in

a

gelatinous mass on the pleopods. W i t h i n a day, an outer m e m Ovaries of decapod Crustacea lie dorsal to the other organs in the

brane forms around each egg and a thin strand attaches it t o

carapace and anterior part of the abdomen (entirely abdominal

pleopodal setae. Young eggs are evenly pigmented. As the y o l k

for hermit crabs and ghost and mud shrimps). T h e y can read-

is gradually displaced by the g r o w i n g embryo, a transparent

634

ARTHROPODA

area appears in the egg; in advanced embryos, eyespots and larval chromatophores may also be recognized. Broods about to hatch often have a grayish cast since all the brightly colored yolk has been absorbed. Information about the reproductive state of male decapods is relatively difficult to obtain, dissection and microscopic examination often being required. Most crustaceans oviposit a single brood in an instar. Some species regularly oviposit more than once in an instar, sometimes stripping old egg shells from the egg-bearing setae leaving the setae a glistening gold color.

MOLTING

Discontinuity of growth is one of the most singular aspects of the lives of arthropods, ECDYSIS—the actual shedding of the old skin, the EXUVIA—and the accompanying increase in size take only a few minutes. However, the entire interval between molts represents a dynamic, cyclical process. Following ecdysis, the animal is soft. In this POSTMOLT period, the cuticle gradually hardens as different areas of the exoskeleton calcify sequentially. A series of animals of a given species must be compared to detect this hardening sequence. Postmolt ends with the deposition of a thin, membranous layer. This may be detected by carefully cracking the carapace. If a shiny membrane holds the cracked pieces together, the animal has passed into the "intermolt" period. The PREMOLT period, or preparation for the coming molt, is signaled by the separation of the epidermis from the old cuticle. A mitotic burst, expanding the number of epidermal cells, precedes the deposition of new cuticular structures. First new setae are organized using the previous cuticle as a template. After the new setae are organized, pre-exuvial layers are secreted over the general body surface. These early premolt stages may be recognized in intact carideans and in ghost and mud shrimps by observing setal formation along the margins of the uropods, telson, or antennal scales. Dissection of the transparent mouth parts is usually necessary to see this condition in more heavily calcified decapods. In late premolt, decalcification of the old exoskeleton may be detected if gentle pressure along the epimeral suture (plate 314C) causes it to crack. Molting is imminent if the epimeral suture of a crab, or the dorsal thoracic-abdominal suture of a shrimp, is visibly split. Passano (1960), Skinner (1985), and Chang et al. (1993) provide a good summary of the molt cycle. Exuviae may be distinguished from the empty remains of a dead animal by the absence of pigment from the corneas of the eyestalks of an exuvia. Discovery of a fragile intact exuvia suggests that a very soft, recently molted animal may be hiding nearby. The previous owner of the exuvia can be certified by matching details of the pigment patterns of the exuvia and the soft animal. Comparison of the soft animal and its exuvia will demonstrate the growth increment per molt for animals of that size.

REGENERATION

Decapods are able to cast off (AUTOTOMIZE) their limbs under duress and then regenerate the appendages at subsequent molts. Autotomy is readily demonstrated by squeezing basal segments of an appendage. A specific muscle is stimulated that slices through a cuticular apodeme, severing the limb. This is not a haphazard process. The autotomized limb is always severed at a

preformed breakage plane. Upon autotomy, a flap of skin closes over the severed limb base so that scarcely a drop of blood is lost. The regenerating limb forms in a bud that protrudes from the stump of the autotomized limb. Limb buds are transparent in early regenerative stages. Only when the animal passes into premolt does the bud become pigmented (the new cuticle is being deposited on the regenerating appendage). Limb buds take various shapes depending on the species and the limb lost. They are generally compact, conserving space. This interesting developmental variation has not been much studied. Recently regenerated appendages are smaller than normal limbs, but this size discrepancy is no longer apparent after a second or third molt. In some species the regenerated appendage always has a distinctive appearance. Since spider crabs (e.g., Pugettia) and purse crabs (e.g., Randallia) cease molting after the molt of puberty, a calcified cap is secreted over stumps of limbs lost in their terminal instar. Presence of such a cap verifies that the animal is an adult. Frequency of missing appendages is high among porcelain crabs, true crabs, and Betaeus shrimps; it is low for hermit crabs and rare for most local carideans.

BEHAVIOR

All copulating pairs merit careful study, noting molt stages, reproductive states, and relative sizes. Some species appear to form long-term pair bonds; Alpheus, Betaeus, and Pachycheles are examples (see MacGinitie 1937). Several species of majid crabs form seasonal pods in deeper water with males gathering around mounds of many females. Loxorhynchus grandis is the best-studied example (Culver and Kuris 2001). Crabs migrate long distances to join these pods. Examining mating behavior in other majids would be interesting. Hermit crabs spend much time and energy procuring and retaining their snail shell resource. Competition for shells is associated with complex behavioral signaling. Dominance among species and by large crabs over smaller individuals has often been noted. Some species of hermit crabs have strong preferences for certain species of snail shells, while others may be more concerned with size of the shell resource. Further study of the kinds of snail shells that hermit crabs occupy, how they fit, and the relative sizes of the hermits and their shells will increase our understanding of the use of their limited shell resource. In local decapods, burrowing ranges from the brief escape behavior of some caridean shrimps to the construction of deep, complex, permanent burrows by ghost and mud shrimps. Crangon often settles into shallow depressions leaving only its eyes and antennae exposed. Sand crabs burrow backward as waves recede on sandy beaches. Their long, setose, second antennae are then extended to feed in the moving sand. Ghost shrimps (Neotrypaea) build poorly defined burrows in muddy sand; mud shrimps (Upogebia) construct permanent U-shaped burrows with strong walls cemented by mucous secretions. Upogebia burrows may have enlarged sections, side chambers and two or three openings. Some decapods display strong tidal rhythms. Emerita moves up and down the beach with the incoming and outgoing tides. Diel rhythms are less obvious, but at least Pachygrapsus is distinctly nocturnal, foraging at night and tightly wedged into crevices by day. Many rhythmic behavior patterns remain to be observed and described. Many species of majid crabs are decorators, attaching fragments of algae, hydroids, bryozoans, and other encrusting organisms to specialized hooked setae on their carapaces (Wicksten 1980, 1978). EUCARIDA:

DECAPODA

635

been replaced by P. leniusculus. Epizoic branchiobdellid worms may

first (antepenultimate) article of third maxilliped (see plate 316A) broadly expanded Lissocrangon stylirostris — One gastric spine; rostrum relatively broad, tip round, straight; telson equal to or longer than uropods; first article of third maxilliped narrow, not dilated Crangon 5 5. Finger of hand (dactyl of chela) turned down almost parallel (180°) to hand (plate 319A); an acute spine on posterodorsal corner of fifth abdominal segment; inner flagellum of first antenna more than two times as long as outer flagellum (plate 316F) Crangon franciscorum — Finger of hand at a 45° angle, or less, to hand; no spine on posterodorsal corner of fifth abdominal segment; inner flagellum on first antenna distinctly less than two times as long as outer flagellum 6 6. Flagella of first antenna equal in length; length of antennal scale about equal to or less than two times width; spine of antennal scale not exceeding blade (plate 319E); anterodistal corner of first pleopod without spine, color mottled, including orange and magenta blotches Crangon handi — Inner flagellum of first antenna distinctly longer than outer flagellum; antennal scale length always greater than two times width; spine of antennal scale almost always distinctly exceeding blade (common exception is nigricauda); anterodistal corner of first pleopod with a spine color speckled 7 7. Tip of telson without three small spines, flanking each side (but with a single small spine on each side slightly proximal to tip); dorsum of sixth abdominal segment smooth; without a distinct row of small setae; antennae as long or longer than body; finger of hand at about a 30° angle to hand (plate 319F) (in living specimens, always distinguished by one prominent circular spot [blue center with concentric black and yellow rings] on side of sixth abdominal segment; this often fading in preservative) Crangon nigromaculata

be found on the body and gills.

—

KEYS TO DECAPOD CRUSTACEA A R M A N D M. KURIS, PATRICIA S. SADEGHIAN, A N D JAMES T. CARLTON

Schmitt's classic monograph, Marine Decapod Crustacea of California (1921), and Jensen's (1995) photographic guide are the most useful references for local decapods. Revisions to major groups (families) are given in the list of decapod species below. Terms used in the following keys are illustrated in plates 314A-C and 315B. The key to Betaeus is adapted from the work of Josephine Hart (1964, Proc. U.S. Natl. Mus. 115: 431-466), and the key to Petrolisthes from the work of Janet Haig (1960, Allan Hancock Pac. Exped. 24, 440 pp.).

KEY TO MAJOR D E C A P O D G R O U P S

1. Abdomen shrimplike, with well-developed tail fan 2 — Abdomen small and folded under carapace or soft, reduced, usually asymmetrical 4 2. Body generally laterally compressed, shrimplike in form; side plates (pleura) of second abdominal segment overlap those of first; abdomen usually with a sharp bend, third pair of legs chelate Caridea (Key A) — Third pair of legs not chelate, abdomen dorsoventrally flattened, lateral margins of second abdominal segment not overlapping first segment 3 3. Chelipeds large and strong usually symmetrical, carapace cylindrical; freshwater Astacura See Riegel, 1959 (Calif. Fish Game 45: 29-50). Along the coast, two introduced crayfish, Pacifastacus

leniusculus (Dana, 1852) and Pro-

cambarus clarkii (Girard, 1852), occur in shallow muddy sloughs, irrigation ditches, lakes, streams, and at the heads of estuaries. An endemic species, Pacifastacus

nigrescens (Stimpson, 1859), was pres-

ent in the San Francisco Bay Area in the 19th century, but may have

Chelipeds variable usually asymmetrical, sometimes subchelate. Carapace flattened, burrowing shrimp Thalassinidea (Key C) 4. Abdomen small, folded under thorax, symmetrical; uropods absent; last pair of legs not markedly reduced; antennae between eyes Brachyura (Key B) — Abdomen usually asymmetrical and/or reduced; uropods present or absent; last (fourth) pair of legs almost always reduced, folded up behind bases of preceding pair; posterior sternite of thorax not fused to others; antennae external to eyes Anomura (Key C) —

KEY A: C A R I D E A

1. Rostrum absent or very short, without dorsal teeth 2 — Rostrum present, distinct, usually well developed and spinose 18 2. Rostrum very short, dorsally flattened; eyes free (not covered by carapace); hands subchelate 3 — Rostrum absent or very small and spinelike; eyes free or covered by carapace; hands chelate 9 3. Carapace with two median gastric spines Mesocrangon munitella — Carapace with none or one median gastric spines 4 4. No gastric spine; rostrum narrow, tip pointed (plate 319G) curving strongly downward; telson shorter than uropods; 636

ARTHROPODA

8.

—

9.

— 10. —

11.

Tip of telson with three spines on each side; dorsum of sixth abdominal segment slightly grooved, with a distinct row of central setae (may be worn) (living specimens never with colored spot on sixth abdominal segment) 8 Antennal scale blade tip narrow, spine long, much exceeding blade (plate 319B); scale greater than two-thirds length of carapace; finger of hand at about 45° angle to hand; antennae about two-thirds body length Crangon alaskensis Antennal scale blade tip broad, spine generally short, hardly exceeding blade (plate 319C); scale about two-thirds length of carapace; finger of hand tending toward transverse, at about 30° angle to hand (plate 319D); antennae from two-thirds body length to as long as body (a variable species) Crangon nigricauda Eyes free, chelae not powerfully developed; rostrum very small, reduced to a small spine on frontal margin; three teeth on carapace behind rostral spine, the median the largest; one very prominent supraorbital spine extending beyond anterior margin of carapace; antennal scale broad, subrectangular Lebbeus lagunae Eyes covered by carapace; one or both chelae powerfully developed 10 Rostrum present; one chela greatly enlarged and complex, with dactyl above 11 Rostrum absent, one chela usually and about equal, inverted so that dactyls are below (plate 317I-317M); see note in species list Betaeus 13 Pteryostomian spine at anterolateral margin of the carapace,

palpjS carpus /propodus ' dactyl

basis

epipod protopod

caridean

brachyuran TYPICAL THIRD MAXILLIPEDS

supraorbital spine

PLATE 316 Caridea and Brachyura. Typical third maxillipeds of caridean, A and brachyuran, B (C, after Hedgpeth 1968; D, after Holmes 1900; E, after Newman 1963; F, after Schmitt 1921).

F1

— 12. — 13. — 14. — 15. —

Crangon franciscorum

dactyls of legs bifid yellowish green with red spots Synalpheus lockingtoni Anterolateral margin of the carapace smooth dactyls of legs simple Alpheus 12 Tips of walking legs 3 - 5 simple (plate 317A2), claws mottled orange, yellow, white, body red Alpheus bellimanus Tip of walking legs 3-5 with two spines (plate 317A1), claws with black blotches and spots Alpheus clamator Dactyls of ambulatory legs slender and simple 14 Dactyls of legs stout and bifid 15 Chelae with fingers longer than palm (plate 317F, 317K) Betaeus longidactylus Chelae with fingers not longer than palm (plate 317B, 317E, 317L, 317M) Betaeus harrimani Front of carapace rounded, not emarginated (notched) (plate 317G) Betaeus macginitieae Front emarginated (plate 317C, 317D, 317H) 16

16. Emargination shallow (plate 317D); telson with posterolateral spines small or absent Betaeus harfordi — Emargination deep (plate 317C, 317H); telson with welldeveloped posterolateral spines 17 17. Peduncle of antennule less than one-half carapace length; lower inner ridge of merus of cheliped with long bristles, upper ridge ending in sharp tooth, chelae three times as long as wide, with fingers subequal to palm length (plate 317C, 317J) Betaeus gracilis —

Antennular peduncle approximately equal to carapace length; merus of cheliped with lower inner ridge usually tuberculate, upper ridge with tuft of hairs, not ending in sharp tooth; chela twice as long as wide, with fingers longer than palm (plate 317H, 3171) Betaeus setosus

18. Both legs of first pair simple; second pair of legs very unequal, both with multiarticulate carpus; medium- to largesize, to about 13 cm or more Pandalus danae E U C A R I D A : DECAPODA

637

Alpheus

bellimanus

PLATE 317 Caridea. A, walking legs of Alpheus; Betaeus: B, adult female; C-H, females, frontal region, dorsal; 1, male right cheliped; J, female right cheliped; K, female right chela; L, variations in female right chela; M, male left chela (A, after Word and Charwat 1976 [SCCWRP Natantia], redrawn by Dottie McLaren; rest after Hart 1964).

M

— 19. — 20.

— 21.

—

22. 638

B. harrimani

Both legs of first pair chelate (chelae small); second pair equal or nearly so 19 Carpus of second legs not annulated 20 Carpus of second legs annulated 23 Rostrum with one to two dorsal teeth; supraorbital spine present (plates 316C, 3181); in freshwater streams Syncaris pacifica Rostrum with four or more dorsal teeth, supraorbital spine absent, in brackish or marine waters 21 Abdominal tergites smooth, lacking ridges, rostrum with at least eight dorsal teeth, at least three teeth behind the orbit, length of dactyl of second walking leg short, less than half the length of the propodus (plate 316E) Palaemon macrodactylus Abdominal tergites with dorsal ridges, no orbital teeth behind the orbit, length of dactyl of second walking leg long, more than half the length of the propodus Exopalaemon 22 Dactyl of claw long, more than half the length of the ARTHROPODA

— 23.

— 24. — 25. — 26.

cf

L3

B. harrimani

$

propodus Exopalaemon carinicauda Dactyl of claw short, less than half the length of the propodus Exopalaemon modestus Carpus of second legs with three articles (plate 318H2); colors usually bright green, sometimes brown and red Hippolyte 24 Carpus of second legs with seven articles; color green, red brown, mottled, or various 25 Rostrum ending in two points (plate 318H1) Hippolyte califomiensis Rostrum ending in three points (plate 318G) Hippolyte clarki Carapace with more than 20 segments Lysmata califomica Carapace with seven segments 26 With two to three small, supraorbital spines in a longitudinal series; rostrum high, leaflike, with three dorsal teeth bearing serrate margins, third maxilliped with small exopod; body opaque in life Spirontocaris prionota

A1 A2 Heptacarpus

palpator Heptacarpus

brevirostris

Heptacarpus Heptacarpus

taylori

stimpsoni

PLATE 3 1 8 Caridea. A-I, outline views of carapaces and antennal scales, as labeled; E, rostral variations; H2, female second right leg (A, B, D-F, after Holmes 1 9 0 0 ; C, G, after Word and Charwat 1 9 7 6 [SCCWRP Natantia], redrawn by Dottie McLaren; El, after Schmitt; H2, after Chace 1 9 5 1 ; I, after Hedgpeth 1968).

E1

Heptacarpus

Heptacarpus

sitchensis

H1

\v

y Hippolyte

Hippolyte

27.

— 28. — 29.

—

30.

W2

califomiensis

clarki

second leg

Syncaris

—

paludicola

pacifica

No supraorbital spines; rostral teeth various, not as above; third maxilliped without exopod Heptacarpus 27 Rostrum (length measured from posterior margin of orbit to tip) generally as long as or longer than rest of carapace 28 Rostrum generally shorter than rest of carapace 30 Anterior half of rostrum with some dorsal teeth 29 Anterior half of rostrum lacking dorsal teeth 31 Rostral teeth in mature specimens 4-8 dorsally and 1-5 below 4-8/1-5 (plate 318F), subadults with fewer teeth, spine at the anterolateral margin of the carapace (pterygostomian spine) present; uniform green with broken, red brown stripes on carapace (do not confuse with H. sitchensis, the rostrum of which does not reach the end of the antennal scale) Heptacarpus paludicola Rostral teeth 5 dorsally and 6-7 below 5/6-7, spine at anterolateral margin of carapace (pterygostomian spine) absent Heptacarpus franciscanus Sixth abdominal segment less than two times as long as wide; rostrum deep, one-fourth as deep as long; rostral teeth 4-6/4-6 (plate 316D); epipod present on third max-

illiped color highly variable, often matches algal substrate Heptacarpus cannabis — Sixth abdominal segment elongate, more than two times as long as wide; rostrum very narrow; rostral teeth 4/4-5; epipod absent on third maxilliped; transparent with a long red line Heptacarpus tenuissimus 31. Rostrum elongate, generally reaching beyond middle of antennal scale, but not to end; rostral teeth in mature specimens 6-7 dorsally and 2-4 below (6-7/2-7) (plates 318E), subadults with fewer teeth, greenish, translucent, with oblique red bands on carapace and crimson bars on legs (do not confuse with H. paludicola, the rostrum of which is larger and reaches to or beyond end of antennal scale) Heptacarpus sitchensis —

Rostrum short, generally no reaching middle of antennal scale 32 32. Rostrum not reaching as far as cornea of eye; rostral teeth 5-7/0 (plate 318D); anteriormost rostral teeth often above and slightly behind, rather than well behind, tip; color highly variable, including red-brown, greenish with white carapace, or mottled colors Heptacarpus taylori EUCARIDA: DECAPODA

639

Crangon franciscorum

Crangon nigricauda

Crangon alaskensis

Crangon handi

Crangon ? nigromaculata

Lissocrangon stylirostris

PLATE 319 Caridea and Brachyura. A-C, E, antennal scales; D, F, chela; G, dorsal anterior view of carapace (A, B, D, F, after Rathbun 1904, redrawn by Emily Reid; E, after Kuris and Carlton, 1977, redrawn by Dottie McLaren; C, G, after Holmes 1900, redrawn by Reid; H-K, after Schmitt; L, M, A. Kuris, drawn by Dottie McLaren).

Platymera gaudichaudii

— Rostrum reaching as far as or farther than cornea 33 33. Rostrum reaching beyond first segment of peduncle of antennule; in male may only overlap second antennular segment; rostral teeth 5 - 8 / 1 - 3 (plate 318C); dactyls of ambulatory legs long and slender, about one-third to onehalf length of propodus Heptacarpus stimpsoni — Rostrum not reaching beyond first segment of antennular peduncle; dactyls of legs short and stout, not long and slender 34 34. Epipods on first two pereiopods Heptacarpus pugettensis — Epipods on first three pereiopods 35 35. Antennal scale equal to or shorter than telson; rostral teeth 5-6/0 (plate 318B) Heptacarpus brevirostris — Antennal scale distinctly longer than telson; rostral teeth 5-6/0-1 (plate 318A) Heptacarpus palpator 640

ARTHROPODA

KEY B: B R A C H Y U R A

1.

Carapace round, with two prominent posterior spines, or ovate with large, straight, lateral spines and more than 12 teeth on anterolateral margin ; mouth field triangular, narrow in front 2 — Carapace nearly square, triangular, ovate, or round; if round, without spines on posterior margin and, if bearing long lateral spines, then with not more than 10 anterolateral teeth; mouth field square 3 2. Carapace round with two short, prominent spines posteriorly (plate 319J); color white, often with purple patches Randallia omata — Carapace ovate with pronounced lateral spines and about 15 small, anterolateral teeth (plate 319K); reddish Platymera gaudichaudii

3.

Carapace nearly square; sides approximately parallel; anterior edge nearly transverse; eyes at anterolateral corners 4 — Carapace triangular, oval, or nearly round, not square; sides not parallel 8 4. Carapace margin smooth, without teeth Planes cyaneus 5 — Carapace margin with teeth 5. Carapace about as long as wide, frontal margin toothed, outer margin of claws hairy, claws white-tipped Eriocheir sinensis — Carapace considerably broader than long, frontal margin without teeth, outer margin of claws not hairy, claws brown-tipped 6 6. Carapace with transverse flat ridges; strongest laterally; two teeth on anterolateral margin; surface blackish green with numerous red or purple transverse lines Pachygrapsus crassipes — Carapace smooth; three teeth on anterolateral margin; without transverse lines Hemigrapsus 7 7. Color red, purple, or whitish; no hair on legs; chelipeds red-spotted (plate 320A) a green morph lacking spots is fairly common in the northern part of the range Hemigrapsus nudus — Color dull brownish green; legs hairy; chelipeds without red spots (plate 315A, 315B) (see note in species list to distinguish young Hemigrapsus) Hemigrapsus oregonensis 8. Body narrow anteriorly; rostrum single or bifid 9 — Body broad anteriorly; rostrum usually reduced or absent 21 9. Rostrum single 10 — Rostrum bifid 12 10. Chelipeds short and stout; carapace broadly pyriform (pear-shaped), with tubercles and fine hairs; short, prominent, spinelike tubercle on first abdominal s e g m e n t . . . . 11 — Chelipeds much longer and heavier than ambulatory legs; carapace broadly triangular (plate 3191) Heterocrypta occidentalis 11. Carapace pear-shaped with large tubercles, curved spine behind eye Pyromaia tuberculata — Carapace triangular, no spine near eye Podochela hemphilli 12. Carapace about as broad as long with lateral margins markedly flattened and produced, leaflike; surface smooth, usually encrusted with sponges, bryozoans, etc. (plate 319H) Mimulus foliatus — Carapace longer than broad; lateral margins not flattened and produced; surface smooth or rough, sometimes encrusted, obscuring carapace 13 13. Posterolateral margin of carapace without spines 14 — Prominent posterolateral projections 18 14. Small crabs < 5 cm wide, rostrum straight 15 — Large crab to 25 cm wide, rostrum curved down Loxorhynchus 17 15. Rostrum two flat plates, claws usually with orange markings, often encrusted with sponges Scyra acutifrons — Rostrum pointed 16 16. Rostrum short, carapace almost circular, tan to orange, often encrusted with sponges, legs slender Herbstia parvifrons — Rostrum long, carapace pear-shaped, very small (to 15 mm), sponges mostly on stocky walking legs

Pelia tumida 17. Very large crabs to 25 cm, rostral spines curve strongly down, carapace inflated, covered with small spines and tubercles in juveniles, worn smooth in older terminal adults Loxorhynchus grandis — Large crabs to 12 cm, rostral spines slightly decurved, carapace triangular with few large blunt tubercles (plate 320E) Loxorhynchus crispatus 18. Rostrum consisting of two long, very slender spines; preorbital spine (internal to eye) absent; postorbital spine (external to eye) prominent, slender and acute, far from eye Oregonia gracilis — Rostrum otherwise, preorbital spine present or absent Pugettia 19 19. Surface of carapace smooth; distance between eyes less than one-third width of carapace in adult specimens (plate 320C) Pugettia producta — Carapace tuberculate or spiny; distance between eyes about half the greatest width of carapace 20 20. Carapace distinctly broader posteriorly; anterolateral teeth narrow, laterally directed; legs moderately long and slender; merus of cheliped with a few tubercles dorsally, not carinate, fingers of claw white Pugettia richii — Carapace not expanded posteriorly; anterolateral teeth broad, anteriorly directed; legs relatively short; merus of cheliped with irregularly dentate keel dorsally, fingers of claw with orange tips Pugettia gracilis 21. Front (area between eyes) either five-toothed or divided by median notch; carapace hard, anterolateral margin toothed; free living 22 — Front area entire (with the exception of some species of Pinnixa, see below); carapace often membranous, frequently rounded or may be much wider than long; carapace margin not toothed but may have anterolateral acute tubercles or conical spines; commensals in polychaete tubes, molluscan mantle cavities, sea cucumber cloacas, echiuran, and polychaete, bivalve and ghostand mud-shrimp burrows Pinnotheridae (see key, below) 22. Front five-toothed; carapace broadly oval; antennules fold back longitudinally Cancer 23 — Front area with four or fewer teeth or divided by median notch; antennules fold back longitudinally, transversely, or obliquely 30 23. Carapace widest at seventh or eighth tooth, 12-13 teeth, small, to 55 mm Cancer oregonensis — Carapace widest at ninth or tenth tooth, nine to 11 teeth 24 24. Dactyl of cheliped black and spiny Cancer branneri — Dactyl of cheliped smooth 25 25. Front area markedly produced beyond outer orbital angles forming five nearly equal teeth; fingers of chelipeds black tipped (plate 320D); adults uniformly brick red above, young often brightly and variably colored with spots or stripes Cancer productus — Front not markedly produced, with five unequal teeth, color of young not variable, usually similar to a d u l t s . . . 26 26. Carapace widest at tenth anterolateral tooth (first anterolateral tooth is external to eye)(plate 314B); fingers of chelipeds not black-tipped Cancer magister — Carapace widest at eighth or ninth tooth 27 27. Carapace widest at eighth tooth; tenth, and eleventh teeth distinct; teeth with entire edges, curving forward; EUCARIDA: DECAPODA

641

A

Hemigrapsus

nudus

C B

Paraxanthias

Pugetlia

producta

taylori

PLATE 320 Brachyura. B, male chela; F-G, male, dorsal right side of carapace (A, after Hedgpeth 1962; El, after Rathbun 1925; F, G, after Menzies 1954; rest after Schmitt).

D

Cancer

F to,

E1

productus

Lophopanopeus bellus

H G

— 28. — 29. — 30.

—

642

Cancer

antennarius

Lophopanopeus ieucomanus

red-spotted beneath; black on fingers of chelipeds (plate 320H) Cancer antennarius Carapace generally widest at 9th tooth; not red-spotted beneath 28 Upper surface of carapace hairy (pubescent); teeth sharp, curving, with entire edges Cancer jordani Carapace smooth, not hairy (glabrous); teeth blunt, with serrate posterior edges 29 Fingers of chelipeds white-tipped; merus of third (outer) maxilliped (plate 316B) rounded anteriorly Cancer gracilis Fingers black-tipped; merus of outer maxilliped truncate anteriorly Cancer anthonyi Carapace subcircular with 6 large lateral spines, hairy, attenules fold back longitudinally, antennal flagellae long and hairy Telmessus cheiragonus Carapace shape and spines otherwise, antennules fold back transversely or obliquely, antennal flagellae shorter not hairy 31 ARTHROPODA

Loxorhynchus crispatus

31. Front with teeth, carapace with a prominent lateral spine, legs sometimes flattened for swimming 32 — Front divided by a median notch 33 32. Fourth pereiopod a flattened paddle for swimming, carapace with a long sharp lateral spine (plate 319M), claws blue Callinectes sapidus — Fourth pereiopod somewhat flattened, carapace with five large teeth pointing forward (plate 319L), body and claws mottled green Carcinus maenas 33. Chelipeds with numerous, prominent, rounded tubercles (plate 320B); legs hairy Paraxanthias taylori — Chelipeds otherwise 34 34. Fingers whitish, in brackish water Rhithropanopeus harrisii — Fingers black; not in brackish water 35 35. Anterolateral margin with eight to 10 small, subequal, acute teeth; carapace broadly oval Cycloxanthops novemdentatus

B2

B3

C3

C1

C4

D3

D1

PLATE 321 Brachyura. Pinnotheridae. MXP3 = third maxilliped; WL = walking legs; arrow indicates the external lobe of the exopod of MXP3. Parapinnixa afftnis: Al, dorsal view; A2, MXP3; Fabia subquadrata: Bl, dorsal view; B2, MXP3; B3, male abdomen; Opisthopus transversus: CI, dorsal view; C2, WL2-WL4; C3, MXP3; C4, male abdomen; Scleroplax granulata: Dl, carapace dorsal view; D2, WL1-WL4; D3, MXP3 (Bl, modified from Bonfil et al. 1992, Ciencias Marinas 18: 37-56). Not to scale.

—

Anterolateral margin with 3 prominent, subequal teeth (plate 320F, 320G) Lophopanopeus 36 36. Carapace with distal segments of ambulatory legs hairy (plate 320F) Lophopanopeus bellus — Carapace and ambulatory legs smooth, not pubescent (plate 320G) Lophopanopeus leucomanus

KEY TO PINNOTHERIDAE ERNESTO CAMPOS

1.

First pair of walking legs (WL) stouter and longer than the others (plate 321A1); dactylus of the third maxilliped (MXP3) inserted distally on the propodus (plate 321A2) EUCARIDA: DECAPODA

643

PLATE 322 Brachyura. Pinnotheridae. WL = walking legs. Pinnixa bamharti: A, dorsal view; P. longipes: Bl, dorsal view; B2, WL5, arrows indicate tubercles of the ischium; P. tubicola: CI, dorsal view; C2, WL1-WL4; P. tomentosa: D, dorsal view, (all after Zmarzly 1992, J. Crust. Biol. 12: 677-713). Scale (mm): A = 2; Bl = 2.5; B2 = 1; CI, D = 5; C2 = 2.

Parapinnixa affinis Second or third pair of WL longer than the others (plates 321B1, 322A); dactylus of MXP3 inserted on the ventral margin of the propodus (plate 321B2, 321C3, 321D3) . . 2 2. Carapace transverse, wider than long (plates 321D1, 322A); third pair of WL longest than the others (plates 321D2, 322C1); exopod of the MXP3 with a lobe on the external margin (plate 321D3, arrow) 4 — Carapace suborbicular or subquadrate (plate 321B1, 321C1); second pair of WL longest than the others (plate 321B1, 321C2); external margin of the exopod without a lobe (plate 321C3) 3 3. Female: carapace subquadrate, whitish, with two longitudinal sulci arising from the upper margin of orbit and extending as far as gastric region (plate 321B1); male: carapace porcelainlike; anterolateral carapace margin with a fringe or hairlike setae; abdominal somites 2-4 fused (plate 321B3) Fabia subquadrata —

644

ARTHROPODA

—

Female: carapace suborbicular, red-spotted to green, without longitudinal sulci (plate 321C1); male: carapace redspotted to green, anterolateral carapace margin without a fringe of hairlike setae; abdominal somites and telson well separated (plate 321C4) Opisthopus transversus 4. Third pair of WL slightly longer than the others (plate 321D1); WL slender and somewhat rounded; carapace hard, dorsally convex and often granulated (plate 321D2) Scleroplax granulata — Third pair of WL distinctly longer and larger than the others (plate 322B1, 322C2); WL flattened; carapace variable, but if dorsally hard and convex it is smooth (plate 322A) 5 5. Carapace strongly convex and calcified, 1.5 times wider than long (plate 322A) Pinnixa barnharti — Carapace flat or slightly convex, not strongly calcified, > 1 . 5 times wider than long 6 6. Dactylus shorter than propodus on WL3 (plate 322C2) 7

PLATE 323 Brachyura. Pinnotheridae. WL

= walking legs. Pinnixa faba: Al, dorsal view; A2, female cheliped; A3, male cheliped; P. littoralis: Bl, dorsal view; B2, female cheliped; B3, male cheliped; P. weymouthi: CI, carapace, dorsal view; C2, WL1-WL4 (C, after Zmarzly 1992). Scale (mm): Al = 4; A2, B3 and CI = 2; A3, Bl = 5; B2 = 3; C2 = 1.

B1

C1

—

Dactylus subequal to or exceeding length of propodus o n WL3 (plates 3 2 3 C 2 , 324A1) 11

7.

Distal tip of dactylus of W L 4 falling short of or just reaching to distal end of merus of W L 3 when both legs extended (plate 322B1, 3 2 2 C 1 ) 8

—

—

Distal tip of dactylus of W L 4 r e a c h i n g b e y o n d distal end of merus of W L 3 w h e n b o t h legs e x t e n d e d (plate 3 2 2 D ) 9

8.

Posteroventral margin o f i s c h i u m of W L 4 with two or t h r e e large tubercles (plate 3 2 2 B 2 arrow); m a r g i n s of

10. Female: carapace oblong (plate 323A1), fingers of cheliped not gaping when tightly closed (plate 323A2); male: fixed finger of chela straight relative to line defined by ventral margin of palm (plate 323A3); inner margin of dactylus of chela

carinae granulate or serrate; dactylus of WL3 spinous and slightly curved Pinnixa tomentosa

with single blunt triangular tooth (plate 323A3)

W L 4 with long setal fringe (plate 3 2 2 B 1 ) —

Pinnixa longipes Posteroventral margin of ischium of W L 4 without tubercles; W L 4 without long setal fringe (plate 3 2 2 C 1 )

9.

Pinnixa tubicola Carapace and legs covered with short coarse setae (plate 322D); ventral margin of propodus of WL3 bicarinate, t h e

Carapace and legs without short coarse setae; ventral margin of propodus of WL3 without carinae; dactylus of WL3 without spines and strongly curved 10

—

Pinnixa faba Female: carapace pointed at sides (plate 323B1); fingers of cheliped gaping when tightly closed (plate 323B2); male: fixed finger of chela slightly deflexed relative to line defined by ventral margin of palm (plate 323B3); inner margin of dactylus of chela toothless (plate 3 2 3 B 3 ) Pinnixa EUCARIDA: DECAPODA

littoralis 645

PLATE 324 Brachyura. Pinnotheridae. Closed arrows indicate the subhepatic tooth; open arrows indicate the granulate or serrate anterolateral ridge. Pinnixa scamit: Al, A2, female and male, dorsal view; A3, female cheliped; P. occidentalis: Bl, B2, male and juvenile male, dorsal view; B3, B4, male and female cheliped (Al, A3, after Martin and Zmarzly, 1994; A2, after Campos et al, 1998; Bl, B2, B3, B4, after Zmarzly 1992). Scale (mm): Al, A2 = 2; A3 = 1; Bl = 4; B2, B3, B4 = 1.

B2

11. Anterolateral area of carapace smooth and round (plate 323C1) Pinnixa weymouthi — Anterolateral area of carapace with granulate or serrate ridge (plates 324A2, open arrow, 325A1, 325A2, 325B1, 325B2) 12 12. Fixed finger of chela deflexed (plate 324A3, 324B3, 324B4) 13 — Fixed finger of chela straight or curving upward (plate 325A3, 325B3, 325B4) 14 13. Carapace (plate 324A1, 324A2) with a well-developed granular cardiac ridge; larger, acute, slightly curved teeth along the anterolateral margin of carapace; a well-developed subhepatic tooth (plate 324A1, 324A2, closed arrows); length of propodus of WL3 at least 2.5 times width Pinnixa scamit — 646

Carapace (plate 324B1, 324B2) with an acute sometimes ARTHROPODA

bilobate cardiac ridge; granulated ridge along the anterolateral margin of carapace; no traces of subhepatic tooth; length of propodus of WL3 1 . 5 - 2 times width Pinnixa occidentalis 14. Anterior face of chela of male and female with prominent line of densely packed granules forming ridge just above ventral margin, running most of length of propodus (plate 325A3, 325A4); females often with a second row of granules medially on anterior face (plate 325A3) —

Pinnixa franciscana Anterior face of chela of mature male entirely smooth, without granules (plate 325B4); female and immature males with line of coarse granules just above ventral margin of propodus and scattered granules over rest of propodus, without a second row of granules medially on anterior face (plate 325B3) Pinnixa schmitti

PLATE 325 Brachyura. Pinnotheridae. Pinnixa franciscana: A l , A2, female and male dorsal view; A3, A4, female and male cheliped; P. schmitti: B l , B2, female and male dorsal view; B3, B4, female and male cheliped (all after Zmarzly 1992). Scale ( m m ) : A l , A 2 = 5; A3, A4, B l , B3, B4 = 1; B2 = 3.

KEY C: ANOMURA AND THALASSINIDEA 1.

Abdomen reflexed

—

Abdomen not reflexed, may be twisted

2.

Abdomen not folded against thorax, body shrimplike, legs greatly elongate, slender

—

Abdomen folded against thorax, body crablike

3.

Body egg-shaped; second to fourth legs with last joint

—

Body not egg-shaped; 2nd to 4th legs w i t h last joint

2 18

curved and flattened; on sandy beaches ending

in

sharp,

pointed

dactyl;

3 4

in

rocky

areas

6

Pleuroncodes planipes EUCARIDA:

DECAPODA

647

4.

— 5.

—

6. — — 7. — 8.

— 9.

— 10. — 11.

—

12. —

13.

—

14. — 15.

—

16.

648

First pair of legs without claws; carapace without sharp spines along anterolateral margin (plate 80); color gray Emerita analoga First pair of legs chelate or subchelate 5 Carapace and chelipeds with several sharp spines, claws chelate; large to 60 mm, white, not iridescent Blepharipoda occidentalis Chelipeds smooth, carapace with small spine, claws subchelate, small to 20 mm, color iridescent white Lepidopa californica Uropods absent; carapace as long as, or longer than, broad; abdomen thick and fleshy 7 Uropods absent; carapace wider than long; abdomen small and flattened 10 Uropods present; carapace nearly round in outline, abdomen folded against body 11 Carapace completely covering claws, legs, and body Cryptolithodes sitchensis Claws and legs visible dorsally 8 Claws, legs, and carapace with large spines, carapace triangular, adults brown, juveniles variable in color Phyllolithodes papillosus Claws, legs, and carapace smooth 9 A large smooth foramen formed by the lateral margin of the carpus of the claw against the first walking leg, reddish brown to tan Lopholithodes foraminatus Claws without smooth concavity on carpus, brightly colored, red, orange, yellow Lopholithodes mandtii Legs and carapace hairy, flattened Hapalogaster cavicauda Legs and carapace roughly tuberculate, not hairy, legs nearly cylindrical Oedignathus inermis Body and chelae thick; chelae unequal and tuberculate or granular; carpus of chelipeds as long as broad Pachycheles 12 Body and chelae flattened; chelae equal or nearly so, smooth; carpus of chelipeds longer than broad Petrolisthes 14 Telson with five plates (plate 326B2), lacking small plate at anterior margin of each lateral plate 13 Telson with 7 plates, small plate at anterior margin of each lateral plate (plate 326C) (sometimes missing in females) Pachycheles pubescens Chelipeds with long, scattered hairs, carpus of cheliped with a broad triangular lobe on inner margin Pachycheles rudis Chelipeds with dense coat of short soft hairs, carpus of cheliped with a toothed lobe on inner margin, occurs in sponges Pachycheles holosericus Carpus of chelipeds more than twice as long as wide 15 Carpus twice as long as wide or less 16 Carapace covered with short, transverse, hairy striations and large, flattened tubercles; carpus about 2.5 times as long as wide; distal portion of maxillipeds bright orange red Petrolisthes rathbunae Carapace nearly smooth posteriorly, often granular anteriorly, never with hairy striations; carpus a little over twice to nearly three times as long as wide; outer edge of palp of maxilliped blue (see note in species list) Petrolisthes manimaculis Carpus without lobe on anterior margin, margins subparallel; outer edge of palp of maxilliped arthrodial membrane of cheliped bright blue (see note in species list) ARTHROPODA

—

17.

—

18. — 19.

—

20. — 21. — 22.

— 23. —

Petrolisthes eriomerus Anterior margin of carpus with a distinct proximal lobe, margins of carpus converging distally from their highest points; palp of maxilliped and arthrodial membrane of dactyl of cheliped orange red (plate 326A) 17 Carpus of chelipeds with an anterior lobe about one-quarter the length of the carpus, excluding lobe carpus margins almost parallel, carpus with dense covering of hair, body color usually light brown Petrolisthes cabrilloi Carpus of chelipeds with long anterior lobe extending more than .25 the length of the carpus, carpus margins excluding lobe converge distally, carpus smooth without hairs Petrolisthes cinctipes Burrowing in mud or sand; abdomen symmetrical, extended, externally segmented; ghost and mud shrimps 19 Living in snail shells or worm tubes, abdomen soft, hermit crabs 22 First pair of legs approximately equal and subchelate, other legs simple; eyestalks cylindrical, corneas terminal; four pairs of fanlike pleopods; body hairy, often bluish Upogebia pugettensis First pair of walking legs very unequal and chelate, second pair chelate; eyestalks flattened, corneas dorsal; three pairs of fanlike pleopods; body smooth, whitish to reddish Neotrypaea 20 Median rostral tooth sharply pointed Neotrypaea gigas Rostrum blunt 21 Tip of eyestalk pointed, color orange to pinkish Neotrypaea californiensis Tip of eyestalk blunt, rounded, color white Neotrypaea biffari Abdomen straight, living in worm tubes; right claw slightly larger than left, body color light, claws tipped with orange, legs with orange-brown bands Discorsopagurus schmitti Abdomen twisted, asymmetrical, usually in snail shells, color various 23 Left cheliped equal to or larger than right; outer maxillipeds approximated at base 24 Right cheliped larger than left, outer maxillipeds widely separated at base Pagurus 26 Note: The key for Pagurus species is primarily based on color; for preserved specimens also consult McLaughlin and Fisher (1974) and Kozloff (1987).

24. No appendages on anterior abdominal segments, fourth legs subchelate, body whitish with median brown stripe, claws and legs with blue blotches Isocheles pilosus — Paired pleopods present on first abdominal segment, fourth legs not chelate Paguristes 25 25. Eyestalks stout, less than three-quarters the width of hard portion of carapace, propodus of claw wide, only one-fifth longer than wide, outer margin strongly convex, antennae with sparse hairs, reddish, legs with blue spots Paguristes bakeri — Eyestalks slender, at least as long as hard portion of carapace is wide, propodus of claw narrow, at least one-third larger than wide, outer margin almost straight, antennae with a row of long setae, orange to brown, obscured by golden setae Paguristes ulreyi 26. Minor (left) cheliped with flat dorsal surface, dactyl of walking legs 2 and 3 twisted, with two brown stripes 27

A

Petrolisthes

cinctipes

B1

Pachycheles

rudis PLATE 326 Anomura. B2, C, female telsons; E, young male; G, H, second right pereopods (A, Bl, D, after Hedgpeth; G, H, Rogene Thompson, redrawn by Emily Reid; rest after Schmitt 1921).

C

Pachycheles pubescens

D

Emerita

analoga

d E

Pagurus

granosimanus

californiensis propodus

H Neotrypaea gigas Neotrypaea: second pereopods

— 27.

—

28.

— 29.

—

F

Pagurus

Minor (left) cheliped with rounded dorsal surface, dactyl of walking legs straight 28 Dactyl and propodus with more spines in dorsal than on ventral surface, cornea of eye yellowish green, claws with red stripe Pagurus ochotensis Spines distributed rather equally on dorsal and ventral surfaces of claw, cornea black, claws and legs with orange bands Pagurus armatus Merus of major (right) cheliped without prominent tubercules, antennae irregularly banded, chelipeds brown with gray tubercules Pagurus quaylei Merus of major (right) cheliped with one to two prominent tubercules 29 Legs not banded, antennae orange, body color uniform dark green stippled with blue or white granulations, major chelae evenly granulated, rostrum rounded (plate 326E) Pagurus granosimanus Legs banded, color various, major chelipeds not evenly granulated 30

samuelis

30. Eyes with yellow circles, antennae red, overall body color deep red, dactyl of walking legs with white spot at tip, rostrum triangular, acute; carpus of major cheliped flat perpendicular face Pagurus hemphilli — Color not deep red, carpus otherwise 31 31. Body color pale, chelipeds red and spiny, walking legs light blue with red spots and bands, antennae light translucent orange, rostrum rounded Pagurus beringanus — Body color dark, major cheliped with tubercules, granules or spines, rostrum rounded or acute 32 32. Antennae red, walking legs with bright blue dactyls and bands on distal portion of propodus (white bands and dactyls on small crabs), body and claw color green, rostrum triangular, acute, chelae with tubercles, hard carapace longer than wide (plate 326F) Pagurus samuelis — Antennae banded or orange, body color brownish, hard carapace about as long as wide 33 33. Antennae banded green and white, propodus with white distal band and blunt tips, small crabs with white bands EUCARIDA: DECAPODA

649

o n chelipeds and other walking legs, rostrum triangular, acute, chelipeds with tubercles and granules Pagurus hirsutiusculus — Antennae pale orange, n o blue color o n walking legs, chelipeds with orange tips and rows of spines, rostrum rounded, small crabs, carapace < 1 0 m m Pagurus caurinus

LIST OF SPECIES FOR DECAPODA Jensen (1995) provides good photographs and considerable information on habitat, geographic range, color and behavior of m a n y of these species. McLaughlin et al. 2005 provide a comprehensive species list.

PLEOCYEMATA CARIDEA

CR A N G O N ID AE

See Zarenkov (1965, Zoologicheskii Zhurnal 44: 1761-1775, in Russian) for an older review of group in general and aspects of evolution and biology; Kuris and Carlton (1977, Biol. Bull. 153: 540-559) for relative growth analyses and taxonomy of west coast species. These shrimp are parasitized by bopyrid isopods, such as Argeia pugettensis, which induce a large, asymmetrical swelling of t h e gill chamber. Crangon alaskensis Lockington, 1877. C o m m o n , in shallow water of bays on soft bottoms; should n o t be confused with Crangon nigricauda, a larger species. Crangon franciscorum Stimpson, 1859. In bays o n m u d bottoms, c o m m o n to abundant; also offshore in deeper waters. See Israel 1936, Calif. Fish Game, Bull. 46 (life history, biology, fishery). Crangon handi Kuris & Carlton, 1977. Coarse sand of coves and surge channels, sometimes a m o n g surfgrass along rocky outer coast, matching substrate in color. Most Crangon spp. have salt-and-pepper pattern for crypsis on m u d or sand. C. handi is cryptic over gravelly substrates, and its beautiful large splotches of color include orange and magenta. See Kuris and Carlton 1977, Biol. Bull. 153: 540-559. Crangon nigricauda Stimpson, 1856. C o m m o n to abundant in bays and offshore in deeper waters; a m o n g eelgrass, rocks, and o n sand bottoms. See Israel 1936, above. Crangon nigromaculata Lockington, 1877. On m u d and sand bottoms. Lissocrangon stylirostris (Holmes, 1900). C o m m o n in surf zone of semiprotected sandy beaches; sublittoral o n sandyrocky bottoms. Mesocrangon munitella Walker, 1898. Recorded by Schmitt from shallow rocky bottoms in San Francisco Bay. ALPHEIDAE

See Ache and Case, 1969, Physiol. Zool. 42: 361-371 (Betaeus spp., antennular chemoreception). Alpheus spp. "Pistol shrimps" injure prey by percussion, producing a high-speed jet of water by clicking dactyl of chela against palm; the snapping sound is caused by the implosion of a cavitation bubble in the jet (Versulis et al. 2000, Science 289: 2114-2117). Very low rocky intertidal, in sponges, kelp holdfasts, 650

ARTHROPODA

old pholad bore holes. See Kim and Abele 1988, Smith. Contrib. Zool. 454, 119 pp. (taxonomy of Eastern Pacific species). Alpheus bellimanus Lockington, 1877. Very low intertidal, under rocks, and in holdfasts. Alpheus clamator Lockington, 1877. A southern species, comm o n in low tide pools, burrows under rocks, paired. Betaeus gracilis Hart, 1964. Intertidal o n rocky shores; kelp holdfasts. See Hart (1964, Proc. U.S. Natl. Mus. 115: 431-466) for a detailed treatment of this genus. Size, shape, and dentition of chelae vary with age, sex, and extent of regeneration and are not reliable systematic characters. Betaeus harfordi (Kingsley, 1878). Commensal in mantle cavities of abalones (Haliotis spp.); leaves host readily and often missed when abalones are collected. Betaeus harrimani Rathbun, 1904. In burrows of Upogebia and Neotrypaea o n mudflats. Betaeus longidactylus Lockington, 1877. Intertidal on rocky shores; kelp, kelp holdfasts, and in eelgrass; also recorded in southern California from Urechis and Upogebia burrows. Betaeus macginitieae Hart, 1964. Occur in pairs under sea urchins (Strongylocentrotus spp.). Betaeus setosus Hart, 1964. Under rocks and in algae o n semiprotected rocky coasts; in kelp holdfasts (especially Laminaria) and surfgrass (Phyllospadix) roots; o n pilings. Small, symbiotic with pairs of Pachycheles rudis, underneath crabs, translucent, easily missed. Synalpheus lockingtoni (Coutiére, 1909). Rare in central and northern California; more c o m m o n to the south. Records include collections o n wharf piles at Santa Cruz, and in Elkhorn Slough. PANDALIDAE

Pandalus danae Stimpson, 1857. Dock shrimp; sublittoral, but occasional in shallow water near harbor channels and over eelgrass (Zostera) beds. ATYIDAE

Syncaris pacifica (Holmes, 1895). Formally designated an endangered species in California and restricted to freshwater streams of Marin, Sonoma, and Napa counties; see Hedgpeth 1968, Intern. Revue Ges. Hydrobiol. 53: 511-524; Martin and Wicksten 2004, J. Crust. Biol. 24: 447-462. Its southern counterpart, Syncaris pasadenae (Kingsley, 1896), is extinct; its type locality is said to be underneath the site of the Rose Bowl in Pasadena. PAL AEM O N I DAE

See Wicksten 1989, Bull. So. Calif. Acad. Sci. 88: 11-20 (key to species of Eastern Pacific). Exopalaemon carinicauda (Holthuis, 1950). A Korean and Chinese species first collected in San Francisco Bay in 1993. Introduced either in ballast water or as live bait. See Wicksten 1997, Calif. Fish Game 83: 43-44. Exopalaemon modestus (Heller, 1862). An Asian species introduced to t h e Columbia River m o u t h in ballast water in the 1990s. See Emmett et al. 2002, Biol. Invas. 4: 447-450 (introduction to West Coast). Palaemon macrodactylus Rathbun, 1902. An Asian species introduced to San Francisco Bay in ballast water in the early 1950s and now found from southern California to Oregon, especially in brackish water, where it may be abundant along floats, wharf

pilings, and in algae; see Newman 1963, Crustaceana 5:199-132; Born, 1968, Bio. Bull. 134: 235-241 (osmoregulation); Little 1969, Crustaceana 17: 69-87 (larval development). HIPPOLYTIDAE

See Wicksten 1990, Fishery Bulletin 88: 587-598 (key to Eastern Pacific species). Heptacarpus brevirostris (Dana, 1852). In low-intertidal pools in algae and under rocks; on floats, pilings; sublittoral on algae and on rocky bottoms. Heptacarpus carinatus Holmes, 1900. Low intertidal; in algae and surfgrass, often matching color of algae. Heptacarpus franciscanus (Schmitt, 1921). Recorded from shallow water of San Francisco Bay over sandy and rocky bottoms. Heptacarpus palpator (Owen, 1839). Low intertidal to sublittoral; in tidepools and under rocks to the sublittoral; also on wharf piles. See Wicksten 1986, Bull. So. Calif. Acad. Sci. 85: 46-55 (^description). Heptacarpus paludicola Holmes, 1900. In Zostera beds and on algae, such as Ulva, in shallow pools on mudflats; on wharf pilings, floats; also in mid-intertidal pools of rocky coast; common to abundant. Heptacarpus pugettensis Jensen, 1983. Very low intertidal; aggregate under boulders. Heptacarpus sitchensis (Brandt, 1851) (=H. pictus (Stimpson, 1871). Common to abundant in middle and lower tide pools of rocky coasts, to the sublittoral; also in Zostera beds, and on floats. See Wicksten et al. 1996, Crustaceana 69: 71-75 (taxonomy). Heptacarpus stimpsoni Holthius, 1947. Low intertidal to sublittoral on soft bottoms. Heptacarpus taylori (Stimpson, 1857). Mid- to low intertidal under rocks and clumps of bryozoans, sponges; in algae; wharf pilings. Heptacarpus tenuissimus Holmes, 1900. Low intertidal; soft bottoms. Hippolyte californiensis Holmes, 1895. California green shrimp; locally common in bays on Zostera, matching its color and oriented longitudinally along blade; see Chace 1951, J. Wash. Acad. Sci. 41: 35-39 (taxonomy); Barry 1974, Mar. Biol. 26: 261-270 (habitat selection). Hippolyte clarki Chace, 1951 Similar to H. californiensis, low intertidal in eelgrass beds. Lebbeus lagunae (Schmitt, 1921). Rare, in rocky pools; a southern species. Lysmata califomica (Stimpson, 1866). Low intertidal; rocky shores, may behave as a cleaner, feeding on fish parasites. A southern species, more common in central California and Oregon after El Niños. Spirontocaris prionota (Stimpson, 1864). Uncommon, underneath rocks in tide pools.

BRACHYURA

Some of the traditional families of true crabs have been split into groups (superfamilies) of related families. These include the Majidae, now superfamily Majoidea (Epialtidae, Inachidae, Inachoididae, Oregoniidae, Pisidae); the Xanthidae, now superfamily Xanthoidea (Xanthidae, Panopeidae); and the Grapsidae, now superfamily Grapsoidea (Grapsidae, and Varunidae).

LEUCOSIIDAE

Randallia ornata (Randall, 1840). Subtidal; rarely intertidal, sandy substrates; occasionally washed inshore. Frequently infested with corkscrew nemertean Carcinonemertes. See Sadeghian and Kuris 2001, Hydrobiologia 456: 59-63 (nemertean egg predator). CALAPPIDAE

Platymera gaudichaudii (Milne-Edwards, 1837). Sublittoral; occasional specimens in harbors released from fishing boats. GRAPSIDAE

Pachygrapsus crassipes Randall, 1840. Lined shore crab; ubiquitous in upper intertidal of rocky areas of bays as well as rocky outer coast, abundant; in burrows in Salicornia marshes; active, aggressive, nocturnal; see Hiatt 1948, Pac. Sci. 2: 135-213 (biology); Bovbjerg 1960, Ecology 41: 668-672 (behavioral ecology), 1960 Pac. Sci. 14: 421-422 (courtship behavior); Willason 1981, Mar. Biol. 64: 125-133 (salt march ecology). Planes cyaneus Dana, 1852. Flotsam crab; pelagic; occasionally washed ashore on drift logs with goose barnacle Lepas, and also associated with sea turtles; see Chace 1951, Proc. U.S. Nat. Mus. 101: 65-103 (taxonomy); Wicksten and Behrens 2000, SCAMIT Newsletter 19(5): 7 (California record). VARUNIDAE

Eriocheir sinensis Edwards, 1853. Chinese mitten crab; introduced from Asia in the 1990s, this large catadromous species is abundant in the rivers and sloughs draining into the San Francisco Bay. In the brackish water of the Petaluma River, small juveniles are common among the tubes of the tubeworm Ficopomatus enigmaticus. It is much larger than native grapsids and varunids. E. sinensis is amphibious; during migration, it can be an abundant pest in low-lying areas, ditches, and canals, clogging pipes, undermining banks and levees, and entering houses. This edible species is highly valued in some Asian cuisines. In Asia, it is an intermediate host for the human lung fluke, an important pathogen. See Cohen and Carlton 1997, Pac. Sci. 51: 1-11, and Rudnick et al. 2005, Bio. Invasions 7: 333-350 (introduction to California). Hemigrapsus nudus (Dana, 1851). Purple shore crab; midintertidal of semiprotected and protected rocky coasts and bays, locally abundant; prefers coarse sand to gravel substrates overlain with large rock cover; sluggish. Sometimes infected with the parasitic castrator entoniscid isopod, Portunion conformis. Uncommon south of Morro Bay. See Morris et al. 1996, Physiol. Zool., 69: 864-886 (air breathing); McGaw 2003, Bio. Bull. 204: 38-49 (behavioral thermoregulation); Keppel and Scrosati 2004, Animal Behav. 67: 915-920 (prey avoidance). Hemigrapsus oregonensis (Dana, 1851). Green shore crab; mid and low intertidal of bays under rock cover overlying mud or muddy sand, abundant; sometimes exposed and active over large areas of mudflats; sublittoral populations in shallow water of bays with profuse Ulva cover; small populations along protected outer coast under rocks over mud; also in burrows in Salicornia marshes; moderately active. The entoniscid isopod, Portunion conformis, a parasitic castrator, often attains infection rates above 40%. In turn, P. conformis suffers frequent mortality EUCARIDA:

DECAPODA

651

from a picornavirus (Kuris et al. 1979, 1980). Both species of Hemigrapsus and also Pachygrapsus crassipes can be infested with the egg predator Carcinonemertes epialti. At times, brood mortality is substantial (Shields and Kuris 1988). These shore crabs are also intermediate hosts for a variety of trematode metacercariae, larval trypanorhynch tapeworms, larval Polymorphic acanthocephalans, and larval Ascarophis nematodes. Very small Hemigrapsus nudus may be distinguished from very small Hemigrapsus oregonensis by a combination of the following characters: in H. oregonensis there is a marked frontal notch, in H. nudus a shallow depression; in H. oregonensis the lateral spines are sharp and clearly set out, in H. nudus they are not sharp, nor as clearly separated from the side; the dactyls of ambulatory legs 1-3 are long in H. oregonensis, shorter in H. nudus; the dactyl of leg 4 is quite flat in H. nudus, rounded in H. oregonensis. See Lindberg 1980, Crustaceana 39: 263-281 (behavior); Willason 1981, Mar. Biol. 64: 125-133 (salt marsh ecology). PARTHENOPIDAE

Heterocrypta occidentalis (Dana, 1854). Sublittoral; sandy bottoms; rare in intertidal.

also occurring in Japan. Very effective decorator; sexual dimorphism pronounced. EPIALTIDAE

Mimulus foliatus Stimpson, 1860. Low intertidal of rocky coast; among algae, under rocks, often encrusted with sponges or bryozoans. Pugettia gracilis Dana, 1851. In low, rocky intertidal; in bays among Zostera. Pugettia producía (Randall, 1840). Northern kelp crab; low intertidal and sublittoral of protected and semiprotected rocky coasts, in kelp beds and other macro-algae and on jetties, wharf pilings; pods of aggregated females sometimes reported subtidally; adults often encrusted with barnacles, bryozoans, and sponges; a lively and aggressive spider crab with a strong pinch. Occasionally parasitized by rhizocephalan barnacles, egg masses with commensal turbellarians and rarely the egg predator nemertean Carcinonemertes epialti. The similar Taliepus nuttallii occurs south of Point Conception. Pugettia richii Dana, 1851. Low intertidal among corallines and other algae; often encrusted with hydroids and coralline algae.

INACHOIDIDAE

Podochela hemphilli (Lockington, 1877). Low intertidal and subtidal; wharf pilings. Decorators, particularly on first walking legs. Pyromaia tuberculata (Lockington, 1877). Sublittoral on wharf pilings; often encrusted with sponges and algae; common in shallow dredge hauls in San Francisco Bay. Introduced in recent years to Asia, New Zealand, and Australia. PISIDAE

Herbstia parvifrons (Randall, 1840) Rare; sponge-encrusted under stones; retreats into crevices, low intertidal. Monterey Bay and north. Loxorhynchus crispatus Stimpson, 1857. Moss crab; sublittoral; low intertidal on semiprotected rocky coasts in crevices; often heavily decorated with hydroids, sponges and algae. See Wicksten 1977, Calif. Fish Game 63: 122-124 (feeding), 1978, Trans Amer. Micr. Soc. 97: 217-220,1979, Crustaceana 5 Suppl: 37-46, and 1980, Sci. Amer. 242: 146-154 (decorating). Loxorhynchus grandis Stimpson, 1857. Sheep crab; a southern species, subtidal, occasionally lower intertidal, very large, males reach 24 cm in length, 11 kg in weight; females are smaller. Subtidal breeding pods in the spring include hundreds of females with many males gathered at periphery. See Culver and Kuris (2001) for information on biology and mating. Hairy outer surfaces wear away in adult terminal molt phase males, revealing blue-green tubercules. Egg masses with the nemertean egg predator, Carcinonemertes; supports a fishery in southern California. Pelia túmida (Lockington, 1877). A southern species; under stones, low-intertidal zone on rocky shores. Scyra acutifrons Dana, 1851. Uncommon in low intertidal of semiprotected rocky coasts, often encrusted; rare; south of Monterey. OREGONIIDAE

Oregonia gracilis Dana, 1851. Occasional on wharf pilings and in Zostera; usually sublittoral and generally northern; boreal, 652

ARTHROPODA

PINNOTHERIDAE

The pea crabs, symbionts with annelids, mollusks, sea cucumbers, and in crustacean and echiuran burrows; see Schmitt et al. 1973, Crustaceorum Catalogus. Dr. W. Junk B. V., The Hague, The Netherlands, pp. 1-160; Rathbun 1918, U.S. Nat. Mus. 97: 1-461; Schmitt 1921. Fabia subquadrata Dana 1851. Taxonomy and distribution see Campos, 1996, J. Nat. Hist. 34: 1157-1178. In bivalve mollusks, especially Mytilus califomianus. The females undergo several postplanktonic stages (prehard, hard to posthard IV) before they become a large, soft-shelled, ovigerous female (=posthard V). The small hard-shelled (hard stage) males may move between hosts and like female in hard stage are able to swim; see Pearce 1966, Pac. Sci. 20: 3-35. Opisthopus transversus Rathbun, 1893. This species appears to be non-host specific; symbiont in the mantle cavity of mollusks and the cloaca of sea cucumbers; see Campos et al. 1992, Proc. Biol. Soc. Wash. 105: 753-759; Campos et al. 1998, Proc. Biol. Soc. Wash. I l l : 372-381 (taxonomy and distribution); Hopkins and Scanland 1964, So. Calif. Acad. Sci. Bull 63: 85-88 (hosts). Parapinnixa afftnis Holmes. 1940. In tubes of polychaetes Terebella californica and Loimia; see Glassell 1933, Trans. San Diego Soc. Nat. Hist. 7: 319-330; Berkeley and Berkeley 1941, So. Calif. Acad. Sci. Bull. 40: 16-60; Campos et al. 1992, Proc. Biol. Soc. Wash. 105: 753-759. Pinnixa barnharti Rathbun, 1918. A southern species; an obligated symbiont of the sea cucumber Caudina arenicola. See Campos et al. 1998, Proc. Biol. Soc. Wash. I l l : 372-381 (taxonomy and distribution). Pinnixa faba (Dana, 1851). Predominantly a symbiont of clams; it prefers the gaper clams Tresus capax and T. nuttallii; see Pearce 1966, pp. 565-589, in H. Barnes ed. Some contemporary studies in marine science. Allen & Unwin, London. Pinnixa franciscana Rathbun, 1918. Adults recorded from the burrows of Urechis caupo, and the ghost shrimps Neotrypaea californiensis, N. gigas and Upogebia pugettensis; juveniles inhabit the tubes of polychaetes; see Garth and Abbott (1980).

Pinnixa littoralis Holmes, 1894. In the mantle cavity of clams; prefers the gaper clam Tresus capax; see Pearce 1965, Veliger 7: 166-170; Campos-González 1986, Veliger 29: 238-239. Pinnixa longipes (Lockington, 1877). Common in sandy sediments in tubes of the polychaete worms Axiothella rubrocincta, Pectinada californiensis, and Pista elongata, and occasionally in burrows of Urechis caupo; see Garth and Abbott (1980). Pinnixa occidentalis Rathbun, 1893. A northern species, in burrows of the echiuran Echiurus sp., and free-living; may represent a species complex; see Zmarzly 1992, J. Crust. Biol. 12: 677-713; Martin and Zmarzly 1994, Proc. Biol. Soc. Wash. 107: 354-359; Campos et al. 1998, Proc. Biol. Soc. Wash. I l l : 372-381. Pinnixa scamit Martin and Zmarzly, 1994. See Martin and Zmarzly 1994, Proc. Biol. Soc. Wash. 107: 354-359 (taxonomy and distribution); Campos et al. 1998 Proc. Biol. Soc. Wash. I l l : 372-381. Pinnixa schmitti Rathbun, 1918. Adults in the burrows of Urechis caupo and the ghost shrimps Neotrypaea californiensis, N. gigas and Upogebia spp.; see Zmarzly 1992, J. Crust. Biol. 12: 677-713 (taxonomy and distribution); Garth and Abbott (1980). Pinnixa tomentosa Lockington, 1876. In tubes of chaetopterid, onuphid and terebellid polychaete worms; see Scanland and Hopkins 1978, Proc. Biol. Soc. Wash. 91: 636-641. Pinnixa tubicola Holmes, 1894. Heterosexual pairs occur in tubes of large polychaete worms, particularly terebellids and chaetopterids; see Zmarzly 1992, J. Crust. Biol. 12: 677-713. Pinnixa weymouthi Rathbun, 1918. Nothing is known of the biology or symbiotic relationships of this species. Scleroplax granulata Rathbun, 1893. Common in burrows of the echiuran Urechis caupo and the ghost shrimps Neotrypaea californiensis, N. gigas, Upogebia pugettensis, and U. macginitieorum; see Garth and Abbott 1980; Campos 2006, Zootaxa, 1344: 33-41 (systematics and distribution). CANCRIDAE

Juvenile Cancer species under 20 mm are not readily distinguished using the key. See Schmitt (1921) for a key to the small specimens. See Nations 1975 Los Angeles Co. Mus. Natur. Hist. Sci. Bull. 23: 1-104, Schweitzer and Feldmann (2000) (systematics, biogeography, fossil record). Cancer antennarius Stimpson, 1856. Pacific rock crab; lower intertidal, common in subtidal; partially imbedded in sand among rocks; protected and semiprotected coast, as well as in bays; often encrusted; common. Iphitimid polychaetes recorded from branchial cavity in southern California (Pilger 1972, Bull. So. Calif. Acad. Sci 70: 84-87). With Cancer anthonyi and Cancerproductus it supports a rock crab fishery in southern California. Cancer anthonyi Rathbun, 1897. Yellow rock crab; low intertidal; under rocks, common in subtidal; in bays. Cancer branneri (Rathbun, 1926) (=Cancer gibbosulus [De Haan, 1835]). A small species (reaching about 35 mm in width) that may be mistaken for young Cancer antennarius (the granules on the carapace in branneri are in scattered groups; in antennarius crowded); rare in intertidal; in bays on shelly gravel; subtidal. Cancer gracilis Dana, 1852. Graceful crab; intertidal to sublittoral on sandy shores; megalops and post-larval instars phoretic on scyphozoan medusae. Cancer jordani Rathbun, 1900. Hairy rock crab; low intertidal and subtidal in bays; uncommon, under rocks and in holdfasts. Cancer magister Dana, 1852. Dungeness crab; generally offshore on sandy bottoms; occasionally inshore, juveniles in bay

and estuary nurseries; support an important fishery see Armstrong et al. 1995, Fish. Bull. 93: 456-470; Hobbs et al. 1992, Can. J. Fish. Aq. Sci. 49: 1379-1388; Paul et al. 2002, Univ. Alaska Sea Grant Coll. Rpt.; Wild et al. 1983, Calif. Dept. Fish and Game Fish Bull.; suffers substantial brood mortality from the symbiotic nemertean egg predator, Carcinonemertes errans (see Wickham 1978, Proc. Biol. Soc. Wash. 91:197-202). Cancer oregonensis (Dana, 1852). Lower intertidal; semiprotected rocky coast, under well-embedded rocks; rare south of Oregon. Cancer productus Randall, 1840. Red rock crab; under rocks of semiprotected outer coast; also in bays, under rocks or partly buried in sand and mud; active nocturnally; common. Juveniles highly variable in color and pattern (from white to red and brown with spots and stripes or vermiculations; all gradually grow towards a uniform brick red color through successive molts. See Boulding and LaBarbera 1986, Biol. Bull. 171: 538-547 (repeated claw pressure (loading) at the same location on shells facilitates predation on the clam Leukoma staminea); Robles et al. 1989, J. Nat. Hist. 23: 1041-1049 (diel variation in intertidal foraging). CHEIRAGONIDAE

Telmessus cheiragonus (Tilesius, 1815). Helmet crab; northern, subtidal, rarely low intertidal. PORTUNIDAE

Callinectes sapidus Rathbun, 1896. The Atlantic blue crab; low intertidal to shallow subtidal; will swim in the water column; very aggressive. Occasional specimens are found in San Francisco Bay. May be confused with Callinectes bellicosus, C. arcuatus, or Portunus xantusii, southern species which may reach central California when there is a strong El Niño. Carcinus maenas (Linnaeus, 1758). European green or shore crab; low intertidal and shallow subtidal; introduced to San Francisco Bay in early 1990s, population exploded and geographic range extended north to British Columbia in just 10 years; a voracious predator, it has caused substantial declines in the abundance of native crabs and clams in Bodega Harbor; see Grosholz and Ruiz 1995; Grosholz 2005, Proc. Natl. Acad. Sci. 102: 1088-1091 (fisheries and aquaculture). The native symbiotic nemertean egg predator, Carcinonemertes epialti, now also infests green crabs (Torchin et al. 1996, J. Parasitol. 83: 449-453), threatens fisheries and aquaculture. Young crabs are variable in color and gradually grow toward the greenish adult color through successive molts. Rapidly growing crabs are yellow or green on the underside, while slow growing crabs are orange to red. See Cohen et al. 1995, Mar. Biol. 122: 225-237 (introduction to California); Lafferty and Kuris 1996, Ecol. 77: 1889-2000 (potential for biological control); Jensen et al. 2002, Mar. Ecol. Prog. Ser. 225: 251-262 (competition with Hemigrapsus); Behrens, Yamada, and Hunt 2000, Dreissena 11: 1-7 (introduction to Pacific Northwest); Carlton and Cohen 2003, J. Biogeog. 30: 1809-1820 (global distribution). XANTHIDAE

See Knudsen 1957, Bull. So. Calif. Acad. Sci. 56: 133-142 (molting); 1959, Wasmann J. Biol. 17: 9-104 (autotomy and regeneration); 1959, Ecology 40: 113-115 (shell formation and growth); 1960, Ecol. Monogr. 30: 16-185 (ecology). EUCARIDA: DECAPODA

653

Cycloxanthops novemdentatus (Lockington, 1877). Low intertidal under rocks in gravel and shell substrate; usually rare north of Point Conception, locally common south of Monterey. Active and aggressive for a xanthid. See Knudsen 1960, Bull. So. Calif. Acad. Sci. 59: 1-8 (life cycle). Paraxanthias taylori (Stimpson, 1860). Lower intertidal; protected outer coast, under well-impacted rocks; rare north of Point Conception. See Knudsen 1959, Bull. So. Calif. Acad. Sci. 58: 138-145 (life history). PANOPEIDAE

Like most xanthids, panopeids are slow-moving, inactive crabs that "play dead" when handled. For taxonomy of Lophopanopeus species, see Menzies 1948. Lophopanopeus bellus (Stimpson, 1860). Intertidal under rocks; stones of protected and unprotected coast; see Menzies 1948, Allan Hancock Found. Pubis. Occ. Pap. 4, 45 pp. (taxonomy). See Knudsen 1959, Bull So. Calif. Acad. Sci. 58: 57-64 (life cycle). Lophopanopeus leucomanus Lockington, 1876. Intertidal in coarse sand under rocks and in surfgrass roots; see Menzies 1948, above. See Knudsen 1958, Bull So. Calif. Acad. Sci. 57: 51-59 (life cycle). Rhithropanopeus harrisii (Gould, 1841). Mud crab; introduced from Atlantic coast; common to abundant in sloughs, estuarine habitats with mud banks in San Francisco Bay, as well as Coos Bay and other estuaries in Oregon. ANOMURA,

GALATHEOIDEA

BLEPH ARIPODIDAF,

Blepharipoda occidentalis Randall, 1840. Spiny mole crab; low intertidal; more common sublittorally; exposed sandy beaches; filter feeders. Important sea-otter food. The small clam Mysella pedroana is commonly attached in the gill chamber (Carpenter 2005, Nautilus 119: 105-108). See Knight 1968, Proc. Calif. Acad. Sci. (4) 35: 337-370 (larval development, distribution, ecology.); Dugan et al. 2000, J. Exp. Mar. Biol. Ecol. 255: 229-245 (burrowing abilities and swash behavior); Kreuder et al. 2003, J. Widl. Dis. 39: 495-509 (parasites); Boyko 2002, Bull. Amer. Mus. Natl. Hist. 272 (systematics, literature).

LITHODIDAE

Cryptolithodes sitchensis Brandt, 1853. Umbrella crab; low intertidal to subtidal; in crevices, on sponges; algae; color widely variable. Hapalogaster cavicauda Stimpson, 1859. Low intertidal of protected rocky coast; under rocks and in deep crevices; uncommon. Oedignathus inermis (Stimpson, 1860). Exposed and semiprotected rocky coasts; deep in old pholad bore holes, sea urchin holes, or on rock crevices; uncommon, infrequently seen because habitat is inaccessible. Phyllolithodes papillosus Brandt, 1849. Juveniles rare under low intertidal rocks, adults subtidal. Lopholithodes foraminatus (Stimpson, 1859). Box crab; very low intertidal; juveniles rare under rocks. Lopholithodes mandtii Brandt, 1845. Very low intertidal; juveniles under rocks.

GALATHEIDAE PORCELLANIDAE

Pleuroncodes planipes Stimpson, 1860. Pelagic red crab; sometimes beached in vast swarms from Monterey south, more common in El Niño years; for occurrence, biology, and fisheries, see Kato 1974, Mar. Fish. Rev. 36: 1-9; Gomez, G. J. and Sanchez 1997, Bull. Marine Sci. 61: 305-326.

ANOMURA, HIPPOIDEA (MOLE AND SAND CRABS)

HIPPIDAE

Emérita analoga (Stimpson, 1857). Pacific sand crab; intertidal of exposed sandy beaches; abundant but distribution patchy; moves up and down beach with tidal cycle, burrowing to depth of several centimeters when tide is out; regularly found south of Oregon; larvae long-lived in some years they settling in great numbers on outer beaches north to Vancouver Island and sometimes even Alaska. Commonly serving as an intermediate host for bird acanthocephalans, (Polymorphus spp.). Important food source for shorebirds. See Dugan et al. 2000 (see above); Jaramillo et al. 2000 Mar Ecol-PSZNI 21: 113-127 (abundance, population structure, burrowing rate); Barron et al. 1999, Bull. Environ. Contam. Toxicol. 62: 469-475 (sensitivity to weathered oil).

ALBUNEIDAE

Lepidopa califomica Efford, 1971. A southern California mole crab; low intertidal and subtidal of sandy beaches; filter feeders. See Dugan et al. 2000 (above) and Boyko 2002 (above). 654

ARTHROPODA

Porcelain crabs are filter feeders; they readily autotomize their claws and legs and are positively thigmotactic; see Haig (1960, Allan Hancock Pac. Exped. 24, 440 pp.) for detailed descriptions and systematics; Stillman and Somero 2000, Physiol. Biochem. Zool. 73: 200-208 (physiology); Stillman and Somero 1996, J. Exp. Biol. 199: 1845-1855 (morphology); Stillman and Reeb 2001, Mol. Phylo. Ecol. 19: 236-245 (molecular phylogenetics). Pachycheles holosericus Schmitt, 1921. A southern species; low intertidal, embedded in sponges. Pachycheles pubescens Holmes, 1900. Low intertidal; rocky areas. Pachycheles rudis Stimpson, 1859. Low intertidal; semiprotected rocky coast; adults live in permanent pairs, often trapped in old pholad bore holes, and in concavities of Laminaria and Egregia holdfasts, also under rocks, on wharf pilings; a bopyrid isopod (Aporobopyrus muguensis) may occur in branchial cavity reducing fecundity by about 50% (Van Wyk 1982, Parasitol. 85: 459-473). Petrolisthes cabrilloi Glassell, 1945. Southern species; under rocks and cobble habitats and in mussel beds. Frequently infected with the rhizocephalan barnacle parasitic castrator, Lernaeodiscus porcellanae (Hoeg and Lutzen 1995, Ocean. Mar. Biol. Ann. Rev. 33: 427-485). See Kropp 1981, Crustaceana 40: 307-310 (deposit feeding). Petrolisthes cinctipes (Randall, 1840). Mid- and upper intertidal of exposed protected; semiprotected rocky coast, under rocks in mussel beds; often abundant, replaced to the south by P. cabrilloi, see Wicksten 1973, Bull. So. Calif. Acad. Sci. 72:

161-163 (feeding); Donahue 2004, Mar. Ecol. Prog. Ser. 2004, Mar. Ecol. Prog. Ser. 267: 196-207 (competition). Petrolisthes eriomerus Stimpson, 1871. Mid-intertidal of protected rocky coasts; bays, under rocks over gravel substrates; also in eelgrass and kelp holdfast can occur in sandier habitats than P. cinctipes; the rhizocephalan Lemaeodiscus porcellanae has been reported from specimens from southern California. Petrolisthes manimaculis Classell, 1945. Low intertidal under rocks; females and juveniles often closely resemble P. eriomerus. Petrolisthes rathbunae Schmitt, 1921. A southern species, under stones, rarely subtidal, low intertidal under rocks and in crevices. ANOMURA, PAGUROIDEA (HERMIT CRABS)

See McLaughlin and Fisher (1974) for systematics. DIOGENIDAE (LEFT-HANDED HERMIT CRABS)

Isocheles pilosus (Holmes, 1900). Moon snail hermit; found in low intertidal in sand on semiprotected beaches; often in moon snail shells; more common in subtidal. Paguristes ulreyi Schmitt, 1921. Furry hermit; low intertidal to subtidal; orange to brown covered with golden hairs. Paguristes bakeri (Holmes, 1900). In quiet waters over sand or mud; subtidal, rarely intertidal. Dark reddish brown, often in moon snail shells. PAGURIDAE (RIGHT-HANDED HERMIT CRABS)

See Elwood and Stewart 1985, Anim. Behav. 33: 620-627 (behavior of European hermit crab Pagurus bemhardus); Hazlett 1981, Ann. Rev. Ecol. Syst. 12: 1-22 (behavioral ecology), Rittschof 1980, J. Chem. Ecol. 6: 103-118 (chemical attraction to simulated gastropod predation sites), Osorno et al. 1998, J. Exp. Mar. Biol. Ecol. 222: 163-173 (shell selection). Shells inhabited by hermit crabs usually become encrusted with a crabassociated biota (discussed in sections on intertidal parasites and commensals). See Williams and McDermott (2004) J. Exp. Mar. Biol. Ecol. 305: 1-128 for a review of these associations. Discorsopagurus schmitti (Stevens, 1925) Low intertidal and subtidal; in broken or attached worm tubes. Pagurus armatus (Dana, 1851). Low intertidal to subtidal; often in moonsnail shells encrusted with hydroids. Pagurus beringanus (Benedict, 1892). Low intertidal on rock jetties; sublittoral. Pagurus caurinus Hart, 1971. Rare; a northern species found in protected waters. Pagurus granosimanus (Stimpson, 1859). Exposed and semiprotected outer coast; lower intertidal pools; common. Pagurus hemphilli (Benedict, 1892). Mid to low intertidal. Pagurus hirsutiusculus (Dana, 1851). Mid intertidal of rocky coast; common; in bays, under rock cover; tide pools, coarse sand to gravel substrates; uses a variety of shells, frequently unable to fully withdraw into its shell. Pagurus ochotensis Brandt, 1851. Low intertidal to subtidal over sandy or softer bottoms; often in moon snail shells. Pagurus quaylei Hart, 1971. In gravelly areas; shallow water; see Hart 1971, J. Fish. Res. Bd. Canada 28: 1527-1544. Pagurus samuelis (Stimpson, 1857). Rocky coasts; mid to lower tidepools, abundant, usually in turban shells, behaviorally dominant in shell exchanges to P. hirsutiusculus; occasionally in coarse substrates in bays.

THALASSINIDEA UPOGEBIIDAE (MUD SHRIMP)

Upogebia pugettensis (Dana, 1852). Blue mud shrimp; mid- to lower intertidal of bays; and occasionally on outer coast in protected areas, such as at Cape Arago, Oregon. Locally common; builds D- or Y-shaped burrows, replaced south of Pt. Conception by Upogebia macginitieorum Williams, 1986, a white, less robust species (see Williams 1986, Mem. San Diego Soc. Natl. Hist. 14: 1-60 for taxonomy, morphology); firm-walled burrows in mud or muddy sand; commensals include Betaeus, Hesperonoe, the clam Cryptomya califomica, pinnotherids, copepods, and the phoronid Phoronis pallida; the isopod Phyllodurus abdominalis and the clam Neaeromya rugifera may both occur on the abdomen; the parasitic castrator isopod, Orthione griffenis Markham 2004, can attain high prevalence; see MacGinitie 1930, Amer. Midi. Nat. (10) 6: 36-44 (natural history); Powell 1974, Univ. Calif. Publ. Zool. 102: 1—41 (gut morphology of Upogebia and Neotrypaea); Griffen et al. 2004, Mar. Ecol. Prog. Ser. 269: 223-236 (bioturbation); Santagata 2004, Biol. Bull. 207: 103-115 (behavioral cues). CALLIANASSIDAE (GHOST SHRIMP)

See Manning and Felder 1991, Proc. Biol. Soc. Wash. 104: 764-792 (taxonomic revision of family, including the new genus Neotrypaea). See Sakai 2005, Callianassoidea of the World (Decapoda, Thalassinidea). Crustaceana, Monographs Volume 4, 200 pp. Neotrypaea biffari (Holthuis, 1991). Tidepool ghost shrimp; pools under rubble on outer coast; paired, usually in turn with a pair of blind gobies, Typhlogobius califomiensis. Neotrypaea californiensis (Dana, 1854) (=Callianassa californiensis) Bay ghost shrimp; burrowing in mud or sand of upper to mid-intertidal in bays; often covering large areas of intertidal flats; locally abundant; burrows with poorly defined walls; commensals include shrimp Betaeus spp., polynoid worms, various pinnotherid crabs, copepods (Hemicyclops and Clausidium), and the goby Clevelandia ios; the parasitic castrator bopyrid isopod, lone, may occur in gill chamber. See Hoffman 1981, Pac. Sci. 35: 211-216 (association with Clevelandia); Labadie and Palmer 1996, J. Zool. 240: 659-675 (claw dimorphism); Feldman et al. 1997, Mar. Ecol. Prog. Ser: 150: 121-136 (recruitment), Lau et al. 2002, Microbial Ecol. 43: 455^466 (digestive bacteria). Bioturbation by ghost shrimps is a very serious problem for oyster mariculture; sediment suspended by these shrimp alters water quality and can foul oyster gills (Dumbauld et al. 2004, pp. 53-61, and DeWitt et al. 2004, pp. 107-118, both in: Proc. Symp. Ecology Large Bioturbators in Tidal Flats and Shallow Sublittoral Sediments. Nagasaki University). Neotrypaea gigas (Dana, 1852); Giant ghost shrimp; low to subtidal; rare, burrowing in sand; builds deep burrows. More common south of Pt. Conception. The rostral distinction between N. gigas and N. californiensis is noted in the keys; a further character that distinguishes these species is the nature of the second pereopod: in N. californiensis, the propodus and dactyl of the second pereopod is approximately equal (plate 326G), whereas in N. gigas, the propodus of the second pereopod is curved and wider than the dactyl (plate 326H). REFERENCES Boyko, C. B. 2 0 0 2 . A worldwide revision of the Recent and fossil sand crabs of the Albuneidae Stimpson and Blepharipodidae, new family (Crustacea: Decapoda: Anomura: Hippoidea). Bulletin of the American Museum of Natural History, number 272, 3 9 6 pp. EUCARIDA: DECAPODA

655

Chace, F. A. 1951. The grass shrimp of the genus Hippolyte from the west coast of North America. J. Wash. Acad. Sci. 41: 35-39. Chang E. S., M. J. Bruce, and S. L. Tamone 1993. Regulation of crustacean molting: a multi-hormonal system. Am. Zool. 33: 324-329. Clayton, D. A. 1990. Crustacean allometric growth: A case of caution. Crustaceana 58: 270-290. Culver, C. S., and A. M. Kuris. 2001. Sheep Crab, pp 115-117. In California living marine resources: a status report. W. S. Leet, C. M. Dewees, R. Klingbiel, and EJ. Larsen, eds. Univ. Calif. ANR Publ. #SG01-11. DeWitt, T. H„ A. F. D'Andrea, C. A. Brown, B. D. Griffen, and P. M. Eldridge. 2004. Impact of burrowing shrimp populations on nitrogen cycling and water quality in western North American temperate estuaries, pp. 107-118. In: Proceedings of the Symposium on Ecology of Large Bioturbators in Tidal Flats and Shallow Sublittoral Sediments—from individual behavior to their role as ecosystem engineers. Nagasaki University. Dumbauld, B., K. Feldman and D. Armstrong. 2004. A comparison of the ecology and effects of two species of thalassinidean shrimps on oyster aquaculture operations in the eastern North Pacific, pp. 53-61. In: Proceedings of the Symposium on Ecology of Large Bioturbators in Tidal Flats and Shallow Sublittoral Sediments from individual behavior to their role as ecosystem engineers. Nagasaki University. Elwood R.W., and A. Stewart 1985. The timing of decisions during shell investigation by the hermit crab, Pagurus bernhardus. Anim. Behav. 33: 620-627. Haig, J. 1960. The Porcellanidae (Crustacean, Anomura) of the eastern Pacific. Allan Hancock Pac. Exped. 24, 440 pp. Hart, J. F. L. 1964. Shrimps of the genus Betaeus on the Pacific coast of North America with descriptions of three new species. Proc. U.S. Nat. Mus. 115: 431-466. Hartnoll, R. G. 1985. Growth, pp. 111-196. In: The Biology of Crustacea v. 2. L.G. Abele (ed.) Hazlett, B. A. 1981. The behavior ecology of hermit crabs. Ann. Rev. Ecol. Syst. 12: 1-22. H0eg, J. T., and J. Lutzen. 1995. Life cycle and reproduction of the Cirripedia Rhizocephala. Oceanography and Marine Biology Annual Review 33: 427-85. Iguchi and Ikeda. 2004. Vertical distribution, population structure and life history of Thysanoessa longipes (Crustacea: Euphausiacea) around Yamato Rise, central Japan Sea. J. Plankton Res 26: 1015-1023. Jensen, G. C. 1995. Pacific Coast Crabs and Shrimps. Sea Challengers, Monterey, 87 pp. Kozloff, E. 1987. Marine Invertebrates of the Pacific Northwest. University of Washington Press: Seattle and London, 511 pp. Kuris, A. M., and J. T. Carlton. 1977. Description of a new species, Crangon handi, and new genus, Lissocrangon, of crangonid shrimps (Crustacea: Caridea) from the California coast, with notes on adaptation in body shape and coloration. Biol. Bull. 153: 540-559. Kuris A. M., G. O. Poinar, R. Hess, and T. J. Morris. 1979. Virus particles in an internal parasite, Portunion conformis (Crustacea: Isopoda: Entoniscidae), and its marine crab host, Hemigrapsus oregonensis. J. Invert. Path. 34: 26-31. Kuris, A. M., G. O. Poinar, and R. Hess. 1980. Mortality of the internal isopodan parasitic castrator, Portunion conformis (Epicaridea, Entoniscidae), in the shore crab Hemigrapsus oregonensis with a description of the host response. Parasitology 80: 211-232. Kuris, A. M, Z. Ra'anan, A. Sagi, and D. Cohen. 1987. Morphotypic differentiation of male Malaysian giant prawns, Macrobrachium rosenbergii. J. Crust. Biol. 7: 219-237. MacGinitie, G. E. 1937. Notes on the natural history of several marine Crustacea. Amer. Midi. Nat. 18: 1031-1037. Martin, J. W., and G. E. Davis. 2001. An updated classification of the recent crustacea. Natural History Museum of Los Angeles County Sci> ence Series 39: 1-124. McLaughlin, J., and L. R. Fisher. 1974. The hermit crabs (Crustacea: Decapoda: Paguridea) of northwestern North America. Zool. Verhandel. No. 130, 396 pp. McLaughlin, J. et al. 2005. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Crustaceans. American Fisheries Society Special Publication 31: 1-325. Passano, L. M. 1960. Molting and its control. In The physiology of crustacea, T. H. Waterman, ed., Vol. 1, Chap. 15, pp. 473-536. Academic Press. Rittschof, D. 1980. Chemical attraction of hermit crabs and other attendants to simulated gastropod predation sites. J. Chem. Ecol. 6: 103-118. 656

ARTHROPODA

Schmitt, W. L. 1921. The Marine Decapod Crustacea of California. Univ. Calif. Publ. Zool. 23: 470 pp. Schweitzer, C. E., and R. M. Feldman. 2000. Re-evaluation of Cancridae Latreille, 1802 (Decapoda: Brachyura) including three new genera and three new species. Contrib. Zool. 69: 1-36. Shields, J. D., and A. M. Kuris. 1988. Temporal variation in abundance of the egg predator Carcinonemertes epialti (Nemertea) and its effect on egg mortality of its host, the shore crab, Hemigrapsus oregonensis. Hydrobiologia 156: 31-38. Skinner D. M. 1985. Molting and Regeneration In D. E. Bliss and L. H. Mantel (eds.), The Biology of Crustacea, pp. 43-146. Academic Press, New York. Teissier, G. 1960. Relative growth. In The Physiology of Crustacea, T. H. Waterman, ed., Academic Press. Vol. 1, Chap. 16, pp. 537-560. Torchin M. E., K. D. Lafferty, and A. M. Kuris. 1996. Infestation of an introduced host, the European green crab, Carcinus maenas, by a native symbiotic nemertean egg predator, Carcinonemertes epialti. J. Parasitol. 83: 449-453. Versulis, M., B. Schmitz, A. von der Heydt, and D. Lohse. 2000. How snapping shrimp snap: through cavitating bubbles. Science 289: 2114-2117. Vogel, S. 1988. Life's Devices: The Physical World of Animal and Plants. Princeton Univ. Press. Princeton, New Jersey. Wicksten, M. K. 1978. Attachment of decorating materials in Loxorhynchus crispatus (Brachyura: Majidae). Trans. Amer. Micr. Soc. 97: 217-220. Wicksten, M. K. 1980. Decorator crabs. Sci. Amer. 242: 146-154. Wicksten, M. K., and M.D. Behrens 2000. New record of the pelagic crab Planes cyaneus in California (Brachyura: Grapsidae). SCAMIT newsletter 19(5): 7.

Pycnogonida C. ALLAN CHILD AND JOEL W. HEDGPETH (Plates 3 2 7 - 3 3 2 )

The Class Pycnogonida are exclusively marine invertebrates found in all oceans at all depths. Identification of most genera usually relies o n the presence or absence of appendages or reduction of their segment numbers. They have a central linear body or trunk that often has visible segmentation and contains the internal circulatory system, the nervous system, and the gut, parts of w h i c h extend into each leg. The trunk has four paired lateral processes (rarely five or six pairs in non-California and non-Oregon species) each carrying a leg. The anterior or cephalic segment of the trunk carries most of the other appendages: a dorsal ocular tubercle (sometimes lacking) with four eyes or blind and a pair of chelifores that consists of one, two, or three segments and are fully chelate to entirely lacking among the wealth of more than 1 , 2 0 0 species. The cephalic segment also has a pair of tactile palps that have from one to nine segments or are absent; the first pair of lateral processes; and an anterior suctorial proboscis that varies greatly in shape and size. A pair of ventral ovigers, which are unique to pycnogonids, are also born on the cephalic segment. The ovigers consist of 10 segments, less in some genera, and are believed to be modified legs that males use to carry eggs passed by the females. The ovigers sometimes have a distal strigilis (a shepherd's crook) used in some species by both sexes to clean appendages. The strigilis is armed with compound or simple spines and a terminal claw or no claw among the various genera. There are usually eight legs, which carry internal gonads along with gut diverticula. Each leg consists of eight segments: three short proximal coxae, a femur, two tibiae, a shorter tarsus, and a propodus. The propodus has a terminal claw and usually a pair of lateral auxiliary claws. The femur contains a cement gland in males only, exiting

PLATE 327 A diagrammatic pycnogonid (after Child).

through a single or multiple tube, pore, or sieve plate and used to cement the eggs together. The trunk has a small posterior abdomen that contains nothing but the anus. Identification of most pycnogonids does not require dissection or fancy preparation. A low-power dissecting microscope is usually all that is required to identify almost all California species. The few diagnostic appendage pairs are located on the cephalic segment. Their presence or absence can be determined under a microscope's low power. The number of appendage segments and claw lengths might require slightly higher magnification. Specimens should be stored in the same preservatives as for Crustacea. Our shallow waters are known to contain five of the nine families, 12 of the 80 genera, and 29 of the more than 1,200 known species of Pycnogonida. Several of the following species are found in the sublittoral as well as littoral habitats. There are many more pycnogonid species and genera found in deeper waters off California and Oregon.

Ammotheidae This is the most heterogeneous family among the pycnogonids; the ammotheids contain more species and genera than any other family. Chelifores are usually present (see generalized pycnogonid, plate 327) in each species. They can be fully chelate, with chelae atrophied, or with chelae lacking or with-

out chelifores entirely. Their palps are one- to 10-segmented. Ovigers are nine- to 10-segmented, found in both sexes but larger in males, and all known local species lack a functional strigilis. Six genera are known in our shallow waters.

ACHELIA Genus size small to very small, leg span usually < 1 0 mm; trunk circular or ovoid; lateral processes compact, touching or nearly so, often with distal tubercles and a few setae or spines. Ocular tubercle usually low, eyes present, usually prominent as befits shallow-water species. Abdomen often carried horizontally. Chelifore scapes of one segment; chelae almost always atrophied, without fingers. Palps with seven to nine segments, usually eight, with four or five short distal segments. Ovigers with denticulate or plain spines on pseudostrigilis (merely a curve in the strigilis), without a terminal claw. Leg segments short, propodus with strong heel spines, robust claw and usually long auxiliary claws. One dorsodistal cement gland pore. Seven known species along this coast.

KEY TO ACHELIA SPECIES 1. —

Chelae atrophied to fingerless bumps in adults Adult chelae fully formed (plate 328A) Achelia

2 chelata

PYCNOGONIDA

657

Achelia

A

chetata

PLATE 328 A, Achelia chetata; B, Achelia simplissima; C, Achelia gracilipes; D, Achelia spinoseta; E, Achelia echinata; F, Achelia alaskensis; G, Ammothea hilgendorfi (A, after Hedgpeth; B, D, after Child; C, F, after Cole; E, after Sars; G, after Nakamura).

E

2.

Achelia

echinata

W i t h conspicuous dorsal tubercles o n distal lateral processes, chelifores, and/or first coxae; palps eight-seg-

AMMOTHEA

mented 3 Without conspicuous tubercles o n lateral processes, chelifores, coxae; palps seven-segmented (plate 3 2 8 B )

5 Distal palp segments 5, 6, and 7 with ventral projections, eighth segment club-shaped (plate 3 2 8 D )

There is a single known California species, Ammothea hilgendorfi (plate 3 2 8 G ) . Trunk without dorsomedian tubercles, fully segmented, posterior segment sometimes faint, ocular tubercle a low broad c o n e with large eyes, proboscis a long oval; lateral processes well separated, glabrous; chelifores one-segmented, short, chelae entirely lacking; palps nine-segmented, distal short segments oval; ovigers 10-segmented, without strigilis, distal three segments carried anaxially on seventh segment, with few tiny spines; legs moderately long, with few short spines, tarsus very short, propodus with heel, four to five large heel spines; claw robust, auxiliary claws well curved, half m a i n claw length. Cement gland a pore o n dorsodistal swelling proximal to tip of femora.

Lateral processes with two pointed dorsolateral tubercles, first and second coxae with four to five pointed tubercles

AMMOTHELLA

Achelia simplissima First coxae with paired or several tubercles all shorter than segment diameter 4 First coxae with single conspicuous dorsal tubercle longer t h a n segment diameter and two to three short lateral tubercles (plate 3 2 8 C ) Achelia gracilipes 4.

Distal palp segments 5, 6, and 7 ovoid, without projections

Achelia spinoseta

5.

each; ocular tubercle taller than wide (plate 328E)

Achelia echinata

Lateral processes with tiny tubercles, first coxae with two, second coxae with n o dorsal tubercles; ocular tubercle low, shorter t h a n wide (plate 328F) Achelia alaskensis 658

ARTHROPODA

Genus: Trunk with or without dorsomedian tubercles or other adornment; lateral processes often with large spines or dorsodistal tubercles; appendages often with long tubular or pointed spines; chelifore scapes with two segments, chelae atrophied

B

Ammothella

menziesi

PLATE 329 A, Ammothella biunguiculata; B, Ammothella menziesi; C, Ammothella tuberculata; D, Eurycyde spinosa; E, Nymphopsis spinosissima; F, Nymphopsis duodorsospinosa (A, D, E, F, after Child; B, Hedgpeth, original; C, after Cole).

F

Nymphopsis

duodorsospinosa

E

Nymphosis

into bumps; palps nine-segmented; ovigers 10-segmented, without strigilis, distal segments with denticulate spines; legs usually setose, sometimes heavily, tarsus short, propodus usually quite long, with large heel spines; claw robust, auxiliaries long. Cement gland outlet usually a long dorsodistal tube. Four species. KEY TO AMMOTHELLA SPECIES 1.

Trunk with spines or glabrous, without dorsomedian tubercles 2 — Trunk with large or small dorsomedian tubercles . . . . 3 2. Trunk with one to two dorsomedian spines per segment; trunk and lateral processes lacking tubular spines; ocular tubercle and abdomen long, erect; chelifore scape first segment shorter than second; palp distal three segments slender, twice longer than diameters; oviger usually with

spinosissima

denticulate spines on two distal segments only; cement gland opening on a long robust dorsodistal tube Ammothella spitiifera — Species much like Ammothea. Trunk without adornment, fully segmented, ocular tubercle a low cone, eyes small, abdomen moderately short; chelifores short, tiny; palp fifth to eighth segments with small ventral extensions; ovigers distal four segments with one to three denticulate spines each; legs typical except for propodus, which is straight, lacks larger heel and heel spines, bears robust auxiliary claws but lacks main claw; cement gland pore inconspicuous (plate 329A) Ammothella biunguiculata 3.

Trunk, lateral processes with short, rounded dorsal tubercles wider than tall, lateral processes crowded, touching; ocular tubercle little taller than wide; proboscis very wide, bulbous; chelifores short, scapes of equal length (plate 329C) Ammothella tuberculata PYCNOGONIDA

659

— Trunk with three tall, slender tubercles pointed anterior or posterior, lateral processes crowded, narrowly separated, with long or short distal tubercles; ocular tubercle three times taller than wide; proboscis narrow, ovoid; chelifores long, second segment longest (plate 329B) Ammothella menziesi EURYCYDE

There is a single known California species, Eurycyde spinosa (plate 329D). Trunk fully segmented, segment posteriors swollen, lateral processes crowded, almost touching. Ocular tubercle and abdomen very short, with group of spines toward tips of each. Proboscis of two sections, a short basal cylinder and distal slender pyriform process. Chelifore scapes slender, two-segmented; palps 10-segmented; ovigers with weak strigilis having a single row of denticulate spines and short terminal claw. Legs with very long spines each bearing spinules, tarsus short, propodus without major spines, main claw short, robust, auxiliaries lacking. Cement gland a bulge with distal tube proximal on side of femora. NYMPHOPSIS

Description of the two known California species: tuberculate, all tubercles with lateral and distal spines; trunk with dorsomedian tubercles; ocular tubercle, chelifore scapes, abdomen all tall; chelifore scapes two-segmented, chelae atrophied, carried within trumpet-shaped scape tip; palps nine-segmented; ovigers 10-segmented, without strigilis, with few distal denticulate spines; legs short, with tall tubercles on both tibiae, claw robust, auxiliaries minute. — Trunk with three tall dorsomedian tubercles; tibiae with fields of crowded dorsal tubercles (plate 329E) Nymphopsis spinosissima — Trunk with two tall dorsomedian tubercles; legs with few tall tubercles on tibiae (plate 329F) Nymphopsis duodorsospinosa TANYSTYLUM

Genus: trunk very tiny, unsegmented, lateral processes crowded, touching, forming circular shape, usually with small dorsolateral tubercles; proboscis usually short, tapering distally. Chelifores usually one-segmented stumps, chelae usually lacking. Palps four to seven segmented, short; oviger 10-segmented, with few denticulate or plain spines, without strigilis, most species with distal three oviger segments anaxial to enlarged seventh. Legs short, robust, major segments with dorsal bulges, tarsus short, propodus well curved, with heel spines, main claw robust, auxiliaries present. Cement gland outlet a dorsodistal pore or tiny tube. Three species are represented in the following key. Two Tanystylum species are not keyed below. T. duospinum is noted in the species list. T. nudum Hilton, 1939, was inadequately described and cannot be identified with certainty. Its type specimen is lost. KEY TO TANYSTYLUM

1.

660

SPECIES

Chelifores lacking any form of chelae, scape a onesegmented stump 2 ARTHROPODA

—

Chelifores with chelae retained as knobs; short lateral processes with large dorsal tubercle matching three on first coxae; proboscis narrow, pyriform; palp seven-segmented, short; leg segments elongate; cement gland tube on dorsodistal tubercle (plate 330A) Tanystylum intermedium 2. Trunk very compact, without tubercles, abdomen erect, placed toward anterior, not extending as far as first coxa, proboscis short, distally rounded; palps four-segmented; oviger with few plain setae, without anaxial placement of distal segments; legs typical, auxiliary claws half main claw length (plate 330B) Tanystylum occidentalis — Trunk less compact, with low paired lateral process tubercles, abdomen with basal bulge, carried more horizontally, extending to first coxae, proboscis longer, tapered, styliform; palps six-segmented; oviger distal three segments placed anaxially on seventh; legs more robust, stout, auxiliary claws very short, only 0.2 main claw length (plate 330C) Tanystylum califomicum

Rhynchothoracidae This is a family with a single genus of peculiar species, some of which have repeatedly been found in beach sand, sometimes at considerable depth (1 + m). Their structure is usually adapted for this interstitial form of living in that most species (but not all) lack protruding tubercles and major spines and setae. Perhaps the few species with long tubercles have a different habitat. Several species have a low eye tubercle (some lack both tubercle and eyes) and dorsomedian tubercles that slightly protrude but apparently do not hinder progress among sand grains. All species are among the smallest pycnogonids and rarely have leg spans greater than 4-5 mm. The proboscis extends out in the same flat plane as the trunk and usually has three anterior lips rather than a circular oral surface. Chelifores are lacking in adults. The short palps have three to five segments and originate on lateral extensions of the cephalic segment, which in the past were often considered an additional segment. The 10-segmented ovigers are very reduced in size, lack a strigilis, and have a peculiar large terminal segment bearing a row of tiny spines opposing a terminal claw that is carried laterally. Leg segments are usually short with the propodus longer than the second tibia. The tarsus is short, propodus well curved, claw robust, and with or without auxiliaries.

RHYNCHOTHORAX

There is one species in our range, Rhynchothorax philopsammum (plate 330D) Trunk dorsally compressed, fully segmented, lateral processes shorter than their diameters, with small anterior and posterior tubercles. Cephalic segment with small paired tubercles at anterior and lateral corners; ocular tubercle and eyes lacking; proboscis ovoid, tapering distally; abdomen short, a truncate cone; palps four-segmented with low dorsodistal tubercle on third, fourth upturned. Oviger distal segments with one to two lightly denticulate spines, terminal segment carried anaxially, terminal claw well curved, not as long as segment diameter. Cement gland outlet on legs unknown; in other species, where known, it is a single ventral tube or pore.

PLATE 330 A, Tanystylum intermedium; B, Tanystylum occidentalis; C, Tanystylum califomicum; D, Rhynchothorax philopsammum; E, Anoplodactylus compactus; F, Anoplodactylus califomicus (A, after Stock; B, after Cole; C, Child, original; D, after Hedgpeth; E, F, after Child).

F

Anoplodactylus

californicus

E

Anoplodactylus

Phoxichilidiidae A large family of mostly shallow-water species living for the most part in tropical-temperate habitats with few found in cold or deep waters. The trunks of species in this family have no tubercles or other decoration, are seldom fully segmented, and the lateral processes sometimes have rounded or conical dorsodistal tubercles. This family's additional characters include chelifores with full but small chelae; palps entirely lacking but species sometimes have palp "buds" on the first lateral process anteriors. They have ovigers carried only by males. The ovigers consist of six segments, although a few have only five. The leg has a short tarsus and a propodus with larger heel spines and often a variable length cutting lamina of tiny fused spines on the distal sole. Species of the genus Anoplodactylus have very tiny auxiliary claws on proximal sides of the main claw, while species of the genus Phoxichilidium have larger distal auxiliaries that are presumably functional, unlike the tiny lateral form. The cement

compactus

gland opening is dorsal and prominent, consists of one or more tubes, swollen or flat cups, slits, or pores of different sizes and shapes.

ANOPLODACTYLUS,

PHOXICHILIDIUM

Anoplodactylus contains the majority of species in the family and can be separated from the only other California genus, Phoxichilidium, by close examination of the propodus and its claws. The auxiliary claws in this genus are tiny, difficult to discern, and sometimes are lacking entirely. KEY TO ANOPLODACTYLUS PHOXICHILIDIUM

AND

SPECIES

1. Trunk with closely crowded lateral processes; neck and proboscis short, robust; palp buds appear as bumps lateral PYCNOGONIDA

661

PLATE 331 A, Anoplodactylus viridintestinalis; B, Anoplodactylus erectus; C, Anoplodactylus nodosus; D, Phoxichilidium femoratum; E, Phoxichilidium quadradentatum (A, C, after Child; B, Child, original; D, E, after Hedgpeth).

A Anoplodactylus

Anoplodactylus

to neck; propodal lamina as long or slightly less than entire sole, with large heel 2 — Trunk elongate, lateral processes well separated; neck moderately long, slender; palp buds lacking or not evident; propodal lamina very short, to less than half length of sole, heel small or lacking 3 2. Trunk ovoid in dorsal view, lateral processes less than twice longer than wide, each with broad rounded tubercle, ocular tubercle distally rounded, height equal to that of abdomen; oviger first segment twice wider than distal segments; cement gland a tiny pore on slightly raised bump, auxiliary claws robust (plate 330E) Anoplodactylus compactus — Trunk round in dorsal view, length of lateral processes twice their diameters, each with narrow conical tubercle, ocular tubercle with narrow distal cone, abdomen taller than cone; oviger first segment little wider than distal segments; cement gland a small truncate cone, auxiliary claws usually lacking or minute (plate 331A) Anoplodactylus viridintestinalis 662

ARTHROPODA

nodosus

Phoxichilidium

viridintestinalis

quadradentatum

Lateral process tubercles as tall or taller than wide; female proboscis without ventral adornment; second coxae with ventral tubercle shorter than segment diameter or lacking 4 Lateral process tubercles low, wider than tall; female proboscis with paired proximoventral alar processes; second coxae ventrodistal tubercle longer than segment diameter; femur with distal tubercle (plate 330F) Anoplodactylus californicus Lateral processes separated by less than their diameters; ocular tubercle with narrow apical cone; proboscis swollen at midlength; legs with many low bumps or nodes, second coxae lack ventral tubercle (plate 331C) Anoplodactylus nodosus Lateral processes separated by their diameters or more; ocular tubercle rounded at tip; proboscis cylindrical; legs smooth, second coxae of male with ventral tubercle shorter than coxal diameter (plate 331B) Anoplodactylus erectus Four to five major heel spines alternate laterally, auxiliary claws as long or slightly longer than main claw diameter at

PLATE 332 A, Anoropallene palpida; B, Callipallette califomiensis; C, Pycnogonum rickettsi; D, Pycnogonum stearnsi (A, B, D, after Child; C, after Schmitt).

C

Pycnogonum

rickettsi

D

Pycnogonum

their point of insertion; abdomen at least twice as long as its maximum diameter; lateral processes separated by more than their diameters (plate 331D) Phoxichilidium femoratum — Two major heel spines in single row, auxiliary claws very short, about half main claw diameter; abdomen only slightly longer than its diameter; lateral processes separated by less than their diameters (plate 33IE) Phoxichilidium quadradentatum

stearnsi

ment; proboscis short, tapering distally to narrow oral surface; chelifore scapes one-segmented, chelae with long fingers and teeth; palps four-segmented, little longer than proboscis, few long distal setae; ovigers 10-segmented, fifth segment longest, with distal lateral apophysis in males, strigilis with short denticulate spines, without claw; legs short, segments robust, tarsus very short, propodus short, with stout heel having two major spines bearing serrate anterior edges, claw short, without auxiliaries. Cement gland with several ventral tubes.

Callipallenidae This family is top heavy with more than 20 genera, only three of which occur in our waters. Family members have a fully segmented trunk, chelifores with large functional chelae, most of which have teeth, and nine- to 10-segmented ovigers in both sexes. The genera of this family often lack palps or have palps of reduced segment numbers only in the males. Sometimes the palp is represented by a bump having a single blunt segment, but not in any recorded California genera. The legs are variously short or long, usually do not have tubercles, and more of the genera lack auxiliary claws than have them. Cement glands are usually difficult to discern but sometimes are found as tiny ventral pores or tubes. ANOROPALLENE

One local species, Anoropallenepalpida (plate 332A). Trunk fully segmented, lateral processes well separated, without adorn-

CALLIPALLENE

One species in our range, Callipallene califomiensis (plate 332B). The genus is similar in habitus to Anoropallene, except that Callipallene species all lack palps in any form and have auxiliary claws. Ocular tubercle rounded at apex; chelae with seven to 10 well-formed blunt teeth; oviger bases large, round, crowding posterior of short neck; leg segments moderately short, propodus with many short endal and distal setae, main claw less than half as long as propodus.

Pycnogonidae This is probably the most advanced family of the pycnogonids in terms of reduction of appendage segments or complete loss of the appendage itself. The approximately 60 species of Pycnogonum lack chelifores, palps, and have small ovigers with reduced PYCNOGONIDA

663

segment numbers in the male only or they lack ovigers entirely. Some species' integument is finely reticulate with the entire animal embraced with m a n y fine lines of darker pigment. Other species have pebbled integument without reticulation. All species have the proboscis and abdomen carried horizontally, have short leg segments, and have short auxiliary claws or lack t h e m entirely. Most cement gland outlets have not been described, but scant evidence places t h e m ventrally o n a few species. Pycnogonum species are often f o u n d at t h e base of anemones o n which they presumably feed.

KEY TO PYCNOGONUM SPECIES — Integument fully reticulate with conspicuous lines; trunk with three conical mediandorsal tubercles taller than low ocular tubercle; proboscis with proximoventral swelling and uneven dorsal surface with bumps; lateral processes, first coxae, femora, and first tibiae with dorsodistal nodes or bumps; oviger nine-segmented, with small terminal claw, few tiny simple spines o n distal segments; propodus hardly curved, claw short, without auxiliaries (plate 332C) Pycnogonum rickettsi — Integument pebbled, without reticulations; trunk with swellings anterior to segmentation lines, with small dorsal tubercles; proboscis barrel-shaped, without bumps, swellings; lateral process tubercles low, inconspicuous; ovigers nine-segmented, with large terminal claw; legs without tubercles, femur with proximoventral swelling, propodus tapering distally, curved, without auxiliaries (plate 332D) Pycnogonum steamsi

LIST OF S P E C I E S

AMMOTHEIDAE Achelia alaskensis (Cole, 1904) (=Ammothea nudiuscula Hall, 1913). Described by Cole from Alaska, it occurs as far south as San Francisco; also in Japan, Korea, and Russian far east, mostly in t h e intertidal; also in bays, tolerating reduced salinities. Achelia chelata (Hilton, 1939) (=Ammothea chelata; Ammothea euchelata Hedgpeth, 1940 [redescription and plates]). Distribution very limited with a few intertidal localities confined to central California, including Moss Beach, and o n the bryozoan Bugula at Pescadero. Also in mussel beds and, in winter, in Mytilus califomianus (Benson and Chivers 1960 Veliger 3:16-18). Achelia echinata (Hodge, 1864). This far-ranging species was first collected in Europe and later in b o t h Atlantic and Pacific shallows. It is extremely variable and has several subspecific names. Achelia gracilipes (Cole, 1904) (=Ammothea gracilipes). A few shallow records from San Francisco to British Columbia. Achelia simplissima (Hilton, 1939). Most Achelia species, including this one, were designated as Ammothea until Achelia came into general use by the 1940s. This species is rare and only known by two syntypes from the central California coast. Redescribed by Child, 1996, Proc. Bio. Soc.Wash. 190: 679-681. Achelia spinoseta (Hilton, 1939). Known from only a unique type collected in shallows. Redescribed by Child, 1996, Proc. Biol. Soc. Wash. 109: 681-684. Ammothea hilgendorfi (Bohm, 1879) (=Comiger hilgendorfi; Lecythorhynchus hilgendorfi; L. marginatus Cole, 1904). This species is c o m m o n along shores and shallows of the Pacific Rim 664

ARTHROPODA

from California to Japan, China, and to t h e Society Islands. Among hydroids and in sheltered crevices; one of the characteristic species of the central California intertidal. See Russell and Hedgpeth, 1990. Ammothella biunguiculata (Dohrn, 1881). This variable species was given three subspecific names over m a n y years that are n o longer valid. It occupies subtidal habitats from California to Hawaii and Australia. Ammothella menziesi Hedgpeth, 1951. A rare species with only two records north of San Francisco. Ammothella spinifera Cole, 1904. This rather c o m m o n species is k n o w n f r o m southern California shores to Ecuador, t h e Caribbean, and Brazil. It is one of a few trans-Panamanian species known. Ammothella tuberculata Cole, 1904. This is one of only a few Ammothella species with dorsal trunk tubercles. Known from British Columbia to southern California shallows in a restricted distribution; the most c o m m o n pycnogonid of the surfgrass Phyllospadix holdfasts. Eurycyde spinosa Hilton, 1916. It has been k n o w n from southern California in most of its records but was lately collected afar in t h e Galapagos. Redescription: Child, 1992, Smiths. Contrib. Zool. 526: 17. Nymphopsis spinosissima (Hall, 1912) (=Ammothella spinosissima). Known only from the intertidal of the southern California coast, it is easily recognized by its three tall spinose trunk tubercles. Nymphopsis duodorsospinosa Hilton, 1942. There are only two tall spinose trunk tubercles o n this species, and the leg tubercles are clumped. It is known from South Carolina and the Gulf of Mexico to California and to the Galapagos Islands, mostly intertidal. Tanystylum califomicum Hilton, 1939. Infrequently collected; o n the hydroid Aglaophenia; k n o w n only from central and southern California. Its ocular tubercle arises o n a m o u n d and it has very tiny chelifore stumps. *Tanystylum duospinum Hilton, 1939. Similar to T. californicum, but smaller and less pigmented; palp 5-segmented; T. califomicum abdomen about as long as last pair of lateral processes, while T. duospinum abdomen is longer t h a n last pair of processes; see Child, 1996; Russell and Hedgpeth, 1990. On hydroids; larvae ectoparasitic on hydroid Orthopyxis everta. Tanystylum intermedium Cole, 1904. Known from Monterey Bay to Chile and the Galapagos in shallow depths, this is the only California species to retain chelifore stumps. Tanystylum occidentalis (Cole, 1904) (=Clotenia occidentalis). This rare species has a clean rounded appearance and its horizontal abdomen originates from a trunk swelling. Found in littoral habitats from Oregon to southern California. RHYNCHOTHORACIDAE Rhynchothorax philopsammum Hedgpeth, 1951. This frequently recorded species has a distribution that is almost pantemperate/pantropical. It was described from the intertidal of central California. It is very tiny and has slender legs spanning about 3 mm-4 mm. PHOXICHILIDIIDAE Anoplodactylus califomicus Hall, 1912 (=Anoplodactylus portus Caiman, 1927; A. robustus Hilton, 1939; A. carvalhoi Marcus, * = Not in key.

1940; A. projectus Hilton, 1942). The species has a pantropical/ pantemperate range and is one of the few species of the genus with female ventral proboscis outgrowths of unknown use. Anoplodactylus compactus (Hilton, 1939) (=Phoxichilidium compactum; Halosoma compaction Marcus, 1940). This tiny rare form has crowded lateral processes and a short proboscis. It has only been taken in three localities south of San Francisco. Figures and «description: Child 1975, Proc. Bio. Soc. Wash., 88: 191-193. Anoplodactylus erectus Cole, 1904. Occurs around the North Pacific Rim and at several Pacific island groups in littoral and shallow localities. Anoplodactylus nodosus Hilton, 1939. This species has been found only once at Santa Catalina Island but is easily recognized by its many leg outgrowths. Redescription and figures: Child 1975, Proc. Bio. Soc. Wash. 88: 193-196. Anoplodactylus viridintestinalis (Cole, 1904) (=Halosoma viridintestinalis). Common from central California to Panama in shallow depths. It is another species with crowded lateral processes and almost circular trunk dorsally. Common in Tomales Bay, where it may be the most abundant and characteristic sea spider of shallow, sheltered water, conspicuous by virtue of its bright green intestines that branch out to the legs. Phoxichilidium femoratum (Rathke, 1790) (=Phoxichilidium tubulariae Lebour, 1945). This often-taken species is distributed from Europe to Canada and from Los Angeles to Alaska and the Russian far east in littoral depths or mostly deeper. *Phoxichilidium parvum Hilton, 1939. Santa Cruz and Japan. See Child 1975. Phoxichilidium quadradentatum Hilton, 1942. Often collected from nearshore buoys in Alaska and northern California: in the second (1954) edition of this manual, one of us noted that "more than 10,000 specimens" of this species were collected on buoys near the Golden Gate Bridge in fouling surveys of the 1940s. It has extremely short auxiliary claws that are sometimes difficult to see. CALLIPALLENIDAE

Anoropallene palpida (Hilton, 1939) (=Palene [sic] palpida; Oropallene palpida Hilton 1942; O. heterodenta Hilton, 1942; Anoropallene crenispina Stock, 1956). This species is very similar to several Nymphon species, except that it has four rather than five palp segments and its abdomen points down at an angle. Shallow water from California to Peru. Callipallene californiensis (Hall, 1913) (=Pallene californiensis; Callipallene solicitatus Child, 1979). Unlike the previous species, this genus has no palps but does have prominent auxiliary claws; from California to Chile in shallow water. PYCNOGONIDAE

Pycnogonum rickettsi Schmitt, 1934. This species has relatively few records, all from the central California coast, subtidal to intertidal, from wharf pilings, anemones, and hydroids. It can be readily separated from the following species by its fine brown reticulations on a lighter integument and its very large dorsal trunk tubercles. Pycnogonum stearnsi Ives, 1892. This species boasts many records from the California coast (and Mexico) and around the North Pacific rim to the northern Kurile Islands, all in shallow depths. It has small, low dorsal trunk tubercles and similar low distal lateral process tubercles. It lacks reticulation. Often on An* = Not in key.

thopleura, Metridium, and Aglaophenia. Both P. rickettsi and P. stearnsi occur sympatrically at Duxbury Reef on the same species of sea anemones but have not been found on the same individual host.

References Child, C. A. 1975. The Pycnogonida types of William A. Hilton, I. Phoxichilidiidae. Proceedings of the Biological Society of Washington 88: 189-209. Child, C. A. 1979. Shallow-Water Pycnogonida of the Isthmus of Panama and the Coasts of Middle America. Smithsonian Contributions to Zoology 293: 1-86. Child, C. A. 1992a. Shallow-Water Pycnogonida of the Gulf of Mexico. Memoirs of the Hourglass Cruises 9: 1-86. Child, C. A. 1992b. Pycnogonida of the Southeast Pacific Biological Oceanographic Project (SEPBOP). Smithsonian Contributions to Zoology 526: 1-43. Child, C. A. 1996. The Pycnogonida types of William A. Hilton, II. The remaining undescribed species. Proceedings of the Biological Society of Washington 109: 677-686. Cole, L. J. 1904. Pycnogonida of the west coast of North America. Harriman Alaska Expedition 10: 249-298. Hedgpeth, J. W. 1940. A new pycnogonid from Pescadero, Calif., and distributional notes on other species. Journal of the Washington Academy of Sciences 30: 84-87. Hedgpeth, J. W. 1951. Pycnogonids from Dillon Beach and vicinity, California, with descriptions of two new species. Wasmann Journal of Biology 9: 105-117. Hilton, W. A. 1939. A preliminary list of pycnognids [sic] from the shores of California. Journal of Entomology and Zoology of Pomona College 31: 72-74. Hilton, W. A. 1942. Pycnogonids from the Pacific. Family Phoxichilidiidae Sars, 1891. Journal of Entomology and Zoology of Pomona College 34: 71-74. Russell, D. J., and J. W. Hedgpeth. 1990. Host utilization during ontogeny by two pycnogonid species (Tanystylum duospinum) and Ammothea hilgendorfl parasitic on the hydroid Eucopella everta (Coelenterata: Campanulariidae). Bijdragen tot de Dierkunde 60: 215-224. Schmitt, W. L. 1934. Notes on certain pycnogonids including descriptions of two new species of Pycnogonum. Journal of the Washington Academy of Sciences 24: 61-70. Ziegler, A. C. 1960. Annotated list of Pycnogonida collected near Bolinas, California. Veliger 3: 19-22.

Arachnida Marine and maritime arachnids include representatives of the mites (Acari) and the spiders (Araneae). W. G. Evans (1980, in Intertidal Invertebrates of California) notes the presence of the small linphyiid spider Spirembolus mundus Chamberlin and Ives, 1933, on the high intertidal shore on rock surfaces on the green algae Ulva and under debris on sand (it also occurs in inland situations and along freshwater creeks). A large number of species of spiders are to be expected in supralittoral habitats and other nearshore environments, especially in salt marshes. We treat the marine mites, below.

Acari IRWIN M. NEWELL A N D ILSE BARTSCH (Plates 3 3 3 and 334)

Intertidal mites include representatives of the four major suborders of Acari, but most marine mites are in a single family, the Halacaridae, of the superfamily Halacaroidea in the suborder Prostigmata. This family has been unusually successful in ARACHNIDA: ACARI

665

its evolutionary adaptation to numerous marine niches. Halacaridae probably evolved in the sea from several semiaquatic lines and should be regarded as polyphyletic. They have also invaded fresh water. Some species are phytophagous, others are predators, and several have developed truly parasitic habits. Krantz (1973) reported upon predatory halacarid mites in the genera Agauopsis, Halacarus, and Halacarellus, from intertidal mussel beds in Oregon; Krantz (1976) reported upon arenicolous species, and MacQuitty (1983, 1984) has reported on marine halacaroids from California.

turned to seawater for further study. Intertidal mites tolerate immersion in fresh water for one to three hours, but longer periods are usually fatal. Temporary mounts of Halacaridae can be made in Berlese fluid or Hoyer's modification of it. They may also be cleared with lactic acid and transferred to 15% glycerine in water, which is then allowed to evaporate slowly while the mites are being examined. For permanent mounts the mites should be cleared with enzymes and mounted in Hyrax or glycerine, following procedures outlined by Newell (1947).

An abundant and easily observed supralittoral and high intertidal mite, reaching 3 mm-4 mm in length, is the bright red "velvet mite," Neomolgus littoralis (Linnaeus, 1758) in the family Bdellidae, reported widely in the North Atlantic and North Pacific Oceans. These tiny predators that feed on flies and other prey may be seen actively moving on rock surfaces and on splash zone lichens and are also common under small stones, rocks, and beach wrack. A photograph of Neomolgus may be found in Evans (1980), and Abbott (1987) presents a sketch of the external anatomy of Neomolgus from Monterey Bay.

The interested student should then begin with the classic works of Newell cited below, updated by Krantz (1973, 1976), MacQuitty (1983, 1984), and Bartsch (2004). The following key to genera is based on adults only. Males are distinguishable by the phorotype (plate 333E), the organ that produces the spermatophore (spermatopositor). Probably all species of Halacaridae utilize spermatophores. There is a six-legged larva in the life cycle, followed by one, two, or three nymphal instars, depending on the genus. Protonymphs have one, deutonymphs two, and tritonymphs (known in Isobactrus) have three pairs of provisory genital acetabula, but no genitalia. Protonymphs also have the femur of leg IV undivided.

The other major suborders with intertidal representatives are the Mesostigmata, Astigmata, and Oribatida (Cryptostigmata). One common species of the Mesostigmata is the eviphidid Thinoseius orchestoideae (Hall, 1912) (=Gammaridacarus brevisternalis Canaris, 1962), which attaches to the undersides of the amphipod beach hoppers Traskorchestia and Megalorchestia, and preys upon rhabtidid nematodes that also reside on the amphipods (Canaris 1962; Kitron 1980; Rigby 1996a, b). Other genera of the Mesostigmata occur free-living; they are mostly predatory. The Astigmata are represented by the Hyadesioidea, with small weakly sclerotized forms. Hyadesiids may locally be very abundant, especially among green algae in tide pools. The Oribatida are dark colored mites, the adults being heavily sclerotized. Representatives of the superfamily Ameronothroidea are often aquatic or semiaquatic; on the seashore, they are mostly herbivorous and may be found in large numbers, generally restricted to the upper intertidal. Of the marine genera of Halacaridae, at least 14 are known from the North Pacific (Newell 1975), and one, Thalassacarus, is known only from this region. Halacaridae occupy a great number of marine habitats, even to depths of more than 5,000 m (Newell 1971). Nevertheless, the ecological distribution of any given species is probably fairly restricted. For example, Isobactrus spp. are usually confined to brackish tide pools or estuaries; Rhombognathus spp. are rarely encountered subtidally, and never below the euphotic zone; Scaptognathus, Anomalohalacarus, and Actacarus are interstitial in coarse sand. Halacaridae range from 0.18 mm-2 mm in body length. They are usually abundant: a liter of coralline algae may contain hundreds of individuals and up to 15 species. Despite their small size they are a conspicuous and omnipresent element, well worth a few hours of the student's time. Ecological studies are of particular importance, since little is known of the actual niches occupied by the various species. Halacaridae are easily collected by placing algae, gravel, barnacles, mussels, and other substrates in seawater, anesthetizing for about 10 minutes with chloroform, and washing the substrate vigorously with either salt or fresh water. Washings can be preserved in 65% alcohol. If the mites are to be observed alive, the chloroform treatment should be greatly reduced or eliminated, and a vigorous jet of tap water should be used to separate the mites from the substrate. They should then be re666

ARTHROPODA

KEY TO G E N E R A OF M A R I N E HALACARIDAE OF T H E EASTERN NORTH PACIFIC

1.

Insertions of palpi lateral to rostrum; trochanters separated by an interval appreciably greater than their width, so they are largely or fully visible in ventral view; abundant to rare, on various substrates, occasionally interstitial in coarse sand (plate 333A) 2 — Insertion of palpi dorsal to rostrum; trochanters separated by an interval less than their width, so they are largely concealed in ventral view; palpi very long to short; generally rare, often interstitial in coarse sand (plate 333B-333D) 12 2. Middle piece of claw articulating directly with tip of the tarsus (note that oil immersion may be necessary at first to interpret this important character); color in life yellow, brown, or rarely green or green black; predaceous or parasitic (plate 334M) 3 — Middle piece of claw articulating with an intermediate sclerite, the carpite, and this in turn articulates freely with (plate 334K) or is a flexible extension of (plate 334L), the tip of the tarsus (note that some species of Agauopsis have a minute, carpitelike structure at the tip of the tarsus, but it appears to be rigid, rodlike extension of the tarsus); color in life green to black; phytophagous; not living under conditions precluding algal growth 11 3.

Patella of palp with a seta, variable in position and form (plate 334E-334F); note that in Copidognathus pseudosetosus and related species, there is a sharp spine here, but there is no alveolus (socket) and it is not a seta (plate 3 3 4 G ) . . . 5 — Patella of palp lacking a seta (plates 333A, 334G) 4 4. Tarsi of legs bowed; median claw massive, thicker than lateral claws; slow-moving forms, adapted for clinging to hydroids or bryozoans (plate 333F) Bradyagaue Newell, 1971 — Tarsi of legs not bowed, but straight; median claw minute, not as thick as lateral claws (plate 333G) Copidognathus Trouessart, 1888

PLATE 3 3 3 H a l a c a r i d a e . A,

Copidognathus

curtus Hall, gnathosoma, ventral; B, Simognathus sp., gnathosoma, ventral; C, Lohmannella faicata (Hodge), gnathosoma, ventral; D, Scaptognathus sp., gnathosoma, ventral; E, Copidognathus curtus Hall, genitoanal plate, male, phorotype in dotted line; F, Bradyagaue bradypus Newell, tarsus of leg III, showing curvature and massive median claw; G, Halacarus frontiporus Newell, leg I, showing segmentation (Newell, original).

b a s e of g n a t h o s o m a

5.

— 6.

—

7.

—

8.

— 9.

Patella of legs relatively long, nearly as long as either the telofemur or the tibia (plate 333G); femur of palp with two setae (plate 334E); usually rare 6 Patella of legs distinctly shorter than telofemur or tibia; femur of palp with only one seta 7 Idiosoma (body, exclusive of gnathosoma or "capitulum" slender, very flexible in life, modified for moving freely and quickly through interstices in sand, posterior dorsal plate often divided into right and left halves Anomalohalacarus Newell, 1949 Idiosoma neither slender nor flexible, not modified for interstitial life; posterior dorsal plate either absent, or (if present) not divided into right and left halves Halacarus Gosse, 1855 Ocular plates large, readily visible on dorsal surface; habitat variable, but not normally interstitial in coarse sand (plate 334A-334C) 8 Ocular plates very small, at sides of idiosoma (body), often easily overlooked; normally interstitial in coarse sand and under boulders Actacarus Schulz, 1936 Leg I rakelike in appearance, with a row of several very heavy peg setae, along anterior ("medial") margin; palpi very short, straight (plate 334D) Agauopsis Viets, 1927 Leg I not rakelike, although some heavy setae may be present ventrally or anteroventrally; palpi longer 9 Ocular plates with a thick, taillike extension (cauda), reaching nearly to insertions of legs IV (plate 334C);

cheliceral tarsus with two massive teeth on basal half of dorsal margin, minutely denticulate in distal margin (plate 334H) Thalassacarus Newell, 1949 — Ocular plates without such a cauda, not reaching beyond level of insertions of legs III 10 10. Tarsus of chelicera minutely denticulate throughout (plate 3341) Halacarellus Viets, 1927 Note: (As Thalassarachna

in previous edition, but there are no Pa-

cific records of this genus)

—

Tarsus of chelicera with a few (five to seven) coarse teeth along dorsal margin (plate 334J) Agaue Lohmann, 1889 11. Each ocular plate with two setae; with three or more setae on or near lateral margin of body, between insertions of leg II and III; carpite straight, stiff, rodlike (plate 334K); gnathosoma readily visible in dorsal view, projecting anteriorly or anteroventrally; usually abundant (plate 334A) Rhombognathus Trouessart, 1888 — Ocular plates without setae, a few setae free in the striated, membranous cuticle (plate 334B); with only one seta on lateral margin of body between insertions of legs II and III; gnathosoma directed ventrally so it is concealed in dorsal view (undistorted specimens) by the overhanging anterior dorsal plate (AD); carpite flexible, curved, monoliform (plate 334L); generally in brackish water Isobactrus Newell, 1947 ARACHNIDA: ACARI

667

PLATE 334 Halacaridae. A, Rhombognathus sp., dorsum, right side; B, Isobactrus sp., dorsum, right side; C, Thalassacarus commatops Newell, dorsum, right side; D, Agauopsis productus Newell, basifemur-tibia I, right side, ventral view; E, Halacarus frontiporus Newell, left palp, anterior (="medial") view; F, Agauopsis sp., right palp, dorsal view; G, Copidognathus pseudosetosus Newell, left palp, dorsal view, showing spine (not a seta) on patella of palp; H, Thalassacarus commatops Newell, tarsus of chelicera, side view; I, Halacarellus capuzinus (Lohmann), tarsus of chelicera, side view; J, Agaue longiseta Newell, tarsus of chelicera, side view; K, Rhombognathus sp., ambulacrum and tip of tarsus III, left side, ventral view, showing rodlike carpite; L, Isobactrus sp., ambulacrum III, showing moniliform carpite; M, Copidognathus curtus Hall, ambulacrum II, ventral view (carpite absent); note that in figures K and L, middle piece and carpite (where present) are shown as dotted outlines and are surrounded by thin, membranous cuticle (Newell, original).

12. Tip of rostrum flared at end; palpi with an exceptionally heavy spiniform seta at tip (plate 3 3 3 D ) Scaptognathus —

Trouessart, 1 8 8 9

minute setae at tip (plate 333B, 3 3 3 C )

13

13. Palpi long, slender, extending to or only slightly beyond t h e end of t h e long rostrum;

rostrum

parallel-sided

throughout most of length; claws of tarsus I similar in form to those o n tarsi II-IV (plate 3 3 3 C ) Lohmannella

Trouessart, 1 9 0 1

Palpi shorter, but extending well beyond t h e tip of the short, thick, subtriangular rostrum; median claw of tarsus

668

Simognathus

Trouessart, 1 8 8 9

Tip of rostrum narrowly or bluntly rounded at end, not flared; rostrum long and slender, or short and thick; palpi with only

—

I grossly enlarged, median and lateral claws markedly different in form from those of tarsi II-IV (plate 333B)

ARTHROPODA

REFERENCES Abbott, D. P. 1987. Observing marine invertebrates. Drawings from the laboratory. Edited by G. H. Hilgard. Stanford, CA: Stanford University Press, 380 pp. Bartsch, I. 1997. Thalassarachna and Halacarellus (Halacaridae: Acari): two separate genera. J. Nat. Hist. 31: 1223-1236. Bartsch, I. 2004. Geographical and ecological distribution of marine halacarid genera and species. Exp. Appl. Acarol. 34: 37-58. (Lists of genera, number of species, and geographical distribution).

Garypus PLATE

californicus

Halobisium

335 Pseudoscorpions. A, Garypus californicus; B, Halobisium occidental

Canaris, A. G. 1962. A new genus and species of mite (Laelaptidae) from Orchestoidea califomiana (Gammaridea). J. Parasitology 48: 467^469. Evans, G. O. 1963. The systematic position of Gammaridacarus brevisternalis Canaris (Acari: Mesostigmata). Ann. Mag. Nat. Hist. (13) 5: 395-399. Evans, W. G. 1980. Insecta, Chilopoda, and Arachnida: Insects and allies, pp. 641-658. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds. Stanford, CA: Stanford University Press, 666 pp. Kitron, U. D. 1980. The pattern of infestation of the beach-hopper amphipod Orchestoidea corniculata, by a parasitic mite. Parasitology 81: 235-249. Krantz, G. W. 1973. Four new predatory species of Halacaridae (Acari: Prostigmata) from Oregon with remarks on their distribution in the intertidal mussel habitat (Pelecypoda: Mytilidae). Ann. Ent. Soc. Amer. 66: 979-985. Krantz, G. W. 1976. Arenicolous Halacaridae from the intertidal zone of Schooner Creek, Oregon (Acari: Prostigmata). Acarologia 18: 241-258. MacQuitty, M. 1983. Description of a new species of marine mite, Agauopsis filimstris (Acari: Halacaroidea) from southern California. Acarologia 24: 59-64. MacQuitty, M. 1984. The marine Halacaroidea from California. J. Nat. Hist. 18: 527-554. Newell, I. M. 1947. A systematic and ecological study of the Halacaridae of eastern North America. Bull. Bingham Oceanogr. Coll. 10: 1-232. Newell, I. M. 1952. Further studies on Alaskan Halacaridae (Acari). Amer. Mus. Novitates 1536: 1-56. Newell, I. M. 1971. Halacaridae (Acari) collected during Cruise 17 of the R/V Anton Bruun in the southeastern Pacific Ocean. Anton Bruun Report No. 8: 1-58. Newell, I. M. 1984. Antarctic Halacaroidea. Antarctic Res. Ser. 40:1-284. Proches, S., and D. J. Marshall. 2001. Global distribution patterns of non-halacarid marine intertidal mites: implications for their origins in marine habitats. J. Biogeography 28: 47-58. Pugh, P. J. A., and P. E. King. 1988. Acari of the British supralittoral. J. Nat. Hist. 22: 107-122. Rigby, M.C. 1996. The epibionts of beach hoppers (Crustacea: Talitridae) of the North American Pacific coast. J. Natl. Hist. 30:1329-1336. Rigby, M.C. 1996. Association of a juvenile phoretic uropodid mite with the beach hopper Traskorchestia traskiana (Stimpson, 1857) (Crustacea: Talitridae). J. Nat. Hist. 30: 1617-1624.

occidentale

(both drawn by R. O. Schuster, from 3rd ed.).

Pseudoscorpiones V I N C E N T F. LEE (Plate 3 3 5 )

Pseudoscorpions, or chelonethids, are minute (1 m m - 5 m m ) animals resembling tiny scorpions, but with a flattened, discshaped, or elongated posterior body, relatively enormous pincers, and tailless. They are active hunters, and in woodlands are found in leaf mold and under bark. Two species are often encountered along the shore. Garypus californicus Banks, 1 9 0 9 (plate 335A), occurs under driftwood and beach wrack on sandy beaches above high-tide mark from northern Baja California to northern California. Donald P. Abbott (1987) provides a sketch of a specimen of G. californicus, with details of the prosoma, from under rocks on the beach at Hopkins Marine Station. Lighton and Joos (2002a, b) provide one of the few studies on this species. Halobisium occidentale Beier, 1931 (plate 335B), occurs intertidally in the mud and under logs and rocks in salt marshes (particularly in flats of the pickleweed Salicomia) and in crevices of intertidal rocks and under cobblestones on the open coast from central California to Alaska (Schulte 1976). Initially described from a single female specimen collected in 1 9 2 7 "in the rubble beneath a log above the high-tide line" at Cannon Beach, Oregon, Parobisium hesperum (Chamberlin 1930) is also found under driftwood. The only other record, if correct, appears to be one from an inland locality (Dunsmuir) in California. Collecting pseudoscorpions in the marine environment is fairly straightforward. Turning over driftwood, kelp, and other debris o n sandy beaches can yield the c o m m o n G. californicus. Prying crevices in driftwood is not very productive, but crevices of rocks might yield H. occidentale, although they are more c o m m o n in marshes and estuaries. Here, by digging into the ARACHNIDA: PSEUDOSCORPIONES

669

exposed mud at the base of the pickleweed, one can find them in their silken chambers. For keys to genera, see Chamberlin (1931) and Muchmore (1990). REFERENCES Abbott, D. P. 1987. Observing marine invertebrates. Drawings from the laboratory. Edited by Galen Howard Hilgard. Stanford University Press, 3 8 0 pp. Chamberlin, J. C. 1930. A synoptic classification of the false scorpions or chela-spinners, with a report on a cosmopolitan collection of the same. Part II. The Diplosphyronida (Arachnida-Chelonethida). Ann. Mag. Nat. Hist. (10) 5: 1 - 4 8 . Chamberlin, J. C. 1931. The arachnid order Chelonethida. Stanford Univ. Pub. Biol. Sci., 7: 1 - 2 8 4 . Lee, V. F. 1979. The maritime pseudoscorpions of Baja California, México. Occas. Pap. Calif. Acad. Sci. 131, 38 pp. Lighton, J. R. B., and B. Joos. 2002a. Discontinuous gas exchange in a tracheate arthropod, the pseudoscorpion Garypus califomicus: Occurrence, characteristics and temperature dependence. J. Insect Sci., 2, No. 23, 1 ^ . Lighton, J. R. B., and B. Joos. 2002b. Discontinuous gas exchange in the pseudoscorpion Garypus califomicus is regulated by hypoxia, not hypercapnia. Physiol. Biochem. Zool. 75: 3 4 5 - 3 4 9 . Muchmore, W. B. 1990. Pseudoscorpionida, pp. 5 0 3 - 5 2 7 . In Soil biology guide. D. L. Dindal, ed. New York, Chichester, Brisbane, Toronto, Singapore: John Wiley & Sons. Schulte, G. 1976. Littoralzonierung von Pseudoskorpionen an der nordamerikanischen Pazifikkiiste (Arachnida: Pseudoscorpiones: Neobisiidae, Garypidae). Entomol. Germ. 3: 1 1 9 - 1 2 4 . Weygoldt, P. 1969. The Biology of Pseudoscorpions. Harvard University Press, 145 pp.

Insecta Orders of Intertidal Insects HOWELL V. DALY

Few features of insects are as striking as the difference in the diversity of insects and other terrestrial arthropods among terrestrial, freshwater, and marine faunas. Nearly three-quarters of the earth's animal species are insects, but only about 3% of insect species are aquatic, and a fraction of these are marine or intertidal. Judging by the tracheate respiratory system and impermeable cuticle, insects evolved as terrestrial arthropods and colonized aquatic habitats only secondarily. Some continued to use oxygen in air, while others developed various devices to obtain oxygen dissolved in water (Eriksen et al. 1996). Five orders (Odonata, Ephemeroptera, Plecoptera, Megaloptera, Trichoptera) and many entire families in other orders are now restricted almost exclusively to fresh water. Many other insects in groups that are normally terrestrial also live in fresh water as herbivores on aquatic plants or as predators or parasites of aquatic organisms. In the marine environment, a surprising number of insects have been recorded, including parasites of other insects and of marine mammals. Insects as individual organisms are not scarce on the coasts or the surface of the ocean; indeed, some species are exceedingly abundant. Cheng and Frank (1993) list 21 orders from pelagic, coastal, intertidal, mangrove and other tropical/ subtropical brackish waters, and salt-marsh and other temperate brackish waters. Almost all species in marine environments belong to families that are found elsewhere in freshwater or terrestrial habitats. Of well over 700 families of insects, only two families are exclusively marine: the rare but worldwide, intertidal coral treader (Hermatobatidae, order Hemiptera; one genus and nine species; Cheng 1977; Foster 1989) and the marine caddis670

ARTHROPODA

flies of New Zealand and Australia (Chathamiidae, order Trichoptera; two genera and four species; Cheng and Frank 1993). Why is the largest group of animals virtually absent from the largest habitat? Cheng (1976), Norris (1991), Wallace and Anderson (1996), and Usinger (1957), among others, provide discussions about this fascinating question. Regarding the intertidal, Hinton (1977) presented the argument that, on a world basis, the coastline measured in miles is much smaller than the miles of freshwater rivers and streams. Consequently, the intertidal habitat is actually relatively more diverse in species than fresh water. Insects have succeeded in living under certain physical and chemical aspects of the intertidal environment. Examples are tidal submergence (species in several orders including the widespread collembolan Anurida marítima [Hypogastruridae, order Collembola], whose presence on the Pacific coast remains uncertain, the bug Aepophilus bonairei (Saldidae, order Hemiptera) in England, and the coral treader mentioned above); life cycle synchronized with tides (the midge Clunio marinus [Chironomidae, order Diptera]); wave action (larvae of midges of the widespread genus Clunio [Chironomidae, order Diptera] and the barnacle-eating larvae of the Pacific coast fly Oedoparena glauca [Dryomyzidae, order Diptera] live here, but species richness of populations of shore flies [Ephydridae, order Diptera] is reduced in areas of violent wave action); and salinity (especially salt-marsh mosquitoes, e.g., Aedes taeniorhynchus [Culicidae, order Diptera], shore flies, water boatmen Trichocorixa [Corixidae, order Hemiptera], and, in Australia, the intertidal rockpool caddisfly larva of Philanisus [Chathamiidae, order Trichoptera]). Of various reasons why insects have not dominated the intertidal, Hinton (1977) supported the view that the physical violence of intertidal areas tends to exclude insects (see also Steinly 1986). Hynes (1984) deemed this implausible and argued in favor of competitive exclusion. While insects were evolving on land in the Paleozoic Era, they were prevented from colonizing the marine environment by already wellestablished invertebrates. To this may be added the observation of Vincent Resh (personal communication) that the average body size of benthic invertebrates in the intertidal is larger than the size of the comparable fauna in fresh water, hence the marine benthic fauna is a decided threat to the survival of insects. Offshore on the surface of the ocean are five species of pelagic water striders, Halobates (Gerridae, Hemiptera), that occur far from land in the Atlantic, Pacific, and Indian Oceans. Beneath the surface, larvae of the midge Chironomus oceanicus have been dredged from 36 m and another midge, Pontomyia sp., from 30 m (Chironomidae, order Diptera). However, insects are entirely absent in deeper waters of the ocean. Usinger (1957) noted that, except for some chironomids, insects also are rarely successful in colonizing deep freshwater lakes. He proposed that the most limiting factor is probably the inability of insects to respire indefinitely beneath the water's surface. As adults, nearly all insects have access to oxygen in air. Perhaps the energy needed for their reproductive physiology depends on the rich supply of oxygen in the atmosphere. Eriksen et al. (1996) describe several problems involved in obtaining oxygen dissolved in water among which the amount dissolved, even in cold saturated, water is only 0.01% of the amount available in air. Two exceptional freshwater insects complete their lives entirely submerged. The bug Aphelocheirus (Aphelocheiridae, order Hemiptera) completes its life history in cold water by the use of a plastron (Hinton 1976). The peculiar stonefly Capnia lacustria (Capniidae, order Plecoptera; first reported as Utacapnia sp. by Jewett, 1963; Baumann, personal communication)

in Lake Tahoe exists indefinitely in deep water. Possibly other stoneflies, such as Baikaloperla in Lake Baikal, complete their life cycles in the lacustrian environment (Zapekina-Dulkeit and Zhiltzolva 1973; Baumann, personal communication). The insects discussed in this manual are limited to species regularly living part or all of their lives in the intertidal zone of the outer coast. Only the water strider, Halobates sericeus Eschscholtz (Gerridae, order Hemiptera), inhabits the open ocean near our shores. It occurs in warm, offshore waters 50 miles or more from the coast and as far as 40° north latitude. Halobates eggs have been found glued to floating material at sea. Our species is one of the true pelagic forms that are taken nearshore only after severe storms. Zooplankton (e.g., copepods and euphausiids) trapped at the sea surface is their usual food. Cheng (1985) provides a review of the biology of Halobates. The rich insect faunas of the beaches above the tide, coastal dunes, salt marshes, and estuaries are beyond the scope of this treatment. Insects from these areas and inland may occur by accident in the intertidal zone. Honeybees, for example, may fly offshore from inland colonies and are commonly found in the surf. Unless an insect is clearly an adult resident of brackish tidal pools, intertidal rocks, or beaches, readers are advised to identify order and family with the aid of general keys for adult insects (Johnson and Triplehorn 2004; Daly et al. 1998), adult and larval aquatic insects (Merritt and Cummins 1996), or larval insects (Stehr 1987,1991). Further information on the biologies of marine insects is provided by Benedetti (1973), Cheng (1976), Cheng and Frank (1993), and Evans (1980). ACKNOWLEDGMENTS

I wish to thank R. Baumann, L. Cheng, K. Christiansen, V. Resh, H. Sturm, and D. S. White for information and comments provided during the preparation of this section. KEY TO THE ORDERS OF ADULT INTERTIDAL INSECTS

1. Wings absent; insects often jump to escape capture 2 — Wings present, though sometimes concealed by leathery front wings (elytra), or reduced to small, articulated lobes; insects usually fly or run to escape capture 3 2. Hump-backed insects about 1 cm in length; eyes very large and meeting along the midline; long filamentous antennae; three long filaments at the tip of the abdomen (a long median filament and two shorter, lateral cerci); abdomen with more than six segments jumping bristletails, order Archaeognatha — Small, soft-bodied, insects; body length usually 1 mm-5 mm in length; often with short antennae; abdomen with only six segments; first abdominal segment with short, thick, ventral projection (ventral tube); many species with a distally bifurcate jumping appendage (furcula) on the ventral side of the fourth abdominal segment; furcula normally folded forward (furcula reduced in Anurida maritima and often absent in littoral species) springtails, order Collembola Note: (the phylogenetic position of Collembola amongst the hexapods is unclear)

3.

Front wings overlapping apically when at rest, the basal part divided by converging sutures which form a triangle on the dorsum; brackish pools water boatmen, Corixidae, order Hemiptera

—

Front wings not as above: either entirely free and membranous, reduced to vestigial stumps, or covering the dorsum without overlapping 4 4. Front wings free and membranous or reduced to vestigial stumps; hind wings highly modified as halteres flies and midges, order Diptera — Front wings leathery, completely or sometimes only partly covering dorsum, concealing hind wings when at rest 5 5. Tip of abdomen with strongly sclerotized forcep-shaped cerci earwigs, order Dermaptera — Tip of abdomen without forcep-shaped cerci beetles, order Coleoptera REFERENCES Benedetti, R. 1973. Notes on the biology of Neomachilis halophiia on a California sandy beach (Thysanura: Machilidae). Pan-Pacific Entomologist 49: 246-249. Cheng, L. 1976. Marine insects. Amsterdam: North-Holland Publishing Company, 581 pp. Cheng, L. 1977. The elusive sea bug Hermatobates (Heteroptera). PanPacific Entomologist 53: 87-97. Cheng, L. 1985. Biology oí Halobates (Heteroptera: Gerridae). Ann. Rev. Entomol. 30: 111-135. Cheng, L., and J. H. Frank. 1993. Marine insects and their reproduction. Oceanography and Marine Biology: An Annual Review 31: 479-506. Daly, H. V., J. T. Doyen, and A. H. Purcell III. 1998. Introduction to insect biology and diversity. 2nd ed. New York: Oxford University Press, 680 pp. Eriksen, C. H., V. H. Resh, and G. A. Lamberti. 1996. Aquatic insect respiration, pp. 2 9 ^ 0 . In An introduction to the aquatic insects of North America, 3rd ed. W. Merritt and K. W. Cummins, eds. Dubuque, IA: Kendall/Hunt Publishing Co. Evans, W. G. 1980. Insecta, Chilopoda, and Arachnida: insects and allies, pp. 189-200. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds, Stanford, CA: Stanford University Press. Foster, W. A. 1989. Zonation, behavior and morphology of the intertidal coral-treader Hermatobates (Hemiptera: Hermatobatidae) in the south-west Pacific. Zoological Journal of the Linnaean Society 96: 87-105. Hinton, H. E. 1976. Plastron respiration in bugs and beetles. Journal of Insect Physiology 22: 1529-1550. Hinton, H. E. 1977. Enabling mechanisms. Proceedings of the XV International Congress of Entomology, Washington, D.C., 1976, pp. 71-83. Hynes, H. B. N. 1984. The relationships between taxonomy and ecology of aquatic insects, pp. 9-23. In The ecology of aquatic insects. V. H. Resh and D. M. Rosenberg, eds. New York: Praeger. Jewett, S. G., Jr. 1963. A stonefly aquatic in the adult stage. Science 139: 484-485. Johnson, N. F., and C. A. Triplehorn. 2004. Borror and DeLong's An introduction to the study of insects. 7th ed. Pacific Grove, CA: Brooks/Cole, 864 pp. Merritt, R. W., and K. W., Cummins, eds. 1996. An introduction to the aquatic insects of North America. 3rd ed. Dubuque, IA: Kendall/Hunt Publishing Company, 862 pp. Norris, K. R. 1991. General biology, pp. 68-108. In The insects of Australia, vol. 1, Commonwealth Scientific and Industrial Research Organisation. Ithaca, NY: Cornell University Press. Stehr, F. W. 1987. Immature insects. Volume 1. Dubuque, IA: Kendall/Hunt Publishing Company, 754 pp. Stehr, F. W. 1991. Immature insects. Vol. 2. Dubuque, IA: Kendall/Hunt Publishing Company, 975 pp. Steinly, B. A. 1986. Violent wave action and the exclusion of Ephydridae (Diptera) from marine temperate intertidal and freshwater beach habitats. Proceedings of the Entomological Society of Washington 88: 427—437. Usinger, R. L. 1957. Marine insects, pp. 1177-1182. In Treatise on marine ecology and paleoecology. Vol. 1. J. W. Hedgpeth, ed. Ecology, Geological Society of America Memoir 67. Wallace, J. B., and N. H. Anderson. 1996. Habitat, life history, and behavioral adaptations of aquatic insects, pp. 41-73. An introduction INSECTA: ORDERS OF INTERTIDAL INSECTS

671

thoracic terga

abdominal terga

lateral ocelli

PLATE 3 3 6 General structure of Archaeognatha, semidiagrammatic: A, lateral view; B, dorsal view; color pattern of dorsal scales implied; abdominal segment XI is hidden under segment X (Helmut Sturm, original).

to the aquatic insects of North America. 3rd ed. R. W. Merritt and K. W. Cummins, eds. Dubuque, IA: Kendall/Hunt Publishing Co. Zapekina-Dulkeit, J. I., and L. A. Zhiltzolva. 1 9 7 3 . A new genus of stoneflies (Plecoptera) from Lake Baikal. Entomol. Obozr. 52: 3 4 0 - 3 4 6 . (English translation in Entomol. Review)

Archaeognatha HELMUT STURM

(the two species co-occur, for example, near Baker Beach). Occurring closer to the high-tide line are Petridiobius canadensis Sturm, 2001 (on the Queen Charlotte Islands), and Petridiobius arcticus (Paclt, 1970) (on the rocky shores of southern Alaska) (Sturm 2001, Sturm and Bowser, 2004). Neomachilis, Pedetontus, and Petridiobius are in the family Machilidae and specifically in the subfamily Petrobiinae, a common feature of which is the absence of scales on the flagellum of the antennae.

(Plate 336)

Archaeognatha, or bristletails, are primitively wingless insects generally < 2 0 mm long as adults (plate 336). All species have a unique jumping mechanism; the tergites, abdominal coxites, and caudal appendages are scaled, and the compound eyes are large and contiguous. Along the western beaches of North America, the halophilous Neomachilis halophila Silvestri, 1911 (adults 12-13 mm in length), occurs in the high intertidal and supralittoral zone. Benedetti (1973) working in Pacific Grove on the shores of Monterey Bay, "found it most abundant just on the seaward side of the last terrestrial vegetation in areas covered with rocks too high on the beach to be disturbed by most high tides, and especially among rocks piled in such a manner that a small space occurs between rock and sand." It also occurs a short distance inland, where it may be found on the bark of trees and on stones some 20 m-30 m from the shore, as at Baker Beach in San Francisco (H. Sturm, personal observations). On the beaches of San Francisco and in southern California, females of Neomachilis are generally much more abundant than males; however, Benedetti (1973) reported that males and females were in approximately equal numbers at Pacific Grove. Benedetti found that Neomachilis was largely nocturnal, with the greatest activity occurring just before dawn. Neomachilis eats unicellular green algae, apparently derived from grazing lichens, as well as yeast and pine pollen. Similarly, Willem (1924) found that the European maritime archaeognathid Petrobius maritimus feeds on the unicellular alga Pleurococcus growing on gravel and sand grains. Near or along the beach zone on the Pacific coast are at least three additional bristletails. Pedetontus californicus Silvestri, 1911, may co-occur with Neomachilis not far from the shore 672

ARTHROPODA

REFERENCES Benedetti, R. 1 9 7 3 . Notes o n the biology of Neomachilis halophila o n a California sandy beach (Thysanura: Machilidae). Pan-Pacific Entomologist 49: 2 4 6 - 2 4 9 . Sturm, H. 2 0 0 1 . Possibilities and problems of morphological t a x o n o m y shown by North American representatives of the subgenus Pedetontus s. str. and Petridiobius canadensis (Archaeognatha, Machilidae, Petrobiinae). Mitteilungen aus d e m Museum für Naturkunde in Berlin, Deutsche Entomologische Zeitschrift 4 8 : 3 - 2 1 . Sturm, H., and M. Bowser. 2 0 0 4 . Notes o n some Archaeognatha (Insecta, Apterygota) from extreme localities and a complementary description of Petridiobius (P.) arcticus (Paclt, 1970). Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg 14: 1 9 7 - 2 0 3 . Willem, V. 1 9 2 4 . Observations sur Machiiis maritima. Bulletin Biologique de la France et de la Belgique 5 8 : 3 0 6 - 3 2 0 .

Collembola KENNETH CHRISTIANSEN AND PETER BELLINGER (Plates 337-343)

There have been many studies of littoral Collembola in Europe, beginning with the work of Laboulbéne and Moniez in the last century and continuing to the present (i.e., Sterzynska and Ehrnsberger 1997), and there are scattered records and descriptions from many parts of the globe. Records from North America are comparatively few, and mainly from the East Coast. Christiansen and Bellinger (1988) summarized what was known of the fauna north of Panama and recorded nine species from the Pacific coast. Since then, seven more species have been described and nine recorded from the Pacific coasts of Mexico and Nicaragua, but none from farther north. Collembola are

B

- 1 0 0 mm; fins triangular, less than half mantle length, attached along entire length; arms long, angular in transverse section, lengths unequal, ventral pair long and broad; left ventral arm of male hectocotylized (plate 351C) Order Teuthoidea (Doryteuthis opalescens) Note: Two additional teuthoids may be encountered, as noted below.

List of Species SEPIOLIOIDEA SEPIOLIDAE

Rossia pacifica Berry, 1911. Plate 351D. Body size small, mature females larger than males (ML to 55 mm in females and to 35 mm in males); fins small, round; eggs large (4 mm-5 mm),

PLATE 351 Decapods with details of tentacle clubs: A, Moroteuthis robustus with labeled anatomy; B, Dosidicus gigas; C, Doryteuthis opalescens; D, Rossia pacifica (all from Roper et al. 1984).

laid in capsules that are attached in small groups to objects on the bottom. Depth 10 m - 2 5 0 m; typically neritic in shallow coastal waters, where they live on sand and mud bottoms. Taxonomy of this species in the North Pacific has not been stabilized. See Anderson and Shimek 1993 Veliger 37: 17-19 (egg masses).

TEUTHOIDEA LOLIGINIDAE Doryteuthis opalescens (Berry, 1911) [=Loligo opalescens; formerly L. stearnsii Hemphill, 1892]. Plate 351C. Body medium CEPHALOPODA

699

size, mature males larger than females (ML to 190 mm in males and to 170 mm in females); eggs small (2.3 mm) laid in cylindrical capsules anchored in soft substrates. Depth range not known; common in near shore (neritic waters); seasonally aggregate in shallow water (15 m-35 m) to mate and spawn. See Fields 1965, Calif. Dept. Fish Game Fish Bull. 131: 1-108 (morphology, development, biology); Hixon 1983, pp. 95-114 in Boyle, ed., Cephalopod Life Cycles, Vol. I, Academic Press; Yang et al. 1986, Fish Bull. 84: 771-798 (growth, behavior); Wing and Mercer 1990, Veliger 33: 238-240 (in Alaska); Recksiek and Frey, eds. 1978, Calif. Dept. Fish Game Fish Bull. 169:1-185 (monograph on biology, oceanography, acoustics); McGowan 1954, Calif. Fish Game 40: 47-54 (spawning). OMMASTREPHIDAE

Dosidicus gigas (d'Orbigny, 1835) [=Ommastrephes gigas; formerly Ommastrephes giganteus Gray, 1849; D. eschrichti Steenstrup, 1857; D. steenstrupi Pfeffer, 1884]. Plate 35IB. Body size large (adult ML to 150 cm); surface of mantle smooth; fins large, about one-half length of mantle, sagittate; tentacle clubs with suckers only; eggs small (1.0 mm), spawning habits unknown. Often washed ashore in large numbers from Baja California to Washington. Depth 0 m-1,200 m; oceanic species known to migrate diurnally. ONYCHOTEUTHIDAE

Moroteuthis robustus (Verrill, 1876) [=Onykia robusta; Ommastrephes robustus; formerly M. japonica (Taki, 1964); M. pacifica Okutani, 1983], Plate 351A. Body size large (adult ML to 230 cm); surface of mantle with numerous fine longitudinal ridges; fins large, occupy more than one-half length of mantle, sagittate; tentacle clubs with 15-18 pairs of hooks in two characteristic rows; eggs small (1.0 mm), spawning habits unknown. Depths of capture range from 100 m-600 m; pelagic in coastal waters; occasionally washed ashore or caught by trawl fishermen. See Pattie 1968, Fish. Res. Papers Wash. Dept. Fisheries 3: 47-50; Green 1989, Calif. Fish Game 75: 241-243 (strandings in British Columbia); van Hyning and Magill 1964, Res. Briefs Fish Comm. Oregon 10: 67-68 (off Oregon); Tsuchiya and Okutani 1991, Bull. Mar. Sci. 49: 137-147 (growth); Hochberg 1974, Tabulata 7: 83-85 (southern California records). OCTOPODA OCTOPODIDAE

Enteroctopus dofleini (Wulker, 1910) [=Octopus dofleini; Paroctopus dofleini; formerly O. punctatus Gabb, 1862; O. hongkongensis Hoyle, 1885; O. gilbertianus Berry, 1912]. Plate 350B. Body size large (adult ML to 350 mm); dark ocelli absent; gills with 12-15 lamellae; enlarged suckers present on all arms of mature males; copulatory organ (ligula) of males very long (16%-18% of arm length); spawned eggs small (6 mm-6.5 mm), laid in festoons; hatchlings planktonic. Depth 0 m-1,500 m; intertidal in northern part of range; inhabit substrates littered with rocks and boulders. See Pickford 1964, Bull. Bingham Ocean. Coll. 19: 1-70; Hartwick 1983, pp. 277-291 in Boyle, ed., Cephalopod Life Cycles, Vol. 1. Academic Press. "Octopus" albescens Berry, 1953. Plate 350A. Body size medium (adult ML to 100 mm); dark ocelli absent; gills with 11-13 lamellae; enlarged suckers present on all but ventral 700

MOLLUSCA

arms in mature males; spawned eggs small (3 mm-4 mm), laid in festoons; hatchlings planktonic. Depth 0 m-300 m; common in the intertidal from northern California to Alaska; live in rocky inshore areas and on sand/mud bottoms offshore. Octopus bimaculoides Pickford and McConnaughey, 1949. Body size medium (adult ML to 200 mm); two dark ocelli present, each with necklace-like iridescent blue ring; gills with 8-10 lamellae; enlarged suckers on lateral arms of mature males; copulatory organ (ligula) of males very small (2%-4% of arm length); spawned eggs large (10 mm-17 mm), laid in festoons; hatchlings benthonic. A more southern species, occurring from San Simeon south. Depth 0 m-25 m; common in the intertidal; live on mudflats or in protected holes and crevices on rocky substrates. See Forsythe and Hanlon 1988, Malacologia 29: 41-55 (biology). Octopus bimaculatus Verrill, 1883. Similar in size, general appearance and characteristic features to preceding species but typically larger and with longer arms; two dark ocelli present, each with iridescent blue ring with radiating spokes; spawned eggs small (2 mm-4 mm), laid in festoons; hatchlings planktonic. A southern species, from Point Conception south. Depth 0 m - 5 0 m; common in the low intertidal in Mexico; typically associated with rocky substrates. See Ambrose 1981, Veliger 24: 139-146 (development); 1984, J. Exp. Mar. Biol. Ecol. 77: 29-44 (feeding); 1988, Malacologia 29: 23-29 (population dynamics). "Octopus" micropyrsus Berry, 1953. Body size very small (adult ML less than 30 mm); gills with 5 - 6 lamellae; 1 or 2 enlarged suckers on arms 1-3 of both mature males and females; copulatory organ (ligula) moderately long (7%-15% of arm length); spawned eggs large (10 mm-12 mm), attached singly to substrate in small clusters; hatchlings benthonic. A short range transition endemic that often is common in the intertidal in the northern part of range which extends from Point Conception, California to Pt. Eugenia and the islands off Baja California, Mexico. Depth 0 m-20 m; typically found in kelp holdfasts, piddock holes or in empty gastropod shells. See Haaker 1985, Shells and Sea Life 17: 39-40 (photos).

References Berry, S. S. 1912. A review of the cephalopods of western North America. Bulletin of the Bureau of Fisheries 30 (1910): 267-336. Berry, S. S. 1953. Preliminary diagnosis of six west American species of Octopus. Leaflets in Malacology 1: 51-58. Hanlon, R. T., and J. B. Messenger. 1996. Cephalopod Behaviour. Cambridge: Cambridge University Press, 2 3 2 pp. Hochberg, F. G. 1998. Class Cephalopoda, pp. 175-236. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and the Western Santa Barbara Channel. Vol. 8. The Mollusca Part 1. P. Valentich Scott and J. A. Blake, eds. Santa Barbara, CA: Santa Barbara Museum of Natural History. Hochberg, F. G. and W. G. Fields. 1980. Cephalopoda: The squids and octopuses, pp. 4 2 9 - 4 4 4 . In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, E. C. Haderlie, eds. Stanford, CA: Stanford University Press. Lang, M. A., and F. G. Hochberg, eds. 1997. Proceedings of the Workshop on The Fishery and Market Potential of Octopus in California. Washington, D.C.: Smithsonian Institution, 192 pp. Phillips, J. B. 1933a. Description of a giant squid taken at Monterey, with notes on other squid taken off the California coast. California Fish and Game 19: 128-136. Phillips, J. B. 1933b. Octopi of California. California Fish and Game 20: 20-29. Phillips, J. B. 1961. Two unusual cephalopods taken near Monterey. California Fish and Game 47: 416-417. Pickford, G. E., and B. H. McConnaughey. 1949. The Octopus bimaculatus problem: a study in sibling species. Bulletin of the Bingham Oceanographic Collection 12: 1-66.

Roper. C. F. E., M.J. Sweeney, C. E. Naun. 1984. FAO species catalogue. Volume 3. Cephalopods of the world. An annotated and illustrated guide to species of interest to fisheries. FAO Fish Synopsis 125(3): 1-277. Verrill, A. E. 1883. Descriptions of two species of Octopus from California. Bulletin of the Museum of Comparative Zoology 11: 117-123. Winkler, L. R., and L.M. Ashley. 1954. The anatomy of the common octopus of northern Washington. Walla Walla College Publications in Biological Science 10: 1-30.

Polyplacophora DOUGLAS J. EERNISSE, ROGER N. CLARK, AND ANTHONY DRAEGER (Plates 352-354)

Chitons are conspicuous in intertidal and shallow subtidal habitats along m u c h of the Pacific coast of North America, where they are often abundant and ecologically important members of the c o m m u n i t y (Dethier and Duggins 1984; Duggins and Dethier 1985). Indeed, the Pacific coast supports b o t h an unusually high diversity of species and t h e largest-bodied chiton species in the world. This diversity was relatively well known when t h e noted malacologist Allyn G. Smith wrote the c h i t o n key in the previous edition of this manual. Nevertheless, m a n y changes have occurred in our understanding of the diversity of the chiton fauna, nomenclatural advances have been introduced, and we have added more species that, although largely subtidal, find their upper limits in the lower intertidal zone. Most chitons found within 15 m (a depth readily accessible by scuba) may also be expected to occur occasionally in t h e intertidal. T h e number of recognized species has also increased due to morphological and molecular studies (see especially the worldwide m o n o g r a p h series by P. Kaas and R. A. Van Belle [ 1 9 8 5 1994], and t h e publications of A. J . Ferreira, R. N. Clark, and D. J. Eernisse). T h e following key and species list include some reassignments of genera and the revival of some older n o m i n a l species rescued from synonymy. Those that are higher-level changes are based on phylogenetic studies (D. J . Eernisse, unpublished; R. P. Kelly and D. J. Eernisse, unpublished; see also Kelly and Eernisse, 2 0 0 7 ; Kelly et al., 2 0 0 7 ) , which have extended earlier worldwide phylogenetic (Okusu et al. 2 0 0 3 ) and morphological analyses (review by Eernisse and Reynolds 1994; see also Buckland-Nicks 1995; Sirenko 1993; 1997; 2 0 0 6 ) . Chitons are exclusively marine and relatively conservative in appearance and life styles. All chitons normally have eight shells, or VALVES, embedded in a tough but flexible mantle referred to as the GIRDLE (plate 352A, 352B). Rare specimens may have six, seven, or nine valves (Roth 1966, Veliger 9: 2 4 9 - 2 5 0 ) . Chitons cling to rocks or other hard substrates with their muscular broad foot. Their anterior m o u t h is separated from the foot, but chitons lack a true head—a condition typical of mollusks except for gastropods and cephalopods. Alongside the foot are paired rows of interlocking CTENIDIA (referred to here as GILLS). Noting t h e length and position of each gill row and whether the size of gills decreases toward t h e posterior anus can aid in identification. Most chitons (members of order Chitonida), including most in this key, have an INTERSPACE between the posterior ends of the left and right gill rows, and each gill row extends at least halfway to t h e anterior end of t h e groove alongside the foot. W i t h this arrangement, each gill row functionally divides this pallial groove between t h e foot and girdle into outer inhalant and inner exhalant spaces because t h e gills have interlocking

cilia, hanging curtainlike from the roof of each pallial groove. Cilia o n each gill power water through the row and eject it at surprising velocities past t h e anus, allowing these chitons to have effective aquatic respiration despite their firm attachment to hard substrates (Yonge 1939). W h e n chitons are exposed during low tide, when oxygen is more abundant, they have a large surface area of gills with which to respire in air by direct diffusion, provided they are able to keep their gills moist. Chitons of the suborder Acanthochitonina (including Lepidochitonidae and Mopaliidae in this key) have an ABANAL gill arrangement in which the largest gill in each gill row is the most posterior. In contrast, members of the suborder Chitonina (Chaetopleuridae and Ischnochtionidae in this key) have an ADANAL gill arrangement with the largest gill away from the posterior end of the gill row. Members of the mostly deep-water order Lepidopleurida (Leptochitonidae in this key, =Lepidopleuridae) are most readily distinguished by their posterior gill arrangement. As in Chitonina, their gill rows are adanal but they do not have an interspace. Instead, the left and right gill rows form a nearly continuous Ushaped arrangement adjacent to the anus. T h e respiratory mantle cavity, including all the gills, is restricted to the posterior one-third of the animal, resulting in a different and probably primitive functional arrangement with implications not well studied by Yonge (1939) or subsequent authors. Chitons sense their surroundings with numerous sensory organs distributed on their girdle and across the upper surface of their valves. The presence of these shell organs, called ESTHETES (or AESTHETES), in the upper layer of valves known as t h e TEGMENTUM is unique to chitons a m o n g mollusks. Elsewhere (especially certain genera in tropical seas), esthetes are impressively modified as shell eyes (ocelli) large enough to be visible to the naked eye. Many Pacific coast species have photosensory esthetes, a m o n g those used for other sensory functions. Chitons also have m a n y sensory organs a m o n g their diverse girdle ornamentation (Leise and Cloney 1982). It is relatively easy to learn to recognize most chiton genera, whereas distinguishing species within some genera can be quite challenging. T h e shape of the girdle and t h e various structures on it provide m a n y of the clues to species identification. Within chitons t h e girdle shape varies from merely a flexible skirt surrounding the valves, through various degrees of intrusion between the valves, to a covering completely enclosing the valves. The elements o n the dorsal girdle surface (bare girdle, granules, scales, spicules, spines, fleshy bristles, or setae) are even more varied and useful for distinguishing species (plate 3 5 2 C - 3 5 2 H ) . Closer examination is required to reveal finer diagnostic girdle element features: the organization of scales variously ranges from IMBRICATING (i.e., shingled and overlapping) (plate 352E, 352F), to scattered without apparent order, to scales sculptured with microscopic bumps and ridges; the distribution of spines (or setae) varies from scattered to specifically located at the valve sutures, and from individual structures to several structures gathered into tufts, and the setae usually bear further species-specific elaborations of the form of spicules and bristles, which often o r n a m e n t individual setae. In particular, seta features are the most reliable morphological clues for identifying the 17 species of the most diverse genus in this key: Mopalia (plates 3 5 3 , 354). These setae distinctions have been corroborated with molecular sampling (Kelly et al. 2 0 0 7 ; R. P. Kelly and D. J. Eernisse, unpublished). There are three structures of diagnostic importance o n setae. First, setae emerge from a follicle in t h e girdle as a central supporting shaft, and this can have or lack a dorsal groove. POLYPLACOPHORA

701

Second, there can be thinner flexible bristles borne on the shaft and attached either in the groove or in a matrix adhering to the shaft. Third, setae can have or lack rigid, sharp, fracturable mineral spicules, and these spicules can either be located directly on the shaft or be mounted on the end of short to long bristles. If one searches for bristles that are intact, and those found are carefully examined, this will reveal that most species of Mopalia have bristles with a spicule at their tip. Likewise, most species lack spicules or bristles on the ventral surfaces of the setae. Setae are subject to erosion, fouling, and malformation. The setae chosen as models (plates 353, 354) reflect our experience with typical variation in setae due to erosion, and extremely high or low levels of erosion could lead to setae that differ from our key descriptions and drawings. For example, some species have setae with long shafts that we suspect are typically worn clean of bristles and spicules, but exceptionally uneroded setae might have bristles or spicules clear to the tip. Similarly, we have used the proportion of the length of the setal shaft versus the length of valve 5 tegmentum to distinguish some species, but these distinctions might not work well for the occasional animal subject to exceptionally high or low erosion. Such challenges can partly be avoided by examining a selection of setae from different regions of each animal's dorsal girdle surface. Some environments generate biological and sediment fouling of the setae and valves, which can impede identification. Fouled preserved specimens can be cleaned with needle-pointed forceps and cautious brushing with fine-bristled brushes a few millimeters wide. For field identification of living animals, the jet from a pump-spray bottle filled with seawater aids in dislodging enough material to facilitate identification of familiar species. The details of the bristles, spicules, and shaft of the setae are minute and are best viewed with a magnification of 50x or higher. With experience, a hand lens will usually suffice to identify species. However, very small Mopalia remain challenging: their setae often differ from the adult form. Chiton valves are typically divided into regions, more pronounced in species with heavier sculpturing patterns, and these partly reflect the radiating or longitudinal rows of esthete sensory organs. Valves are of three types: the anterior or HEAD valve, six INTERMEDIATE valves, and posterior or TAIL valve. The dorsal surface of an intermediate valve can have as many as three distinctive symmetrical regions of sculpturing. The median longitudinal ridge is called the JUGUM (or JUGAL RIDGE), and the area along the ridge is referred to as the JUGAL AREA only if it is set off with distinctive sculpturing. Most chitons with a distinctive jugal area are more southern in California (e.g., Acanthochitona spp.), but Oldroydia percrassa is a local (albeit rare) exception. The jugum can be sharp-angled in chitons with a high profile or rounded when chitons are flat and broad. The apices of the valve can have or lack a pointed beak. On either side of the jugum is the CENTRAL area, extending to paired triangular LATERAL areas. The anterior portion of the tail valve has sculpturing similar to the central areas, often with longitudinal riblets or latticelike sculpturing. The posterior part of the tail valve has sculpturing like the lateral areas, often with radiating rows of RIBS, finer RIBLETS, or discrete nodules. The apex of the tail valve, called the MUCRO (or beak), requires special notice. In lateral view, chitons differ in the position of the mucro and in whether the POST-MUCRONAL SLOPE (from the mucro to the posterior shell margin) is concave, straight, convex, or even bulging. 702

MOLLUSCA

The different patterns of pitting, ribbing, nodules, and growth lines alone are seldom sufficient to enable correct identifications. These seemingly fundamental aspects of the skeletal structure can display intraspecific variations in both the number and magnitude of features ornamenting the valves, as well as interspecific similarities in structure. Being aware of some causes for this variability is helpful. This variability results from the nature of the valve's growth, from environmental insults and from genetic variability within a species. Except for the posterior portion of the tail valve, valves grow primarily from their anterior and lateral edges, with the number of sculpturing elements (nodules, ribs, etc.) increasing as the animal grows. Valves are also subject to environmental factors from simple erosion and breakage to damage from encrusting organisms. Even individuals within a species of similar size and apparently pristine sculpture can show enough variability so valve sculpturing is not by itself sufficient for identification. Although in this key we have largely avoided using characteristics that can only be viewed in disarticulated specimens, important additional characters may often include normally hidden features of the valves. For some species of similar appearance, knowing to search for these normally hidden valve features could be the most efficient route to positive identification. A preserved chiton can be disarticulated by slow heating in a beaker, starting with cold water and a monolayer of KOH pellets. The individual valves can then be carefully separated and rinsed. This will reveal that the valves have an upper exposed, and often colored, layer (the tegmentum) overlaying a thicker, often porous (or solid) intermediate layer, and an inner, porcelain ARTICULAMENTUM layer. In some species, the color of the articulamentum varies away from white and can help distinguish between species of similar appearance. In all but some ancient fossil chitons, the articulamentum layer extends anteriorly beneath the preceding valve as paired s e m i - c i r c u l a r t o a n g u l a r E A V E S (or SUTURAL LAMINAE

or APOPHYSES). The proportions of the tegmentum versus the eaves, as well as variances in the profile of the anterior and posterior margins of the valves, can also be of taxonomic value. In all but the most phylogenetically basal living chitons (e.g., Leptochiton spp.), this layer also extends laterally from the intermediate valves or distally from the terminal valves as INSERTION PLATES to anchor the valves firmly in the girdle. These can often be exposed without complete disarticulation by temporarily teasing the girdle tissue away from the valves at their dorsal margin. Most chitons have SLITS in the insertion plates, which correspond to the innervation of the radiating rows of esthetes in the tegmental layer. Some keys to chitons (including the one in the previous edition of this volume) list a SLIT FORMULA expressing the number, or range of numbers, of slits observed in the head, each side of an intermediate, and tail valves, respectively. Their omission here reflects our opinion that these are not generally necessary or informative for species-level identifications, besides requiring disarticulation to observe. Two features that are apparent at first glance are coloration and body proportions. These turn out to be of only modest utility for identifying species. Coloration and pattern can be striking in many of the chiton species. Unfortunately coloration and pattern are also strikingly variable within most species, and it is the exceptional case where color is diagnostic. The body proportions of length to width to height do provide clues, but the ratio of these proportions is not constant between species for some genera. Allometry, or shape change with size,

Exterior

Interior insertion - plate teeth

spines

\ - slit

head valve (radially ribbed) head valve

intermediate valve

sutural laminae

nodules divaricating lines jugum

apex intermediate valve

lateral area central area

muero (beak) ^ ^

slit

girdle cleft

tail valve

head-flap

precephalic tentacles — s

Placiphorella velata

c

r Mopalia muscosa

Lepidozona cooperi

Lepidozona mertensii

Cyanoplax dentiens

Nuttallina californica

PLATE 3 5 2 Chitons: A, diagrammatic chiton showing girdle and shell ornamentation; B, terminology of valves; C, Mopalia muscosa; D, Placiphorella velata; E-H, other representative chitons (A, B, redrawn by Emily Reid after Yonge (1960); D, McLean, 1962; not to scale).

is a n o t h e r confounding factor as the proportions are often quite different for smaller chitons of any species. As a chiton grows, its cross-sectional profile tends to change from flattened to more peaked. In some species, the change is only a mild increase in proportional height, but in other species the change

can be from a flat juvenile cross section to a nearly circular adult cross section. T h e outline of m a n y species will also change from a rounded oval in juveniles to more elongated in large specimens. Finally, the addition of sculpturing can intensify as a chiton reaches adult size. For example, members of POLYPLACOPHORA

703

Mopalia

portiera

Mopalia

acuta

PLATE 3 5 3 Mopalia setae, species as labeled (original artwork by Anthony Draeger).

Callistochiton of similar length can vary dramatically in the prominence of their ribs and bulging tail valves, and juveniles barely exhibit these sculpturing features. For these reasons, we have tried to use characteristics that are evident regardless of the chiton's age. However, this key generally describes adult animals, and juveniles can be challenging to identify. 704

MOLLUSCA

Chitons feed with a ribbon of teeth, or RADULA. Radular properties are relatively conservative within chitons compared to the tremendous variation found in gastropods. Chitons typically have 17 teeth in each row and up to hundreds of rows of teeth. The main (MAJOR LATERAL or SECOND LATERAL) paired teeth are the primary working teeth and, in chitons, are always

H \ 1 5 m (R. N. Clark and B. Sirenko, unpublished)]. Rare, under rocks resting on soft substrate but not silt (5 m-10 m) and from granitic ridge under rocks resting on a mixture of course gravel and finer sediment (22 m-24 m). *Hanleyella oldroydi (Dall, 1919). Subtidal, > 1 5 m.

CHAETOPLEURIDAE

Chaetopleura gemma Dall, 1879 (assigned to subgenus Pallochiton by Kaas and Van Belle, 1985-1994, volume 3). Common on top and sides of rocks throughout Monterey Peninsula kelp forest down to 10 m.

ISCHNOCHITONIDAE

Stenoplax fallax (Carpenter in Pilsbry, 1892). Primarily subtidal. Along Monterey Peninsula, juveniles < 1 . 5 cm are often under thin layers of sediment on top of rocks, while adults are buried below the sand line along the sides of rocks. Stenoplax heathiana Berry, 1946 (assigned to subgenus Stenoradsia by Kaas and Van Belle, 1985-1994, volume 3). Intertidal down to 7 m under rocks well submerged in sand. Named for Harold Heath who, as a Stanford University professor at Hopkins Marine Station, pioneered the study of California chitons, including an extensive cell lineage study of this species (Heath, 1899). This species is unusual in spawning a sticky egg mass from which crawl-away larvae emerge (Haderlie and Abbott, 1980). Look for the tiny commensal snail Vitrinella oldroydi in the mantle cavity. See Andrus and Legard 1975 (habitat); Linsenmeyer 1975, Veliger 18 Supplement: 83-86 (behavior); Putman 1990, Veliger 33: 372-374 (diet). Stenoplax conspicua (Pilsbry, 1892) (assigned to subgenus Stenoradsia by Kaas and Van Belle, 1985-1994, volume 3). Rare north of southern California, where it is common under rocks in a similar habitat to S. heathiana. May be preyed upon by octopus, which drill small holes through the plates (Pilson and Taylor 1961, Science 134: 1366-1368). Abbott and Haderlie (1980) note that tiny snails in the genera Teinostoma and Vitrinella may occur under the girdle. 710

MOLLUSCA

Lepidozona cooperi (Dall, 1879) (=Ischnochiton cooperi). Most common from the low intertidal to 8 m, under rocks and hidden beneath sediment deposits on rocky surfaces. For a review of the genus, see Ferreira (1978). Lepidozona radians (Pilsbry, 1892) (=Ischnochiton radians) Recognized as distinct herein; formerly (e.g., Ferreira, 1978) considered a synonym of the somewhat more northern (Alaska to Washington) and more uniformly tan-colored or reddish L. interstincta (Gould, 1852) (=Ischnochiton interstinctus). L. radians is highly variable in its coloration pattern and is found at shallower depths and in somewhat more exposed habitats, and its range is from southeastern Alaska to northern Baja. Molecular distinctions have also been found (DJE and R. P. Kelly, unpublished). Occasional in the intertidal but most common between 5 m-13 m (ranging deeper) under rocks and hidden beneath sediment deposits on rocky surfaces. Lepidozona mertensii (Middendorff, 1847). Common in the intertidal to about 8 m, but ranging deeper, on bottom and sides of rocks. See Helfman 1968, Veliger 10: 290-291 (ctenostome bryozoan Farella elongata on ventral surface of girdle). *Lepidozona pectinulata (Carpenter in Pilsbry, 1893) \=L. californiensis (Berry, 1931)]. Rare north of southern California, where it is common under rocks in the low intertidal. Lepidozona regularis (Carpenter, 1855) (=Ischnochiton regularis). Assigned to subgenus Tripoplax by Kaas and Van Belle, 1985-1994, volume 4. Relatively rare, sometimes occurring under smooth cobbles in high energy shores. *Lepidozona retiporosa (Carpenter, 1864). Rare in < 1 5 m. *Lepidozona scabricostata (Carpenter, 1864). Rare in < 1 5 m and not likely north of southern California. Lepidozona scrobiculata (von Middendorff, 1847) [=Lepidozona sinudentata (Carpenter in Pilsbry, 1892)]. Most common from 5 m-10 m, under rocks and shells on sand. *Lepidozona willetti (Berry, 1917). Rare in < 1 5 m. Callistochiton connellyi Willett, 1937. Apparently a rare small species, known to occur in the intertidal. See Ferreira (1979) for a review of the genus. Callistochiton crassicostatus Pilsbry, 1893. Especially common under rocks in shallow subtidal habitats. Callistochiton palmulatus Dall, 1879. Especially common under rocks in sandy to silty shallow subtidal habitats; juveniles lack the bulging terminal valves typical of adults. LEPIDOCHITONIDAE

Cyanoplax berryana (Eernisse, 1986) (=Lepidochitona berryana). Especially common in sandy flat shelves on the top and sides of rocks at 0 m-3 m; not known north of San Mateo County. Cyanoplax caverna (Eernisse, 1986) (=Lepidochitona caverna). A small hermaphroditic chiton that normally appears to selffertilize its brooded embryos (or is parthenogenetic), only locally common and with limited known range between Santa Cruz and San Luis Obispo Counties (Eernisse 1988). Sometimes found nestled in the pallial groove of the larger Nuttallina californica, even while brooding, creating Russian doll-like layers of nested chitons (Gomez 1975, Veliger 18 Supplement: 28-29 mistakenly as C. dentiens; Eernisse 1986). Cyanoplax dentiens (Gould, 1846) (=Lepidochitona dentiens). Very common species, especially from the low intertidal to about 1 m, on the top and sides of rocky outcrops and boulders between central California and Alaska. Often overlooked because of its small size and cryptically variable color patterns. * = Not in key.

This species is easy to confuse with other members of the genus (Eernisse 1986; 1988). See Piercy 1987 (habitat, feeding). Cyanoplax hartwegii (Carpenter, 1855) (=Lepidochitona hartwegii). Common under the rockweed Silvetia compressa as well as in mid-intertidal tide pools, from Santa Cruz to northern Baja California. See DeBevoise (predation by seastars and crabs); Lyman (behavior); Robb (diet), Andrus and Legard (habitat), McGill (osmotic stress), and Connor (ecology), all in Veliger 18 Supplement, 1975. Cyanoplax keepiana (Berry, 1948) (=Lepidochitona keepiana). Found in warm protected pools under small stones, only rarely observed north of Cayucos. Cyanoplax lowei (Pilsbry, 1918) (=Cyanoplax fackenthallae Berry, 1919). Found exclusively amongst the holdfasts of the giant kelp, Macrocystis pyrifera, but rarely collected. *Cyanoplax cryptica (Kues, 1974). Found exclusively on the southern sea palm kelp, Eisenia arborea. Originally proposed as subspecies of Cyanoplax dentiens; not known north of Catalina Island. Cyanoplax thomasi (Pilsbry, 1898) (=Lepidochitona thomasi; =Nuttallina thomasi). A brooder with separate sexes, only locally abundant in mid-intertidal rocky cracks or under barnacle hummocks; known from the Monterey Peninsula to the southern Big Sur coastline. Closely related to the Pacific Northwest to southeastern Alaska C. femaldi (Eernisse, 1986), which reproductively resembles C. cavema in being a selfing (or parthenogenetic) hermaphroditic brooder. Nuttallina califomica (Reeve, 1847). Extremely common midintertidal species. Rare north of central California or south of Point Conception, California, but does occur as far south as northern Baja California. See Moore (predation by gulls), Nishi (feeding), Robbins (respiration), Andrus and Legard (habitat), Gomez (association with Cyanoplax), Linsenmeyer (behavior), Piper (physiology), Simonsen (osmotic stress), all in Veliger 18 Supplement, 1975. Nuttallina fluxa (Carpenter, 1864) [=Nuttallina scabra (Reeve, 1847), see Piper 1984], Rare north of southern California, where it is common in mid- to low intertidal habitats, including home depressions when the substrate is sandstone. Nuttallina sp. of Piper, 1984. More common in southern California, but does occur at central California localities with sandstone shelves, where it forms home depressions in the low intertidal.

MOPALIIDAE Placiphorella velata Dall, 1879. Can entrap small prey beneath anterior girdle flap (McLean 1962, Proc. Malacol. Soc. London 35: 23-26). Occasionally found in the intertidal but more common at 5 m-10 m on sides and bottoms of rocks. *Placiphorella mirabilis Clark, 1994. Greater than 15 m. See Clark 1994, Veliger 37: 290-311. Katharina tunicata (Wood, 1815). Occurs with Nuttallina califomica in central California; lives among corallines and mussels on exposed rocks from the Big Sur coastline to Alaska. See Giese et al. 1959 (reproduction); Tucker and Giese 1959 (shell repair); Nimitz and Giese 1964, Quart. J. Micr. Sci. 105: 481-495 and Lawrence and Giese 1969, Physiol. Zool. 42: 353-360 (both, chemical changes in reproduction and nutrition); Himmelman 1978, J. Exp. Mar. Biol. Ecol. 31: 27-41 (reproduction); Piercy 1987 (habitat, feeding); Stebbins 1988, Veliger 30: 351-357 (population structure, tenacity); Rostal and Simpson 1988, Veliger 31:120-126 (salinity); Dethier and Duggins 1984, Amer.

Nat. 124: 205-219 (ecology); Markel and DeWreede 1998, Mar. Ecol. Prog. Ser. 166: 151-161 (impact on kelp Hedophyllum). Tonicella lineata (Wood, 1815). Much rarer than the next species in the central California intertidal but not uncommon at 3 m - 8 m and by far the most common intertidal and shallow subtidal member of the genus from northern California to Alaska. Feeds on the upper layer of persistent coralline crustose algae, keeping other organisms from attaching. See Piercy 1987 (habitat, feeding); Clark 1999 (for discussion of literature prior to 1999 and proper species attributions). Tonicella lokii Clark, 1999. The most common of four lined chiton species in the intertidal of central California; formerly confused with the previous species. Tonicella undocaerulea Sirenko, 1973. Rare in the intertidal in central California; most common on top and sides of rocks at 12 m-17 m; our species is probably not the same as the one originally described from the northwestern Pacific, based on mitochondrial DNA distinctions (DJE, unpublished; see also Clark 1999). Tonicella venusta Clark, 1999. Most common on top and sides of rocks at 13 m-18 m. Cryptochiton stelleri (von Middendorff, 1847). A northern species found south to Monterey; intertidal throughout much of its range, but more commonly subtidal from 3 m-13 m around Monterey Peninsula. Occasionally found south to the Channel Islands, although it has been found in Native American middens from cold upwelling regions of northern Baja California (Emerson, 1956). See Heath 1897, Proc. Acad. Nat. Sci. Phil. 1897: 299-302 ( juvenile morphology); Okuda 1947, J. Fac. Sci. Hokkaido Univ. Zool. 9: 267-275 (postlarval development); Tucker and Giese 1959 (shell repair); Tucker and Giese 1962, J. Exp. Zool. 150: 33—43 (reproduction); MacGinitie and MacGinitie 1968, Veliger 11: 59-61 (food, growth, age, external cleaning); Webster 1968, Veliger 11: 121-125 (commensals; Palmer and Frank 1974, Veliger 16: 301-304 (growth); McDermid 1981 Veliger 23: 317-320 (association with epizoic red alga Pleonosporium). Talmadge (1975, Veliger 17: 414) reported that the carnivorous snail Ocinebrina lurida makes pits on the dorsal surface of C. stelleri, rasping down to the flesh under the valves. Dendrochiton flectens (Carpenter, 1864). [=Basiliochiton heathii (Pilsbry, 1898)] Mostly subtidal, 5 m-10 m, common on all sides of rocks, occasionally in low intertidal. Dendrochiton thamnoporus (Berry, 1911). Common on the Monterey Peninsula on top and sides of rocks from 4 m-15 m; rare in low intertidal. Mopalia acuta (Carpenter, 1855). Formerly confused with M. plumosa, in part (see below). Lowest intertidal to subtidal under rocks and shells on sand and beneath the sand line on larger rocks. Most abundant on Monterey Peninsula at 5 m-13 m. Mopalia ciliata (Sowerby, 1840). Locally common in low intertidal, under overhangs and in crevices to about 10 m on all sides of rocks; rare north of Monterey Bay. See Fitzgerald 1975, Veliger 18 Supplement: 37-39 (movement, phototactic responses); Piercy 1987 (habitat, feeding). Mopalia cirrata Berry, 1919. Subtidal in California. *Mopalia egretta Berry, 1919. Rare in central California; > 1 5 m. Mopalia ferreirai Clark, 1991. Subtidal in California at 5 m-15 m, on top and sides of rocks. Mopalia hindsii (Sowerby in Reeve, 1847). Most common in the mid intertidal to 2 m on exposed coasts, often found deep in crevices or on the walls of sea caves. See Giese et al. 1959 (reproduction); Tucker and Giese 1959 (shell repair); Andrus and Legard 1975 (habitat); Himmelman 1980 (reproduction, * = Not in key. POLYPLACOPHORA

711

British Columbia); Piercy 1 9 8 7 (habitat, feeding); Rostal and Simpson 1988, Veliger 31: 1 2 0 - 1 2 6 (salinity). Mopalia imporcata Carpenter, 1865. Subtidal in California, especially at about 8 m - 1 2 m, or apparently somewhat deeper in canyons, but occurs in the intertidal further north. Mopalia kennerleyi Carpenter, 1864. Recognized as distinct herein; formerly considered a synonym of Mopalia ciliata; rare south of San Francisco Bay. Himmelman 1 9 8 0 (reproduction, British Columbia, as M. ciliata). Mopalia lignosa (Gould, 1846). C o m m o n under rocks in intertidal. Around Monterey Peninsula, populations extend below 10 m in the kelp forests. See Fulton 1 9 7 5 (diet), Watanabe and C o x (reproduction), Andrus and Legard (habitat), Lebsack (physiology), Linsenmeyer (behavior), all in Veliger 18 Supplement, 1975; Himmelman 1 9 8 0 (reproduction, British Columbia). Mopalia lionota Pilsbry, 1918. Of the m a n y species of Mopalia with dense setae, this is probably the most heavily ornamented. Most c o m m o n from the low intertidal to about 3 m, especially in the granite and sand channel habitat in Monterey. Mopalia lowei Pilsbry, 1918. Subtidal in California, especially from 5 m - 1 0 m on all sides of rocks. Mopalia muscosa (Gould, 1846). A familiar high- to low-intertidal chiton often covered with algae. Its stiff setae and oval shape distinguish it from the superficially similar but narrower members of Nuttallina, which also differ in bearing spines on close inspection. See Fitzgerald (movement, phototactic responses), Smith (behavior), Watanabe and C o x (reproduction), Andrus and Legard (habitat), and Westersund (movement), all in Veliger 18 Supplement, 1975; Monroe and Boolootian 1965, Bull. So. Calif. Acad. Sei. 64: 2 2 3 - 2 2 8 (reproduction); Himmelman 1 9 8 0 (reproduction, British Columbia); Leise 1984, Zoomorphology 104: 3 3 7 - 3 4 3 (metamorphosis); Piercy 1 9 8 7 (habitat, feeding). See also Barnawell (1960), who found that Mopalia muscosa, M. ciliata, and M. hindsii include bryozoans, hydroids, and barnacles in their diets. *Mopalia phorminx Berry, 1919. Greater than 15 m. Mopalia plumosa Carpenter in Pilsbry, 1893. Recognized as distinct herein; formerly considered a synonym of Mopalia acuta. Ranges from low intertidal to 7 m in Monterey Bay. Mopalia porifera Pilsbry, 1893. More c o m m o n in northern Baja California. Mopalia sinuata Carpenter, 1864. Subtidal in California, most c o m m o n on the upper surfaces of rocks, from 8 m downward. Mopalia spectabilis Cowan and Cowan, 1977. Subtidal in California, under rocks at 7 m - 1 2 m. See Cowan and Cowan 1977, Syesis 10: 4 5 - 5 2 . Mopalia swanii Carpenter, 1864. Rare south of Oregon. Mopalia vespertina (Gould, 1852) (=Mopalia laevior Pilsbry, 1918). Includes M. hindsii recurvans Barnawell, 1960. Rare in central California, usually on sides and top of rocks at 3 m - 1 5 m.

References Abbott, D. P. 1987. Observing marine invertebrates. G. H. Hilgard, ed. Stanford, CA: Stanford University Press, 380 pp. Andrus, J. K., and W. B. Legard. 1975. Description of the habitats of several intertidal chitons (Mollusca: Polyplacophora) found along the Monterey Peninsula of central California. Veliger 18 (supplement): 3-8. Barnawell, E. B. 1960. The carnivorous habit among the Polyplacophora. Veliger 2: 85-88. Berry, S. S. 1917, 1919. Notes on West American chitons—I and II. Proc. Calif. Acad. Sei. (4) 7: 229-248 and 9: 1-36. * = Not in key. 712

MOLLUSCA

Berry, S. S. 1961. Chitons, their collection and preservation, pp. 44-49. In How to collect shells. 2nd ed. American Malacological Union. Buckland-Nicks, J. 1995. Ultrastructure of sperm and sperm-egg interaction in Aculifera: implications for molluscan phylogeny. Mémoires du Muséum national d'Histoire naturelle 166: 129-153. Burghardt, G. E., and L. E. Burghardt. 1969. A collector's guide to west coast chitons. San Francisco Aquarium Society, Special Publication 4, 45 pp. Clark R. N. 1991. A new species of Mopalia (Polyplacophora: Mopaliidae) from the northeast Pacific. Veliger 34: 309-313. Clark R. N. 1999. The Tonicella lineata (Wood, 1815) species complex (Polyplacophora: Tonicellidae), with descriptions of two new species. American Malacological Bulletin 15: 33-46. Clark R. N. 2004. On the identity of von Middendorff's Chiton sitchensis and Chiton scrobiculatus. Festivus 36: 49-52. Dethier, M. N., and D. O. Duggins. 1984. An "indirect commensalisms" between marine herbivores and the importance of competitive hierarchies. Am. Nat. 124:205-219. Duggins, D. O., and M. N. Dethier. 1985. Experimental studies on herbivory and algal competition in a low intertidal habitat. Oecologia 67: 183-191. Eernisse, D.J. 1986. The genus Lepidochitona Gray, 1821 (Mollusca: Polyplacophora) in the northeastern Pacific Ocean (Oregonian and Californian provinces). Zoologische Verhandelingen 228: 3-52. Eernisse, D. J. 1988. Reproductive patterns in six species of Lepidochitona (Mollusca: Polyplacophora) from the Pacific coast of North America. Biological Bulletin 174: 287-302. Eernisse, D. J. 1998. Class Polyplacophora, pp. 49-73. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and the Western Santa Barbara Channel. Volume 8. The Mollusca, Part 1: Aplacophora, Polyplacophora, Scaphopoda, Bivalvia and Cephalopoda. P. V. Scott and J. A. Blake, eds. Santa Barbara, CA: Santa Barbara Museum of Natural History. Eernisse, D. J., and P. D. Reynolds. 1994. Chapter 3. Polyplacophora, pp. 56-110. In Microscopic anatomy of invertebrates, Volume 5, Mollusca 1. New York: Wiley-Liss. Eernisse, D. J., N. B. Terwilliger, and R. C. Terwilliger. 1988. The red foot of a lepidopleurid chiton: Evidence for tissue hemoglobins. Veliger 30: 244-247. Emerson, W. K. 1956a. Upwelling and associated marine life along Pacific Baja California, Mexico. Journal of Paleontology 30: 393-397. Ferreira, A. J. 1978. The genus Lepidozona (Mollusca: Polyplacophora) in the temperate eastern Pacific, Baja California to Alaska, with the description of a new species. Veliger 21: 19-44. Ferreira, A. J. 1979. The genus Callistochiton Dall, 1879 (Mollusca: Polyplacophora) in the eastern Pacific, with the description of a new species. Veliger 21: 444-466. Ferreira, A. J. 1982. The family Lepidochitonidae Iredale, 1914 (Mollusca: Polyplacophora) in the northeastern Pacific. Veliger 25: 93-138. Giese, A. C., J. S. Tucker, and R. A. Boolootian 1959. Annual reproductive cycles of the chitons Katharina tunicata and Mopalia hindsii. Biol. Bull. 117: 81-88. Haderlie, E. C., and D. P. Abbott. 1980. Polyplachophora: the chitons, pp. 412-428. In Intertidal invertebrates of California. Morris, R. H., D. P. Abbott, and E. C. Haderlie, eds. Stanford, CA: Stanford University Press. Hanselman, G. A. 1970. Preparation of chitons for the collector's cabinet. Of Sea and Shore 1: 17-22. Heath, H. 1899. The development of Ischnochiton. Zool. Jahrb., Abt. Anat. Ontog. Tiere 12: 567-656. Himmelman, J. H. 1980. Reproductive cycle patterns in the chiton genus Mopalia (Polyplacophora). Nautilus 94: 39^49. Hyman, L. H. 1967. The Invertebrates: Mollusca I, Vol. VI. McGraw-Hill, pp. 70-142. Kaas, P., and R. A. Van Belle, 1985-1994. Monograph of living chitons. Vols. 1-5. E. J. Brill/Dr W. Backhuys, Leiden. Kelly, R. P., and D. J. Eernisse. 2007. Southern hospitality: A latitudinal gradient in gene flow in the marine environment. Evolution, 61. Kelly. R. P., I. N. Sarkar, D. J. Eernisse, and R. Desalle. 2007. DNA barcoding using chitons (genus Mopalia). Molecular Ecology Notes 7. Lamb, A., and B. P. Hanby. 2005. Marine life of the Pacific Northwest: a photographic encyclopedia of invertebrates, seaweeds and selected fishes. Madeira Park, B.C., Canada: Harbour Publishing. Leise, E. M., and R. A. Cloney. 1982. Chiton integument: ultrastructure of the sensory hairs of Mopalia muscosa (Mollusca: Polyplacophora). Cell and Tissue Research 223: 43-59. Lowenstam, H. A. 1962. Magnetite in denticle capping in Recent chitons (Polyplacophora.) Bull. Geol. Soc. Amer. 73: 435-438.

Okusu, A., E. Schwabe, D. J. Eemisse, and G. Giribet. 2 0 0 3 . Towards a phytogeny of chitons (Mollusca: Polyplacophora) based on combined analysis of five molecular loci. Organisms Diversity and Evolution 3 : 2 8 1 - 3 0 2 . Omelich, P. 1 9 6 7 . The behavioral role and the structure of the aesthetes of chitons. Veliger 10: 7 7 - 8 2 . Piercy, R. D. 1 9 8 7 . Habitat and food preferences in six Eastern Pacific chiton species (Mollusca: Polyplacophora). Veliger 2 9 : 3 8 8 - 3 9 3 . Pilsbry, H. A. 1 8 9 2 - 1 8 9 4 . Polyplacophora (Chitons). Manual of Conchology 14, 3 5 0 pp.; 15, 133 pp. Piper, S. C. 1 9 8 4 . Biology of the marine intertidal mollusc Nuttallina, with special reference to vertical zonation, t a x o n o m y and biogeography (electrophoresis, growth, movement). Ph.D. Dissertation, University of California, San Diego, 6 9 8 pp. Sirenko, B. I. 1 9 9 3 . Revision of the system of the order Chitonida (Mollusca: Polyplacophora) o n the basis of correlation between the type of gills arrangement and the shape of the c h o r i o n processes. Ruthenica 3: 9 3 - 1 1 7 . Sirenko, B. I. 1 9 9 7 . The importance of the development of articulam e n t u m for t a x o n o m y of chitons (Mollusca, Polyplacophora). Ruthenica 7: 1 - 2 4 . Sirenko, B. 2 0 0 6 . New outlook on the system of chitons (Mollusca: Polyplacophora). Venus 6 5 : 2 7 ^ 4 9 . Smith, A. G. 1 9 6 0 . Amphineura. In Treatise on invertebrate paleontology. Part I, Mollusca 1, pp. 4 1 - 7 6 . R. C. Moore, ed. Univ. Kansas Press and Geol. Soc. Amer. Smith, A. G. 1 9 6 6 . The larval development of chitons (Amphineura). Proc. Calif. Acad. Sei. (4) 32: 4 3 3 - 4 4 6 . Smith, A.G. 1 9 7 7 . Rectification of West Coast chiton nomenclature (Mollusca: Polyplacophora). Veliger 19: 2 1 5 - 2 5 8 . Strathmann, M., and D. J. Eernisse. 1 9 8 7 . Phylum Mollusca, Class Polyplacophora, pp. 2 0 5 - 2 1 9 in The Friday Harbor Labs Handbook of Marine Invertebrate Embryology. Seattle: Univ. of Wash. Press. Thorpe, S. R., Jr. 1 9 6 2 . A preliminary report o n spawning and related p h e n o m e n a in California chitons. Veliger 4: 2 0 2 - 2 1 0 . Tomlinson, J., D. Reilly, and R. Ballering. 1 9 8 0 . Magnetic radular teeth and geomagnetic responses in chitons. Veliger 2 3 : 1 6 7 - 1 7 0 . Tucker, J. S., and A. C. Giese. 1 9 5 9 . Shell repair in chitons. Biol. Bull. 116: 3 1 8 - 3 2 2 . Yonge, C. M. 1 9 3 9 . O n the mantle cavity and its contained organs in the Loricata (Placophora). Quart. J. Micro. Sei. 8 1 : 3 6 7 - 3 9 0 . Yonge, C. M. 1 9 6 0 . General Characters of Mollusca, pp. 3 - 3 6 . In Treatise on invertebrate paleontology. Part I. Mollusca 1. R.C. Moore, ed. New York: Geol. Soc. Amer.; Lawrence: University of Kansas Press.

Gastropoda Shelled Gastropoda JAMES H. McLEAN (Plates 3 5 5 - 3 7 3 )

The gastropods are the largest class of mollusks and exhibit enormous diversity in form and habitat. Limpets, top shells, abalone shells, periwinkles, slipper shells, and whelks are well known to observers of tide pool animals. T h e beauty of m a n y gastropod shells, especially from tropical regions, has long made t h e m favored objects for collections. Our relatively advanced knowledge of t h e t a x o n o m y of the gastropods is in large part due to the interest of amateur shell collectors. This section deals with those gastropods with external shells that occur between Oregon and Point Conception, California, other than t h e patellogastropod limpets (see separate text by David Lindberg), all species of Littorina (separate text by David Reid) and pelagic gastropods (separate text by Roger Seapy and Carol Lalli). As in the 1975 text, shelled opisthobranchs are included, w h i c h are also treated separately by Gosliner and Williams.* Gastropods possess a muscular foot for creeping or burrowing, a head with sensory tentacles and eyes, and a characterist i c s section is revised from 1975 text by James T. Carlton and Barry Roth.

tic rasping radula (absent in some). As in all mollusks, the mantle secretes the shell and provides, in the pallial cavity, a shelter for the gills (CTENIDIA). A hallmark of the gastropods that sets t h e m apart from other mollusks is the p h e n o m e n o n of TORSION, which occurs early in development. Torsion consists of a 180° counterclockwise rotation of the visceral mass upon the head and foot; the result is that the mantle cavity, ctenidia, and anus, w h i c h were originally at the rear, c o m e to lie just above the head. Torsion in its fullest expression characterizes the prosobranch grade (meaning front gills), in which the ctenidia lie anteriorly and the nervous system is twisted into a crude figure 8 (the STREPTONEUROUS condition). Other groups of gastropods have tended to modify the extreme effects of torsion, o n e change being a straightening out of the nervous system to the EUTHYNEUROUS condition. Euthyneury has been attained in two ways: in opisthobranchs, the body has " u n w o u n d " itself in DETORSION; in the pulmonates, the body has retained m u c h of its torsion, but the central nervous system has straightened out by condensation into a ring of ganglia around the esophagus. Torsion is n o t the same thing as the coiling of the shell and visceral h u m p of most gastropods. Coiling serves to strengthen the shell, but it is lost in limpetlike gastropods, land slugs, and nudibranchs, which as adults have reduced or lost the shell and flattened the visceral h u m p . Coiling is not unique to the gastropods; it is also found in the cephalopod Nautilus and m a n y extinct, shelled cephalopods.

CLASSIFICATION Higher classification of gastropods has undergone fundamental changes in the 3 0 years since the 1 9 7 5 publication of t h e last edition of Light's Manual. In that work, the prevailing classification was followed in which the divisions for the class Gastropoda were the subclasses Prosobranchia, Opisthobranchia, and Pulmonata; the prosobranchs were further subdivided into the orders Archaeogastropoda, Mesogastropoda, and Neogastropoda. That classification scheme is now considered to have been based on recognition of grades of complexity. T h e basic hypotheses of gastropod phylogeny have been greatly altered by the application of cladistic methodology and molecular genetics (see Introduction to Mollusca). The classification system adopted here was introduced by consensus during the 1990s, in papers by Lindberg, Haszprunar, and Ponder and other authors w h o preceded the publication of the two mollusk volumes for the m o n u m e n t a l Fauna of Australia (Beesley et al., 1998). A general phylogeny for Mollusca was presented in simplified form and reiterated by Lindberg, Ponder and Haszprunar (2004) in their section on Mollusca for the Tree of Life volume. The two major divisions for the class Gastropoda are t h e subclasses EOGASTROPODA (represented by t h e living Patellogastropoda) and ORTHOGASTROPODA (containing all other gastropods), n o w placed within five m o n o p h y l e t i c clades. These five groups are t h e superorders: VETIGASTROPODA, NERITOGASTROPODA, COCCULINIDA, CAENOGASTROPODA, a n d HETEROBRANCHIA.

The eogastropod superorder Patellogastropoda is treated separately by Lindberg. Two of t h e five orthogastropod superorders are n o t represented in the intertidal of Oregon and central California: t h e Neritogastropoda, w h i c h are mostly tropical, and the Cocculinida, which occur offshore in deep water.

GASTROPODA:

SHELLED

713

body whorl

PLATE 355 Generalized gastropod shell.

shoulder

outer lip

inner lip and portion of columella

aperture

columellar folds

anterior (siphonal) canal

Classification at t h e family and superfamily level remains m u c h the same as in the 1975 edition of Light's Manual and follows the usage by Ponder and others in the Fauna of Australia (1998). That work should be consulted for greater detail at all levels of higher classification to the family and subfamily level. The families and superfamilies n o t represented in shallow water from central California to Oregon are omitted in the outline of classification that follows.

included here were previously considered to comprise t h e primitive prosobranch order Archaeogastropoda, along with the excluded "docoglossate" limpets, which are now known as the Patellogastropoda. Superfamilies treated here are: Fissurelloidea, Pleurotomarioidea, and Trochoidea.

After the text for this work was completed, a revised classification of gastropods was provided as Part 2 of Bouchet and Rocroi (2005). The nomenclátor of Part 1 provides a long-needed standard source for authorship and dates at the family, subfamily, and superfamily level. It was too late to fully adopt the new classification, which introduced a few changes to the content of superfamilies. The content of families has remained essentially unchanged in the revised classification of Bouchet and Rocroi.

Shell never nacreous, operculum usually present at maturity (except in those of limpet form), ctenidium single, monopectinate, fused with roof of mantle cavity. Radula with seven teeth per row (taenioglossate condition), simplified to t h e fanglike ptenoglossate condition in some parasitic members, or reduced to three teeth per row (rachiglossate condition), or lost. There are substantial modifications in shell form correlated with diverse kinds of feeding. Shell form ranges f r o m groups with simple apertures to groups with siphonal canals, including some that are mucus- and filter-feeders (calyptraeids and vermetids), carnivores o n sessile invertebrates (velutinoids), shell drillers of bivalves (naticids), sponge feeders (triphoroids), and ectoparasites (epitoniids and eulimids). Most have the males with a cephalic penis, and t h e females produce egg capsules that allow for direct development or release of veliger larvae. Some are protandrous hermaprodites, c h a n g i n g f r o m males to females (calyptraeids).

VETIGASTROPODA Shell coiled or limpet-shaped; with nacreous or non-nacreous shells; ctenidia bipectinate (with cilia-bearing filaments on both sides of gill axis); operculum usually present at maturity (except in limpet groups). Those groups with paired ctenidia have the shell with a slit or holes for excurrent flow of water. Groups that have lost the right ctenidium have also lost the slit or holes in the shell. The radula is rhipidoglossate (many teeth in row), used for grazing on algae or diatoms, but some groups are carnivores on sponges and other sessile invertebrates. Sexes are separate, and most are broadcast spawners. The superfamilies 714

MOLLUSCA

CAENOGASTROPODA

This is the largest monophyletic clade of gastropods; this name has long been in use to include all groups that were previously regarded as mesogastropod and neogastropod prosobranchs. Among this large group, only t h e neogastropods

(rachiglossate or toxoglossate radula) are now regarded as a distinct monophyletic clade within the Caenogastropoda. Superfamilies treated here are: Cerithioidea, Littorinoidea, Cingulopsoidea, Rissoidea, Vanikoroidea, Calyptraeoidea, Vermetoidea, Velutinoidea, Naticoidea, Triphoroidea, Epitonioidea, and Eulimoidea. NEOGASTROPODA

Shell with siphonal canal to shield the incurrent siphon formed by mantle edge; predaceous feeding by means of long, extensible proboscis with mouth and radula at the tip; heightened development of sensory osphradium for detection of living prey; some scavenging of fresh dead prey (Nassariidae). Radula with three teeth per row (rachiglossate condition), or single hollow tooth in Conoidea, modified for injection of venom (toxoglossate condition). Superfamilies treated here are the Muricoidea and Conoidea. HETEROBRANCHIA This clade now includes the large orders Opisthobranchia and Pulmonata, as well as some basal members, which previously had been considered to be mesogastropod prosobranchs. Members with external shells have a heterostrophic protoconch, in which the coiling direction of the mature whorls changes abruptly. All are hermaphroditic and engage in reciprocal copulation. There are various kinds of development. The basal groups (here represented by the first three superfamilies) are operculate, by which they differ from opisthobranchs, in which the operculum is lacking. Superfamilies treated here are Rissoelloidea, Omalogyroidea, and Pyramidelloidea. OPISTHOBRANCHIA

Opisthobranchs are characterized by full detorsión, which places the gills on the right side or rear. They are highly diverse, the best known are shell-less nudibranchs or sea-slugs (treated in a separate section by McDonald). Several clades (suborder Cephalaspidea and Notaspidea) retain a shell in the adult; only these two suborders are keyed in this section (see separate section for further details about anatomy and biology in these two groups).

CEPHALASPIDEA

Shell retained at maturity, body with a broad head-shield. Includes carnivores, herbivores, and detritus feeders. They are included here for comparison of the shells with those of caenogastropods. Superfamilies treated here are Acteonoidea, Philinoidea, Diaphanoidea, Haminoidea, and Bulloidea. Shelled species of cephalaspideans are also here treated by Gosliner and Williams. NOTASPIDEA

Shell limpet-shaped, body much larger than shell. Superfamily treated here: Umbraculoidea. See also Gosliner and Williams. PULMONATA

The vascularized lining of the mantle cavity serves as a lung; ctenidia are lost. Most members are terrestrial or freshwater;

only a few families are marine or live in brackish water. Marine pulmonates are primarily tropical; there are only a few species in temperate waters. BASOMMATOPHORA

Eyes at the base of the cephalic tentacles. Herbivores and filter feeders. Superfamilies treated here: Siphonarioidea, Ellobioidea, Trimusculoidea.

TERMINOLOGY

Many of the terms used in the key are illustrated in plate 355, which shows a generalized gastropod shell. The gastropod shell is essentially a spirally coiled tube of increasing diameter; each turn of the spiral is a WHORL. Coiling may take place in a single plane (PLANISPIRAL coiling) or, more frequently, in descending stages encircling a projected C O I L I N G A X I S . The spiral trace of juncture with preceding or succeeding whorls is the S U T U R E , which may be weakly or strong I M P R E S S E D . The A P E X of the shell is formed by the early growth stage, the PROTOCONCH, together with the early T E L E O C O N C H whorls, forms the A P I C A L WHORLS. The apical and subsequent whorls, except the final whorl, form the S P I R E . The FINAL W H O R L , also called the B O D Y WHORL, terminates at the APERTURE, which may be marked by a thickening of the I N N E R and O U T E R LIPS. The base of the shell near the coiling axis forms the C O L U M E L L A (or PILLAR), which may be marked by C O L U M E L L A R F O L D S , and the outer lip may bear D E N T I C L E S or elongate L I R A T I O N S . Shell profile of coiled gastropods ranges from A U R I F O R M (broadly inflated), T R O C H I F O R M (shell diameter greater than shell height), F U S I F O R M (with siphonal canal or notch), or long and slender. Trochiform shells may have a rounded aperture ( C O M P L E T E P E R I S T O M E ) or an aperture interrupted above the columella (incomplete peristome); there may be a hollow indentation, an UMBILICUS, on the base of the shell that coincides with the coiling axis. The upper part of the aperture above the columella is the PARIETAL area, which may produce a PARIETAL S H I E L D that thickens the body whorl to the left of the aperture. The area of greatest breadth in a coiled shell is termed the P E R I P H E R Y of the whorls. The whorl profile may be ROUNDED, ANGULATE, or SHOULDERED.

Most gastropods have a separate, usually uncalcified, chitinous OPERCULUM, which is attached to the upper part of the foot in an active snail, but occludes part or all of the aperture when the animal withdraws into its shell. Opercular shapes include MULTISPIRAL, if the surface is evenly coiled (as in trochids), P A U C I S P I R A L if unevenly coiled (littorinids and naticids), or L E A F - S H A P E D if the operculum is uncoiled and has its nucleus toward the anterior edge (most neogastropods). Calcified opercula (Turbinidae and Tricoliidae and in some members of Naticidae) are enveloped by the foot and have a pattern unlike that of the inner side. The surface of gastropod shell may be smooth or variously sculptured. Surface features are described as A X I A L if oriented in the direction of the coiling axis, S P I R A L if following the direction of the growing whorl. Features of axial sculpture are R I B S , N O D E S , and L A M E L L A E (thin, raised, platelike structures); features of spiral sculpture are C O R D S , T H R E A D S , or I N C I S E D STRIAE. A netlike sculpture composed of equally strong radial and concentric ribs is termed R E T I C U L A T E or C A N C E L L A T E . On limpet shells, sculpture that extends from the apex of the shell GASTROPODA:

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outward toward the margin is termed RADIAL; sculpture that parallels the margin is termed CONCENTRIC. Some gastropods, notably certain Muricidae, periodically develop prominent axial thickenings that may be ornamented with scales or spines; these thickenings are called VARICES (singular VARIX) and represent resting periods during which shell length does not increase, instead increasing the axial calcification at the VARIX, which may become the final lip in species that have DETERMINATE growth. Fine axial GROWTH LINES may traverse the whorls; these represent traces of the former position of the aperture. A thin exterior layer of organic material, at times textured or embellished, forms the PERIOSTRACUM, which may be removed by wear, exposing the calcareous shell layer beneath. Shells of marine gastropods have at least two layers, a pearly NACREOUS layer (if present) is the innermost layer; shell pigments are usually confined to the outermost layer. The PROTOCONCH, at the shell apex (formerly called the nuclear whorls), consists of the embryonic whorls, which directly represents the apical view of the larval shell (if it is retained at later growth stages). If the protoconch has numerous microscopic whorls (MULTISPIRAL condition), it represents the entire VELIGER shell of the free-swimming larval stage; if it has few whorls and the tip is relatively large and off-center, it is called PAUCISPIRAL and is indicative of direct development without a free-swimming larval stage. The apical whorls of mature specimens may be worn away if the animal lives in exposed habitats, as frequently occurs in the intertidal zone; in such cases, calcareous deposits form plugs from within that seal the apical whorls so that the shell continues to be fully protective. In some species, it is unusual to find a fully mature shell with an intact protoconch, so for such species it is necessary to examine growth stages to observe protoconch morphology. Some shells of living animals may be so heavily encrusted with epizoic bryozoa or algae that the encrustations have to be chipped away to reveal the surface sculpture. Shells of species that live at greater depths are least affected by encrusting organisms. Direction of coiling is usually to the right (DEXTRAL) or rarely to the left (SINISTRAL), when viewed with the apex uppermost and the aperture in view. If the aperture lies to the right of the coiling axis, the shell is dextral; if to the left, it is sinistral. With regard to the living animal, the apex of a shell is posterior, its base anterior. The coiling axis, however, does not coincide with the long axis of the extended animal, because the spire projects posteriorly and to the right. Height or length of a coiled gastropod shell are the same and should be measured along the projected coiling axis. In limpets, length indicates the longest dimension. Width or breadth is measured at right angles to height. Shells that are cap-shaped have arisen several times, but all are known collectively as limpets. In calyptraeid and hipponicid limpets, the early coiling stage is retained in the adult shell, but in patellogastropod limpets and some fissurellid limpets, the coiled stage may be limited to the protoconch, which is seldom retained at later growth stages. In most limpet shells, the anterior and posterior may be determined from the muscle scar, which is open anteriorly corresponding to the head and opening of the mantle cavity.

COLLECTION AND PRESERVATION

Examination of particular habitats will reveal many species that would otherwise be overlooked. Species living on algae or marine 716

MOLLUSCA

grasses can be collected with a hand net or strainer. Dark overhanging ledges or deep crevices may hide nocturnal, negatively phototactic species. The expanded mantle of Trivia and Lamellaria match the color and shape of ascidians they prey upon; apertures of hermit crab shells may be examined for Crepidula and sponges for triphorids and cerithiopsids; the base and column of sea anemones are often fruitful hunting grounds for epitoniids; echinoderms should be examined for eulimids. Mollusks, sedentary polychaetes, and other invertebrates may be examined for ectoparasitic pyramidellids. Microgastropods may be collected by vigorous shaking or washing of algae, and the holdfasts or roots of the surfgrass Phyllospadix and the eelgrass Zostera. Other methods are the shaking of small rocks in plastic bags or buckets and the direct sampling of sand and gravel sediments that accumulate under rocks. If the entire sample is placed in a basin of seawater, living specimens will emerge from the sediments and crawl up the sides of the container. Sand, gravel, or detritus collected in such ways may be screened to separate the size fractions and preserved in alcohol or dried, the microgastropods later to be sorted out under low magnification. Minimal damage to the habitat should always be the rule in collecting; overturned rocks should be replaced in their original positions, and only small amounts of algae or grasses should be taken from any one area. Large collections of a single species from one area should be avoided. Snails may be relaxed with the bodies extended, either for dissection or subsequent fixation, in a 7% solution of MgCl2-6H20 in fresh water, which is isotonic with seawater and may be used to partially or completely replace seawater. Another method is to sprinkle menthol crystals on the surface of a shallow dish of seawater, or by adding one or two drops of propylene phenoxetol in 200 ml-400 ml of seawater. It is usually necessary to crack the shells of living specimens in a vise so the columellar muscle may be separated from the shell for a dissection or to ensure that preservatives can reach the gonads. Bodies may be preserved in 75% ethyl or isopropyl alcohol, or in 95% ethanol for genetic studies; the use of formalin will leach the shell surface and make the tissues unfit for purposes of molecular genetics. Specimens for collections or retained as vouchers should be preserved both wet and dry. For long-term preservation, microshells are best preserved dry because fluid preservation will eventually damage the shell.

THE FAUNA AND THE KEYS

The relatively low sea surface temperatures in central California and Oregon are indicative of a temperate, cool water faunal province, known to molluscan workers as the Oregonian faunal province. The Californian faunal province prevails in the subtropical conditions to the south of Point Conception, where summer sea surface temperatures are higher. Many northern species extend south to Point Conception, and a number of more southern species do not extend north of Point Conception. Toward the north, the transition to the boreal, cold water conditions is not as sharply defined; many of the species of central California have distributions that extend to Alaska. For entry to the literature on faunal provinces, see Roy et al. (1998). The intertidal, shelled gastropod fauna of the region is generally well known. The majority of species were described

before 1875, with P. P. Carpenter, W. H. Dall, and A. A. Gould naming most of the species treated here. However, some wellknown taxa have long masked the presence of cryptic species. Two common species (Littorina plena and Nucella ostrina) were recently distinguished from Littorina scutulata and Nucella emarginata, respectively, based on anatomical distinctions that are also reflected in finer details of shell morphology (see species lists for further details). Nucella analoga is here distinguished from N. canaliculata, although further work is needed to confirm this. More such cases are to be expected. Except for microgastropods, few new species have been found in our intertidal fauna after 1920. Northern range extensions of southern species during warm water years, new records of microgastropods, and newly introduced species are to be expected. A surprisingly large number of species have been introduced to the northeastern Pacific, most arriving from the North Atlantic or northwestern Pacific with oyster culture, including Batillaria attramentaría, Littorina littorea, Crepidula plana, Ocenebrellus inomatus, Urosalpinx cinerea, Ilyanassa obsoleta, and Busycotypus canaliculars. Littorina saxatilis is a recent arrival introduced in seaweed packed with bait worms from Maine. The keys to species include most of the intertidal shelled gastropods occurring between the Columbia River and Point Conception. Certain species common in southern California or Washington have not been included, and users of the key are cautioned against attempting to apply it outside its intended range. Worn, eroded, or juvenile specimens with immature lips will not key out or will key out incorrectly. Sizes given in the keys are average sizes. For most species of shelled gastropods, the intertidal zone represents an upper limit of the available marine habitat in which conditions are not severe for very long and the amount of exposure to air is minimal. For such species, most members of a local population live and reproduce in a much more extensive sublittoral region. There is only a very small group of species for which sublittoral occurrences are not generally known. Of the species treated here, the exclusively intertidal species are: most Patellogastropoda, Fissurella volcano, Homalopoma baculum, Chlorostoma funebralis, Lirularia succincta, Cerithidea californica, Batillaria attramentaria, all Littorina, Assiminea californica, Fartulum orcutti, all Acanthinucella, all Nucella, Lirabuccinum dirum, Ilyanassa obsoleta, Myosotella myosotis, and Trimusculus reticulatus. There were 106 gastropod species keyed and illustrated by Carlton and Roth (1975), including 17 species of patellogastropods and three species of Littorina. Here I key and illustrate 170 species (not counting patellogastropods and Littorina), which amounts to the inclusion of about 88 species not previously treated. This increase is due to the inclusion of microgastropods and the addition of some species that are more likely to occur in the shallow sublittoral than in the intertidal zone. Shells of offshore species are frequently inhabited by hermit crabs in shallow water. The key to the families is an artificial key based on shell characters intended to reach the correct family in the shortest number of steps. Some families have species with such a range of shell morphology that the family for certain genera has had to be keyed more than once. Families and the keys to species within families are arranged in the now current systematic order so that their position in the classification can be kept in mind. Notes on superfamilies are given only if there is more than one family in the superfamily treated here. General information for each family precedes the keys to the species for each family.

CHANGES TO NAMES

An extensive number of changes to names at the generic, specific, and in some cases at the family level, compared to the 1975 edition, are evident here. In many cases, the changes are necessitated by the need to recognize the recent work of specialists. Some of the changes have already been introduced in an account that treated offshore gastropods of southern California (McLean 1996). Some species have until now been known under broadly defined genera, and their more correct assignment to more narrowly defined subgenera have been recognized in current taxonomic works but ignored in faunal guides. In such cases, I make changes that are elevations of long-established subgenera to full genera, recognizing that our species differ in significant ways from the familiar genera, for which the type species may be from a far distant faunal province. Examples of such changes introduced here are the replacement of Tegula by Chlorostoma and the replacement of Olivella by Callianax. Another reason to avoid the usage of subgenera is that modern systematists have not wanted to imply relationships not demonstrated by cladistic analysis. All changes and the reasons for making them are noted in the text. This effort is part of a larger taxonomic manual and full revision of the northeastern Pacific marine gastropods, comparable to the book on the northeastern Pacific bivalves of Coan, Scott, and Bernard (2000). Changes in taxonomy are justified in greater detail in the forthcoming revisions and taxonomic guides (northern and southern) to the shelled gastropods of the northeastern Pacific. MAJOR SOURCES

For detailed treatments of the morphology, biology, and classification of gastropods at the family and superfamily level, the current standard is provided in the gastropod volume of Fauna of Australia (Beesley et al. 1999), with separate contributions by authors in their group of specialization. Excellent accounts and drawings of gastropod anatomy are provided in the revised edition of British Prosobranch Molluscs (Fretter and Graham 1994). For shell character terminology see Cox (1960). See the general introduction to Mollusca for other useful works on mollusks. Marine gastropods from Washington and the Pacific Northwest were treated by Kozloff (1987); those of southern California by McLean (1978); and some deeper-water species of southern California by McLean (1996). D. P. Abbott and Haderlie (1980) provided color illustrations and accounts of biology for some of the common intertidal gastropods of both northern and southern California. Basic works on taxonomy are Dall's (1921) distributional checklist, Oldroyd's (1927) copies of original descriptions of species listed by Dall, and R. T. Abbott's American Seashells (1974); common and scientific names were updated by Turgeon (2nd ed., 1998). Palmer's (1958) treatment of species described by P. P. Carpenter is an extremely useful compilation; Boss, Rosewater, and Ruhoff (1968) and Johnson (1964) have provided listings of the taxa of W. H. Dall and A. A. Gould respectively.

KEY TO FAMILIES

Based on shell characters. 1. Shell of limpet form — Shell spirally coiled or tubular GASTROPODA:

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2. — 3. — 4. — 5. — 6. — 7. — 8. — 9. — 10. — 11. — 12. — 13. — 14. — 15. — 16. — 17. — 18. — 19. — 20. — 21. — 22. — 23. — 24. — 25. — 26. — 27.

718

Shell Shell Shell Shell Apex

with apical foramen or interior septum 3 not with apical foramen or interior septum 4 with apical foramen Fissuerellidae with interior septum Calyptraeidae anterior, above opening of muscle scar Patellogastropoda Apex central or posterior 5 Shell colored 6 Shell white under periostracum 7 Periostracum thick, extending beyond shell margin Tylodinidae Periostracum thin, extending only to shell margin Siphonariidae Apex posterior Hipponicidae Apex central Trimusculidae Shell tubular 9 Shell with regular coiling 10 Shell a curved tube Caecidae Shell an irregular tube Vermetidae Shell with slit-band and single foramen or with row of tubular holes 11 Shell not with single foramen or row of tubular holes 12 Shell large, inflated, nacreous, with row of tubular holes Haliotidae Shell minute, white, non-nacreous, slit band and single hole Scissurellidae Shell interior nacreous 13 Shell interior not nacreous 15 Operculum multispiral with short growing edge Trochidae Operculum with long growing edge, calcareous externally, or multispiral with calcareous beads 14 Operculum multispiral with calcareous beads Liotiidae Operculum calcareous on outer surface Turbinidae Operculum calcareous Tricoliidae Operculum corneous 16 Aperture lacking siphonal notch 17 Aperture with siphonal canal or siphonal notch 38 Aperture round or oval 18 Aperture elongate 54 Protoconch not heterostrophic 19 Protoconch heterostrophic, immersed or at angle to body whorls 52 Shell low-spired, few whorls 20 Shell slender and high-spired, numerous whorls 34 Shell white 21 Shell colored 25 Height greater than breadth 22 Breadth greater than height 24 Sculpture of axial ribs Rissoidae (part) Sculpture smooth 23 Shell transparent, under 1 m m Rissoellidae Shell translucent, over 3 m m in height Hydrobiidae Spire moderately high, with strong spiral cords Skeneidae Spire low, profile discoidal Vitrinellidae Shell small to large (over 5 mm) 26 Shell minute (under 4 mm) 30 Final whorl greatly inflated Velutinidae Final whorl not greatly inflated 27 Peritreme interrupted, shell thin, purple

MOLLUSCA

Janthinidae (treated in separate section) — Peritreme entire, shell not purple 28 28. Small to medium (height to 15 mm), suture impressed 29 — Large (height to 35 mm), suture not impressed Naticidae 29. Shell with strong spiral sculpture Littorinidae (Littorininae) — Shell lacking strong spiral sculpture Littorinidae (Lacuninae) 30. Inner lip set off from columella by shelf Anabathridae — Inner lip set off from columella by shelf 31 31. Shell surface smooth 32 — Shell surface sculptured Rissoidae (part) 32. Shell narrowly umbilicate Cingulopsidae — Umbilicus lacking 33 33. Inner lip narrow Barleeidae — Inner lip broad, forming callus Assimineidae 34. Shell white 35 — Shell brown colored 36 35. Aperture circular, surface not glossy, with axial sculpture Epitoniidae — Aperture narrow posteriorly, surface glossy, no axial sculpture Eulimidae 36. Small (under 15 mm), outer not flaring Cerithiidae — Large (over 20 mm), outer lip flaring 37 37. Lacking varices Batillariidae — With varices Potamididae 38. Aperture long and narrow, more than two-thirds length of shell 39 — Aperture short, less than one-half length of shell 41 39. Lacking denticles on inner and outer lip Conidae — With denticles on inner or outer lip 40 40. Lip dentition wrapping across inner and outer lip Triviidae — Lip dentition set back from edge of inner and outer lip Cystiscidae 41. Shell small (under 12 m m in height), profile tall and narrow 42 — Shell moderately large to large (not extremely slender) 43 42. Shell dextral Cerithiopsidae — Shell sinistral Triphoridae (also dextral Metaxia) 43. Shell with shiny black periostracum and strong columellar placations Mitridae — Shell not with shiny black periostracum and strong columellar placations 44 44. Siphonal canal a short notch 45 — Siphonal canal moderately long to very long 48 45. Shell surface smooth, glossy Olividae — Shell surface with periostracum 46 46. Base with shallow groove Nassariidae — Base lacking shallow groove 47 47. Sculpture not coarsely clathrate Columbellidae — Sculpture coarsely clathrate Turridae (part) 48. Shell sculpture imbricated (scaly) Muricidae — Shell sculpture not imbricated 49 49. Shell with posterior anal sinus Turridae (part) — Shell lacking posterior anal sinus 50 50. Very large (over 90 mm), spire low, canal long Melongenidae — Not large (under 60 mm), spire high 51

51. — 52. — 53. — 54. — 55. — 56. — 57. — 58. —

Suture not strongly impressed Buccinidae Suture strongly impressed Fasciolariidae Shell discoidal Omalogyridae Shell not discoidal 53 Umbilicus narrow or lacking Pyramidellidae Umbilicus broad Amathinidae Tip of spire recessed 55 Tip of spire projecting 57 Lip not extending above apex Diaphanidae Lip flaring above apex 56 Shell large (to 50 mm), color pattern mottled Bullidae Shell relatively small, pale green (under 25 mm) Haminoeidae Aperture length about one-half length of shell Ellobiidae Aperture length at least two-thirds length of shell 58 Shell with dark bands and spiral rows of pits Acteonidae Shell lacking dark bands and rows of pits Cylichnidae (Actocininae)

KEYS TO SPECIES BY FAMILY

EOGASTROPODA PATELLOGASTROPODA

See the section on Patellogastropoda by Lindberg. ORTHOGASTROPODA VETIGASTROPODA

SUPERFAMILY FISSURELLOIDEA, FAMILY FISSURELLIDAE

Fissurellid limpets, the keyhole limpets, have non-nacreous shells in which the operculum is lacking in the adult. Bipectinate ctenidia are paired and of nearly equal size; there is an anterior notch or hole in the shell, corresponding to the excurrent hole or notch in the mantle. Epipodial tentacles are stubby and in a single row on foot sides. The mantle folds are capable of expansion to envelop the shell, head, and foot; shells of some genera are normally fully enveloped. Left kidney greatly is reduced. The radula is rhipidoglossate, outer lateral tooth greatly enlarged. Many species are carnivorous grazers. Broadcast spawners, lecithotrophic development. See Hickman, 1995, Gastropod volume of Fauna of Australia, p. 669 (general features); See McLean and Geiger 1998, Nat. Hist. Mus. L. A. Co., Cont. Sci., 475: 1-32 (phylogeny). 1.

Apical hole large, widely oval; animal much larger than shell, the mantle nearly covering shell 2 — Apical hole small, either circular or elongate, mantle not extending over shell 3 2. Shell small (to 16 mm); margin set off on inner side by a broad, shallow, encircling groove; ends slightly elevated, shell buff color with radiating brown or gray bands; mantle variously colored (red, orange, lemon yellow, gray, brown) (plate 356C) Fissurellidea bimaculata — Shell very large (to 13 cm); inner margin crenulate, lacking groove; shell buff color, without radiating bands;

mantle black or gray (plate 356D) . . . Megathura crenulata Internal apical callus truncate posteriorly; with concentric sculpture 4 — Callus rounded posteriorly, not sharply truncate; radiating ribs of varying sizes, or faint radial striae; no concentric sculpture; shell pink with red-brown or black rays; foot yellow, mantle red-striped, length to 25 mm (plate 356E) Fissurella volcano 4. Shell outline oval, apical hole round, length to 35 mm (plate 356A) Diodora aspera — Shell outline elongate, apical hole oval, length to 20 mm (plate 356B) Diodora amoldi 3.

Diodora arnoldi McLean, 1966. Mostly sublittoral, occasionally washed ashore; differs from D. aspera in smaller size, nearly parallel sides, and oval rather than round apical hole. Diodora aspera (Rathke, 1833). Low intertidal zone under rocks, in crevices; diet includes encrusting bryozoans (Gonor, 1968, Veliger 11: 134); commensal polychaete Arctonoe vittata often in mantle cavity (Dimock and Dimock 1969, Veliger 12: 65-68). See Margolin 1964, Animal Behav. 12: 187-194 (escape response); Pernet 1997, Veliger 40: 77-83 (development). Fissurellidea bimaculata (Dall, 1871) (=Megatebennus bimaculatus). Low intertidal zone to sublittoral, feeding on compound ascidians. See Ghiselin et al. 1975, Veliger 18: 40-43 (feeding); McLean 1984, Amer. Malac. Bull. 2: 21-34 (taxonomy). Fissurella volcano Reeve, 1849. Rocky intertidal zone only, on and under coralline-encrusted rocks. See McLean 1984, Cont. Sci., L. A. Co. Mus. Nat. Hist., 354: 1-70 (taxonomy). *Lucapinella callomarginata (Dall, 1871). A southern species feeding on sponges, Morro Bay south, could move northward. See Miller 1968, Veliger, 11: 130-134 (feeding). Megathura crenulata (G. B. Sowerby I, 1825). Giant keyhole limpet; low intertidal zone to sublittoral, in rocky areas; peacrab Opisthopus transversus among commensals. See Beninger et. al. 2001, J. Shellfish Res. 20: 301-307 (reproduction). PLEUROTOMARIODEA

Pleurotomarioideans are vetigastropods with paired ctenidia and coiled shells; the right ctenidium is reduced as a result of space reduction toward the columella of the coiled shell. Shell with slit or series of holes. Two families are treated here: Haliotidae and Scissurellidae. FAMILY H A L I O T I D A E

Shell very large, with nacreous interior layer; apical whorls of such low profile and expansion of final whorl so extensive that shell form is limpetlike; right shell muscle greatly enlarged, producing large clamping foot; mantle cavity shortened and displaced to left side; ctenidia paired, unequal in size, left the largest. Excurrent openings in shell a series of open holes along left side, formed at aperture and sealed at later stages. Epipodium well developed, producing fluted lobes and numerous tentacles. Radula rhipidoglossate. Broadcast spawners, with lecithotrophic veliger stage. Halitotids, or abalones are large-shelled species used for sport and commercial fisheries to such an extent that there are strict * = N o t in key.

GASTROPODA:

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PLATE 356 Fissurellidae and Scissurellidae: A, Diodora aspera (three views), length 34.6 mm; B, Diodora amoldi (three views), length 17.7 mm; C, Fissurellidea bimaculata (three views), length 19.2 mm; D, Megathura crenulata (three views), length 109 mm; E, Fissurella volcano (two views), length 20.8 mm; F, Sinezona rimuloides (two views), height 0.8 mm.

regulations for size and seasonal limits. There is a large collection of literature o n the biology of West Coast species. See Owen, McLean, and Meyer 1971, L.A. Co. Mus., Bull. 9 (hybridization); Geiger 1998, Nautilus, 11: 8 5 - 1 1 6 (taxonomy of family). For status of aquaculture see McBride 1998, J. Shellfish Res. 17: 593-600. 720

MOLLUSCA

1.

Shell greenish black to dark blue; holes round and flush with surface, w h i c h is nearly smooth; muscle scar m a y be present in older specimens; length to 12 cm (plate 3 5 7 D )

—

Shell not black or dark blue; holes oval, raised above shell surface 2

Haliotis cracherodii

PLATE 357 Haliotidae: A, Haliotis rufescens (two views), length 218 mm; B, Haliotis kamtschatkana walallensis (two views), length 108 mm; D, Haliotis cracherodii (two views), length 114 mm.

2.

Sculpture of low, rounded, spiral ridges crossed by closely spaced, raised striations; shallow, indistinct groove along shell margin; shell flat, elongated; brick red with white, blue, and green mottling; no muscle scar; length to 11 cm (plate 35 7C) Haliotis walallensis — Sculpture irregular, lumpy, undulating; shell moderately deep, not flat 3 3. Shallow, broad channel parallel to shell edge; shell thin,

(two views), length 57.4 mm; C, Haliotis

mottled green-brown or red-brown with scattered blue and white areas; no muscle scar; length to 9 cm (plate 35 7B) Haliotis kamtschatkana — Lacking broad channel; shell dull brick red, may have light color bands (pink, white, green); muscle scar prominent; usually covered with algae, barnacles, and other organisms; length to 22 cm (plate 35 7A) Haliotis rufescens GASTROPODA: SHELLED

721

Haliotis cracherodii Leach, 1814. Black abalone; mid- to low intertidal; in crevices or under large rocks. See Douros 1987, J. Exp. Mar. Biol. Ecol. 108:1-14 (stacking behavior); Haaker et al. 1995, J. Shellfish Res. 14: 519-525 (growth); Schiel et al. 2006, J. Exp. Mar. Biol. Ecol. 331: 158-172 (genetics, withering syndrome disease). Haliotis kamtschatkana Jonas, 1845. Pinto abalone; specimens from south of Marin County may show characters approaching the subspecies H. k. assimilis Dall, 1878, found south of Point Conception, which has a higher, more rounded, less corrugated shell. Sublittoral, shells occasionally washed ashore. See Paul et al. 1977, Veliger 19: 303-309 (feeding, growth). Haliotis rufescens Swainson, 1822. Red abalone; primarily sublittoral, extending to low intertidal in areas of considerable wave action in northern California. See Olsen 1968, Biol. Bull. 134: 139-147 (banding patterns); Haaker et al. 1998, J. Shellfish Res. 17: 747-753 (growth). Haliotis walallensis Stearns, 1899. Chiefly sublittoral, rarely intertidal. Stohler (1975, Veliger 17: 250, figs. 1-4) provided notes o n the righting response.

FAMILY

SCISSURELLIDAE

Scissurellids, t h e minute slit shells, non-nacreous white shells; either with open slit or elongate foramen; animal with paired ctenidia; operculum present. See Geiger 2003, Molluscan Res. 23: 21-83 (phylogeny). 1.

operculum is not enveloped by the foot. This family is better represented in tropical waters. Prior to Hickman and McLean 1990 (above), this was regarded as a full family; for a time it was regarded as a subfamily of Turbinidae, but it is here returned to family-level status. 1.

Liotia fenestrata Carpenter, 1864. In gravel under rocks. The biology of this species has n o t been studied.

FAMILY T U R B I N I D A E

The turbinids resemble trochids in having nacreous interiors, low profiles, and broad apertures, differing from trochids in having a solid calcareous operculum enveloped by t h e foot and thickened o n its outer side. Two subfamilies are represented: the Turbininae are large-shelled, with mostly tropical species, and the Colloniinae, with small shells, for which little is known of the biology. See Hickman and McLean, 1990 Nat. Hist. Mus. L.A. County, Sci. ser. 35, 1-169 (systematics and subfamilial classification of Turbinidae and Trochidae). 1.

Shell m i n u t e (0.8 m m height); white, turbinate; three rapidly enlarging whorls; sculpture of axial folds on upper part of whorl, spiral cords on base; with elongate foramen in outer lip near aperture (plate 356F) Sinezona rimuloides

—

Sinezona rimuloides (Carpenter, 1865). Interstitial in sand and gravel. See McLean 1967, Veliger 9: 404-419 (taxonomy, distribution).

— 3.

TROCHOIDEA

Trochoideans are vetigastropods in which the left ctenidium remains and the right one is lost; there is n o slit or hole in t h e shell; excurrent flow takes place at the shell edge o n the right side. Cephalic tentacles have sensory structures; epipodium well developed with long sensory tentacles; neck lobes assist in moving water through t h e mantle cavity. Families differ in structure of the operculum and whether it is enveloped by the foot. Shells of most groups are nacreous, but nacre is lost in some groups. The radula is rhipidoglossate and provides distinctions useful in classification. See Hickman and McLean 1990, Nat. Hist. Mus. L.A. Co., Sci. Ser. 35, 1-169 (systematics and subfamilial classification of Turbinidae and Trochidae). For an alternative in high-level classification see Bouchet and Waren (2005, Malacologia 47: 245). Some changes to family level classification are m a d e here. Families treated here are Liotiidae, Turbinidae, Tricoliidae, Trochidae, and Skeneidae.

FAMILY

LIOTIIDAE

Genera of the family Liotiidae have rounded apertures and a fine lamellar shell surface. The operculum is multispiral, and its outer surface has fine calcareous beads, formed at the long growing edge. Unlike t h e Turbinidae, the outer surface of the 722

MOLLUSCA

Shell white, spire low, umbilicus deep, aperture circular, interior nacreous; operculum with fine calcareous beads; sculpture cancellate, of deep square pits formed by strong spiral and axial ribs; small, height to 3 m m (plate 358A) Liotia fenestrata

2.

— 4.

—

Shell medium to large (25 mm-75 m m in height), conical; brick red; sculpture of diagonal folds and small, rounded nodes; periphery angulate or rounded; base with strong spiral cords (plate 358F) Pomaulax gibberosa Shell small, n o t more t h a n 10 m m in height, with columellar denticles and some spiral sculpture 2 Small (to 3.5 m m in height), with coarse spiral and axial ribbing; white with pink dots o n spiral cords (plate 358E) Homalopoma radiatum Sculpture spiral only 3 Small (to 4.5 m m in height), with few prominent spiral cords only; color white, pink, or red (plate 358D) Homalopoma paucicostatum Spiral cords numerous 4 Small (to 4.8 m m in height), globose; nearly smooth with faint, incised, spiral grooves; gray to reddish gray or brown (plate 358B) Homalopoma baculum Small (to 9 m m in height), numerous rounded spiral cords over body whorl and base; often purple or red; juveniles grayish; highly variable in color (plate 358C) Homalopoma luridum

Homalopoma baculum (Carpenter, 1864). Restricted t o midintertidal zone under rocks. Subfamily Colloniinae. Homalopoma luridum (Dall, 1885) (=H. carpenteri Pilsbry, 1888). Rocky intertidal to sublittoral. Homalopoma paucicostatum (Dall, 1871). Under rocks; offshore under kelp in gravel and shell bottoms. Homalopoma radiatum (Dall, 1918) (=H. fenestration Dall, 1919). Found with H. paucicostatum from low intertidal to sublittoral, under rocks. Pomaulax gibberosa (Dillwyn, 1817) (=Astraea inaequalis Martyn, 1784). More c o m m o n at sublittoral depths, occurring in shallower water toward t h e north. Beach shells c o m m o n at Pacific Grove. The genus Pomaulax Gray, 1850, previously a subgenus of Astraea Róding, 1798, is characterized by the nearly smooth outer surface of t h e operculum. It is here regarded as a full genus in the subfamily Turbininae.

PLATE 358 Liotiidae, Turbinidae (subfamilies Colloniinae and Turbininae) and Tricoliidae: A, Liotia fenestrata (two views), height 3.3 mm; B, Homalopoma baculum (two views), height 4.8 mm; C, Homalopoma luridum (two views), height 8.4 mm; D, Homalopoma paucicostatum (two views), height 4.5 mm; E, Homalopoma radiatum (two views), height 3.5 mm; F, Pomaulax gibberosa, height 60 mm; G, Eulithidium pulloides (two views), height 6.0 mm.

FAMILY TRICOLIIDAE

Species in this family are characterized by their lack of interior nacre, small size, rounded whorls of high profile, with mottled color patterns. One genus occurs in the eastern Pacific; it was previously treated as Tricolia in the family Phasianellidae, until the group was separated at a higher level from Phasianella in the Phasianellidae and treated in the subfamily Tricoliinae. See Hickman and McLean 1990, Nat. Hist. Mus. L.A. Co., Sci. Ser. 35, 1-169 (systematics and subfamilial classification of Turbinidae and Trochidae). The genus Eulithidium Pilsbry, 1898, which until then had been regarded as a subgenus of the Indo-

Pacific genus Tricolia, was raised by Hickman and McLean (above) to a full genus, based on radular and opercular differences. 1.

Small (to 6 mm in height), ovate, of high profile; sculpture lacking, surface smooth; shell mottled red and white, occasionally with brown blotches on periphery; thin, green periostracum; sea-green calcareous operculum with linear grooves perpendicular to outer edge (plate 358G) Eulithidium pulloides

Eulithidium pulloides (Carpenter, 1865) (=Tricolia pulloides). In gravel, under rocks, or associated with surfgrass or algae. GASTROPODA; SHELLED

723

Females have substantially larger shells than males. See Mooers, 1981, Veliger 24: 103-108 (feeding, sexual dimorphism and reproduction). FAMILY TROCHIDAE

Trochidae, the top shells, have nacreous interiors, differing from turbinids in having a non-calcified, multispiral operculum not enveloped by the foot. The operculum further differs from that of turbinids in having a short growing edge. They have elaborate sensory tentacles on the epipodium; most are herbivorous. See Hickman and McLean 1990, Nat. Hist. Mus. L.A. Co., Sci. Ser. 35, 169 pp (external anatomy, radula, systematics and subfamilial classification of Turbinidae and Trochidae); Hickman 1992, Veliger 35: 245-272 (review of reproduction). The subfamily Tegulininae is represented by relatively largeshelled species previously placed in the genus Tegula Lesson, 1835, but here placed in the genus Chlorostoma Swainson, 1840 (a raising of subgenus to full genus), necessary because the type species of Tegula is the tropical species elegans Lesson, 1835, from Panama, which has columellar morphology unlike that of temperate species of Chlorostoma. This distinction has long been recognized by Japanese authors. The biology of Chlorostoma species (as Tegula) has been well studied: see Riedman et al. 1981, Veliger 24: 97-102 (zonation); Hellberg 1998, Evolution 52:1311-1324 (genetics and speciation). The radula of the tegulines resembles that of turbinids leading to reconsiderations of the affinity of this group (Bouchet and Waren 2005, Malacologia, 47: 245). Calliostoma species in the subfamily Calliostomatinae have the external anatomy modified to feed on hydroids (see Hickman and McLean 1990, above). The small-shelled Lirularia species have long gill filaments indicative of filter feeding (see Hickman and McLean 1990, above), but species may graze as well; the biology of Lirularia species is much in need of study. 1. Umbilicus closed 2 — Umbilicus open 8 2. Base of columella not having strong nodes 3 — Columella with one or two nodes emerging from umbilical region 7 3. Spiral cords beaded 4 5 — Spiral cords not beaded 4. Whorls flat-sided, with beaded spiral cords; shell golden yellow to yellowish brown with bright purple band adjacent to columella; height to 25 mm (plate 359B) Calliostoma annulatum — Whorls shouldered, yellow-brown with irregular mottling; fine cords strongly beaded on early whorls; height to 14 mm (plate 359E) Calliostoma supragranosum 5. Spiral cords fine; yellow-orange with darker markings at base; height to 24 mm (plate 359F) Calliostoma gloriosum — Spiral cords raised, with darker color in interspaces . . . . 6 6. Whorls flat-sided, yellowish tan to white or buff, with prominent revolving cords, cords paler in color than interspaces; blue stain next to columella; height to 35 mm (plate 359C) Calliostoma canaliculatum — Whorls rounded, chocolate brown, with narrow, light tan spiral cords; nacre blue; height to 25 mm (plate 359D) Calliostoma ligatum 7. Shell purplish black to black; scaly band below suture; mature specimens with two teeth on columella (lower tooth 724

MOLLUSCA

—

8. — 9. — 10.

—

11. — 12. — 13. —

occasionally worn); height to 35 mm (plate 360A) Chlorostoma funebralis Shell brown or orange brown; no scaly subsutural band; one tooth on columella; height to 30 mm (plate 360B) Chlorostoma brunnea Shell relatively large, over 9 mm in height 9 Shell relatively small, under 7 mm in height 11 Uniformly red-brown to orange; subconical; height to 10 mm (plate 359A) Pupillaria salmonea Shell brown (not reddish); height more than 20 mm 10 Whorls flat-sided, base angulate; top of inner lip receding into aperture; umbilicus narrow, defined by a strong spiral cord terminating in node; brown; height to 30 mm (plate 360C) Chlorostoma montereyi Whorls rounded, base rounded, top of inner lip produced into flange on apertural side of umbilicus; no strong spiral cord defining umbilicus; brown or gray, at times with orange, white, or brown spots on periphery, height to 30 mm (plate 360D) Promartynia pulligo With narrow, raised axial lamellae; height to 5 mm (plate 360F) Lirularia parcipicta Lacking narrow, raised axial lamellae 12 Base inflated, with a shallow, spiral channel 13 Base without channel; basal cords strong, few; periphery rounded; height to 7 mm (plate 360E) Lirularia sp. Grayish brown, base rounded, spiral cords broad, low; height to 4 mm (plate 360G) Lirularia succincta Mottled brown and yellow, base angulate, spiral cords narrow; height to 4.5 mm (plate 360H) Lirularia discors

Chlorostoma brunnea (Philippi, 1848) (=Tegula brunnea). Brown turban, occurs lower than T. funebralis and on offshore kelp beds near surface. For trochid species on kelp see Lowry et al. 1974, Biol. Bull. 147: 386-396; see Watanabe 1983, J. Exp. Mar. Biol. Ecol. 71: 257-270 (anti-predator defense against Pisaster and Pycnopodia in Chlorostoma spp.). Chlorostoma funebralis (A. Adams, 1855) (=Tegula funebralis). Black turban; midtide levels, avoiding exposed outercoast habitats; occasional specimens umbilicate. Very tall, older specimens on low-energy flat reefs. See Veliger 6, Suppl. 82 pp. (1964) for papers on ecology, biology; Frank 1975 (and earlier papers), Mar. Biol. 31: 181-192; Paine, 1971, Limnol. Oceanogr. 16: 8 6 - 9 8 (population, energy flow); Moran 1997, Mar. Biol. 128: 107-114 (spawning and larval development). Chlorostoma montereyi (Kiener, 1850) (=Tegula montereyi). Low intertidal zone and on offshore kelp beds. Promartynia pulligo (Gmelin, 1791). This species is better known as Tegula pulligo but is here placed in the genus Promartynia Dall, 1909, which previously had been regarded as a subgenus. This genus completely lacks the denticles at the base of the columella that characterize Chlorostoma species. Uncommon in low intertidal zone and on offshore kelp beds. Pupillaria salmonea (Carpenter, 1864). On and under surfaces of rocks, low intertidal zone. Pupillaria Dall, 1909, has previously been considered a subgenus of Margantes Gray, 1847; it is here raised to generic level, characterized by its strong spiral sculpture and flat, offset base. *Pupillaria rhodia Dall, 1921. Offshore rocky bottoms (illustrated by Abbott, 1974).

* = Not in key.

PLATE 359 Trochidae (subfamilies Margaritinae and Calliostomatinae): A, Pupillaria salmonea (two views), height 8.9 mm; B, Calliostoma armulatum (two views), height 22.8 mm; C, Calliostoma canaliculatum (two views), height 34.2 mm; D, Calliostoma ligatum (two views), height 22.0 mm; E, Calliostoma supragranosum (two views), height 9.0 mm; F, Calliostoma gloriosum (two views), height 23.7 mm.

Calliostoma armulatum (Lightfoot, 1786). With C. canaliculatum and C. ligatum on offshore Macrocystis stands and in low rocky intertidal zone. See Perron 1978, Veliger 18: 52-54 (feeding on hydroids). Calliostoma canaliculatum (Lightfoot, 1786). Largest specimens occur on Macrocystis. Calliostoma ligatum (Gould, 1849) (=C. costatum Martyn, 1784). See Holyoak 1988, Veliger 30: 369-371 (spawning and larval development). Calliostoma supragranosum Carpenter, 1864 (=C. splendens Carpenter, 1864). Generally sublittoral, but shells occasionally washed ashore and occupied by hermit crabs. Calliostoma gloriosum Dall, 1871. Sublittoral rocky bottoms; worn shells on shore. *Calliostoma tricolor Gabb, 1865. Primarily a southern species, rare in central California. See photo in McLean (1978). *Halistylus pupoideus (Carpenter, 1864). Small, slender, living on gravel bottoms offshore. See photo in Hickman and McLean 1990, above. *Norrisia norrisi (Sowerby, 1838). A well-known and distinctive top shell with a bright red animal, occurring south of Monterey Bay, but noted here as a species that may finds its way further north with coastal warming (and a representative of po* = N o t in key.

tentially many other southern California snails that may do the same). The shell is quite solid, broader than high, with smooth, rounded whorls and a deep umbilicus; it is chestnut brown in color, black near the umbilicus, and the columella is tinged with green. The operculum is spirally tufted. May reach 45 mm in height and 55 mm in diameter. The species is common on kelp and other brown algae. Lirularia sp. An undescribed species on mudflats, on hard substrates, algae, Zostera, particularly in Tómales Bay and Bodega Harbor. In the previous edition this was incorrectly identified as the more northern species L. funiculata (Carpenter, 1864). Lirularia succincta (Carpenter, 1864) (=Margarites succinctus). Low intertidal zone; common on gravel, under loose rocks. Lirularia discors McLean, 1984 (Veliger, 26: 237). Occurs with L. succincta, but living in shallow sublittoral where the two occur together. Lirularia parcipicta (Carpenter, 1864) (=Margarites parcipictus). Chiefly sublittoral among rocks, in gravel, among algae. FAMILY SKENEIDAE

Skeneids have minute, non-nacreous, white shells of low profile, with the umbilicus usually open; the radula is GASTROPODA: SHELLED

725

PLATE 3 6 0 Trochidae (subfamilies Tegulinae and Lirulariinae) and Skeneidae: A, Chlorostoma fimebralis (two views), height 24.0 mm; B, Chlorostoma brunnea (two views), height 31.5 mm; C, Chlorostoma montereyi (two views), height 2 6 mm; D, Promartynia pulligo (two views), height 30.3 mm; E, Lirularia sp. (two views), height 6.8 mm; F, Lirularia parcipicta (two views), height 5.0 mm; G, Lirularia succincta (two views), height 4.0 mm; H, Lirularia discors (two views), height 4.3 mm; I, Parviturbo acuticostatus, height 2.7 mm.

rhipidoglossate and the operculum multispiral. This family is highly diverse in Australia and New Zealand; see Marshall 1988, J. Nat. Hist. 22: 949-1004 (taxonomy); also Hickman and McLean 1990, Nat. Hist. Mus. L.A. Co., Sci. Ser. 35, 1-169 (systematic position); Hickman, 1998, Gastropod volume, Fauna of Australia, pp. 690-391 (general review).

shore, H. mimicum LaFollette 1976, Veliger 19: 68-77, that closely resembles this but has a strong columellar denticle and the thick calcareous operculum of Homalopoma.

1.

CERITHIOIDEA

White, interior non-nacreous, profile with moderately high spire, three projecting cords on body whorl and three on base, fine axial lamellae; height 2.5 mm (plate 3601) Parviturbo acuticostatus

Parviturbo acuticostatus (Carpenter, 1864). Intertidal and rocky sublittoral. There is a Homalopoma species living off726

MOLLUSCA

CAENOGASTROPODA

Cerithioideans are mostly slender shells in which the reproductive anatomy of all included families is primitive in having open pallial gonoducts and males that lack a copulatory organ; spermatophores are produced. Detritus feeders or browsers; the radula has seven teeth per row and is taenioglossate. Families

differ in shell form, details of anatomy and opercular morphology. Families treated here are Cerithiidae, Batillariidae, and Potamididae. See Houbrick 1988, Mai. Rev., Suppl. 4: 88-128 (phylogeny); Simone 2001, Arquivos Zoologia 36: 147-263 (phylogeny).

FAMILY C E R I T H I I D A E (Plate 3 6 1 )

Cerithiidae have slender shells of numerous whorls; the operculum is multispiral or paucispiral. Large-shelled members of the subfamily Cerithiinae are primarily tropical; northeastern Pacific species are small-shelled members of the subfamily Bittiinae with a short siphonal canal that is not strongly notched. Protoconchs are paucispiral; development is non-planktotrophic. Species were previously assigned to Bittium subgenera, a European group. S. eschrichtii is placed in the monotypic genus Stylidium based on its large size and anatomic distinctions; all other smaller species are retained in Lirobittium (Houbrick, 1993, Malacologia 35: 262-314). Little is known of their biology other than notes on S. eschrichtii in Strathmann (1987). 1.

— 2. — 3.

—

4.

— 5. —

Shell relatively large, height to 16 mm, no axial sculpture, spiral cords separated by deep grooves, surface with light brown maculations (plate 361A) Stylidium eschrichtii Shell under 12 mm in length, with axial sculpture in early whorls 2 With strongly beaded cancellate sculpture on all whorls 3 Spiral sculpture dominant on final whorl 4 Sculpture of strong beads and square pits, formed by axial ribs and two strong spiral cords per whorl, base with deep channel; height to 9 mm (plate 361B) Lirobittium interfossum Shell with three strongly beaded spiral cords per whorl and two projecting cords at base; height to 11 mm (plate 361C) Lirobittium purpureum Spiral cords of final whorl broad and projecting, separated by interspaces of about same width as cords (plate 361D) Lirobittium latifilosum Spiral cords of final whorl broad and low, not separated by broad interspaces 5 Broad spiral cords of last whorl with upper edge slightly projecting (plate 361E) Lirobittium attenuatum Broad spiral cords of last whorl slightly inflated and separated by narrow grooves (plate 361F) Lirobittium esuriens

Lirobittium attenuatum (Carpenter, 1864) (=Bittium attenuatum). In sand, gravel, under rocks and in surfgrass holdfasts. Lirobittium esuriens (Carpenter, 1864). Previously regarded as a synonym of S. eschrichtii, but is here recognized as a smaller species with prominent axial ribs on the base separated by narrow grooves. Lirobittium interfossum (Carpenter, 1864) (=Bittium interfossim). In gravel, under algae; uncommon intertidally. Lirobittium latifilosum (Bartsch, 1911) (=Bittium latifilosum). In gravel, under algae; uncommon intertidally. Lirobittium purpureum (Carpenter, 1864) (=Bittium purpureum). Algae, surfgrass holdfasts, in sand. Stylidium eschrichtii (Middendorff, 1849) (=Bittium eschrichtii, B. e. montereyense Bartsch, 1907). In clean, coarse sand among rocks. Often inhabited by the shell dwelling amphipod Photis conchicola.

FAMILY P O T A M I D I D A E

Potamidids, like the batillariids, are mud-snail detritivores and also have a multispiral operculum. The family differs from Batillariidae in sperm structure and the radula. Cerithidea differs from Batillaria in the radula and in having a pallial eye on the mantle edge of the siphon. A single species is now living in California; a southern species C. fuscata Gould, 1845, from San Diego Bay is now considered extinct (see Carlton 1993, Amer. Zool. 33: 499-509). See Houbrick 1984, Amer. Malac. Bull. 2:1-20 (systematics); Healy and Wells 1998, pp. 724-727, in Gastropod volume of Fauna of Australia (biology and classification). Populations are often heavily infected with cercarial parasites (see Armitage 2001, S. Calif. Acad. Sci., Bull. 100: 51-58). 1.

Shell dark brown; suture moderately impressed; axial ribs low; a few rounded varices on lower whorls; aperture with inflated lip; operculum multispiral; height 25 mm-30 mm (plate 361G) Cerithidea californica

Cerithidea californica (Haldeman, 1840). California horn snail. In bays, estuaries, on mud, in aggregations, under debris. Populations in San Francisco Bay are endangered; they now live in high intertidal marshes, having been displaced by the invasive Ilyanassa obsoleta (Race 1981, Veliger 24: 18-27). See papers by Byers cited under Batillaria attramentaria, showing that populations of Cerithidea have reduced or been replaced by the invasive Batillaria attramentaria. See also Bright 1958, Bull. So. Calif. Acad. Sci. 57: 127-139 and ibid. 1960, 59: 9-18 (morphology).

FAMILY BATILLARIIDAE

Batillaria species are slender mud-snails, detritivores, feeding by ingesting large quantities of mud. The operculum is multispiral. The family differs from Potamididae most strikingly in its sperm structure (see Healy and Wells 1998, gastropod volume of Fauna of Australia, pp. 720-721). Well represented in the northwestern Pacific by at least four species, a single species has been introduced with Japanese oyster seed and is well established in Elkhorn Slough and Tomales Bay, and other estuaries north to British Columbia. 1.

Profile tall, suture not deeply impressed; aperture projecting, anal sinus pinched, anterior canal short; shell graybrown, often with white band below suture; spiral sculpture of strong cords and low axial ribs; axial ribs fading out on lower whorls; operculum multispiral; height 24 mm-28 mm (plate 361H) Batillaria attramentaria

Batillaria attramentaria (G. B. Sowerby I, 1855) ( = B. cumingi Crosse, 1862; =B. zonalis of authors). In dense intertidal aggregations in bays, on soft mud. There is now a large literature on this species. See Whitlach 1974, Veliger 17: 47-55 (ecology); Whitlach and Obrebski 1980, Mar. Biol. 58: 219-225 (feeding); Driscoll 1972, Veliger 14: 375-386 (functional morphology); Yamada and Sankurathri 1977, Veliger 10: 179 (development). This species has gradually displaced the native Cerithidea californica in bays in which the two species occur together; see Byers 1999, Biolog. Invasions, 1: 339-352; Byers 2000, J. Exp. Mar. Biol. Ecol. 248: 133-150; Byers 2000, Ecol. 81: 1225-1239; Byers and Goldwasser 2001, Ecology 82: 1330-1343. GASTROPODA:

SHELLED

727

PLATE 361. Cerithiidae (subfamily Bittiinae), Potamididae, Batillariidae, and Littorinidae (subfamily Lacuninae). A, Stylidium eschrichtii, height 14.2 mm; B, Lirobittium interfossum, height 8.4 mm; C, Lirobittium purpureum, height 10.2 mm; D, Lirobittium latifilosum, height 9.7 mm; E, Lirobittium attenuatum, height 8.3 mm; F, Lirobittium esuriens, height 9.5 mm; G, Cerithidea californica, height 26.4 mm; H, Batittaria attramentaria (two specimens), height 24.2 mm, height 27.2 mm; I, Lacuna porrecta, height 10 mm; J, Lacuna mormorata, height 6.0 mm; K, Lacuna unifasciata, height 5.5 mm; L, Lacuna variegata, height 6.5 mm.

LITTINOROIDEA

Littorinoids are relatively small-shelled with rounded peristome, lacking anterior or posterior canals or grooves; penis present behind the right cephalic tentacle in males; females have a closed oviduct with complex spiral structure. Some lesser known families not represented in the eastern Pacific are mentioned by Reid 1998, p. 737 (Gastropod vol., Fauna of Australia).

728

MOLLUSCA

FAMILY LITTORINIDAE, SUBFAMILY LITTORININAE

See the section on Littorina by Reid. FAMILY LITTORINIDAE, SUBFAMILY LACUNINAE

Five genera have been included in this subfamily, but only Lacuna is represented in the eastern Pacific. Shells are small, umbilicate, with rounded aperture and narrow to broad

columellar shelf. Lacuna resembles Littorina in shell f o r m but is placed in t h e subfamily Lacuninae, differing in having a t h i n n e r shell, t h e animal having a pair of small tentacles beh i n d t h e operculum. Most species occur o n algae or sea grasses, o n w h i c h t h e y browse directly or feed u p o n epiphytic diatoms. All eastern Pacific species have been assigned to t h e subgenus Epheria, in which t h e p r o t o c o n c h is multispiral, indicative of a planktotrophic larval stage, in contrast to species of t h e subgenus Lacuna, for which t h e p r o t o c o n c h is paucispiral, indicative of n o n - p l a n k t o t r o p h i c developm e n t . See Reid 1989, Phil. Trans. Roy. Soc. London B, 324: 1 - 1 1 0 (morphology, classification, phylogeny). Padilla et al. 1996, J. Molluscan Stud. 62: 275-280, studied radular production in eastern Pacific species. Padilla 1998, Veliger 41: 201-204, showed t h a t t h e shape of t h e radular teeth is plastic, changing in individuals transferred between eelgrass a n d kelp, and that this response is triggered by b o t h diet a n d env i r o n m e n t (Padilla 2001, Evol. Ecol. Res. 3: 15-25). Breeding experiments have confirmed t h e L. marmorata and L. unifasciata are distinct species (Langan-Cranford and Pearse 1995, J. Exp. Mar. Biol. 186: 17-31). Population dynamics have been studied by Martel a n d Chia 1991, Mar. Biol. 110: 237-247, defense against seastars by Fishlyn and Phillips, 1980, Biol. Bull. 158: 34-48, feeding preferences by Van Alstyne, et al. 2001. Mar. Biol. 139: 201-210, a n d larval behavior by Martel and Diffenbach 1993, Mar. Ecol. Prog. Ser. 99: 215-220. 1. Shell profile relatively slender 2 — Shell profile relatively broad 3 2. Suture shallow, with dark brown line at sharply angulate base; columellar shelf narrow; height 5 m m - 7 m m (plate 361K) Lacuna unifasciata — Suture deep, usually with brown markings of back-directed chevrons; columellar shelf relatively broad; height 8 m m (plate 361L) Lacuna variegata 3. Shell profile depressed, surface smooth with fine spiral striae; light brown, marbled with white, especially at periphery; aperture often with white band showing o n interior of aperture; columellar shelf broad; height 6 m m - 7 m m (plate 361J) Lacuna marmorata — Large, globose; surface wrinkled with fine, wavy, spiral striae; solid brown color, generally lacking a white b a n d in aperture; columellar shelf broad; height to 12 m m (plate 3611) Lacuna porrecta Lacuna marmorata Dall, 1919. C o m m o n ; intertidal o n rocks, algae, o n surfgrass Phyllospadix. Eaten by the sea star Leptasterias, to which it responds by leaping off the surfgrass blade and lowering itself by a mucous thread into the water below, which it t h e n climbs u p again. See Fishlyn and Philips 1980, above. Lacuna porrecta Carpenter, 1864. On algae and eelgrass. Lacuna unifasciata Carpenter, 1857. Common, generally Monterey Bay south, in kelp beds, eelgrass, algae. Reported also from Bodega Harbor (D. Padilla, pers. comm. to J. T. Carlton 2003). Lacuna variegata Carpenter, 1864. On algae, or grasses in bays; more c o m m o n to north in Puget Sound.

SUPERFAMILY C I N G U L O P S O I D E A , FAMILY

CINGULOPSIDAE

Shells of cingulopsids resemble those of rissooideans, b u t there are major anatomical differences, particularly in males

being aphallate. The operculum has a peg, as in t h e barleeids. Anatomy was first studied by Fretter and Patil 1958, Proc. Mai. Soc. London, 33: 114-126. See Ponder and Yoo 1980. Rec. Aust. Mus. 33: 1 - 8 8 (anatomy, classification); and Ponder and De Keyser 1998: 741, Gastropod volume of Fauna of Australia. 1.

Shell brown, whorls rounded, suture deep; umbilicus deep, narrow; height to 1.4 m m (plate 362A) Mistostigma sp.

Mistostigma sp. Rocky intertidal and sublittoral near brown algae. C o m m o n in sediment samples but yet to be collected alive.

RISSOIDEA

Rissoideans are m i n u t e caenogastropods with round or oval apertures; reproduction in all families involves a cephalic penis. The radula is taenioglossate, as in other basal caenogastropods. Families are defined chiefly on anatomical distinctions and opercular differences. The highly speciose rissooideans occur in marine and fresh water, and there are terrestrial groups. Many families have smooth-surfaced shells, but there are a few groups with strong sculpture. See Ponder and De Keyser 1998, pp. 745-746 (in Gastropod volume of Fauna of Australia). There are m a n y more families t h a n those treated here. Families represented in central California and Oregon are Barleeidae, Anabathridae, Rissoidae, Hydrobiidae, Assimineidae, Caecidae, and Vitrinellidae.

FAMILY BARLEEIDAE (Plate 3 6 2 )

Barleeids are rissooideans with smooth, dark b r o w n shells and an opercular peg on t h e inner side. A single genus Barleeia occurs in t h e northeastern Pacific. They are c o m m o n in the rocky intertidal and sublittoral, often occurring on algae. Biology of t h e northeastern Pacific species has n o t been studied. See Ponder 1983, Rec. Aust. Mus. 35: 2 3 1 - 2 8 1 (taxonomy). 1.

Shell over 3 m m in length, with sharp basal keel, whorls nearly flat-sided 2 — Shell under 3 m m , slight basal angulation; whorls somewhat rounded; color variable, translucent yellow-white to dark brown (plate 362C) Barleeia haliotiphila 2. Large and broad, length 4 m m - 5 m m , surface shiny, with color mottling (plate 362B) Barleeia acuta — Shell length to 3.3 m m , slender, dark brown (plate 362D) Barleeia oldroydi Barleeia acuta (Carpenter, 1864) [=Diala acuta; =Barleeia marmorea (Carpenter, 1864); =B. dalli Bartsch, 1920]. Characterized by its relatively large size. Barleeia haliotiphila Carpenter, 1864 (=B. oldroydi Bartsch, 1920). C o m m o n among algae, rocks, gravel, sand; also in kelp holdfasts, and reported from high intertidal Endocladia/Balanus zone. Barleeia oldroydi Bartsch, 1920. Resembles B. acuta but smaller and more slender, of more c o m m o n occurrence in rocky sublittoral.

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PLATE 3 6 2 Cingulopsidae, Barleeidae, Anabathridae, Rissoidae, Hydrobiidae, and Assimineidae: A, Mistostigma sp., height 1 . 4 mm; B, Barleeia acuta, height 3.8 mm; C, Barleeia haliotiphila, height 2.0 mm; D, Barleeia oldroydi, height 3.1 mm; E, Amphithalamus tenuis, height 1.0 mm; F, Alvania compacta, height 2.1 mm; G, Alvania almo, height 1.8 mm; H, Alvinia aequisculpta, height 2.8 mm; I, Alvinia purpurea, height 2.3 mm; J, Onoba carpenteri, height 2.6 mm; K, Onoba dinora, height 1.8 mm; L, Tryonia imitator, height 3.6 mm; M, Assiminea califomica, height 2.9 mm.

FAMILY

ANABATHRIDAE

See Ponder 1 9 8 8 , Mai. Rev., Suppl. 4: 1 2 9 - 1 6 6 ( a n a t o m y a n d classification).

Anabathrids are m i n u t e rissooideans having an opercular peg, like barleeids, but m u c h smaller a n d with a t h i c k columellar shelf. Two species occur in southern California, but o n l y o n e species e x t e n d s i n t o central California.

730

MOLLUSCA

1.

I n n e r lip offset from c o l u m e l l a by a shelf; slightly over 1 m m in h e i g h t (plate 3 6 2 E ) Amphithalamus tenuis

Amphithalamus on algae.

tenuis Bartsch, 1911. In sand and gravel and

FAMILY R I S S O I D A E

Rissoids are minute rissooideans with a paucispiral operculum that lacks an opercular peg. Most have both axial and spiral sculpture. Feeding on diatoms and microalgal films. This is a very large family with numerous genera and species worldwide. As used here, Alvinia differs from Alvania in having a protoconch with strong spiral cords. Generic assignments follow Ponder (1985, Rec. Aust. Mus., Suppl. 4, 221 pp.), who reviewed the genera worldwide. 1. Shell tan to brown 2 — Shell white or yellowish white 5 2. Sharply clathrate, with narrow projecting axial and spiral sculpture 3 — Finely clathrate, axial and spiral sculpture not strongly projecting 4 3. Coarsely clathrate with two spiral cords at periphery; protoconch with spiral sculpture; height 2.3 mm (plate 3621) Alvinia purpurea — Finely clathrate, with four or more spiral cords at periphery; protoconch with fine clathrate sculpture; height 2.6 mm (plate 362J) Onoba carpenteri 4. Suture shallow, with narrow low axial ribs; protoconch smooth; height 2.1 mm (plate 362F) Alvania compacta — Suture deeper, no axial sculpture, protoconch smooth; height 1.8 mm (plate 362K) Onoba dinora 5. Shell relatively large, three spiral cords; protoconch with spiral sculpture; height 3.3 mm (plate 362H) Alvinia aequisculpta — Shell relatively small, three spiral cords; protoconch smooth; height 1.5 mm (plate 362G) Alvania almo Alvania compacta (Carpenter, 1864); Alvania almo Bartsch, 1911; Alvinia aequisculpta (Keep, 1887); Alvinia purpurea Dall, 1871; Onoba carpenteri (Weinkauff, 1885); Onoba dinora (Bartsch, 1917). All are microgastropods that can be collected by screening algae and eelgrass and by taking sand and gravel samples for later examination.

FAMILY H Y D R O B I I D A E

Hydrobiid species usually have smooth sculpture. They are primarily a freshwater group of rissooideans, with only a few species occurring in lagoons and brackish water estuaries. See Kabat and Hershler 1993, Smithsonian Contr. Zool., 547. 1-94 (classification); Hershler and Ponder 1998, Smithsonian Contr. Zool., 600: 1-55 (taxonomy). 1.

Shell white, smooth except for fine spiral sculpture, suture deeply impressed; height 4 rara-5 mm (plate 362L) Tryonia imitator

Tryonia imitator (Pilsbry, 1899). Muddy bottoms in shallow bays, now restricted to only a few brackish-water localities in central California, including Elkhorn Slough; a victim of extensive estuarine modification and destruction. See Taylor 1966, Malacologia 4: 53 (taxonomy); Kellogg 1980, Calif. Dept. Fish & Game, Special Pub. 80, 23 pp. (ecology and status).

FAMILY A S S I M I N E I D A E

Assimineids are small-shelled rissooideans, characterized the thickened callus on the columella; they live only at the upper limits of the tide in bays and estuaries. The group is speciose in the western Pacific, but there is only one broad-ranging northeastern Pacific species. See Ponder and de Keyzer 1998, pp. 756-758, in Gastropod volume of Fauna of Australia (biology, classification). 1.

Inner lip with small, thickened callus; whorls rounded, convex; shell smooth, stoutly conical; glossy brown; height 3 mm (plate 362M) Assiminea californica

Assiminea californica (Tryon, 1865) [=,4. translucens (Carpenter, 1866)]. Abundant in Salicornia marshes on mud, under debris. See Fowler 1980, Veliger, 23: 163-166 (reproduction); Berman and Carlton 1991, J. Exp. Mar. Biol. Ecol. 150: 267-281 (ecology, diet). FAMILY C A E C I D A E

Caecids are rissooideans with minute, tubular shells that are slightly curved and have a plug that seals the posterior end; the operculum is multispiral. Caecids grow by discarding entire earlier growth stages and forming a succession of new plugs. The initial spiral protoconch is seen only in the first grown stage. Living interstitially in sand and gravel. Much is known about the group, but taxonomic work has been of local scope; there are no worldwide revisions. See Bandel 1996, Mitt. Geol.-Paleont. Inst. Univ. Hamburg 79: 53-115 (fossil record); Ponder 1998, pp. 761-773 (Gastropod volume of Fauna of Australia); Absalao and Pizzini 2002, Archiv. Moll. 131: 167-183 (classification). 1. Shell surface with distinct rings and pointed plug 2 — Shell surface nearly smooth, plug rounded to pointed . . . . 3 2. With 30-40 closely set rings; length to 3 mm (plate 363A) Caecum californicum — With 28-24 rings and interspaces between; length 2.5 mm (plate 363B) Caecum dalli 3. Plug rounded, aperture drawn out; length to 2.3 mm (plate 363D) Fartulum orcutti — Plug angulate to rounded, aperture not drawn out; length to 3.8 mm (plate 363C) Fartulum occidentale Caecum californicum Dall, 1885. Interstitial in sand, gravel, especially near roots of surfgrass Phyllospadix. Caecum dalli Bartsch, 1920. Lower intertidal; more abundant in sublittoral. Fartulum occidentale (Bartsch, 1920) (=Fartulum hemphilli Bartsch, 1920). Intertidal and sublittoral. Fartulum orcutti (Dall, 1885). Among debris under stones at high tide zone. *Micranellum crebricinctum (Carpenter, 1864). Large (5 m m 6 mm), with numerous rings. Offshore, sandy bottoms. See photo in McLean (1978). FAMILY V I T R I N E L L I D A E

Vitrinellids are minute rissooideans with depressed spires and multispiral opercula, best represented in tropical and subtropical * = N o t in key.

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PLATE 363 Caecidae, Vitrinellidae, and Hipponicidae: A, Caecum californicum, length 3.0 mm; B, Caecum dalli, length 2.5 mm; C, Fartulum occidentale, length 3.3 mm; D, Fartulum orcutti, length 2.2 mm; E, Vitrinella oldroydi (three views), diameter 2.7 mm; F, Antisabia panamensis, diameter 20 mm (two views); G, Hipponix tumens (two views), diameter 13.5 mm.

regions. They differ from skeneids in having a taenioglossate rather than rhipidoglossate radula. Many species have never been collected alive, but at least some species are known to live commensally with other invertebrates. No work has been done on the biology of any eastern Pacific species. See Bieler and Mikkelsen 1988 (Nautilus 102: 1-29) for work on western Atlantic species. 1.

Lenticular, minute (to 2.7 mm diameter), white; whorls and aperture rounded; umbilicus broadly open; shell often eroded, with apex missing but replaced by plug from within (plate 363E) Vitrinella oldroydi

Vitrinella oldroydi Bartsch, 1907. Commensal in mantle cavity (foot groove) of the chitons Stenoplax heathiana and S. conspicua. 732

MOLLUSCA

VANIKOROIDEA

Two families are included, the limpet family Hipponicidae, and the Vanikoridae, the latter with coiled shells and represented at sublittoral depths in California.

FAMILY

HIPPONICIDAE

Hipponicids are sedentary limpets that retain a coiled early stage; they obtain food with their extensible snout. Most species coat their site of attachment with a shelly plate; loose shells show a prominent horseshoe-shaped muscle scar. See Ponder, in Gastropod volume of Fauna of Australia, 1998: 770-771 (biology and taxonomy).

1.

Sculpture of flat, concentric lamellae bearing fine radial striae under periostracum; apex low, subcentral or near margin; diameter to 25 m m (plate 363F) Antisabia panamensis — Sculpture of strong radial ridges with weaker concentric sculpture; periostracum with fine hairs; apex elevated, overhanging posterior margin; diameter to 15 m m (plate 363G) Hipponix tumens Antisabia panamensis (C. B. Adams, 1852) [=Hipponix cranioides Carpenter, 1864; =H. antiquatus of authors, not of Linnaeus, 1767], A single species of this genus is thought to occur throughout the eastern Pacific, extending from tropical to temperate regions. In colonies o n under-surfaces of rocks at low tide and in t h e sublittoral. Use of Antisabia follows Ponder 1998 (above). See Yonge 1953, Proc. Calif. Acad. Sci. Ser. 4, 28: 1-24, and 1960, 31: 111-119 (anatomy, biology, ecology). Hipponix tumens Carpenter, 1864. Low intertidal, in rock crevices. This is comparable to t h e Caribbean species H. subrufus (Lamarck, 1819).

SUPERFAMILY CALYPTROIDEA,

FAMILY

CALYPTRAE1DAE (Plate 3 6 4 )

Calyptraeids, the slipper limpets, are sedentary limpets, with coiled early whorls, the mature shell characterized by a shell septum that separates the visceral organs from the broad, posteriorly extended foot. The irregular edge of t h e shell conforms to the area of attachment. Elongate ctenidial filaments function like bivalves gills, collecting food particles that are shunted to a food groove leading to the m o u t h . Protandrous hermaphrodites, changing from male to female with size increase; m a n y with differing reproductive modes. Worldwide species of Crepidula were reviewed by Hoagland, 1977, Malacologia 16: 352-420. See Collin 2003a, Biol. J. Linn. Soc., 78: 541-593 (phylogeny), and Collin 2003b, Syst. Biol. 52: 618-640 (phylogeny); Collin 2003c, Mar. Ecol. Prog. Ser. 247: 103-122 (global development patterns). There is a very large literature on the biology of Crepidula cited by these authors. 1. — 2.

—

3.

— 4.

— 5.

With paired shell muscles, septum extending anteriorly on both sides 2 Not with paired muscles, septum not extending anteriorly o n b o t h sides 3 Shell interior dark brown; septum extending anteriorly o n b o t h sides; apex overhanging shell margin; length to 20 m m (plate 364E) Gamotia adunca Shell interior light brown; septum extending anteriorly on b o t h sides, apex close to shell margin; length to 30 m m (plate 364F) Garnotia norissiarum Septum extending forward o n left side (ventral view) but n o t o n right side, right side with muscle scar, reddish brown; shell length under 10 m m (plate 364G) Crepidula convexa Septum notched at left side 4 Septum deeply notched at left side and with raised medial fold, shell nearly circular in outline; mottled or radially striped brown and white; length to 20 m m (plate 364H) Crepipatella lingulata Septum with shallow notch at left side, septum sinuous with raised medial fold 5 Apex strongly turned to one side and united with margin of shell; shell with brown blotches or interrupted, wavy,

chestnut-colored markings; length to 35 m m (plate 364A) Crepidula fornicata — Apex at shell edge, shell white 6 6. Thick, shaggy, golden brown periostracum; shell planar, relatively thick, often broadly oval; length to 40 m m (plate 364B) Crepidula nummaria — Thin, shiny brown periostracum, shell form planar 7 7. Shell relatively thin; shape variable, may occur as foliated, elongate shells in pholad holes or smooth, very thin, concave specimens in hermit-crab shells (plate 364C1) or as low, white shells o n undersides of rocks; length to 25 m m (plate 364C2) Crepidula perforans — Shell thin, flattened, profile broad; living on inner surface of bivalve shells, in bays; length to 30 m m (plate 364D) Crepidula plana Crepidula convexa Say, 1822 (=C. glauca Say, 1822). Introduced with Atlantic oysters; in San Francisco Bay, often o n shells including hermit crab-occupied Ilyanassa obsoleta. See Franz and Hendler 1970, Univ. Conn. Occ. Pap. (Biol. Sci. Ser.) 1: 281-289 (taxonomy); Hendler and Franz 1971, Biol. Bull. 141: 514-526 (reproductive biology and population dynamics). Crepidula fornicata Linnaeus, 1758. Introduced to Puget Sound with Atlantic oysters; may occasionally occur in central California and Oregon; shape highly variable; occurs in characteristic stacks with male o n top. Crepidula nummaria Gould, 1846 (=C. nivea of authors). Also compare C. plana and C. perforans. Low intertidal zone of outer coast, under rocks, occasionally in abandoned pholad holes. Crepidula perforans (Valenciennes, 1846). Compare with C. nummaria (which possesses a shaggy golden brown periostracum) and C. plana (which occurs in San Francisco Bay); in abandoned pholad holes, hermit crab shells, and under rocks along open rocky coast. Crepidula plana Say, 1822. Introduced with Atlantic oysters; in San Francisco Bay on rocks and often (as concave specimens) in hermit crab shells. C. perforans occurs on the open coast. See Collin 2000, Can. J. Zool. 78: 1500-1514 (taxonomy). Crepipatella lingulata (Gould, 1846). Contrary to Hoagland (1977), this is not the same as Crepipatella dorsata, a tropical eastern Pacific species in which the detachment of the septum o n the left side is not as deep. On rocks, shells, intertidal to offshore depths. See Collin 2000, Veliger 43: 24-33 (reproduction). Gamotia adunca (G. B. Sowerby I, 1825). C o m m o n o n shells of larger snails such as Chlorostoma and Calliostoma. See Vermeij et al. 1987, Nautilus 101: 69-74 (gastropod hosts); Collin 2000, Veliger 43: 23-33 (reproduction). This is the type species of Garnotia Gray, 1867, which is here recognized as a full genus because there are shell muscles on both sides and the septum projects anteriorly o n both sides. Garnotia norissiarum (Williamson, 1905). In southern California occurs chiefly on the teguline trochid Norrisia norrisi; here reported on the teguline trochid Promartynia pulligo at Carmel. See G. MacGinitie and N. MacGinitie, 1964, Veliger 7: 34 (reproduction); Warner et al. 1996. J. Exp. Mar. Biol. Ecol. 204: 155-167 (social control of sex change); Hobday and Riser 1998J. Exp. Mar. Biol. Ecol. 225:139-154 (movement and reproductive potential). S U P E R F A M I L Y V E R M E T O I D E A , FAMILY V E R M E T I D A E

Vermetid shells are attached to a hard substratum, uncoiling with growth; teleoconch whorls irregular, solitary or forming clumps of wormlike tubes. The tubes of vermetid snails are readily GASTROPODA:

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PLATE 364 Calyptraeidae: A, Crepidula fornicata, length 33.5 m m (two views); B, Crepidula nummaria (two views), length 38.7 m m ; C l , Crepidula perforons (two views, shell aperture form), length 20 mm; C2, Crepidula perforons (two views), length 21.6 mm; D, Crepidula plana (two views), length 25.7 m m ; E, Garnotia adunca (two views), diameter 19 m m ; F, Gamotia norissiarum, length 30.1 mm; G, Crepidula convexa (two views), length 8 m m ; H, Crepipatella lingulata, diameter 21 m m .

distinguished from the tubes of serpulid worms: vermetids have a three-layered shell, are glossy and white (often tinged with brown) within, and begin with a spirally coiled embryonic shell; tube worms have a two-layered shell, are dull and lusterless within, and begin with a single noncoiled tubular chamber. Some vermetids feed by casting out a mucous net, which traps planktonic particles o n which they feed. See Keen 1961, Bull. Brit. Mus. (Nat. Hist.) 7:181-213 (taxonomy). See Hadfield and Hopper, 1980, Mar. Biol. 57: 315-325 (spermatophores); Hadfield and Iaea 1989, Bull. Mar. Sci. 45: 377-386 (larvae). 734

MOLLUSCA

1.

Solitary; shell coiled, flat, with a strong dorsal ridge and scaly longitudinal ribs; tube diameter 1.5 m m - 3 m m ; often o n abalones, corroding a channel into shell surface (plate 365A) Dendropoma lituella — Gregarious, generally occurring in clumps or masses (except Serpulorbis squamigerus in central California; see below) 2 2. Tube diameter about 2 m m ; sculpture of diagonal wrinkles o n early portion of tube, projecting tubes smooth; with internal spiral thread o n columella in medial whorls;

occasional isolated individuals tightly coiled (plate 365D) Petaloconchus montereyensis — Tube diameter much > 2 mm 3 3. Lacking operculum; shell relatively large, diameter to about 12 mm; tube scaly to wrinkled, longitudinally ribbed, not embedded in substratum (plate 365C) Serpulorbis squamigerus — With operculum; tube diameter to 15 mm, similar to above in size and sculpture, but initial whorls embedded in substratum (if on a mollusk shell) and later whorls somewhat corroded where one tube crosses another (plate 365B) Dendropoma rastrum Dendropoma lituella (Morch, 1861) (=Spiroglyphus lituellus). Often found embedded in abalone shells; also on other shells and rocks. Dendropoma rastrum (Mórch, 1861). May occur in clusters on soft rock or on shells, such as abalones. Has been confused with Serpulorbis squamigerus with which it may occur in the same cluster. The sculpture is similar to that of S. squamigerus, but D. rastrum possesses an operculum and shows slight corrosion where one tube crosses another. Petaloconchus montereyensis Dall, 1919. Under rocks in low intertidal in areas of heavy but broken wave action; possibly unique among gastropods in periodic production of a new, and molting of the old, operculum. See Hadfield 1970, Veliger 12: 301-309 (anatomy, ecology, biology). Serpulorbis squamigerus (Carpenter, 1857) (=Aletes squamigerus). Twisted masses found south of Point Conception, generally found only as individuals in central California; on rocks, shells, pilings. See Hadfield, above. Larvae settle on bryozoans (see Osman 1987, J. Exp. Mar. Biol. Ecol. I l l : 267-284). VELUNTINOIDEA

Two families comprise the Velutinoidea, the Triviidae and the Velutinidae, which seem not to have shell features in common, although some members of both families have mantle margins that envelop the shell. However, all members are grazing carnivores on ascidians and both groups have the double-walled echinospira larvae; see Wilson 1998, p. 787 (in Gastropod volume, Fauna of Australia). Both families in the superfamily are represented in central California. FAMILY T R I V I I D A E

Triviids, called the false cowries, have small shells that somewhat resemble cowries in having the outer lip of the mature shell inturned and bearing elongate denticles on both the inner and outer lips. Shells are either strongly ridged (subfamily Triviinae) or smooth (subfamily Eratoinae). Shells lack periostracum and are enveloped by the mantle, which can expand over the entire shell and retract when the animal is disturbed; there is no operculum. No work has been done on Californian species, but they have been studied from other areas of the world. See Gosliner and Liltved 1987, Zool. J. Linn. Soc. 90: 207-254 (general features); Wilson 1998, p. 787 (in Gastropod volume, Fauna of Australia). 1.

Aperture slotlike, running full length of shell; shell dark purple brown; about the shape and size of a coffee bean; numerous transverse ridges extending from a dorsal longitudinal furrow to aperture; length to 10 mm (plate 365E) Trivia califomiana

Shell red to gray dorsally, glossy; inverted pear-shaped 2 2. Outer lip with seven to 10 denticles; color purple red dorsally; length to about 16 mm (plate 365G) Erato vitellina — Outer lip with about 12 or more denticles; gray to orangebrown or reddish brown dorsally; length to about 8 mm (plate 365F) Erato columbella —

Trivia califomiana (Gray, 1827). The coffee-bean shell, more common in subtidal zone, associated with ascidians. Erato columbella Menke, 1847. Under rocks, low intertidal to offshore, associated with and feeding upon ascidians. Erato vitellina Hinds, 1844. As above, may be encountered in beach drift. Northern limit is recorded as Bodega Bay, where, along with Trivia, it is common in beach drift at Bodega Head. FAMILY V E L U T I N I D A E

Velutinidae have broadly inflated shells of low profile. There are two subfamilies: the Velutininae, with strongly developed periostracum and external shells, and the Lamellariinae, with thin periostracum and enveloped shells. There are radular distinctions between the subfamilies; one genus Marsenina presents a problem because the shell is like that of Lamellariinae whereas the radula is like that of Velutininae. Members of both subfamilies are found in association with ascidians, on which they feed and deposit their egg masses. The Lamellariinae are often overlooked because of their remarkable similarity in color and texture to the host. See Behrens 1980, Veliger 22: 323-339 (taxonomy of Lamellariinae); Fretter and Graham 1981, J. Moll. Stud., Suppl. 9, 285-262 (biology). 1. Shell with thick brown periostracum 2 — Periostracum very thin, tan 3 2. Periostracum with spiral rows of fine bristles; spire depressed; diameter to 6 mm (plate 3651) Velutina sp. — Periostracum nearly smooth, with irregular axial ridges; spire projecting; diameter to 24 mm (plate 365H) Velutina prolongata 3. Shell internal, fully enveloped by mantle, translucent white 4 — Mantle with dorsal pore that opens to expose translucent white shell 5 4. Body with flat areas separated by angular ridges, shell surface not maleated; diameter 5 mm (plate 366C) Marseniopsis sharonae — Body bulbous, shell surface malleated (like hammered metal); diameter 17 mm (plate 366D) Lamellaria diegoensis 5. Body surface finely pitted; diameter 6 mm (plate 366B) Marsenina stearnsii — Body surface warty; diameter 6 mm (plate 366A) Marsenina rhombica Velutina prolongata Carpenter, 1865. Generally sublittoral; rare in intertidal zone. Velutina sp. [=V. velutina (Muller, 1776), of authors], Intertidal; may be common under rocks, in crevices. This is much smaller and has less projecting apical whorls than the more northern species V. velutina. Marsenina rhombica (Dall, 1871). The two species of Marsenina cannot be told apart on shell characters. GASTROPODA:

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"«SS

ì

PLATE 365 Vermetidae, Triviidae, and Velutinidae (subfamily Velutininae): A, Dendropoma lituella, diameter of individual 16 mm; B, Dendropoma rastrum, diameter 64 mm; C, Serpulorbis squamigerus, diameter of clump 38 mm; D, Petaloconchus montereyensis, diameter of clump 20 mm; E, Trivia californiana (two views), length 9.8 mm; F, Erato columbella, height 6.2 mm; G, Erato vitellina, height 13.7 mm; H, Velutina prolongata (two views), diameter 24 mm; I, Velutina sp. (two views), diameter 5.7 mm.

Marsenina stearnsii (Dall, 1871) [=Lamellaria stearnsi]. See Ghiselin 1964, Veliger 6: 123-124 (on ascidian Trididemnum opacum). Lamellaria diegoensis Dall, 1885. Scarce, on ascidians. See Lambert 1980, Veliger 22: 340-344 (feeding on ascidian Cystodytes). Marseniopsis sharonae (Willett, 1939). Scarce, on ascidians. 736

MOLLUSCA

SUPERFAMILY N A T I C O I D E A , FAMILY N A T I C I D A E

Naticid moon snails have low profiles; shells lack surface sculpture and are fully enveloped by the mantle; the foot has a propodium, which enables the animal to plow through soft bottoms. They prey upon bivalves, which they drill, forming

I-LAI t see veiutininae (subfamily Lamellariinae) and Naticidae: A, Marsenina rhombica (three views), diameter 11.3 mm; B, Marsenina stearnsii (three views), diameter, 6.2 mm; C, Marseniopsis sharonae, liameter 5.5 mm; D, Lamellaria diegoensis (three views), diameter 17 mm; E, Euspira lewisii, height 65 mm; F, Glossaulax reclusianus, heigl t 38.8 mm; G, Glossaulax altus, height 33.6 mm.

rounded, beveled holes. Drilling involves the accessory boring organ of the proboscis. Radula is taenioglossate, with seven teeth per row. Egg masses form "sand collars" in which the gelatinous capsules are embedded. Former subgenera of the genus Polinices are now recognized as genera (for taxonomy see Kabat 1991, Bull. Mus. Comp. Zool., Harvard Univ. 152: 417-499).

—

1.

Euspira lewisii (Gould, 1847) (=Polinices lewisii). Largest living moonsnail. On mud and sand flats in bays, lagoons, Zostera flats, also soft bottoms offshore. A voracious consumer of infaunal bivalves, including Macoma. The older generic name Polinices is from Greek, meaning "many victories." See Bernard

Large (adult 12.5 cm-15 cm), heavy, globose shell with a large, broadly rounded body whorl; umbilicus deep, upper part covered by a wide columellar callus; shoulder weakly angulate with shallow sulcus below (plate 366E) Euspira lewisii

Smaller (30 mm-40 mm), umbilicus partially blocked by tongue of callus 2 2. Profile broad, callus tongue white; height 40 mm (plate 366F) Glossaulax reclusianus — Profile more slender, callus tongue brown, two-Iobed; height 40 mm (plate 366G) Glossaulax altus

GASTROPODA: SHELLED

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1968, Nautilus 82: 1 - 3 (sexual dimorphism); Reid and Friesen 1980, Veliger 23: 25-34 (digestive system). Glossaulax altus (Arnold, 1903) (=Polinices altus). Separation of this species from Glossaulax reclusianus is controversial, but I consider it to be distinct. Glossaulax reclusianus (Deshayes, 1839) (=Polinices reclusianus). More c o m m o n in southern California, but known from Bodega Harbor since the 1970s.

whorl bearing elongate beads; base concave (plate 367D) Metaxia convexa Metaxia convexa (Carpenter, 1857) (=M. diadema Bartsch, 1907). Low tide to sublittoral, gravel, rocks. Triphora pedroana Bartsch 1907 (=T. montereyensis Bartsch, 1907). In sand, gravel, rubble; associated with sponges. EPITONIOIDEA

TRIPHOROIDEA

Triphoroideans have small, slender shells, assigned to two families, the Cerithiopsidae, which are usually dextral and t h e Triphoridae, which are usually sinistral. Both families are aphallate and feed o n sponges. Protoconchs are important for generic-level classification in both families. The radula is usually ptenoglossate, with repeating elements, departing from the taenioglossate condition with seven teeth per row. Both families are represented in central California.

FAMILY

CERITHIOPSIDAE

Cerithiopsids are dextral and have a short, siphonal canal open, notched; the final lip is not flared. Sponge feeders, but biology of eastern Pacific species has not been studied, and there has been n o recent taxonomic work for the region subsequent to that of Bartsch 1911, Proc. U.S. Nat. Mus. 40: 327-367. Cerithiopsids should not be confused with the cerithiid genera Lirobittium and Stylidium, shells of which do not have the siphonal notch of cerithiopsids. The cerithiopsid species treated here also differ in having more protoconch whorls t h a n those of the latter two genera. 1.

Relatively large (to 10 mm), sculpture of raised spiral cords with minute axial threads in interspaces; brown, flat-sided, relatively large (plate 367A) Seila montereyensis — Relatively small (to 3 mm); sculpture clathrate, with strongly projecting beads (plate 367B) Cerithiopsis berryi Seila montereyensis Bartsch, 1907. More c o m m o n offshore; for t a x o n o m y see DuShane and Draper 1975, Veliger 17: 335-345. Cerithiopsis berryi Bartsch, 1911. Shells occur in sediment samples, but living specimens should be found on sponge colonies.

FAMILY T R I P H O R I D A E

Triphorids are usually sinistral (the subfamily Metaxiinae is an exception) and have a flaring final lip, a pinched posterior sinus (which forms a tube in some genera), and a short anterior canal that is usually sealed to form a tube. The family Triphoridae includes the dextral subfamily Metaxiinae and the sinistral subfamily Triphorinae. Like the Cerithiopsidae, they are sponge feeders. See Marshall 1983, Rec. Aust. Mus., Suppl. 2: 1-119 (taxonomy). 1.

Shell sinistral, small (to about 6 mm), slightly convex, with three beaded cords per whorl, the middle cord arising as the shell attains its full size; anterior canal short, closed (plate 367C) Triphora pedroana — Shell dextral (to about 6 mm), whorls convex, sutures deeply impressed; with weak ribs, four spiral cords per 738

MOLLUSCA

Members of the families that comprise the superfamily Epitonioidea are predators or parasites on coelenterates and have a ptenoglossate radula of numerous fanglike teeth that expand over t h e odontophore. Purple dye is secreted by the hypobranchial gland. Two families are represented in the superfamily Epitonioidea, the Janthinidae, which are treated as part of a separate section o n pelagic gastropods, and the Epitoniidae. FAMILY J A N T H I N I D A E

See treatment of janthinids in Pelagic Gastropoda by Seapy and Lalli. FAMILY

EPITONIIDAE

Epitoniids, the wentletrap shells, generally have white shells of high profile and impressed suture, usually with many promin e n t axial ribs or bladelike lamellae; protoconchs are multispiral. The aperture is circular and the operculum paucispiral; purple dye is released by living specimens. They feed o n sea anemones by everting the proboscis and biting chunks of t h e prey; protandrous hermaphrodites, lacking the penis; planktotrophic veligers emerge from egg capsules formed in strings. For biology see Smith 1998, pp. 814-817 (Gastropod volume of Fauna of Australia). See DuShane 1979, Veliger 22: 91-134 (taxonomy of West Coast species). 1.

Base not set off by a spiral keel; axial sculpture of thin, sharp lamellae, continuous from whorl to whorl 2 — Base set off by a spiral keel; axial lamellae thick 3 2. Relatively large (height to 35 mm), lacking brown line (plate 367E) Epitonium indianorum — Relatively small (height to 15 m m ) fresh specimens with a characteristic purplish or brown line below suture (plate 367F) Epitonium tinctum 3. Small (height to 10 mm); axial ribs acute; spiral keel strong, projecting; ribs n o t continuing over o n t o shell base (plate 367G) Opalia montereyensis — Large (height to 35 mm); axial ribs broadly rounded; spiral keel low to obscure; about every third rib stronger, continuing over keel o n t o base of shell (plate 367H) Opalia borealis Epitonium tinctum (Carpenter, 1864) (=Nitidiscala tincta). In sand at base of sea a n e m o n e s Anthopleura elegantissima and A. xanthogrammica; feeds at high tide upon tips of a n e m o n e tentacles (Hochberg 1971, Ann. Rept. West. Soc. Malacologists 4: 22-23). See also Smith 1977, Veliger 19: 331-340 (chemoreception); Salo 1977, Veliger 20:168-172 (feeding); Resch and Breyer 1983, Veliger 26: 37-40 (northern and southern populations); Collin 2000, Veliger 43: 302-313 (anatomy and development). Epitonium indianorum (Carpenter, 1864) (=Nitisdiscala indanorum). More c o m m o n offshore, occasionally at low intertidal zone; hermit-crab shells occur.

PLATE 367 Cerithiopsidae, Triphoridae, Epitoniidae, and Eulimidae: A, Seila montereyensis, height 11.2 mm; B, Cerithiopsis berryi, height 2.6 mm; C, Triphora pedroana, height 6.1 mm; D, Metaxia convexa, height 5.3 mm; E, Epitonium indianorum, height 37.8 mm; F, Epitonium tinctum, height 15.2 mm; G, Opalia montereyensis, height 11.5 mm; H, Opalia borealis, height 34.4 mm; I, Melanella thersites, height 7.0 mm; J, Polygireulima rutila, height 6.8 m m .

*Epitonium hindsii (Carpenter, 1856) (=Nitidiscala hindsiv, E. cooperi Strong, 1930). Very deep suture; on sandy or muddy bottoms offshore. For illustrations see DuShane 1979, Veliger 22, figs. 32-35. Opalia borealis Keep, 1881 ( = 0 . chacei Strong, 1937). In sand at the base of the sea anemone Anthopleura xanthogrammica; feeds at high tide upon the anemone by inserting its proboscis directly in the column. Opalia montereyensis (Dall, 1907). Largely sublittoral; both species also occur occasionally as hermit crab shells intertidally. SUPERFAMILY EULIMOIDEA, FAMILY EULIMIDAE

Eulimids have small, slender, glossy shells. All are suctorial parasitic on echinoderms; most lack a radula. Species of mobile genera have an operculum, others are permanently attached to hosts and lack opercula. Sexes are separate and males have a cephalic penis. Individuals of mobile species away from hosts are thought to be either resting between feedings or searching for their echinoderm host. See Waren * = Not in key.

1984, J. Moll. Stud., Suppl. 13, 1-96 (taxonomic revision of family and review of genera worldwide). 1.

Shell sturdy, white, profile broad, whorls irregular with moderately deep suture; height to 7 mm (plate 3671) Melanella thersites — Shell thin, transparent white, profile slender, whorls even, flat-sided; height to 7 mm (plate 367J) Polygireulima rutila Melanella thersites (Carpenter, 1864) (=Balcis thersites). Occurs on small holothurians at low tide and in the rocky sublittoral, although it is more often found away from its host. Polygireulima rutila (Carpenter, 1864) (=Balcis rutila). Occurs on ventral surfaces of seastars of various species, in the immediate sublittoral zone to moderate depths. The change in the generic name was discussed by McLean (1996: 74). NEOGASTROPODA MURICOIDEA

Muricoidean families generally have fusiform shells with elongate apertures and siphonal canals. The radula is rachiglossate, GASTROPODA: SHELLED

739

PLATE 3 6 8 Muricidae: A, Ocinebrina aspera, height 24.0 mm; B, Ocinebrina lurida, height 18.5 mm; C, Ocinebrina munda, height 17.2 mm; D, Ocinebrina circumtexta, height 19.8 mm; E, Ocinebrina minor, height 9.7 mm; F, Ocinebrina atropurpúrea, height 10.9 mm; G, Ocinebrina irtterfossa, height 13.4 mm; H, Ocinebrina graciHima, height 12.2 mm; I, Ocinebrina subangulata, height 19.0 mm.

with three teeth per row. Most are carnivores, employing an extendable, eversible proboscis to reach food from a distance; digestive system with paired salivary glands, anterior gut with gland of Leiblein, posterior gut with anal gland. See Ponder 1998, pp. 8 1 9 - 8 2 0 (Gastropod volume, Fauna of Australia). Only some families are represented in shallow water of central California; those treated here are Muricidae, Columbellidae, Nassariidae, Buccinidae, Fasciolariidae, Melongenidae, Olividae, Cystiscidae, and Mitridae.

Pacific species has been little studied; species were formerly placed in Ocenebra (see McLean 1996: 80). Species of the genus Acanthinucella were formerly placed in Acanthina (see Vermeij 1993, Cont. Tert. Quat. Geol. 30: 22). There is a large literature on the genus Nucella, species of which are prominent intertidal predators on mussels and barnacles. For evolutionary history of Nucella, see Collins et al. 1996, Evol. 50: 2 2 8 7 - 2 3 0 4 ; and Marko 1998, Evol. 52: 7 5 7 - 7 7 4 . 1.

FAMILY

MURICIDAE

Muricids have elaborate sculpture, both axial and spiral, some forming prominent varices bearing spines or winglike projections. Muricids are carnivorous gastropods, most of which are capable of drilling into the shell of their bivalve or barnacle prey, using both the radula and a special structure called the accessory boring organ. Some (Acanthinucella, Ceratostoma) have a labial spine that is used as a wedge to open bivalves or mussels for insertion of proboscis (see Perry 1985, Mar. Biol. 88: 5 1 - 5 8 ) . Egg capsules are attached to rocks. This is a large family that is well represented in tropical waters; it is the most speciose caenogastropod family in shallow waters of central California. All muricids treated here are members of the subfamily Ocenebrinae, characterized by the fine lamellar sculpture. The genus Ocinebrina is well represented but the biology of eastern 740

MOLLUSCA

— 2. — 3.

—

4. — 5.

Siphonal canal usually sealed may be open in some species 2 Siphonal canal open 11 Three or more varices per whorl 3 Lacking varices on body whorls but mature lip thickened 4 Three prominent varices per whorl; with projecting tooth on outer lip near base; surface smooth, lustrous; height to 65 mm (plate 369A) Ceratostoma foliatum More than three varices per whorl; shell surface dull, texture chalky; sculpture of alternating large and small spiral cords; height to 40 mm (plate 369B) Ocinebrellus inornatus Spiral sculpture equal in strength to axial sculpture 5 Spiral sculpture overriding strong axial ribs 6 Profile slender, shell white; height to 10 mm (plate 368E) Ocinebrina minor

PLATE 3 6 9 Muricidae: A, Ceratostoma foliatum, height 62.3 mm; B, Ocinebrellus inornatus, height 40.2 mm; C, Nucella lamellosa, height 60.6 mm; D, Urosalpinx cinerea, height 33.2 mm; E, Acanthinucella punctulata, height 26.7 mm; F, Acanthinucella spirata, height 27.3 mm; G, Nucella ostrina, height 26.7 mm; H, Nucella emarginata, height 35.4 mm; I, Nucella canaliculata, height 28.4 mm; J, Nucella analoga analoga, height 32.7 mm; K, Nucella analoga compressa, height 35.1 m m .

—

Profile broad, shell brown with yellow rib at periphery; height to 12 mm (plate 368F) Ocinebrina atropurpúrea 6. Shell large (20 mm-25 mm) 7 — Shell smaller (12 mm-15 mm) 8 7. Color orange, suture deeply impressed; height to 25 mm (plate 368A) Ocinebrina aspera — Color black, white, or gray, canal usually not sealed; height to 20 mm (plate 368D) Ocinebrina circumtexta

8. Suture weakly impressed, profile broad 9 — Suture strongly impressed, profile slender 10 9. Dark orange, without varix behind outer lip; height to 20 mm (plate 368B) Ocinebrina lurida — Light orange, small with low varix just behind outer lip; height to 12 mm (plate 368H) Ocinebrina gracillima 10. Spiral ribs alternately large and small; grayish brown; height to 15 mm, sometimes larger; canal may not be sealed (plate 368G) Ocinebrina interfossa GASTROPODA:

SHELLED

741

— Reddish orange; height to 17 m m (plate 368C) Ocinebrina munda 11. Outer lip with a projecting tooth near base (immature specimens may lack tooth); color pattern of revolving, interrupted, brown bands 12 — Outer lip lacking projecting tooth 13 12. Shoulder rounded or weakly angulate; spire low; height to 27 m m (plate 369E) Acanthinucella punctulata — Prominent keel at shoulder; spire produced; height to 28 m m (plate 369F) Acanthinucella spirata 13. Canal short 14 — Canal moderately long 19 14. Sculpture of closely spaced spiral cords 15 — Sculpture of broad, irregular spiral cords 17 15. Interspaces between cords deeply channeled; height to 30 m m (plate 3691) Nucella canaliculata — Interspaces between cords with narrow channels 16 16. Spiral cords narrow; height to 35 m m (plate 369J) Nucella analoga analoga — Spiral cords broad, interspaces narrow; height to 35 m m (plate 369K) Nucella analoga compressa 17. Shell with irregularly nodulose, often well-separated, spiral cords (some populations with shells nearly smooth); columella excavated; umbilicus closed 18 — Sculpture various: nearly smooth, or with prominent axial lamellae, or with spiral cords and weaker, irregular, axial swellings; umbilicus small, sometimes closed; height to 60 m m (plate 369C) Nucella lamellosa 18. Spire relatively high, parietal n u b of aperture lacking, height to 27 mm; egg capsules vase shaped with long neck (plate 369G) Nucella ostrina — Spire relatively low, spiral cords with irregular nodes, aperture with parietal nub, height to 35 m m ; egg capsules cylindrical, with short neck and flared distally (plate 369H) Nucella emarginata 19. Axial sculpture strong across shoulder; numerous fine spiral cords, in older specimens most pronounced between axial ribs; canal short, constricted; shell color variable, gray, yellow-brown, aperture purplish; height to 35 m m (plate 369D) Urosalpinx cinerea — Axial sculpture of seven to nine strong ribs, sharply angled at shoulder of whorl; spiral sculpture reduced to fine threads; whitish, often with brown spiral line at periphery; height to 20 m m (plate 3681) Ocenebrina subangulata Ceratostoma foliatum (Gmelin, 1791) (=Purpura foliata). In low intertidal of semiprotected outer coast and sublittoral. A large species, which may develop prominent varices, especially w h e n living sublittorally. See Kent 1981, Nautilus 95: 38-42 (feeding); Carefoot and Donovan 1995, Biol. Bull. 189: 59-68 and Donovan et al. 1999, J. Exp. Mar. Biol. Ecol. 236: 235-251 (functional significance of shell sculpture). Ocinebrellus inornatus (Récluz, 1851). [=Ceratostoma inornatum; = Ocenebra japónica (Dunker, 1869)]. Introduced f r o m Japan with oysters in Tómales Bay, but presence there variable; now c o m m o n in Puget Sound. Ocinebrina aspera (Baird, 1863). Here distinguished f r o m O. lurida by its larger size and more deeply channeled interspaced between the spiral cords. Ocinebrina atropurpúrea Carpenter, 1865 [= Ocenebra atropurpúrea; = 0 . clathrata (Dall, 1919)]. Often as hermit-crab shells intertidally. Ocinebrina circumtexta Stearns, 1871 (=Ocenebra circumtexta). C o m m o n mid-intertidal species. 742

MOLLUSCA

Ocinebrina gracillima Stearns, 1871 (=Ocenebra gracillima). Under rocks; more c o m m o n in southern California. Ocinebrina interfossa Carpenter, 1864 (=Ocenebra interfossa). C o m m o n under alga-covered rocks. Ocinebrina lurida (Middendorff, 1848) (=Ocenebra lurida). C o m m o n o n and under rocks. See Palmer, 1988, Veliger 31: 192-302 (biology). Ocinebrina minor (Dall, 1919). Here removed from synonymy of O. atropurpúrea. Ocinebrina munda (Dall, 1892). Here separated from O. lurida, differing in its more slender profile. Where sympatric with O. lurida, this occurs in sublittoral zone. Ocinebrina subangulata (Stearns, 1873). This species retains an open siphonal canal and is thereby unlike other members of the genus; its affinity is unsettled. *Ocinebrina sclera (Dall, 1919). A more n o r t h e r n species, m u c h larger t h a n O. aspera, and living sublittorally in central California. Urosalpinx cinerea (Say, 1822). The Atlantic oyster drill, introduced with oysters; may be c o m m o n a m o n g oysters and barnacles in estuaries. See Franz 1971, Biol. Bull. 140: 63-72 (biology); Carriker, 1969, Amer. Zool. 9: 917-933 (drilling). Acanthinucella punctulata (G. B. Sowerby I, 1825) (=Acanthina punctulata). Upper intertidal zone o n rocks; m o v i n g downward during breeding season. See Sleder 1981, Veliger 24: 172-180 (biology). Acanthinucella spirata (Blainville, 1832) (=Acanthina spirata). Where the unicorn snails A. punctulata and A. spirata occur together, as at Monterey, spirata generally is in the lower, and punctulata in the upper intertidal. Feeds o n barnacles and mollusks. See Gianniny and Geary 1992, Veliger 35:195-204 (shell form in genus); Perry 1985, Mar. Biol. 88: 51-58 (function of spine in opening barnacle prey). Nucella analoga analoga (Forbes, 1852) (previously misidentified as N. canaliculata). This n a m e had been considered a synonym of N. canaliculata but represents a species that has incised interspaces rather t h a n deeply channeled interspaces. This is c o m m o n in Oregon and northern California living exposed a m o n g mussels o n which it feeds. Its range overlaps with that of N. canaliculata from Ketchikan, Alaska to Fidalgo Island, Washington. This must have been the species studied by Sanford et al. 2003, Science 300:1135-1136. See McLean 2006, Festivus 38: 17-20 (systematics). Nucella analoga compressa (Dall, 1915). This is a southern subspecies of N. analoga that occurs sparsely in the exposed mussel zone in Monterey County, south of Pacific Grove. See McLean 2006, Festivus 38: 17-20 (systematics). Nucella canaliculata (Duelos, 1832). This is a n o r t h e r n species, occurring from Alaska to Puget Sound; it is c o m m o n in the barnacle zone of waters exposed to tidal currents rather t h a n exposed to strong wave action in the mussel zone. Nucella emarginata (Deshayes, 1839). C o m m o n at upper tide levels. This has more southern distribution, compared to that of N. ostrina. The profile is lower t h a n that of N. ostrina. See West 1986, Ecology, 67: 798-809 (prey selection); Wayne 1987, Veliger 30: 138-147 (defensive behavior of prey Mytilus). Nucella ostrina (Gould, 1852). Marko 1998, Evolution 52: 757-774, and earlier papers by other authors cited therein, showed t h a t n o r t h e r n populations formerly t h o u g h t t o represent N. emarginata, should take t h e n a m e N. ostrina, based o n genetic evidence as well as distinctions in t h e shells. The two species overlap in distribution between Half M o o n Bay * = Not in key.

and Point Conception, California; Marko et al. 2003, Veliger 46: 77-85, noted that in the region of overlap, N. ostrina occurs on wave-swept shores and N. emarginata is found within embayments such as Monterey Bay, Half Moon Bay, and Morro Bay. This has a higher profile than that of N. emarginata. Nucella lamellosa (Gmelin, 1791). Low tide on rocks, often in protected bays; highly variable sculpture, smoother specimens occurring in more exposed situations, delicate and prominent lamellae developing in protected areas; see Spight 1973, J. Expt. Mar. Ecol. 13: 215-228; 1974, Ecology 55: 712-729.

Carter and Behrens 1980, Veliger 22: 376-377 (mimicry by amphipod); Bergman et al. 1983 Veliger 26: 116-118 (variation and shell repair); Tupen 1999, Veliger 42: 249-259 (variation in shell form and color). Alia tuberosa (Carpenter, 1864) (=Mitrella tuberosa). In sand and gravel at low tide and in beach drift; more common sublittorally. Astyris aurantiaca (Dall, 1871) (=Mitrella aurantiaca). Chiefly sublittoral; uncommon in low intertidal zone among rocks and algae.

FAMILY

Buccinid whelks are medium to large-size, with siphonal canals, and extendable proboscis; they are scavengers or feed on living prey. Numerous genera and species occur in cold northern waters, but there are only two species occurring in shallow water in California.

COLUMBELLIDAE

Columbellids are small to minute in size with short siphonal canals, the outer lip may be denticulate and the columella with small plications, or these may be lacking. The radula is rachiglossate. Feeding is varied, some are carnivorous, and some feed on algal films or detritus (see Wilson 1998, pp. 827-829, Gastropod volume, Fauna of Australia). This is a large family with numerous genera and species in tropical regions. There are few papers on the biology of northeastern Pacific species. For taxonomy see Radwin 1977a, Veliger 19: 4 0 3 ^ 1 7 ; 1977b, Veliger 20: 119-133, 1978, Veliger 20: 328-344; Guralnick and de Maintenon 1997, J. Molluscan Stud., 63: 65-77 (radular formation); de Maintenon 1999, Invert. Biol. 118: 258-288 (phylogeny). Amphissa and Alia have multispiral protoconchs indicative of planktonic development; Astyris has a paucispiral protoconch, which is indicative of lecithotrophic development. 1.

— 2.

— 3.

—

4. —

With incised spiral grooves restricted to base of shell; weak fold on columella separating aperture from short siphonal canal 2 Spiral sculpture not restricted to base of shell 4 Protoconch paucispiral; shell small, slender, with a chevron pattern of thin revolving, brown lines on a yellow-brown background (not an irregular pattern of wavy longitudinal lines), relatively small; height 4.5 mm (plate 370C) Astyris aurantiaca Protoconch multispiral; color tan to yellow-brown or variously mottled 3 Shoulder of body whorl varying from smooth to strongly keeled (keel usually lighter in color than rest of shell); whorls somewhat inflated; outer lip sinuous; periostracum smooth; color usually yellow-brown to dark brown, at times with white and darker brown mottling; height to 10 mm (plate 370E) Alia carinata Slender, whorls nearly flat-sided; periostracum forming thin, projecting, axial blades in living animals; color usually tan, sometimes darker, may show fine white dots; height to 7 mm (plate 370D) Alia tuberosa Shell large (to 18 mm in height), columella with fine plications (plate 370A) Amphissa columbiana Shell smaller (to 13 mm in height), variable in color, columella lacking plications (plate 370B) Amphissa versicolor

Amphissa columbiana Dall, 1916. On algae-covered rocks; under rocks in sand and gravel. See Kent 1981, Veliger 23: 275-276 (behavior). Amphissa versicolor Dall, 1871. Common in rocky intertidal and sublittoral zones. Highly variable in color pattern. Alia carinata (Hinds, 1844) (=Mitrella carinata; =Mitrella gausapata of authors). Common on algae and on rocks. See

FAMILY B U C C I N I D A E

1.

Body whorl with distinct spiral sculpture; low, rounded axial ribs on spire; columella arched, glossy; canal short, twisted; color dull gray or brownish purple; sculpture may be obscured by growths of purple coralline algae (plate 370F) Lirabuccinum dirum

Lirabuccinum dirum (Reeve, 1846) (=Searlesia dira). Dire whelk; chiefly intertidal, on coralline-encrusted rocks and among gravel and rocks in crevices; abundant further north, but of spotty occurrence in central California. See Lloyd 1973, Ann. Rept. Western Soc. Malac. 5: 32 (biology, feeding); Vermeij 1991, Veliger 34: 264-271 (taxonomy). *Kelletia kelletii (Forbes, 1852). Kellet's whelk; this largeshelled species common in southern California has since the 1980s occurred offshore in Monterey Bay; see Herlinger 1981, Veliger, 24: 78 (Monterey record); Rosenthal 1979, Veliger 12: 319-324 (reproduction); Lonhart and Tupen 2001, Bull. S. Calif. Acad. Sci., 100: 238-248 (northern occurrence); Zacherl et al. 2003, J. Biogeog. 30: 913-924 (northern occurrence). See photo in McLean 1978.

FAMILY NASSARIIDAE

The Nassariidae, the mud snails, are scavengers occurring on mud or sand. Like other neogastropods, the radula is rachiglossate. Shells are recognized as nassariids by a prominent furrow at the base of the shell. There are posterior pedal tentacles. Most eastern Pacific species produce egg capsules and have planktotrophic larval stages, as indicated by their multispiral protoconchs. See Demond, 1952, Pac. Sci. 6: 300-317 (review of northeastern Pacific species); Cernohorsky 1984, Bull. Auckland Inst. Mus. 14: 1-359 (taxonomy at subgeneric level); Harasewych 1998, Gastropod volume of Fauna of Australia, pp. 829-831 (general features); Hassl 2000, J. Paleont., 74: 839-852 (phylogeny). Until now, most New World species had been placed in the genus Nassarius; however, that genus is based on a large-shelled Indo-Pacific-type species with a broad columellar shield, representing a group unlike any New World species. Here I raise to full generic level two taxa previously regarded as subgenera: Caesia H. and A. Adams, 1853, for large-shelled northeastern Pacific species with broad parietal callus and the lip thickened from the inner side, and the broadly distributed Hima Leach, 1852, for slender species with a narrow parietal callus and with the final lip thickened from both sides. * = N o t in key.

GASTROPODA:

SHELLED

743

P L A T E 370 Columbellidae, Buccinidae, Nassariidae, Fasciolariidae, and Melongenidae: A, Amphissa Columbiana, height 16.7 mm; B, Amphissa versicolor, height 11.3 mm; C, Astyris aurantiaca, height 4.5 mm; D, Alia tuberosa, height 6.5 mm; E, Alia cannata, height 9.8 mm; F, Lirabuccinum dirum, height 38.6 mm; G, Ilyanassa obsoleta, height 30 mm; H, Caesia fossata, height 47 mm; I, Hima cooperi, height 15.8 mm; J, Hima mendica, height 16.5 mm; K, Harfordia harfordii, height 55 mm; L, Harfordia sp., height 41.6 mm; M, Aptyxis luteopictus, height 24.1 mm; N, Busycotypus canaliculars, height 103 mm.

1. With a distinct revolving furrow around base 2 — Lacking a distinct furrow; with columellar fold at base; shell sculpture of revolving, weakly beaded cords crossed by growth lines and oblique axial ribs; apex often eroded; aperture black-glazed; shell dark brown to black, often with adherent detritus and algae; height to 30 mm (plate 370G) Ilyanassa obsoleta 2. Shell relatively large (to 50 mm), broad, with orange callus spreading over parietal area; periphery rounded to carinate; axial sculpture of widely spaced axial ribs, limited to upper part of body whorl (plate 370H) Caesia fossata — Shell small (to 20 mm), generally slender, without parietal callus; periphery rounded; axial sculpture of rounded ribs 3 3. Axial ribs few, broadly spaced; height to 17 mm (plate 3701) Hima cooperi — Axial ribs more numerous, closely spaced; height to 18 mm (plate 370J) Hima mendica Ilyanassa obsoleta (Say, 1822) (=Nassarius obsoletus). Introduced from Atlantic coast; an omnivore and deposit feeder, very abundant on San Francisco Bay mudflats. Only American nassariid having a crystalline style. Differs from most other genera because it lacks the deep basal groove, caudal cirri, bifurcated foot, and other features expected in the family. There is an extensive literature on Atlantic coast populations. See Curtis and Hurd 1981, Veliger 24: 91-96 (crystalline style); Scheltema 1964, Ches. Sci. 5: 161-166 (feeding and growth). Caesia fossatus (Gould, 1850) (=Nassarius fossatus). Common on mud and sand in bays, estuaries; see MacGinitie 1931, Ann. Mag. Nat. Hist. (10) 8: 258-261 (egg-laying). *Caesia perpinguis (Hinds, 1844) (=Nassarius perpinguis). Sublittoral on sandy bottoms; with a narrow shelf below suture and fine cancellate sculpture with beaded axial ridges. See photo in McLean 1978. *Caesia rhinetes (Berry, 1953) (=Nassarius rhinetes). An uncommon, large-shelled species occurring offshore. See photo in McLean 1996. Hima mendica (Gould, 1849) (=Nassarius mendicus). Common in sand, mud, on rocks, of open coast and in bays. Hima cooperi (Forbes, 1852) (=Nassarius cooperi). Differs from H. mendica in having fewer axial ribs. Usually regarded as a variant of H. mendica, but the consistency of shell form in certain populations leaves the question open, a matter for further investigation. *Hima fratercula (Dunker, 1862) (=Nassarius fraterculus). An introduced northwestern Pacific species well established in Puget Sound and southern British Columbia; can be expected to extend its distribution to central California. See photo in Abbott 1974.

FAMILY FASCIOLARIIDAE

Fasciolariids are carnivorous neogastropods with long siphonal canals. The group is mostly tropical; members of subfamily Fusininae occur in California. Aside from radular and anatomical differences, they differ from buccinids in having the animal red-colored. Genera previously regarded as subgenera of Fusinus are here recognized as full genera, distinguished from Fusinus Rafinesque, 1815, a tropical group for which the type species has a very long canal. Biology of the California species has not been studied. * = N o t in key.

1.

Small (height to 26 mm); strong spiral cords continuous over strongly projecting axial ribs; canal short; coloration dark brown, white spiral band at periphery (plate 370M) Aptyxis luteopictus — Larger, strong spiral cords continuous over strongly projecting axial ribs; canal; shell coloration uniformly brown 2 2. Large, to 55 mm in shell height; profile broad, canal relatively short, not strongly constricted (plate 370K) Harfordia harfordii — To 45 mm in height; profile slender, canal more constricted (plate 370L) Harfordia sp. Aptyxis luteopictus (Dall, 1877) (=Fusinus luteopictus). Low intertidal to sublittoral, on and under rocks of protected coast; Monterey Bay and south. Harfordia harfordii (Stearns, 1871) (=Fusinus harfordii). Intertidal in partially exposed rocky areas in northern California. Harfordia sp. Rocky sublittoral; shells occupied by hermit crabs in shallow water. FAMILY

MELONGENIDAE

Melongenids are large-shelled whelks, represented in shallow, mostly tropical waters. The subfamily Busyconinae is well represented along the Atlantic and Gulf of Mexico coasts of the United States. See Hollister 1959, Paleontol. Amer., 4: 59-126 (generic revision); for Atlantic species of Busyconinae see also Abbott (1974: 222-223); Kosyan and Kantor 2004, Ruthenica 14: 9 - 3 6 (anatomy and phylogeny of family). 1.

No axial ribs; outer lip smooth; shell relatively thin; large, height to 160 mm; suture strongly channeled; shoulder keeled; long, slightly curved canal; with a yellow-brown, feltlike, hairy periostracum, often partly worn off (plate 370N) Busycotypus canaliculars

Busycotypus canaliculars (Linnaeus, 1758) (=Busycon canaliculatum). Channeled whelk, introduced from Atlantic; sublittorally and in mud at low tide in San Francisco Bay; distinctive strings of large egg capsules are commonly washed ashore. See Stohler 1962, Veliger 4: 211-212 (occurrence); Rohrkasse and Atema 2002, Biol. Bull. 203: 235-236 (chemoreception). FAMILY O L I V I D A E

The mostly tropical family Olividae is represented in California and more northern regions by the genus Callianax H. and A. Adams, 1853, in the subfamily Olivellinae. Until now, Callianax had been regarded as a subgenus of the tropical genus Olivella Swainson, 1831; here it is regarded as a full genus because it significantly differs in having an operculum, not having multiple columellar folds, and not having columellar callus that extends posteriorly toward the shell apex. All members of the family are carnivores or scavengers of shallow, sandy bottoms. The glossy shell is partially enveloped by the mantle and the propodium is plow-shaped for burrowing. See Olsson 1956, Proc. Acad. Nat. Sci. Phil. 108: 155-225 (taxonomy); Kantor 1991, Ruthenica 1: 17-52 (anatomy and phylogeny). 1.

Shell to about 30 mm in length, broad, and robust; variously colored, from almost all white to a black-gray, often violet at base; base offset with a dark line; columellar callus GASTROPODA:

SHELLED

745

relatively strong; fold at base of columella often with several incised spiral lines (plate 371A) Callianax biplicata — Shell smaller (under 20 mm) 2 2. Shell stout and chunky; often with brown, longitudinal, zigzag lines on a brownish buff, gray, or olive-gray background; occasionally with a red-brown spot beside fold at base of columella; height to 14 mm (plate 371B) Callianax pycna — Shell oblong and slender; may have brown longitudinal lines, color generally gray-brown to tan with faint purplish brown maculations near suture; height to 20 mm (plate 371C) Callianax baetica Callianax biplicata (G. B. Sowerby I, 1825) (=Olivetta biplicata). The purple olive; common intertidally, burrowing in clean sand of sloping, protected beaches and offshore of more exposed beaches. See Edwards 1968, Veliger 10: 297-304 (reproduction) and 1969, Veliger 11: 326-333 (predators); Stohler 1969, Veliger 11: 259-267 (growth); Hickman and Lipps 1983, J. Foraminiferal Res., 13: 198-114 (feeding on foraminifera). Callianax baetica (Carpenter, 1864) (=Olivella baetica). More common offshore, but occasionally found in intertidal zone. Callianax pycna Berry, 1935 (=Olivetta pycna). Least abundant species, more likely found offshore.

FAMILY C Y S T I S C I D A E

Cystiscids have minute, glossy white shells; shells are fully enveloped by the brightly colored mantle; found in gravel, among coralline algae and in surfgrass holdfasts in the low intertidal. This group was first separated at the family level from Marginellidae by Coovert and Coovert (1995, Nautilus 109: 43-110). See also Coan and Roth 1966, Veliger 8: 276-299 (taxonomy). 1. Anterior of shell not notched 2 — Anterior of shell with siphonal notch visible in dorsal view; columella with two folds, outer lip dentate; height less than 4 mm (plate 371D) Gibberula subtrigona 2. Spire concealed by extension of aperture; columella with four folds, outer lip finely dentate; height 2 mm-3 mm (plate 371E) Granulina margaritula — Spire low but not concealed; outer lip smooth within; height to 4 mm-5.5 mm (plate 371F) Plesiocystiscus jewettii Plesiocystiscus jewettii (Carpenter, 1857) (=Cystiscus jewettii). The genus was proposed by Coovert and Coovert (see above). In gravel of tide pools. Gibberula subtrigona (Carpenter, 1864) (=Granula subtrigona). In gravel of tide pools. Granulina margaritula (Carpenter, 1857) [=Cypraeolina pyriformis (Carpenter, 1864)]. Common in gravel of tide pools, and on the undersurfaces of medium-size rocks in the low intertidal; when disturbed, extensively protrudes a brightlycolored, mucus-covered mantle (J. T. Carlton, personal observations).

FAMILY M I T R I D A E

Mitrids are characterized by a long aperture, short canal and pillar with strong plications. Most species of Mitridae are characteristic of tropical habitats; the Californian species is 746

MOLLUSCA

an exception for its subtropical to temperate distribution. All members of the family feed on sipunculans. See Cernohorsky 1970, Bull. Auckland Inst. & Mus. 8, 1-190 (taxonomy); Ponder 1972, Malacologia 11: 295-342 (anatomy). 1.

Shell large, whorls flat-sided, with shiny black periostracum bearing rows of fine pits; base with strong spiral cords; columella with three strong plications, body color white; height to 50 mm (plate 371G) Mitra idae

Mitra idae Melville, 1893. Rocky sublittoral; occasional as hermit crab shells in intertidal, Bodega Head and south. See Cate 1968, Veliger 10: 247-252 (mating); Chess and Rosenthal 1971, Veliger 14: 172-176 (reproduction); Fukuyama and Nybakken 1983, Veliger 26: 96-100 (feeding); West 1990, Bull. Mar. Sci., 46: 761-779 (feeding). CONOIDEA

This neogastropod superfamily is characterized by the poison gland and the toxoglossate radular tooth, a single, hollow tooth used singly and injected with venom from the poison gland. Two families are treated here: Turridae and Conidae. FAMILY T U R R I D A E

Turrids are characterized by the posterior anal notch ("turrid notch") at or near the suture. All have a poison gland; the more advanced members have a single, hollow, harpoonlike radular tooth with which venom is delivered to the prey, consisting mostly of polychaete worms. This is a highly diverse family; numerous genera and species occur in deep water. Shallowwater species treated here are in the advanced group with the hollow tooth, with the exception of Pseudomelatoma in subfamily Pseudomelatominae, a more primitive group with a rachiglossate radula. Most species treated here are small-shelled and easily overlooked, except for the large-shelled genera Pseudomelatoma and Ophiodermella. Authors have not been in agreement over classification. See McLean 1971, Veliger 14: 114-130 (classification); Taylor et al. 1993, Bull. Nat. Hist. Mus., London 59: 125-170 (phytogeny); Rosenberg 1998, Amer. Malac. Bull. 14: 219-228 (phylogeny). 1.

Shell relatively large for group, over 20 mm in length

2 — Shell relatively small, under 10 mm in length 3 2. With strong light-colored nodes at periphery; rusty brown or yellow-brown to blackish; height to 25 mm (plate 371H) Pseudomelatoma torosa — Lacking peripheral nodes; with finely cancellate early sculpture; light colored, with darker axial markings; height to 25 mm (plate 3711) Ophiodermella inermis 3. Anal notch deep, at suture, bordered by thickened callus; with about 15 strong axial ridges per whorl, crossed by spiral ribs; height to 8 mm (plate 371L) Clathurella canfeldi — Anal notch shallow 4 4. Sculpture of strong spiral cords, axial sculpture weak; purplebrown, sometimes mottled with white; height to 7 mm (plate 37IK) Cymakra gracilior — Sculpture coarsely clathrate 5 5. With three spiral cords per whorl, axial sculpture strongly projecting, overridden by narrow spiral cords; height to 9 mm (plate 371N) Perimangelia interfossa

P L A T E 371 Olividae (subfamily Olivellinae), Cystiscidae, Mitridae, Turridae, and Conidae: A, CaUianax biplicata, height 27 mm; B, Callianax pycna, height 13.6 mm; C, Callianax baetica, height 19 mm; D, Gibberula subtrigona, height 3.4 mm; E, Granulina margaritula, height 3.0 mm; F, Plesioq'stiscus jewettii, height 5.3 mm; G, Mitra idae, height 37.5 mm; H, Pseudomelatoma torosa, height 23.0 mm; I, Ophiodermella inermis, height 23.8 mm; J, Cymakra aspera, height 6.0 mm; K, Cymakra gracilior, height 6.5 mm; L, Clathurella canfieldi, height 7.4 mm; M, Clathromangelia fuscoligata, height 9.5 mm; N, Perimangelia interfossa, height 8.5 mm; O, Conus califomicus, height 28 mm.

— With two spiral cords per whorl 6 6. Coarsely cancellate, white with brown spiral banding; height to 8 m m (plate 371M) Clathromangelia fuscoligata — Brown; axial and spiral ribs equally spaced, strongly beaded at intersections, producing squarish cancellations; height to 5 m m (plate 371J) Cymakra aspera Pseudomelatoma torosa (Carpenter, 1865). Intertidal rocky areas. See Kantor, 1988, Apex (Société Beige de Malacologie) 3: 1-19 (anatomy). Unlike other species treated here, in its membership in a primitive group n o t having a toxoglossate radula. Perimangelia interfossa (Carpenter, 1864) (=Clathromangelia interfossa) (=Mangelia interlirata Stearns, 1871). Rocky intertidal and sublittoral. See McLean 1999, Nautilus 114: 101 (generic proposal of Perimangelia). Clathromangelia fuscoligata (Dall, 1871). Rocky intertidal and sublittoral, scarce. Clathurella canfieldi Dall, 1871. In sand a m o n g surfgrass roots. Cymakra aspera (Carpenter, 1864) (=Mitromorpha aspera). Rocky intertidal and sublittoral. Cymakra gracilior (Tryon, 1884) (=Mitromorpha gracilior). Rocky areas of low intertidal. Ophiodermella inermis (Reeve, 1843) [=Ophiodermella ophioderma (Dall, 1909)]. Seldom found intertidally, except for hermit crab shells. See Shimek 1983, Malacologia 23: 281-313 (biology). FAMILY C O N I D A E

been misidentified. See Fretter and Graham 1978, J. Molluscan Stud., Suppl. 6, 153-241; Wise 1998, Nautilus, 111: 13-21 (anatomy and systematics). 1.

Whorls rounded, profile higher t h a n broad, suture impressed, with umbilical chink; height about 1 m m (plate 372A) Rissoella sp.

Rissoella sp. From tide pool micromollusk sampling at Carmel, Monterey County. OMALOGYROIDEA

FAMILY

OMALOGYRIDAE

Omalogyridae are very small heterobranch gastropods with a nearly planispiral shell form. See Fretter 1948. J. Mar. Biol. Assoc. U.K. 27: 597-632 (biology of the European O. atomus); Bieler and Mikkelson 1998, Nautilus 111: 1-112 (species in Florida). 1.

Minute (about 1 m m diameter), planorboid, of about two and a half regularly increasing whorls; spire depressed and base broadly umbilicate; shell smooth, lacking axial sculpture, translucent, with thin, brown periostracum and lighter radial markings (plate 372B) Omalogyra sp.

Omalogyra sp. Minute, in low, rocky intertidal on algae o n which egg capsules are deposited. PYRAMIDELLOIDEA

Although Conidae are speciose in tropical waters, a single species of Conus occurs in California. Many genera or subgenera have been proposed but current authors do n o t agree o n how to subdivide the family; some authors consider that there is a single genus in the family. The toxoglossate radula employs a single hollow tooth to inject v e n o m into the prey; some tropical species have become specialized fish or mollusk feeders, but most species prey u p o n polychaete worms. There is a very large literature o n feeding and venom specializations for tropical species. See Kohn 1998: 852-854 (Gastropod Volume, Fauna of Australia).

Pyramidelloidean are ectoparasitic snails that include a range of shell forms, including limpets (in the family Amathinidae). Aperture oval, lacking siphonal canal; operculum present. Protoconch heterostrophic. Eyes are at the bases of broad based cephalic tentacles, t h e snout o n the m e n t u m , or propodium; with acrembolic proboscis. Hermaphroditic. See Ponder and DeKeyzer 1998, p. 865 (Fauna of Australia). Two families are treated: Pyramidellidae and Amathinidae

1.

Pyramidellids are small to minute ectoparasitic snails t h a t extract body fluids from their molluscan or other invertebrate hosts by means of a long acrembolic proboscis and piercing stylet; the radula is lacking. An operculum is present and there is usually a columellar plication, at least in genera of low profile. The protoconch is heterostrophic—the coiling direction of t h e adult whorls changes abruptly f r o m that of t h e early whorls. Species are hermaphroditic; some produces spermatophores for transfer of sperm. Although hosts of few species from the West Coast are known, there is a large literature o n pyramidellid biology for other faunal regions. See Fretter and Graham 1949, J. Mar. Biol. Assoc. U.K. 28: 493-532 (anatomy, biology); Wise 1996, Malacologia 37: 443-451 (biology, phylogeny).

Shell obconic (inversely conical), spire dome-shaped; dull gray, tan, or gray-brown with fine spiral markings of brown under a heavy, dark brown periostracum (removed for illustration to show color pattern); height to 35 m m (plate 3710) Conus californicus

Conus californicus Reeve, 1844. Low intertidal in rock crevices or sand pockets; offshore o n sand and rock bottoms; diverse diet of worms, mollusks, crustaceans. See Saunders and Wolfson 1961, Veliger 3: 73-76; Kohn 1966, Ecology 47: 1041-1043 (feeding); Stewart and Gilly 2005, Biol. Bull. 209:146-153 (feeding on prickleback fishes). HETEROBRANCHIA

See definition under "Classification" above. SUPERFAMILY R I S S O E L L O I D E A , FAMILY

RISSOELLIDAE

Rissoellids have minute, transparent shells that lack sculpture, with impressed suture, characteristic radula and operculum. Eastern Pacific species previously placed in this family have 748

MOLLUSCA

FAMILY

PYRAMIDELLIDAE

There are two main groups in central California, the variously sculptured, few-whorled Odostominae, which have a columellar plication, a n d the many-whorled, tall and slender Turbonillinae. Hosts are known for some odostomines, b u t little is known about the biology of Turbonillinae, which are usually n o t found associated with hosts. Although m a n y genera were originally proposed as subgenera of Odostomia or Turbonilla, current authors agree in recognizing a large number of full

0 Jk

, - r l

PLATE 372 Rissoellidae, Omalogyridae, and Pyramidellidae (subfamilies Odostomiinae and Turbonillinae), and Amathinidae: A, Rissoella sp., height 1.0 mm; B, Omalogyra sp., diameter 0.6 mm; C, Ividella navisa, height 3.3 mm; D, Boonea lucca, height 2.9 mm; E, Boonea oregonensis, height 3.2 mm; F, Aartsenia pupiformis, height 8.4 mm; G, Brachystomia angularis, height 5.6 mm; H, Evalea tenuisculpta, height 5.4 mm; I, Odetta fetella, height 4.3 mm; J, Turbonilla victoriana, height 7.0 mm; K, Bartschella laminata, height 7.7 mm; L, Pyrgiscus tenuicula, height 6.8 mm; M, Turbonilla cayucosensis, height 9.0 mm; N, Iselica ovoidea, height 7.5 mm.

genera; see Schander, et al. 1999, Boll. Malac. 34: 145-166 (listing of genera). Some authors, starting with Robertson (1978, Biol. Bull. 155: 360-382) have attempted to base generic definitions for certain odostomines on traits relating to spermatophores, but McLean (2002, Amer. Malac. Soc., Charleston, Abstracts), argued that shell characters are best suited for classification in all odostomiine genera. Many species have not been collected alive. Numerous poorly known species occur in the eastern Pacific; species of the region were monographed by Dall and Bartsch (1909, Bull. U.S. Nat. Mus. 68: 1-258), but it is now apparent that our species have been greatly overnamed, which has hampered their study. 1.

Shell slender, with many whorls; axial and spiral sculpture various, columellar plication lacking 8 Shell broadly ovate to conic, with single columellar plication, of few whorls 2 Sculpture both axial and spiral 3 Axial sculpture lacking 5 Suture deeply impressed, whorls shouldered; sculpture broadly clathrate; height 3.3 mm (plate 372C) Ividella navisa Whorls rounded, axial and spiral sculpture forming beads at intersections 4 Profile broad; height 2.9 mm (plate 372D) Boonea lucca Profile slender; height 3.2 mm (plate 372E) Boonea oregonensis Whorls evenly rounded, base also rounded 6 Whorls weakly rounded, base subangulate 7 Relatively large (to 8 mm), often shouldered (plate 372F) Aartsenia pupiformis Smaller (to 5 mm), with fine spiral cords (plate 372H) Evalea tenuisculpta Spiral sculpture deeply incised; height 4.3 mm (plate 3721) Odetta fetella Spiral sculpture of faint incisions; height 5.6 mm (plate 372G) Brachystomia angularis Sculpture axial only 9 Sculpture both axial and spiral 10 Gray, axial ribs extending across base (plate 372J) Turbonilla victoriana White, axial ribs not extending across base (plate 372M) Turbonilla cayucosensis Axial ribs extending whorl to whorl (plate 372K) Bartschella laminata Axial ribs strong only on upper part of whorl (plate 372L) Pyrgiscus tenuicula

— 2. — 3.

— 4. — 5. — 6. — 7. — 8. — 9. — 10. —

Ividella navisa (Dall & Bartsch, 1907). Boonea lucca (Dall & Bartsch, 1909). Boonea oregonensis (Dall & Bartsch, 1907). Aartsenia pupiformis (Carpenter, 1865) ( = 0 . nota Dall and Bartsch, 1909). In roots of surfgrass Phyllospadix. Brachystomia angularis (Dall & Bartsch, 1907). Whorls flatsided, base angulate. Evalea tenuisculpta (Carpenter, 1864). On red abalone. *Odetta bisuturalis (Say, 1812) (=Boonea bisuturalis, Menestho bisuturalis). An Atlantic species introduced to San Francisco Bay in the days of commercial oyster culture (and to be looked for elsewhere along the coast). Found associated with Cerithidea californica and Ilyanassa obsoleta, and to be expected with other species. * = N o t in key.

750

MOLLUSCA

Odetta fetella (Dall & Bartsch, 1909). Occurs on oysters in lagoons. Turbonilla victoriana Dall & Bartsch 1907. In gravel samples, tide pools. Bartschella laminata (Carpenter, 1864). A southern species extending to Monterey. Pyrgiscus tenuicula (Gould, 1853). A southern species extending to Monterey. Turbonilla cayucosensis (Willett, 1929). In gravel in tide pools. FAMILY AMATHINIDAE

The family Amathinidae was proposed by Ponder 1987 (Asian Mar. Biol. 4: 1-34) as a pyramidelloidean family that includes the coiled genus Iselica, as well as some limpet-shaped genera, including Cyclothyca, in the tropical eastern Pacific. Members of the family are suctorial parasites on mollusks. 1.

Shell broadly ovate, with strong spiral ribs and thin axial lamellae; white with brown periostracum; height to 8 mm (plate 372N) Iselica ovoidea

Iselica ovoidea (Gould, 1853) [=/. fenestrata (Carpenter, 1864)]. Among Mytilus beds in bays; also associated with other invertebrates; in mud, gravel. ORDER OPISTHOBRANCHIA, SUBORDER

CEPHALASPIDEA

SUPERFAMILY A C T E O N O I D E A , FAMILY A C T E O N I D A E

Acteonids are usually considered as primitive cephalaspideans opisthobranchs, but were considered by Mikkelsen 1996 (Malacologia 37: 375-442) as transitional between heterobranchs and opisthobranchs. 1.

Columella with one fold; shell with incised, pitted, spiral striations, or grooves; white, with two spiral, gray-black bands on body whorl; height 16 mm (plate 3 73A) Rictaxis punctocaelatus

Rictaxis punctocaelatus (Carpenter, 1864) (=Acteon punctocaelatus). Of sporadic occurrence on mud- and sand flats in bays. SUPERFAMILY PHILINOIDEA, FAMILY C Y L I C H N I D A E

The family Cylichnidae includes two subfamilies, the Cylichninae, in which there are species of Cylichna occurring offshore, and the Acteocininae, with the genus Acteocina, in which species may occur in shallower water. Feeding on foraminifera. For the systematics of Acteocininae, based on Atlantic species, see Mikkelsen and Mikkelsen 1984, Veliger 27: 164-192. 1. Suture not deeply channeled 2 — Suture deeply channeled 3 2. Shoulder strongly keeled; strong axial striations on upper one-half of whorl; small, to about 6 mm (plate 373B) Acteocina harpa — Shoulder subangulate, shell sides nearly parallel, with fine brown periostracum; small, height 4 mm (plate 373C) Acteocina inculta 3. Shoulder subangulate, spire projecting, columellar fold projecting, sculpture of numerous, spiral striations, reflected by brown periostracum; height to 22 mm (plate 373D) Acteocina culcitella

—

Shoulder rounded, spire recessed, columellar fold weakly developed, with pattern of fine brown lines; height to 14 mm (plate 373E) Acteocina cerealis

Acteocina harpa (Dall, 1871) (=Retusa harpa). In sand, gravel, and mud, low intertidal to offshore. Acteocina inculta (Gould, 1855). Monterey Bay south; common in mud of marsh channels, bays, lagoons. Acteocina culcitella (Gould, 1853). Sporadically common in bays and lagoons, on sand and mud. See Shonman and Nybakken 1978, Veliger 21: 120-126 (feeding). Acteocina cerealis (Gould, 1853) [=A. eximia (Baird, 1863)]. More common offshore, but reported on intertidal flats in Bodega Harbor, by Gosliner 1979, Nautilus 93: 85-92. *Cylichna attonsa Carpenter, 1864. On soft bottoms offshore. See photo in Palmer (1958). *Cylichna diegensis (Dall, 1919). On soft bottoms offshore.

on their left edges; height to 50 mm (plate 373J) Bulla gouldiana Bulla gouldiana Pilsbry, 1893. A southern species, occasional in central California; on mudflats in lagoons, bays, estuaries. See Robles 1975, Veliger 17: 278-291 (reproductive system). NOTASPIDEA

SUPERFAMILY U M B R A C U L O I D E A , FAMILY T Y L O D I N I D A E

The Tylodinidae (formerly included in the Umbraculidae) are unlike most other notaspideans in having an external shell of limpet form. Feeding is on sponges. See Willan 1987, Amer. Malac. Bull. 5: 215-241 (phytogeny). 1.

SUPERFAMILY D I A P H A N O I D E A , FAMILY DIAPHANIDAE

The genus Diaphana was revised by Schiótte 1999, Steenstrupia, 24: 77-140. 1.

Shell small (to about 4 mm in height), umbilicate, thin, translucent, smooth, with weak axial growth lines; three whorls, with globular nucleus (plate 373F) Diaphana califomica

Diaphana califomica Dall, 1919. Uncommon intertidally on algae; sublittorally in sand and kelp holdfasts. S U P E R F A M I L Y H A M I N E O I D E A , F A M I L Y H A M I N O EI D A E

The Haminoeidae (formerly Atyidae) have thin shells with involute spires. Upper portion of body whorl tapered, with a shallow constriction; height 24 mm (plate 373H) Haminoea virescens — Upper portion of body whorl relatively broad 2 2. Body whorl slightly elongate; height 14 mm (plate 373G) Haminoea vesícula — Body whorl more shortened; height 14 mm (plate 3731) Haminoea japónica

Tylodina fungina Gabb, 1865. Southern (Cayucos, south); found on yellow sponges, which it closely resembles. ORDER PULMONATA, SUBORDER

SUPERFAMILY B U L L O I D E A , FAMILY B U L L I D A E

Bullids are relatively large-shelled and are known as bubble shells, a tropical group except for B. gouldiana. Feeding on algae. See Willan 1978, J. Malac. Soc Aust. 4: 57-68 (taxonomy). 1.

Aperture broadly rounded anteriorly, not flaring; shell pinkgray to brown with cloudy maculations bordered by white

BASOMMATOPHORA

SUPERFAMILY S I P H O N A R I O I D E A , FAMILY SIPHONARIIDAE

Siphonariids are pulmonate limpets, mostly occurring in tropical intertidal zones. Only the cosmopolitan genus Williamia extends into temperate waters and extends from the intertidal into the sublittoral zone. See Marshall 1981, N. Z. J. Zool. 8: 487-492 (taxonomy of Williamia in western Pacific). 1.

1.

Haminoea vesícula (Gould, 1855). Sporadically abundant among algae Ulva and Polysiphonia, in sloughs, lagoons, bay mudflats. Haminoea virescens (G. B. Sowerby I, 1833). Occasional in higher tide pools of open-coast, rocky areas. Haminoea japónica (Pilsbry, 1895) (=H. callidegenita Gibson and Chia, 1989). Gibson and Chia's species (Can. J. Zool. 67: 914-922) represented an unrecognized invasion of a Japanese species in the northeastern Pacific, where this species is now broadly established.

Shell thin, with central apex, thick brown periostracum extending beyond edge of shell; muscle scar horseshoeshaped, opening on right side of shell, length to 35 mm (plate 373K) Tylodina fungina

Shell smooth, thin, waxy, orange or red-brown with translucent, lighter-colored rays and thin periostracum; apex hooked, one-third distance from posterior end; muscle scar opening on right side, length to 10 mm (plate 373L) Williamia peltoides

Williamia peltoides (Carpenter, 1864) [=W. vernalis (Dall, 1870)]. In protected low intertidal to sublittoral, under rocks, on coralline algae and on coralline-covered shells of Chlorostoma, Pomaulax, etc. See Yonge 1960, Proc. Calif. Acad. Sci. (4) 31: 111-119 (biology); McLean 1998, Veliger 41: 243-248 (taxonomy); Collin 2000, Nautilus 114: 117-119 (development). *Williamia subspiralis (Carpenter, 1864). Of higher profile, occurring in rocky sublittoral, Point Sur and south. See McLean 1998, for photo. SUPERFAMILY E L L O B I O I D E A , FAMILY E L L O B I I D A E

Ellobiidae (formerly Melampidae) are marine pulmonates with sturdy shells, living at high-tide lines in salt marsh habitats. See Martins 1996, Malacologia 37: 163-332 (taxonomy). 1.

Three columellar folds (third may be weakly expressed); spire elevated; color variable, brown or brown-purple to yellow; juveniles with small periostracal hairs; height 6 mm (plate 373M) Myosotella myosotis

Myosotella myosotis (Draparnaud, 1801) [-Ovatella myosotis; =Phytia setifer (Cooper, 1872)]. In Salicornia marshes, often very * = N o t in key.

GASTROPODA:

SHELLED

751

PLATE 373 Acteonidae, Cylichnidae, Diaphanidae, Haminoeidae, Bullidae, Tylodinidae, Siphonariidae, Ellobiidae, and Trimusculidae: A, Rictaxis punctocaelatus, height 16 mm; B, Acteocina harpa, height 5.S mm; C, Acteocina inculta, height 4.0 mm; D, Acteocina culcitella, height 2 0 mm; E, Acteocina cerealis, height 13.4 mm; F, Diaphana californica, height 2.8 mm; G, Haminoea vesícula, height 23.7 mm; H, Haminoea virescens, height 15.3 mm; I, Haminoea japónica, height 14.2 mm; J, Bulla gouldiana, height 50 mm; K, Tylodina fungina (three views), length 32 mm; L, Williamia peltoides, length 8.5 m m (two views); M, Myosotella myosotis, height 3.7 mm; N, Trimusculus reticulatus (two views), length 14 mm.

a b u n d a n t o n m u d , u n d e r debris, a n d in crevices of old docks a n d pilings, at highest levels of spring tides. See B e r m a n a n d C a r l t o n 1 9 9 1 , J. Exp. Mar. Biol. Ecol. 1 5 0 : 2 6 7 - 2 8 1 (ecology, diet). I n t r o d u c e d f r o m t h e Atlantic O c e a n .

SUPERFAMILY T R 1 M U S C U L O I D E A , FAMILY T R I M U S C U L I D A E

T h e p u l m o n a t e l i m p e t family Trimusculidae ( f o r m e r l y Gadinidae) c o n t a i n s a single g e n u s of worldwide o c c u r r e n c e . Herm a p h r o d i t i c , w i t h t h e o p e n i n g of m a n t l e cavity a n d m u s c l e scar o n right side. 1.

Shell white, w i t h o u t p e r i o s t r a c u m , nearly circular; a p e x central; sculpture reticulate (plate 3 7 3 N ) Trimusculus

reticulatus

reticulatus (Sowerby, 1 8 3 5 ) ( = G a d i n i a

Trimusculus

reticulata).

In groups o n roofs of caves a n d u n d e r o v e r h a n g i n g ledges in low intertidal; also in a b a n d o n e d p h o l a d holes. See Yonge, 1 9 5 8 , Proc. Malacol. Soc. L o n d o n 3 3 : 3 1 - 3 7 , a n d 1 9 6 0 , Proc. Calif. Acad. Sci. 3 1 : 1 1 1 - 1 1 9 (biology, ecology); Walsby 1 9 7 5 , Veliger 18:

139-145

(feeding); H a d d o c k 1 9 8 9 ,

Veliger

32:

4 0 3 - 4 0 5 ( e x i s t e n c e in subtidal air pockets).

ACKNOWLEDGMENTS This effort has built u p o n t h e w o r k of J a m e s T. C a r l t o n a n d Barry Roth, t h e t w o p r e v i o u s c o a u t h o r s for t h e s e c t i o n o n shelled g a s t r o p o d s for t h e 1 9 7 5 edition. I h a v e used e x t e n s i v e p o r t i o n s o f their t e x t w i t h slight c h a n g e s a n d s o m e substantial additions. Here I t h a n k David R. Lindberg for advice w i t h t h e section o n t h e revised system of classification. I t h a n k J i m Carlt o n , Lindsey Groves a n d G e n e C o a n for critical c o m m e n t a r y o n the manuscript. All illustrations of shells are from m y original photographs; negatives for each image were scanned and improved in Photoshop by m y imaging assistant Michelle Schwengel. Her work o n this project as well as the work toward m y books in preparation o n northeastern Pacific gastropods has been supported in part by t h e Packard Foundation a n d in part by a gift f r o m Twila Bratcher.

Baja California. Santa Barbara Museum of Natural History, Monographs no. 2, vii + 764 pp. Cox, L. R. 1960. Gastropoda, General Characteristics of Gastropoda, pp. 84-169. In Treatise on Invertebrate Paleontology, Univ. Kansas Press and Geol. Soc. Amer., Part 1, Mollusca 1. R. C. Moore, ed. Dall, W. H. 1921. Summary of the marine shellbearing mollusks of the northwest coast of America, from San Diego, California, to the Polar Sea, mostly contained in the collection of the United States National Museum, with illustrations of hitherto unfigured species. United States National Museum, Bulletin 112, 217 pp., 22 pis. Fretter, V., and A. Graham. 1994. British Prosobranch Molluscs. Their Functional Anatomy and Ecology. Revised and Updated Edition. London: Ray Society, 820 pp. Johnson, R. I. 1964. The Recent Mollusca of Augustus Addison Gould. United States National Museum, Bulletin 239: 1-182. Kozloff, E. N. 1987. Marine Invertebrates of the Pacific Northwest. University of Washington Press, Seattle, vi + 511 pp. Lindberg, D.R., W. F. Ponder, and G. Haszprunar. 2004. The Mollusca: Relationships and patterns from their first half-billion years. In Assembling the tree of life. J. Cracraft and M. J. Donoghue, eds. pp. 2 5 2 - 2 7 8 . New York: Oxford University Press. McLean, J. H. 1978. Marine shells of southern California, Revised edition. Natural History Museum of Los Angeles County, Science Series, no. 24, 1-104. McLean, J. H. 1996. The Prosobranchia. pp. i-vii, 1-160. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. Volume 9. The Mollusca, Part 2—The Gastropoda. P. H. Scott, J. A. Blake and A. L. Lissner, eds. Oldroyd, I. S. 1927. The marine shells of the west coast of North America. Stanford University Publications, University Series, Geological Sciences, vol. 2, part I, pp. 1-298, pis. 1-29; part II, pp. 299-604, pis. 30-72; part III, pp. 605-941, pis. 73-108. Palmer, K. V. W. 1958. Type specimens of marine Mollusca described by P. P. Carpenter from the west coast (San Diego to British Columbia). Geological Society of America, Memoir 76: 376 pp. Ponder, W. F., and D. R. Lindberg. 1997. Towards a phylogeny of gastropod molluscs: an analysis using morphological characters. Zoological Journal of the Linnean Society of London 119: 8 3 - 2 6 5 . Roy, K., D. Jablonski, J. W. Valentine, and G. Rosenberg. 1998. Marine latitudinal diversity gradients: Tests of causal hypotheses. Proceedings of the National Academy of Sciences 95: 3699-3702. Strathmann, M. F., ed. 1987. Reproduction and development of marine invertebrates of the northern Pacific coast. Seattle: University of Washington Press, xii + 670 pp. Turgeon, D. D., ed., with contributions by J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks, 2nd ed. American Fisheries Society Special Publication, 26, ix + 526 pp.

REFERENCES Abbott, D. P., and E. C. Haderlie. 1980. Chapter 13. Prosobranchia: Marine snails, pp. 230-307. In Intertidal invertebrates of California. Morris, R. H„ D. P. Abbott, and E. C. Haderlie, Stanford University Press. Abbott, R. T. 1974. American Seashells, 2nd edition. The Marine Mollusca of the Atlantic and Pacific coasts of North America. New York: Van Nostrand Reinhold, 663 pp., 24 pis. Beesley, P. L., G. J. B. Ross, and A. Wells, eds. 1998. Mollusca: The Southern Synthesis. Fauna of Australia. Vol. 5. CSIRO Publishing: Melbourne. Part A, xvi, 1-653. Part B, viii, 663-1234. [Abbreviated citations in the text cite the author and date, e.g., Ponder, 1998, F of A] Boss, K. J., J. Rosewater, and F. A. Ruhoff. 1968. The zoological taxa of William Healey Dall. United States National Museum, Bulletin 287: 1-427. Bouchet, P., and J-P. Rocroi. 2005. Classification and nomenclátor of gastropod families. Malacologia, 47(1-2): 1-397. Part 1. Nomenclátor of Family-Group Names (Bouchet St Rocroi). Part 2. Working Classification of the Gastropoda (Bouchet, Fryda, Hausdorf, Ponder, Valdés, and Warén). Carlton, J. T., and B. Roth. 1975. Phylum Mollusca: Shelled gastropods, pp. 4 6 7 - 5 1 4 In Light's manual: intertidal invertebrates of the Central California Coast. 3rd ed. R. I. Smith and J. T. Carlton, eds. Berkeley, CA: University of California Press. Coan, E. V., P. V. Scott, and F. R. Bernard. 2000. Bivalve seashells of western North America; Marine bivalve mollusks from Arctic Alaska to

Patel logastropoda DAVID R. LINDBERG (Plates 3 7 4 - 3 7 7 )

T h e California a n d O r e g o n patellogastropod fauna consists o f m o r e t h a n 2 3 species f o u n d in diverse n i c h e s in intertidal a n d n e a r s h o r e habitats. Its potential as a m o d e l s y s t e m for ecological, behavioral, physiological, a n d e v o l u t i o n a r y studies h a s b e e n exploited n u m e r o u s t i m e s over t h e past 7 5 years (see Abb o t t a n d Haderlie 1 9 8 0 , C a r l t o n 1 9 8 1 , Ricketts et al. 1 9 8 5 , a n d references therein). Recent m o l e c u l a r p h y t o g e n i e s ( C l a b a u g h 1 9 9 7 , Simison 2 0 0 0 , Begovic 2 0 0 4 ) h a v e p r o d u c e d m o r e robust estimates of relationships t h a n previously available, w h i c h will u n d o u b t e d l y p r o m o t e a n e w r o u n d of investigations parsed b y phylogenetic pattern. T h e California fauna is c o m p o s e d of t w o distinct c l a d e s — t h e A c m a e i d a e a n d Lottiidae (Lindberg 1 9 9 8 ) . T h e A c m a e i d a e are m o s t l y deep-water species associated w i t h u n i q u e habitats s u c h as waterlogged w o o d a n d low o x y g e n e n v i r o n m e n t s . In t h e GASTROPODA: PATELLOGASTROPOD A

753

northeastern Pacific Ocean. Two species are f o u n d in shallower waters: Acmaea funiculata and A. mitra. The Lottiidae are broadly distributed along the Pacific Rim and is composed of several subclades recognizable by morphology and biogeography, in addition to molecular distinctness. The Lottiidae include all of the remaining central and northern California and Oregon species. In central California, northern and southern groups meet and transition, producing one of the highest diversities of patellogastropods found anywhere in the world. On a single rocky shore in central California, as m a n y as 16 species of acmaeid and lottiid limpets can be found. Molecular work has revealed that previously used radula, shell structure, and gill characters are often n o t congruent with each other or with the molecular groupings. However, often maligned shell characters such as shell sculpture and pigmentation patterns are congruent with molecular groupings. Ecophenotypic variation is c o m m o n in several California lottiid subgroups, and u n n a m e d species remain numerous. These include cryptic species and taxa misidentified as ecophenotypes of other species. However, there are also examples in which long distinguished putative taxa are identical for observed molecular markers. Subgroups are often latitudinally distinct and likely reflect speciation events related to Pleistocene climate events. This mosaic of niche and geographical sister taxa relationships seen in the molecular phytogenies suggest complex interactions possibly involving several different isolating mechanisms. This explanation for the populating of the California patellogastropod fauna is not new. Avery R. G. Test (1946), w h o treated the limpets for Professor S. F. Light in the first edition of this book, observed that, "It has become apparent that in the genus Acmaea [=Lottia], in addition to the process of speciation based on geographical isolation, there has been, perhaps even more frequently, speciation from eurytopic ancestors by the process of ecological isolation and selection." Problems in species identification remain in the Lottiidae, and additional taxa are likely to be discovered as molecular markers for more individuals are obtained and compared. In the past few decades, the generic names Collisella, Notoacmea, Tectura, Niveotectura, Macclintockia, and Discurría have all been applied to limpets in our fauna. Grant (1937) was the first worker to assign some of t h e northeastern Pacific "acmaeids" to Notoacmea, which she considered as a subgenus of Acmaea. Fritchman (1961) adopted Grant's classification and published subgeneric assignments for m a n y of the northeastern Pacific species. Mclean (1966), in a major systematic revision of t h e northeastern Pacific limpet fauna, also used Notoacmea as a subgenus and t h e n later (Mclean 1969) considered Notoacmea as a full genus. Lindberg (1981) followed McLean's classification, but later (Lindberg 1986) synonymized Collisella with Lottia and replaced Notoacmea with Tectura. With the advent of molecular techniques in the early 1990s, it became apparent that there was substantial convergence in m a n y of the characters that were being used to delineate and delimit m a n y of these generic groupings. Based o n this knowledge, I have chosen to adopt a more conservative approach to limpet nomenclature t h e n previously done and use only the genera Acmaea and Lottia to encompass t h e species treated here. The late Harry Fritchman (1961-1962, Veliger, 3-4) studied the reproductive cycles of m a n y of our c o m m o n local species, and Thomas Wolcott (1973, Bio. Bull. 145: 389-422) produced an important study o n the physiological ecology and zonation of central California limpets. Avery R. G. Test produced a classic paper in 1945 o n t h e distributional ecology of our com754

MOLLUSCA

m o n species (Ecology 26: 395-405). A set of student-produced papers, edited by the late Donald P. Abbott and colleagues, on Monterey Bay limpets from a summer course at Hopkins Marine Station (Veliger 11, Supplement, 112 pp., 1968) stimulated m a n y subsequent biological and ecological studies, m a n y of t h e m published in The Veliger as well. Abbott and Haderlie (1980) provided detailed summaries of t h e biology a n d ecology of a number of c o m m o n species.

KEY TO S P E C I E S

Note: Some species key out more t h a n once. 1.

—

2.

—

3. — 4. — 5.

— 6.

—

7.

—

8.

—

9.

—

Shell entirely white or white with irregular brown radial markings; lateral teeth of radula approximately equal in size and shape (plate 374C) (shell c o m m o n l y encrusted with coralline algae) 2 Shell colored; lateral teeth of radula unequal in size and shape (plate 375H) (may or may n o t be encrusted with coralline algae) 4 Shell white or white with sparse brown rays and/or small brown apical spot; apex subcentral; aperture oval or compressed laterally; radula with uncini near base of third lateral teeth (plate 374D) Lottia triangularis Shell entirely white, lacks apical spot; apex central; aperture oval; radula without uncini near base of third lateral teeth (cf. plate 375E, 375H) 3 With radial sculpture (plate 374A) . . . . Acmaea funiculata Without radial sculpture (plate 374B) Acmaea mitra Sides of shell parallel or nearly so; shell compressed, aperture narrow, oblong 5 Sides of shell n o t parallel, aperture oval 9 Ends of shell curved upward; nearly s m o o t h w i t h obscure, low, radial ribbing at margin; exterior brown, interior bluish, with brown apical stain; o n Laminaria and Pterygophora stipes in low intertidal (plate 374G) Lottia instabilis Ends of shell not curved upward 6 Shell three to four times longer t h a n wide; yellow to brown; second and third lateral teeth with straight, broad cutting surfaces (plate 375D); occurring o n the seagrasses Zostera and Phyllospadix spp 7 Shell less t h a n three times longer t h a n wide; exterior dark brown, lustrous, smooth, with fine radial sculpture; occurring on Egregia 8 Shell color light yellow with brown-red chevron markings; sculpture of concentric growth lines; o n intertidal eel grass Zostera marina (plate 375A) "Lottia" depicta Shell color light to dark brown with small, rounded, radial ribs; o n surfgrass Phyllospadix (plate 375C) "Lottia"paleacea Interior of shell rich dark brown; third lateral teeth with prominent lateral extension (plate 375E, 375F) Lottia insessa Interior gray to light brown, usually with brown apical stain; edge of third lateral teeth sigmoidal; externally resembling L. insessa (plate 375H, 375J) (see species list). . . Lottia pelta Shell pink, mottled with white streaks and white and yellow brown dots; thin, elevated, small (to about 8 mm); smooth, or with fine radial ribs; (plate 374E) Lottia rosacea Color otherwise 10

PLATE 374 A, Acmaea funiculata, length 20 mm; B, Acmaea mitra, length 30 mm; C, radular row of Acmaea mitra; D, Lottia triangularis, length 5 mm; E, Lottia rosacea, length 5 mm; F, Lottia sp. from Haliotis spp. length 7 mm; G, Lottia instabilis (kelp form), length 25 mm; H, Lottia instabilis (solid form), length 15 mm; I, Lottia instabilis (tessellate form), length 10 mm; sizes are typical of central California specimens.

10. Apex positioned in the anterior quarter of the shell, may overhang the edge of the shell 11 — Apex position subcentral to anterior third of the s h e l l . . . 13 11. Shell long-oval, low, large (to about 100 mm) and heavy; maculated brown and white; shell often eroded, or small

( < 2 5 mm) blue-black with concentric growth lines; inner margin dark brown, intermediate area black with prominent, owl-shaped muscle scar at center; sides of foot and head black to gray (plate 377A) Lottia gigantea Shell oval, moderate profile, medium size (to about 25 mm); shell white to brown with tessellate markings; intermediate GASTROPODA: PATELLOGASTROPODA

755

.I

m&

mI

P L A T E 375 A, "Lottia" depicta, length 8 mm; B, "Lottia" depicta (oval form), length 8 mm; C, "Lottia" paleacea, mm; D, radular row of "Lottia" depicta, note broad, flat cusps; E, radular row of Lottia insessa, note extensions teeth; F, Lottia insessa, length 12 mm; G, Lottia pelta (rock form), length 35 mm; H, radular row of Lottia pelta, and sigmodial shaped 3rd lateral teeth; I, Lottia pelta (Mytilus form), length 15 mm; J, Lottia pelta (kelp form), mm; sizes are typical of central California specimens.

length 8 on 3rd lateral note uncini length 10

PLATE 376 A, Lottia digitalis (rock form), length 20 mm; B, Lottia austrodigitalis (rock form), length 20 mm; C, Lottia scabra, length 20 mm; D, Lottia digitalis (Pollicipes form), length 8 mm; E, F, Lottia paradigitalis, length 10 mm; G, Lottia asmi, length 5 mm; sizes are typical of central California specimens.

area white to blue-white 12 12. Ribs triangular in profile, usually light colored (often with darker-colored spines) and tessellate interspaces between ribs; ribs project strongly in all directions, forming strong scalloped margin; apical region often covered with callus; animal with black spots on head and sides of foot (plate 376C) Lottia scabra — Ribs rounded in profile, usually not lighter than interspaces; posterior margin sometimes scalloped; anterior slope generally concave, ribs strongest on posterior slope,

may be absent at anterior end; animal lacks dark spots on head and sides of foot (plate 376A) Lottia digitalis — Ribs not pronounced (Monterey Bay southward) (plate 376B) (see species list) Lottia austrodigitalis 13. Exterior shell surface sculpted with coarse radial ribs; sometimes eroded, with ribs visible only at margin of shell 14 — Exterior shell surface sculpted with concentric growth lines, fine radial ribs or striations 15 GASTROPODA: PATELLOGASTROPODA

757

A, Lottìa gigantea (rock form), length 60 mm; B, Lottia gigantea (Mytilus form), length 10 mm; C, Lottìa persona, length 25 mm; D, Lottìa persona (northern form), length 25 mm; E, Lottia fenestrata, length 20 mm; F, Lottia limatula, length 25 mm; G, Lottia scutum, length 35 mm; sizes are typical of central California specimens. PLATE 3 7 7

14. Rib usually light-colored (often with darker-colored spines) and darker interspaces; ribs projecting strongly in all directions, forming strong scalloped margin; apical region often covered with callus; animal with black spots on head and sides of foot (plate 376C) Lottia scabra — Ribs broad and generally equally developed on all slopes, may appear knobby; color various, brown, green, or greenblack, checkered with white tessellations or peripheral rays 758

MOLLUSCA

and bands of white (plate 375G) Lottia pelta 15. Interior intermediate area dark (dark gray or blue-brown) 16 — Intermediate area blue-white to white 17 16. Black to dark gray-brown inside and out; small (to about 10 mm), elevated, exterior often eroded, generally with fine radial striae visible at least at margin; generally on turban snail Chlorostoma funebralis (but not the only limpet

on this Chlorostoma) (plate 376G) Lottia asmi — Intermediate area between shell margin and apex suffused with brown; shell conical with round aperture and weak radial sculpture; olive to gray with small, white tessellations, sometimes drawn out around aperture; apex often eroded to brown (plate 377E) Lottia fenestrata 17. With fine, imbricate (scaly) radial ribbing; margin serrate (with sawlike notching); shell low or elevated; color buff yellow, with fine darker mottlings, or green brown with white tessellations or bands; sides of foot and head black to gray (plate 377F) Lottia limatula — Without imbricate radial ribbing 18 18. Shell profile low, height usually less t h a n one-third of shell length 19 — Shell profile elevated usually greater t h a n one-third of shell length 20 19. Shell thick, large (to about 50 mm); apex subcentral; sculpture coarser, of flat-topped ridges, color pattern of variable spotting, typically arrayed into irregular rays; top of head and mantle tentacles brown (plate 377G) Lottia scutum — Shell thin, small to medium (to about 30 mm); animal white and not pigmented 21 20. Shell elongate oval, medium size (to 30 mm); sculpture of straight threadlike radial riblets color variable, either tessellate pattern of oval white spots on brown background (plate 3741) or solid color (yellow white to red-brown, buff) (plate 374H) Lottia instabilis — Shell oval (half shell length, shell usually < 1 8 mm long, somewhat thickened, transparent to milky white (plate 389C) Haminoea virescens 786

MOLLUSCA

14. Head shield deeply bilobed anteriorly; shell translucent; rocky habitats (plate 389D) Diaphana califomica — Head shield rounded to shallowly lobed; shell opaque; muddy or sandy habitats 15 15. Shell white or pale yellow with brownish spiral lines on surface; unpaired gizzard plates smaller than paired ones (plate 388C, 388D) 16 — Shell uniformly whitish or brownish; unpaired gizzard plates larger than or equal to paired ones (plate 388A, 388B) 17

16. Shell « 1 1 mm; spire poorly developed (plate 388D) Acteocina cerealis — Shell up to 22 mm; spire strongly developed (plate 388C) Acteocina culcitella 17. Shell with strongly carinate keeled shoulder (plate 388B) Acteocina harpa — Shell with rounded shoulder (plate 388A) Acteocina inculta

LIST OF SPECIES ACTEONIDAE

Rictaxis puntocaelatus (Carpenter, 1864) (=Acteon punctocaelatus). Fairly common on mud- and sand flats; a predator on cirratulid polychaetes.

CYLICHNIDAE

Acteocina cerealis (Gould, 1853) (=Cylichnella cerealis). Relatively uncommon but has been found on intertidal flats at Bodega Harbor. Acteocina culcitella (Gould, 1853) (=Cylichnella culcitella, Acteocina rolleri). Found in sandy habitats around Monterey Bay; most common in the shallow subtidal from 5 m to 10 m depth. Acteocina harpa (Dall, 1871) (=Retusa harpa, Cylichnella harpa). Relatively uncommon in central California. Acteocina inculta (Gould, 1856) (=Cylichnella inculta). A common intertidal species on mudflats, especially from Monterey south.

See Mills 1994, pp. 313-319, in: Wilson, Strieker, and Shinn 1994. Reproduction and Development of Marine Invertebrates, Johns Hopkins Univ. Press, Baltimore (seasonal swimming and population dispersal). HAMINOEIDAE

*Haminoea japonica (Pilsbry, 1895) (=H. callidegenita Gibson and Chia, 1989). An introduced Asian species mistakenly redescribed from Puget Sound as new; first found in San Francisco in the 1990s on dock floats in marinas. Shell figured in Shelled Gastropod section. See Gosliner and Behrens 2006, Proceedings of the California Academy of Sciences 57(37): 1003-1007. Haminoea vesicula (Gould, 1855). On boat landings or mudflats of bays. Haminoea virescens (Sowerby, 1833). In higher tide pools of the rocky intertidal. PHILINIDAE

Philine auriformis (Suter, 1913). Introduced to San Francisco Bay from New Zealand presumably during the summers of 1992 and 1993 in freighters' ballast water; found in Bodega Harbor in 1994; now widespread from Oregon to Baja California. See Gosliner 1995, Marine Biology 122: 249-255 (introduction into San Francisco Bay). Philine spp. Three additional introduced species inhabit estuaries of the San Francisco Bay Region. Other native species of the genus are recorded from California; see Behrens 2004, Pacific Coast Nudibranchs, Supplement II, Proceedings of the California Academy of Sciences 55(2): 11-54.

AGLAJIDAE RUNCINIDAE

Aglaja ocelligera (Bergh, 1894). Seasonally common in muddy habitats both intertidally and subtidally. Melanochlamys diomedea (Bergh, 1894) (=Aglaja nana Steinberg & Jones, 1960). Commonly found on mudflats. Navanax inermis Cooper, 1862 (=Chelidonura inermis). A voracious predator of other opisthobranchs such as Bulla gouldiana; on mudflats and intertidal pools from Bodega Harbor to Baja California. Navanax polyalphos (Gosliner and Williams, 1972) (=Chelidonura polyalphos). On mudflats from the Channel Islands to Mexico; feeds on Haminoea vesicula. See Gosliner and Williams 1972, Veliger 14: 424-436.

BULLIDAE

Bulla gouldiana Pilsbry, 1893. On mudflats; the primary food of Navanax inermis. DIAPHANIDAE

Diaphana califomica Dall, 1919. Seasonally common on algal blades (e.g., Mazzaella) in low rocky intertidal pools. GASTROPTERIDAE

Gastropteron pacificum Bergh, 1894. Occasionally encountered on intertidal mudflats, but far more common subtidally.

Runcina macfarlandi Gosliner, 1991. Found in the high intertidal among the algae Endocladia and Cladophora, as well as the tubes of the polychaete Phragmatopoma; Oregon to Monterey Bay. KEY B: ANASPIDEA

1.

Body dorsoventrally flattened; length under 10 cm; parapodia reduced; body color green with black and white striping (plate 390C) Phyllaplysia taylori — Body laterally compressed, often exceeding 10 cm in length; parapodia highly developed; body color not green, unstriped 2 2. Parapodia joined posteriorly: body color uniform dark brown or black (plate 390B) Aplysia vaccaria — Parapodia not obviously joined posteriorly; body color mottled tan or brown (plate 390A) . . . . Aplysia califomica

LIST OF SPECIES APLYS1IDAE

Aplysia califomica Cooper, 1863. Common in southern California and present in northern and central California (including San Francisco Bay) especially during El Nino events. * = Not in key.

GASTROPODA:

OPISTHOBRANCH

787

Aplysia vaccaria Winkler, 1955. The world's largest opisthobranchs: animals may be up to 1 m in length and 14 km in weight have been recorded; Monterey Bay to the Gulf of California. NOTAR ACHI DAE

Phyllaplysia taylori Dall, 1900 (=Phyllaplysia zostericola McCauley, 1960). C o m m o n o n the eelgrass Zostera in the waters and mudflats of bays. KEY C: "NOTASPIDEA" (UMBRACULACEA AND PLEUROBRANCHACEA)

Channel. Vol. 9, The Mollusca Part 2—The Gastropoda. Scott, P. H., J. A. Blake, and A. Lissner, eds. Santa Barbara, CA: Santa Barbara Museum of Natural History: 159-213. Keen, A. M., and J. C. Pearson. 1952. Illustrated key to West North American gastropod genera. Stanford: Stanford University Press, 39 pp. MacFarland, F. M. 1966. Studies of Opisthobranchiate Mollusks of the Pacific Coast of North America. Memoirs of the California Academy of Sciences 6, 546 pp.

Sacoglossa and Nudibranchia GARY R. McDONALD (Plates 3 9 1 - 3 9 2 )

1. — 2. — 3. — 4.

—

With limpetlike external shell often covered with bristles, body yellowish in color (plate 390D) Tylodina fungina External shell absent 2 Bases of rhinophores widely separated (plate 390F) Pleurobranchaea californica Bases of rhinophores very close together 3 Body color uniformly bright orange Berthellina ilisima Body color white to pale yellow 4 Color cream to white, covered with small white dots; dorsum outlined by fine white line (plate 390E) Berthella californica Color very pale yellow, finely punctate with darker yellow; dorsum without conspicuous white outline Berthella strongi

LIST OF SPECIES

1.

— 2.

— 3.

— 4.

PLEUROBRANCHIDAE

Berthella californica (Dall, 1900) (=Pleurobranchus californicus). The most c o m m o n notaspidean on the central California coast. Berthella strongi MacFarland, 1966. Occasionally found in rocky intertidal pools from San Mateo County to Santa Cruz Island. Berthellina ilisima Marcus and Marcus, 1967 (=Berthellina citrina and B. engleli of previous authors). Berthellina citrina was t h o u g h t to be a single circumtropical species but actually represents a series of distinct species globally; may be encountered as far n o r t h as central California during El Niño events. Pleurobranchaea californica MacFarland, 1966. From the shallow subtidal to at least 300 meters; feeds o n various invertebrates and fish. TYLODINIDAE

Tylodina fungina Gabb, 1865. Found commonly o n the yellow sponge Verongia thiona (note: sponge not keyed in this manual), from San Luis Obispo County south to Ecuador. REFERENCES Beeraan, R. D. 1968. The Order Anaspidea. Veliger 3 (Supplement): 87-102. Beeman, R. D., and G. C. Williams. 1980. Opisthobranchia and Pulmonata: The Sea Slugs and Allies. In Intertidal Invertebrates of California. Morris, R. H., D. P. Abbott, and E. C. Haderlie, eds. Stanford, CA: Stanford University Press, 690 pp. Behrens, D. W., and A. Hermosillo. 2005. Eastern Pacific nudibranchs. Monterey, California: Sea Challengers, 137 pp. Gosliner, T. M. 1996. The Opisthobranchia. In Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and western Santa Barbara 788

MOLLUSCA

— 5.

— 6.

— 7.

—

8.

—

Rhinophores in the form of longitudinally rolled plates (plate 391A, 391S) (except in Stiliger) or very reduced, or absent; oral tentacles absent; usually found on algae Order Sacoglossa 2 Rhinophores n o t in form of longitudinally rolled plates; oral tentacles usually present 8 With two parapodia carried folded together in a vertical position over back; ground color rich green to yellowishtan, with small spots of yellow, red, and blue; 10 m m (plate 39IS) Elysia hedgpethi Lacking parapodia; with dorsal cerata 3 Cerata few (usually 6 0 0 jim in length; distal apertural rim formed from distal gymnocyst, no apertural spines; proximal rim formed by fusion of modified frontal costae n o suboral lacunae; ovicell with large costal pores 2

—

2.

No spines or avicularia known; frontal wall a shield with five to seven large flat costae, gymnocyst extensive outside costae, one large pyriform pore near center of each costa, one to two intercostal pores; ovicell formed by pair of modified costae, with one large intracostal pore on each side of median suture Reginella (subgenus Figularia)

— 6.

Aperture otherwise; frontal wall various; avicularia present or absent; ovicells present 5 Three kinds of zooids: large autozooids, smaller female zooids with large ovicells, smaller male zooids 6 Not with three kinds of zooids 7 Frontal walls imperforate with transverse striations, large flared fenestrae on margins for frontal budding, smaller marginal areolae; aperture with U- or V-shaped sinus, small condyles ovicells large with large pores, or imperforate; no

—

Frontal wall shield with smaller costae, gymnocyst reduced, one to two smaller costal pores near ends of costae; four or more intercostal pores; avicularia present or absent 3

—

Colonies tufted, stiff; zooids alternating, biserial; ovoid with large opesia, scutum a single spine or branched, extending over opesia, other spines distal to aperture; small triangular to giant lateral avicularia with curved, acute mandibles; dorsal vibracula with radicle attached at base; ovicells imperforate, flattened or globular with frontal entooecium calcified or not Scrupocellaria

Key D: Order Cheilostomatida, Suborder Cribrimorphina Key to the genera and subgenera of species described briefly herein. 1.

—

3.

—

Zooids small, < 6 0 0 (j,m in length; distal apertural rim curved, five distal apertural spines in eastern Pacific species, proximal rim straight, both rims originating from distal gymnocyst; modified costae below proximal rim leaving small lacuna below aperture; ovicells with or without pores Puellina (subgenus Cribrilaria)

Interzooecial avicularium almost as large as autozooid, with spatulate mandible; four to six pairs of costae with large intracostal pore at outer end, three to four dumbbellshaped intercostal pores; first pair of costae extending distally at outer ends of proximal apertural rim; ovicell a pair of modified costae, one pair of large intracostal pores, one pair of smaller intercostal pores, indistinct median suture Reginella (subgenus Jullienula) No avicularia; aperture bell-shaped, proximal rim formed of modified pair of costae turned distally at outer ends, raised at sides of aperture; five to eight pairs of frontal wall costae, transverse near aperture, radiating proximally from center of shield, one to four intracostal pores, many inter-

5.

avicularia (formerly included in Hippothoa) —

7.

— 8.

Celleporella Frontal walls with numerous large pores; aperture with wide, shallow proximal sinus flanked by strong condyles; small interzooecial avicularia with spatulate mandible directed distally; ovicell large with many small pores Trypostega Aperture arched distally, with or without raised peristome, proximally curved or a wide sinus with large pore or groove within peristome or not, some bearing small rounded avicularium; ovicells imperforate, ribbed or nodular Hippoporina Aperture, ovicells mostly otherwise 8 Zooids large, subhexagonal, frontal walls imperforate, no areolae; aperture large, subtriangular with large notch at lateral ends of proximal rim for opercular muscles; ovicell a small, shallow subtriangular hood with one large pore Eurystomella BRYOZOA

875

— Frontal wall, zooid size and shape, aperture otherwise 9. — 10.

— 11.

— 12.

—

13. —

9 Primary distal apertural rim not beaded 10 Primary distal apertural rim beaded 29 Primary proximal apertural rim with median denticle (lyrula) or wide dental ledge with median notch; avicularia present 17 Aperture without lyrula or dental ledge with median notch; with or without avicularia 11 Aperture elliptical, wider t h a n high, or D-shaped with straight or slightly curved proximal lip, n o avicularia 12 Aperture otherwise; avicularia present or absent 13 Aperture rounded distally, straight or a shallow curve proximally, condyles present or not; frontal wall with pores, reticulate with larger areolae; ovicell with single large pore, sometimes other smaller irregular pores, larger areolae 'Dakaria' Proximal aperture a wide curve or widely V-shaped sinus, very large condyles; ovicell with frontal entooecium a subtriangular array of pores surrounded laterally and distally with imperforate ectooecium Neodakaria Primary aperture rounded without a distinct s i n u s . . . . 26 Primary aperture various, not D-shaped; with distinct proximal sinus 14 Note also t h e bright-red, o f t e n foliaceous Watersipora, a n a b u n d a n t fouling organism; see species list.

14. Frontal wall almost or completely filled with pores 15 — Frontal wall imperforate or with few small pores, or developing from reticulate to imperforate; with marginal areolar pores 24 15. Aperture with V- or U-shaped proximal sinus, large or small condyles, not pyriform; lateral avicularia single, paired or absent 16 — Aperture pyriform, a median suboral avicularium as part of sinus dental ledge or proximal on frontal wall, sometimes o n umbo; some species with other paired lateral avicularia Schizomavella 16. Aperture with widely U-shaped sinus; ovicells of most species with m a n y pores, some ridged; others with central imperforate area or perforate but immersed in next distal zooid may belong in other genera Schizoporella — Aperture with narrowly U-shaped sinus, operculum stem fitted into sinus; n o spines, n o avicularia; ovicell entirely imperforate Arthropoma 17. Frontal wall mostly or completely perforate 18 — Frontal wall mostly imperforate with areolae, or reticulate in development, becoming imperforate with areolae 21 18. Ovicells raised, central entooecium with m a n y pores, rimmed distally or surrounded by imperforate ectooecium 19 — Ovicell composed of one to three flaps, with one or few pores, becoming immersed in next distal zooid 20 19. Aperture with dental ledge containing U-shaped sinus, wide flat condyles above dental ledge flanking sinus, median suboral avicularium o n pedestal; ovicell raised, with large irregular central pores, imperforate ectooecium rim Schizosmittina — Primary aperture with median lyrula, secondary aperture a raised peristome, suboral avicularium recumbent o n base of lyrula or proximal to it; other avicularia present or absent; ovicell with large or small pores Smittina 20. Ovicell with one large distal flap of frontal wall having one 876

BRYOZOA

large pore, meeting rolled lateral margins of peristome; frontal wall pores without granules or spinules inside rims; small oval avicularium on small lyrula inside peristome Dengordonia — Ovicell formed of one distal, two lateral frontal wall flaps from adjacent zooids, with one or a few small pores; frontal wall pores with granules or spinules inside rims, lyrula flanked by condyles, avicularium o n lyrula base or proximal to it Raymondcia 21. Frontal wall imperforate in center but with two t o three rows of marginal pores merging, forming tubules between primary and secondary frontal wall layers moving pores u p frontal wall, sometimes other small scattered pores; peristome rounded, thickened, or erect with spines, spine bases fused into raised collar, n o proximal sinus; a suboral umbo, or a mucro extending down inside collar forming column leading to deep lyrula; n o avicularia; ovicell o n distal peristome or recumbent, imperforate or with few scattered pores Haywardipora — Frontal wall imperforate with areolae, n o frontal tubules extending upward; primary aperture with lyrula or dental ledge, n o m u c r o with column extended downward to lyrula; avicularia present 22 22. Ovicell an imperforate hood 28 — Ovicell with entooecial pores, bordered distally by ectooecium or not 23 23. Primary aperture with proximal sinus, lyrula, paired lateral condyles; secondary aperture forming raised peristome or not; median suboral avicularium within sinus o n lyrula or proximal to base peristome Smittoidea — Avicularia never median suboral, paired or single, lateral oral, or lateral frontal, other avicularia present or absent, sometimes large, interzooecial; ovicell with porous entooecium, rimmed by imperforate ectooecium or not Parasmittina 24. Frontal wall imperforate except a few central pores, larger areolae; aperture with curved sinus; ovicell immersed, with single median pore Stomachetosella — Frontal wall mostly imperforate with few or m a n y areolae, reticulate or not during development; aperture with Vshaped or curved sinus; ovicell with lunate frontal entooecium with or without costae, ectooecium imperforate o n distal, lateral margins 25 25. Colony coarse, heaped; frontal wall reticulate in development or frontal budding, becoming imperforate with areolae; ovicell raised, entooecium forming radiate costae bordered by imperforate ectooecium; raised paired lateral suboral avicularia, some species with median suboral avicularium, large oval interzooecial avicularia Celleporina — Colony vitreous, encrusting, imperforate with few areolae; primary aperture with wide sinus, strong condyles; ovicell with imperforate horseshoe-shaped entooecium ringed by tiny marginal slits, imperforate ectooecium; avicularia small, acute, on frontal wall, or larger, interzooecial Buffonellaria 26. Frontal wall mostly imperforate with one or more rows of areolae; suboral, acute avicularium, short or long, median or skewed to side, but originating at proximal apertural pore; ovicell with m a n y pores, rimmed by imperforate ectooecium Pleurocodonellina — Frontal wall mostly reticulate or perforate; avicularia, ovicells various 27 27. Colonies encrusting, becoming erect, sturdy; zooids flask shaped; frontal walls reticulate or perforate; primary aper-

ture round or oval, secondary aperture a solid tubular peristome or tall peristome like fused spines, some species with added spines or projections; avicularia small, paired, lateral oral, raised on peristomal rim, sometimes a suboral shelf or lip; ovicells suspended from distal peristome, with reticulate crescent of entooecium, imperforate rim of ectooecium; eastern Pacific species formerly placed in Lagenipora which has imperforate frontal walls Lagenicella —

Colony encrusting, fragile; zooids elongate, rectangular; frontal wall porous; aperture with strong condyles, low peristome; avicularium not on raised peristome; avicularia small, median suboral, acute, or replaced by giant spatulate avicularium; ovicell not suspended from peristome, mostly porous with thin rim of imperforate ectooecium Codonellina

28. Colony heaped, coarse, may form irregularly erect cylinders; primary aperture symmetrical, dental ledge with condyles on top almost meeting to form median notch in California species, spines present or not; secondary aperture asymmetrical due to suboral avicularium, may form umbo; giant brown spatulate interzooecial avicularia present; ovicell a shallow imperforate hood —

Celleporaria Primary aperture with wide lyrula, with median avicularium suboral or on lyrula; distal spine bases in some species, secondary aperture symmetrical; colonies thin, flat; no interzooecial avicularia; ovicells, if present, with large imperforate hood in California species Porella

29. Colony erect, fenestrate, all zooids opening on ventral side, frontal wall with a few small pores, few areolae; dorsal side with kenozooid sutural lines; primary aperture symmetrical with small median sinus, sometimes with distal spines; secondary aperture symmetrical with high peristome having proximal notch or closed spiramen; scattered hooked acute frontal wall avicularia; large hooked avicularia on dorsal side at base of fenestrae; ovicell with imperforate entooecial area, may form median labellum extending downward, distal ectooecium imperforate Phidolopora —

Colony encrusting, zooids irregular, heaped; frontal wall imperforate with large areolae; primary aperture symmetrical, sometimes with two distal spines, wide proximal sinus flanked by strong condyles; small, acute, transverse suboral avicularium not median, making secondary aperture asymmetrical, apertures becoming immersed; many acute frontal avicularia; ovicell with circular imperforate entooecium, almost surrounded by wide imperforate ectooecium, narrowing at aperture Rhynchozoon

List of Species Gymnolaemata CTENOSTOMATIDA

The taxonomy of northeastern Pacific Ctenostomatida is in great need of revision since the only extensive work was by J. D. Soule in 1953. New studies on freshly collected material require whole mounts and histological sections, while electrophoresis or molecular genetics would serve to determine whether the organisms are introduced Atlantic/Mediterranean species or are distinct Pacific species, as has seemed the case in the species that have been reexamined. The species names given in the earlier eastern Pacific literature were based prima-

rily on British and European literature, where similarities rather than differences were emphasized and optics were limited. Hayward 1985 and Hayward and Ryland 1985, 1998, 1999, have clarified the northern Atlantic and many Mediterranean species, assisting greatly in comparisons. Ryland (personal communication 2005) has added the following comments on the Alcyonidium of the region. Alcyonidium. Ryland and Porter (2006) have demonstrated that the reproductive mode may represent a potentially valuable tool in distinguishing between species of Alcyonidium. Most Pacific coast species appear to resemble A. mytili, a European species, as they are oviparous and develop planktonically. During some periods of the year the colonies never develop conspicuous embryos and individual members possess a minute, ciliated funnel that is located between the most dorsal tentacles. Larviparous species, such as the European species A. gelatinosum and A. polyoum, can possess clusters of developing oocytes and embryos. This latter mode of development appears to be uncommon in Pacific coast species and it is unlikely that any of the European species occur on the west coast of North America naturally. California and Oregon representatives are placed in A. cf. parasiticum and probably represent at least five species that incrust rocks, shells, kelp holdfasts, various algal species and crab carapaces (Ryland, personal communication 2006). One species is found on the gastropod Ilyanassa in San Francisco Bay. The species probably include one larviparous species with pale peach embryo clusters (European A. cf. gelatinosum) and at least four others that appear to have planktotrophic development (European A. cf. mytili). Common traits shared by all of the species are the hexagonal, brown to gray gelatinous zooids that are generally flat, at least near the growing margins (Plate 439B), but sometimes upright. Orifice is central and located towards the middle of the colony. Peristomes circling the orifice may or may not be raised. The colony surface can vary from smooth to mammillate to raised in lobes. Publications since 1996 have greatly improved understanding of the European species Alcyonidium gelatinosum (Linnaeus 1761), A. mytili Dalyell 1847, and A. polyoum (Hassall 1841) (summarized by Ryland and Porter 2006). In particular, they have demonstrated the importance of reproductive mode in the biology of Alcyonidium. Most Pacific coast species seem to resemble A. mytili in being oviparous, with planktotrophic development. At some (but not all) times of the year, they will have a minute ciliated funnel (intertentacular organ) between the dorsalmost tentacles, and the colony will never contain conspicuous developing embryos. Larviparous species will, at certain times of the year, contain clusters of developing oocytes and embryos, as in A. gelatinosum and A. polyoum. This mode of development seems much the less common in Pacific coast Alcyonidium. It is most unlikely that any of the European species occur here naturally, despite the use of their names in the past. In addition to the distinctive A. cf. parasiticum, at least five encrusting species, and probably more, are present in California and Oregon; all await description (J. S. Ryland, personal communication, 2006). They include one larviparous species with clusters of pale peach embryos (cf. European A. gelatinosum), and four others that probably or certainly have planktotrophic development (cf. European A. mytili). All of these have roughly hexagonal, brown to gray gelatinous zooids; generally flat (at least near the growing margins: plate 439B) but sometimes upright, with the orifice central, toward the middle of the colony. The colony surface may be essentially level, or mammillate or raised in lobes; and peristomes around the BRYOZOA

877

PLATE 439 Ctenostomatida. Carnosina. A, Flustrellidra spinifera; B, Alcyonidium cf. gelatinosum; C, Alcyonidium cf. parasiticum; Stoloniferina: D, Victorella ?pavida; E, Bowerbankia ?gracilis; F, Triticella lelongata-, G, Farella lelongata.

orifice may or may not be raised. Northeast Pacific species occur on rock, shells, kelp holdfasts, other algae, and crab carapaces from the intertidal to about 80 m. A species of Alcyonidium is common at times on the shells of the mudsnail Ilyanassa in San Francisco Bay. Alcyonidium cf. parasiticum (Fleming, 1828). See Soule 1953. Plate 439C. Eastern Pacific form probably an undescribed species; colonies flat with gelatinous, papillate surface, covered with sand, silt; zooids small with papillate border; British A. parasiticum zooids have many short frontal filaments; thickly encrusts erect hydroids, bryozoans; northern Pacific to central California; Tómales Bay colonies on shell; shallow water to 10 m. *Anguinella palmata van Beneden, 1845. Reported by Cohen and Carlton (1995) on floating docks in San Francisco Bay. Bowerbankia ?gracilis (Leidy, 1855). Plate 439E. See Soule 1953, Soule et al. 1980. May be cosmopolitan species or complex of undescribed species in eastern Pacific; see Hayward 1985 for characters of Atlantic species; northeast Pacific specimens form brown tangled masses of tubular zooids with puckered terminal apertures on stolonate stems; Puget Sound, Monterey Bay to Gulf of California; abundant fouling organism on rocks, harbor pilings; intertidal. Farella elongata (van Beneden, 1845) (?=F. tegeticula C. H. and E. O'Donoghue, 1923). Plate 439G. See Soule 1953. Eastern Pacific form(s) may be one or more undescribed species; stolonate colony with tubular zooids having pedunculate base, bilabiate terminal aperture; arising in tangled clusters within internodes; a cool-water species from Britain, Adriatic Sea; in Pacific, from Coos County, Oregon, and Tómales Bay; intertidal. Flustrella corniculata (Smitt, 1871): Soule 1953. Cold-water European species; see Flustrellidra spinifera. Flustrellidra spinifera (C. H. and E. O'Donoghue, 1923). Plate 439A. Colonies cylindrical to foliaceous or flattened, tan to dark brown; large chitinous spines with one to six irregular prongs arising from kenozoids between autozooids; zooids ovate, aperture slitlike, sometimes on raised papillae. Examination of O'Donoghues' types show northeast Pacific specimens have larger zooids and stouter, less branched spines than F. corniculata; see Cook 1964; Alaska to Morro Bay; on algal stipes, especially at bases of Laminaria sinclairii; intertidal to about 70 m. Triticella 7elongata (Osburn, 1912). Plate 439F. See Soule 1953, Soule et al. 1980. Tubular zooids with long pedicels, jointed bases arising from side branches off main stolons; may be the Atlantic species ranging from Massachusetts to North Carolina; collected from gill chambers of pea crab Scleroplax granulata; at Elkhorn Slough on various crabs; perhaps introduced with attempts to rear eastern oysters, or may be undescribed species; intertidal to unknown depth of crab substrate. Victorella 7pavida Saville Kent, 1870. Plate 439D. See Hayward 1985. Colonies form chains or clumps of tubular zooids; new zooids bud from bases of autozooids or from peristomal area; originally described from London docks; reported from northern Atlantic, Mediterranean, Black and Baltic Seas, India, and Japan, if all are same species. Common in some areas of San Francisco Bay, including Lake Merritt (Oakland); also reported from Saltón Sea where it was supposedly introduced on small boat hulls transported from the western Atlantic; brackish waters in marinas, harbors; on wood, stones, shells, barnacles, water plants, hydroids, other bryozoans; intertidal.

*Zoobotryon cf. verticilliatum (Delle Chiaje, 1828). A problematic species complex. Forms are abundant in southern California harbors, where massive colonies (resembling large clumps of transparent spaghetti) may reach several meters in size. Occasionally occurs in San Francisco Bay and would likely be found in other northern locations during periods when coastal waters are warmer.

CYCLOSTOMATIDA Research on eastern Pacific Cyclostomatida species has not been extensively performed since the work of Osburn (1953). Soule et al. (1995) updated some information, illustrating 11 species with SEM, three of which were new. Hayward and Ryland (1985) detailed the northeast Atlantic fauna, making better comparisons of European and Pacific fauna. Much more needs to be done to recharacterize the eastern Pacific fauna. Bicrisia edwardsiana (d'Orbigny, 1839): Osburn 1953. Sterile internodes one to two, zooids, fertile internodes three to five zooids. See Bicrisia robertsonae. Bicrisia robertsonae Soule, Soule and Chaney, 1995. Plate 440D. Colonies erect, feathery, small, jointed, branched; zooids one to two per internode, widened distally, new zooid growing from beside aperture on either side, or a curved, jointed spine or whip outside at that site; gonozooid a simple expanded individual with raised ooeciostome, terminal ooeciostome dorsal on top. See Soule et al. 1995 for discussion; Alaska to San Diego, ? Peru; intertidal in bioturf, on rock, red algae and Laminaria holdfasts; to > 1 2 0 m. Crisia maxima Robertson, 1910: Soule et al. 1995. Plate 440F. Colonies erect, coarse, shrub-like; zooids in double rows, fused, with short, raised peristomes, 12-20 zooids in internode but sometimes up to 40, internode joints brown with age; gonozooid large; lying against multiple zooids, ooeciostome short, straight, forward of adjacent autozooid peristome; British Columbia to Coronados Islands, Baja California, and ? Galapagos; intertidal to 126 m. Crisia occidentalis Trask, 1857: Soule et al. 1995. Plate 440G. Colonies erect, delicate, five to 12 zooids to internode, internode joints whitish to yellow; biserial zooids fused almost to tip, tips pointed on outer ends; gonozooid an inflated individual with short ooeciostome beside autozooid; Puget Sound and south; intertidal to 74 m. Crisia serrulata Osburn, 1953 (=Crisia serrata Gabb and Horn, 1862, preoccupied by d'Orbigny 1853). See Soule et al. 1995. Colony erect, bushy, stiff, with yellowish joints; zooids biserial, alternating, immersed to tips, apertures turned outward with tip extended giving serrate appearance; gonozooid large with flat distal end, ooeciostome a short adnate tube below adjacent zooid aperture; Pleistocene, southern California; Recent, British Columbia to southern California, ? Gulf of California, ? Galapagos Islands; intertidal to 135 m. Crisulipora occidentalis Robertson, 1910. See Soule et al. 1980, 1995. Large, stiff, tangled masses to 30 mm high, attached to substrate by jointed radicles; three to five zooids near base, 40 or more in longer internodes, yellowish joints; zooid tubes long, not connate, with circular apertures; gonozooid a simple inflation on internode surface, or larger, between tubes, ooeciostomes on same colony may be straight tube fused to adjacent autozooid with round or hooded aperture, or short, * = Not in key.

BRYOZOA

879

PLATE 4 4 0 Cyclostomatida. A, Diaperoforma califomica, tangled branches; B, Tubulipora pacifica, ooeciostomes short, ovals between tall zooids; C, Tubulipora tuba, ooeciostome short, oval, mid-right; D, Bicrisia robertsonae; E, Filicrisia franciscana, gonozooid at top left; F, Crista maxima, gonozooid on right; G, Crisia occidentalis, gonozooid mid-left.

freestanding tube with flared opening; Point Conception, possibly central California, Galapagos Islands; low tide to 86 m. Diaperoecia califomica (d'Orbigny, 1852). See Diaperoforma californica. Diaperoforma californica (d'Orbigny, 1852) (=Diaperoecia californica, Idmonea californica). Plate 440A. See Osburn 1953, Soule et al. 1995. Large, branching, subtidal colonies forming thickets on tube molluscans, worm colonies, or heavy balls on submerged lines; zooids are long tubes fused into bundles (fascicles) of four to eight tubules, apertures slightly raised; interior of tubes with numerous minute hooks; dorsal surface with striations, no perforations; gonozooid at bifurcating branches, surrounding autozooid tubules, ooeciostome short with flared rim; British Columbia to the Coronada Islands, Mexico; described from Nicaragua and "Vermillion Sea" (Gulf of California), but not recorded there since 1852; shallow water to > 2 0 0 m. Diplosolen harmelini Soule et al. 1995; =Diplosolen obelium: Johnston 1838: Osburn 1953; fan-shaped colonies with straight, stout autozooid tubules embedded in porous surface crust, nanozooids are small accessory tubules scattered among autozooids, sometimes connate with autozooids below, not above, colony surface. D. obelium, a north Atlantic species, has smaller nanozooid tubules connate with each autozooid above colony surface; recorded Arctic Alaska to Santa Cruz Island; shallow water to 160 m. Disporella spp. Genus tentatively includes living 'Lichenopora' spp. of Osburn 1953 and others; taxonomy of Disporella and 'Lichenopora' worldwide needs revision; discoid colonies with erect connate or nonconnate tubules radiating from center; on algal blades, hydroids, shell, stone; intertidal to 200 m. Filicrisia franciscana (Robertson, 1910). Plate 440E. See Soule et al. 1980, 1995. Sparse delicate branches, white with black joints; zooids mostly uniserial, long slender tubules with small pores, round, terminal apertures, widened gonozooid a single zooid, flattened on top, tubular ooeciostome extended from frontal margin toward autozooid dorsal to it, or erect; Alaska to ? Baja California, common in San Francisco Bay, Monterey Bay; undersides of rocks, bioturf; intertidal to 100 m. Filicrisia cf. geniculata (Milne Edwards, 1838). See Osburn 1953. Delicate, whitish branches with large black joints; gonozooid slender, tapered, connate with short ooeciostome tube originating dorsally, straight or bending forward; undersides of rocks; British Colombia to San Pedro, CA; common in Monterey Bay; intertidal, shallow water. F. geniculata (Hayward and Ryland 1985) is a north Atlantic/Mediterranean species with pale joints; gonozooid adnate, club shaped. Lichenopora spp. Lichenopora is a Cretaceous-Miocene genus with inverted conical colonies (Gordon and Taylor 1997). Pacific colonies formerly placed in the genus are flat discs or with a few layers of similar size; now tentatively placed in Disporella; prominent on algal blades, shell, stone, hydroids, coral in tropics; intertidal to deep water. Proboscina cf. major (Johnston, 1847). Hayward and Ryland (1985) placed British species P. major in new genus Annectocyma, but view records from outside temperate northeast Atlantic with caution; northeast Pacific colonies encrusting, or raising erect growths; autozooid tubules large, coarsely perforate, irregularly extending from base; gonozooid at distal ends of lobes or at branchings, with many fine pores, simple or ex-

panded around tubules, ooeciostome short; Puget Sound in shallow water, Monterey Bay, Channel Islands to ? Galapagos Islands; more common in deeper water. Stomatopora cf. granulata (Milne-Edwards, 1838). Hayward and Ryland 1985 placed S. granulata of Hincks 1880, but not of Milne-Edwards, 1836, in Entalophoroecia deflexa. The MilneEdwards species is supposedly uniserial, with very short tubules, but this may represent only youngest colonies; additional growth may produce multiserial, sometimes erect branches with tubules curving outward all around branch. Northeast Pacific specimens differ, need «description; colony encrusting; zooids smaller than European species, uniserial except at branches and where gonozooid grows around multiple tubules, autozooids curving upward to round apertures, walls finely perforate; gonozooid walls with larger pores, ooeciostome shorter. Shallow water to 100 m. Tubulipora aliciae Soule, Soule and Chaney, 1995 (=T. pulchra of Robertson, 1910; ? C. H. and E. O'Donoghue 1923; Osburn 1953). Small fan-shaped colonies recumbent, loosely attached to algae by small projections; raised and recumbent separate autozooid tubules anchored by serrate, discoid base of kenozooids; gonozooid a striated, enlarged tubule or expanded between tubules, ooeciostome short, flaring, may be compressed against adjacent tubule; central California coast, to Clarion Island off Mexico, ? Galapagos Islands, ? British Columbia; intertidal to > 6 0 m. Tubulipora pacifica Robertson, 1910. Plate 440B. See Osburn 1953; Soule et al. 1995. Small, fan-shaped to circular or lobate colonies with initial tubules separate, others connate to tips in radiate rows, with scattered small pores, smooth discoid base; often on algae; gonozooid a single chamber with one to four lobes, large pores, ooeciostome short, oval, flaring; British Columbia; Monterey Bay and south; shallow water to about 100 m. Tubulipora pulchra MacGillivray, 1885: Osburn 1953. Australian species, not found in eastern Pacific. See Tubulipora aliciae. Tubulipora tuba (Gabb and Horn, 1862). Plate 440C. See Soule et al. 1995. Large colonies of bundles of thick tubules, gray, white, or purplish; tubules tall, raised, radiating from base in connate series, with small pores; gonozooid large, inflated, with large pores, ooeciostome tall, ovate, flaring, compressed by adjacent tubules; encrusting algae, rock, shell; British Columbia to Baja California, Pleistocene to Recent; intertidal zone to 235 m. T. tuba var. fasciculifera may be younger stage of T. tuba.

CHEILOSTOMATIDA ANASCINA

Aetea anguina (Linnaeus, 1758). See Aetea pseudoanguina. British species with zooids tubular, 600 |xm-800 |j.m long; see Hayward and Ryland 1998. Aetea ligulata Busk, 1852. See Aetea paraligulata. Busk's species collected by Darwin from tip of South America, described as having tubules 450 |xm long, no annulations, with terminal apertures. Aetea paraligulata Soule, Soule and Chaney, 1995 (=Aetea ligulata of Osburn, 1951, in part). Plate 441B. Zooids erect annulated tubules about 700 ^m long, rising from stoloniform, terete bases; zooid distal half with opesia beneath membranous frontal, aperture subterminal extending to distal tip; see BRYOZOA

881

P L A T E 441 Cheilostomatida. Anascina. A, Aetea pseudoanguina, tangled zooids with spoon-shaped distal ends; B, Aetea paraligulata, long opesia, subterminal aperture; C, Membranipora fusca, with distal knobs; D, Membranipora membranacea (France), note mid-lateral wall bends; E, Membranipora serrilamella; F, Conopeum cf. reticulum, m a n y small pores in distal wall, upper right; G, Electra venturaensis, with proximal spine, small oval kenozooids on left; H, Cellaria diffusa, D-shaped apertures with distal ovicell openings; I, Cellaria mandibulata, large avicularium center, zooid apertures above.

PLATE 442 Anascina, continued. A, Hincksina alba, ovicell shallow hood lower right, avicularium middle; B, Hincksina pallida, acute avicularium mid-bottom; C, Hincksina velata, ovicell center, avicularium right; D, Cauloramphus californiensis, single zooid with stout spines, tall avicularia with open mandibles; E, Cauloramphus echinus, shorter spines, tall avicularia; F, Alderina tbrevispina, zooid with shallow hood distally, tiny spine scars on opesial rim, central zooid; G, Callopora corniculifera; H, Copidozoum adamantum, diamond-shaped avicularia, lanceolate mandibles; I, Copidozoum protectum, interdigitating spines arching over frontal membrane of opesia.

PLATE 443 Anascina, continued. A, Tegella armífera, ovicell with slit between layers, interzooecial avicularium migrates to ovicell top; B, Tegella circumclathrata, loose connections between zooids, many spines, acute avicularium atop ovicell; C, Tegella hórrida, avicularium with ovicell directed distally; D, Tegella laruensis; E, Tegella robertsonae; F, Chaperiopsis patula, with paired distal shelves below opesia; G, Thalamoporella califomica, paired opesiules below aperture (opesia) large, bluntly acute avicularium to left; H, Thalamoporella califomica ovicell typical of genus; I, Thalamoporella gothica, smaller avicularium shaped like gothic arch at tip.

Soule et al. 1995 for discussion; central, southern California; shallow water to 100 m. Aetea pseudoanguina Soule, Soule and Chaney, 1995 (=Aetea anguina of Osburn 1951, in part). Plate 441 A. Whitish, tangled colonies of stoloniform bases with erect striate tubules, zooids 1,200 (xm-1,500 |xm long with tiny spinules or tubercles; distal area spoon shaped with oval opesia beneath frontal membrane, aperture subterminal, 20%-25% of length of opesia; on algae, rock, other bryozoans; California, ? Baja California; shallow waters to 100 m. Alderina Ibrevispina (C. H. O'Donoghue and E. O'Donoghue, 1926). Plate 442F. See Soule et al. 1995. Small encrusting colonies on rock, shell, other hard substrates; zooids small with widely open opesia, granular cryptocyst wider proximally, gymnocyst almost absent; sometimes tiny spinous processes around opesia; ovicell shallow, inconspicuous, granular proximal entooecial front, distal ectooecial rim, slitlike aperture; tiny spinules not seen in the O'Donoghues' specimens. British Columbia to ? Santa Barbara Channel; shallow waters to 90 m. Bugula californica Robertson, 1905. Plate 445F. See Soule et al. 1980, 1995. Distinctive spiral colony growth, often confused with tufted growth of other species; zooids elongate with large opesia, two large blunt outer distal spines, one thinner inner distal spine; numerous "birds-heads" avicularia; ovicells large, numerous, sculpted with thin entooecial area almost surrounded by thicker, wider ectooecial area; British Columbia to southern California, ? Gulf of California, ? Galapagos Islands; fouling community, shallow water to about 70 m. Bugula cf. mollis Harmer, 1926: Osburn, 1950. Not Harmer's tropical western Pacific species with three long distal spines jointed at bases. Northeast Pacific material with short points on distally truncate zooids, no spines; small avicularia medially, ovicell a small distal flap; needs redescription; San Francisco, ? Panama, ?Galapagos Islands; shallow to > 4 0 m. Bugula longirostrata Robertson, 1905. Plate 445G. See Soule et al. 1995. Colony erect with slender branches, zooids elongate; distinctive, long, slender, terete avicularia; ovicells like shallow bowls; British Columbia to Mexico, and the Galapagos Islands; intertidal on pilings to 230 m. Bugula neritina Linnaeus, 1758. Plate 445D. See Soule et al. 1980, 1995. Colonies bushy, reddish to purple, biserial branching, zooids with large frontal membrane, outer distal wall forming acute tip, no spines; ovicell large, globose at inner distal corner of zooid; obverse proximal end of zooid like forked tail or Y-shaped at branches; no avicularia; in fouling community worldwide in warm temperate to tropical waters, but is most likely a complex of species as discussed by Davidson et al. (1999, Biol. Bull. 196: 273-280). Common on harbor rocks, pilings, ship's hulls; Monterey Bay to Gulf of California, Panama, Galapagos Islands; intertidal to about 100 m. Bugula pacifica Robertson, 1905. Plate 445E. See Soule et al. 1995. Colonies delicate, erect, in pinkish tufts; zooids biserial, elongate, gymnocyst curved over frontal membrane with two spines on outer distal tip, one on inner tip; avicularia large, pedunculate birds' heads; ovicell a shallow incomplete hood; Bering Sea to Channel Islands; intertidal to 123 m. Bugula pugeti Robertson, 1905. See Soule et al. 1995. Erect, branching, multiserial colonies, four to seven rows wide; zooids on margins with two outer blunt spines, one inner; avic-

ularia birds' heads; ovicells unknown, but distal corners of central zooids curve over until almost touching, possibly to shelter ovum; Alaska to Channel Islands; mostly northern; in fouling community; low tide to 117 m. Bugula stolonifera Ryland, 1960. An introduced Atlantic species common in San Francisco Bay fouling communities as reported by Okamura (1984, J. Exp. Mar. Biol. Ecol. 83: 179-193) and discussed by Cohen and Carlton (1995). Caberia ellisii (Fleming, 1818). Plate 444D, 444E. See Soule et al. 1995. Colony erect, fan shaped, branches two to four zooids wide, tangled; zooids with long, barbed vibracula, radicles grouped in rigid cords on dorsal side; no scutum; ovicell a shallow imperforate hood with incompletely calcified frontal entooecium; arctic Atlantic to English Channel and Cape Cod; reported from Alaska, British Columbia, Puget Sound, Channel Islands, and Baja California; no significant differences found between Pacific, Atlantic specimens; shoreline to > 4 5 0 m. Callopora circumclathrata (Hincks, 1881): Osburn 1950. See Tegella circumclathrata. Callopora comiculifera (Hincks, 1882). Plate 442G. See Soule et al. 1995. Zooids ovate with large opesia, rolled cryptocyst bristling with three to four pair of thinner marginal spines proximally, two to three pair of stout marginal spines distally; avicularia small, on lateral wall outside spines distal to midzooid; ovicells wide, shallow, coarsely granular, with slit-like opening between ectooecium, entooecium; encrusting rock, shell; British Columbia to Santa Catalina Island; intertidal to 126 m. Caulibugula californica (Robertson, 1905). Plate 445H. See Soule et al. 1995. Erect, jointed, stalked colonies with palmate tufted tips, zooids resemble those of Bugula spp.; two spines on outer distal margin; ovicell pedunculate on inner margin; intertidal in British Columbia, to 231 m off La Jolla. Caulibugula ciliata (Robertson, 1905). Plate 4451. See Soule et al. 1995. Tiny, delicate, erect fanlike tufts with five or more long, incurved spines on outer margin; pedunculate ovicell on inner margin of distal end; common on red algae; British Columbia to Channel Islands; depths from lower intertidal to over 100 m. Cauloramphus californiensis Soule, Soule and Chaney, 1995 (=C. spiniferum of Osburn, 1950, in part). Plate 442D. Brown to tan, unilaminar colony; oval opesia with lateral walls bearing 13-15 stout spines covering frontal membrane; one to two long, stalked avicularia flanking operculum, similar to spines in size; ovicells not known; encrusts shell, rock, kelp holdfasts; Monterey Bay to La Jolla; common in Channel Islands, perhaps from Alaska to Galapagos Islands; shallow water to > 1 0 0 m. Cauloramphus echinus (Hincks, 1882). Plate 442E. See Soule et al. 1995. Unilaminar colonies, ovate zooids loosely connected by small tubules; large opesia, four erect distal spines, seven to eight pair of short marginal spines extended over opesia but not touching; paired pedunculate avicularia flanking aperture; ovicells not known; British Columbia to Santa Barbara Channel; intertidal to > 1 0 0 m. Cauloramphus spiniferum (Johnston, 1832): Osburn 1950, in part. A north Atlantic species not found on Pacific coast. See Cauloramphus californiensis. Cellaria diffusa Robertson, 1905. Plate 441H. See Soule et al. 1995. Erect, club-shaped internodes, brown or black joints; branching colony; zooids bluntly diamond shaped

BRYOZOA

885

PLATE 444 Anascina, continued. A, Tricellaria circumtemata, with paddle-shaped central scutum; B, Tricellaria occidentalis, tall spines, lateral avicularia directed outward; C, Tricellaria occidentalis, obverse with pores, three pair long spines, scutum at bottom; D, Caberia eltisi, ovicell below, lateral vibracula; E, Caberia ellisi, obverse, radicles forming cords down back; F, Scrupocellaria diegensis, with large scutum; G, Scrupocellaria diegensis, obverse view; H, Scrupocellaria various, with giant avicularium, forked scutum; I, Scrupocellaria varians, obverse view with vibracula.

PLATE 445 Anascina, continued. A, Dertdrobeania curvirostris, zooids with large opesiae, hooked lateral avicularium; B, Dendrobeania laxa, stout spines over opesiae; C, Dendrobeania lichenoides, with thin, short spines; D, Bugula neritina, with ovicells, no spines, no avicularia; E, Bugula pacifica, shallow ovicell hoods, stout avicularium on pedicell; F, Bugula californica, with well-calcified ovicells, avicularia on pedicles; G, Bugula longirostrata, with long, thin zooids; H, Caulibugula californica, with slanted apertures, small marginal avicularia; I, Caulibugula ciliata, with long curved spines, small erect avicularia.

with large, depressed cryptocyst; opesia consists only of aperture, arched proximally and distally, with strong blunt condyles on proximal lip, smaller distal denticular rests for operculum; avicularium interzooecial, between transverse walls, almost square, with elliptical rostrum, rounded mandible; ovicell internal but opening by large pore distal to aperture, pore becoming eroded, larger than avicularium opesia; Pleistocene of Santa Monica; Recent, Puget Sound to southern California, ? Galapagos Islands; intertidal to > 2 0 0 m. Cellaria mandibulata Hincks, 1882. Plate 4411. See Soule et al. 1995. Erect, branching internodes, brown or black joints; zooids diamond shaped, aperture rounded distally and proximally with two large condyles on proximal lip; giant avicularia with large brown semicircular mandible (looks like an open mouth); ovicells internal with large pore distal to aperture; on hard substrates; British Columbia to Baja California; intertidal to > 1 4 0 m. Chapperia patula (Hincks, 1881). =Chapperia: Willey 1905; Osburn 1950, a misspelling of Chapería, preoccupied; see Chaperiopsis patula. Chaperiopsis patula (Hincks, 1881). Plate 443F. See Soule et al. 1995. Encrusting, reddish purple; opesia a wide oval, cryptocyst raised like saucer rim, occlusor laminae shelves distally; four to six large spines around distal half; ovicell a large imperforate hood, sometimes sculpted, slit between ectooecium, entooecium open or fused; British Columbia to Baja California; shallow water to 90 m. Colletosia radiata (Moll, 1803). See Cribrimorphina: Puellina ('Cribrilaria) californiensis. Conopeum osbumi Soule, Soule and Chaney, 1995 (=Electra crustulenta var. undescribed of Osburn, 1950). Encrusting; linear, loosely connected oval zooids bordered with three to six pair of thin spines, two tiny spines at distal corners, no proximal spine; no ovicells known; Oregon to Gulf of California; intertidal in north, to about 73 m in south. Conopeum cf. reticulum (Linnaeus, 1767). Plate 441F. See Soule et al. 1995. May be one or more, probably undescribed, encrusting species; zooids with narrow cryptocyst and gymnocyst, cryptocyst crenulate, sometimes with small spinules extending over frontal membrane, opesia large, oval; small triangular kenozooids at distal corners, sometimes absent; internal distal transverse wall with large multiporous communication plate or sometimes smaller single pore plates flanked by vertical buttresses, in some colonies causing confusion with British species; no ovicells known: brackish water of San Francisco Bay, Berkeley Yacht Harbor, often found with ctenostome Victorella cf. pavida and entoproct (kamptozoan) Barentsia sp; coastal embayments south to La Jolla, CA; intertidal, shallow water. San Francisco Bay is also home to the abundant Conopeum tenuissimum (Canu, 1928) which was introduced with Atlantic oysters in the 19th century. Copidozoum adamantum Soule, Soule and Chaney, 1995 ( = C . tenuirostre of Osburn 1950, includes C. planum of Osburn 1950; not M. tenuirostris Hincks 1880). Plate 442H. Encrusting, oval zooids, separated, with raised crenulated cryptocyst, diamond-shaped interzooecial avicularia with lanceolate mandibles; squared, porous ovicells; British Columbia to Channel Islands, ? Galapagos Islands and ? Peru; intertidal to 129 m. Copidozoum planum (Hincks, 1880): Osburn, 1950. See C. adamantum. C. planum is an Australian species, not found in eastern Pacific. 888

BRYOZOA

?Copidozoum protectum (Hincks, 1882). Plate 4421. See Osburn, 1950: Soule et al. 1995. Generic placement questioned because C. protectum has imperforate ovicells and large acute interzooecial avicularia as in Copidozoum, but has thick branching spines on gymnocyst in distal half of zooid arching over large opesia as in Chaperiopsis, although there are no occlusor laminae; British Columbia to Gulf of California; encrusting hard substrates; shallow water to 50 m or more. Copidozoum tenuirostre (Hincks, 1880). Osburn, 1950. See Copidozoum adamantum. Dendrobeania curvirostrata (Robertson, 1905). Plate 445A. See Soule et al., 1995. Erect or recumbent strap-like colonies four to eight zooids wide, attached by rootlets; zooids elongate, one very short inner spine, one outer distal spine, one to two tiny spines flanking operculum; beaked avicularium very large, at base of outer zooids; ovicells large, imperforate but sculpted due to uncalcified areas in entooecium; British Columbia to southern California; shallower water in north, deeper in south, to > 1 0 0 m. Dendrobeania laxa (Robertson, 1905). Plate 445B. See Soule et al. 1995. Loosely attached by rootlets; recumbent colonies on hard substrates, zooids separated by small gaps; two distal spines, four pair medium large lateral spines arching over long, slim opesia; no avicularia; large, globose, striate ovicells; British Columbia to southern California; intertidal to 100 m. Dendrobeania lichenoides (Robertson, 1900). Plate 445C. See Soule et al. 1995. Greenish, loosely attached recumbent fronds; opesia large, ovoid; two tiny distal spines, two to three pair small lateral spines present or absent; ovicell globular, imperforate with striations; often associated with green colonial ascidian Perophora; British Columbia to southern California; common in low, shaded intertidal to 100 m. Electra crustulenta arctica (Borg, 1931). See Osburn 1950. A north Atlantic brackish water species; var. arctica described from Spitsbergen. See Electra venturaensis. Electra venturaensis Banta and Crosby, 1994 ( = £ . crustulenta of Osburn, 1950; =E. crustulenta arctica of 0sburnl950, in part: see Soule et al. 1995). Plate 441G. Single proximal spine typical of genus; colonies encrusting, large opesia, gymnocyst wide with transverse wrinkles as in Celleporella hyalina, cryptocyst narrow; no known ovicells; oval dwarf zooids on San Francisco specimens, small rectangular kenozooids on Alaskan material (may be separate species); ? Alaska; central, southern California; encrusting rocks, shells, algae, intertidal to > 3 0 m. Figularia hilli Osburn, 1950. See Cribrimorphina: Reginella (Figularia) hilli. Hincksina alba (C. H. O'Donoghue and E. O'Donoghue, 1923). Plate 442A. See Soule et al.1995. Encrusting species with large open opesia, granular cryptocyst, no spines; large, winged interzooecial avicularium between lateral walls of adjacent zooids; ovicell visible as small, shallow, granular hood; encrusting rock, molluscan and brachiopod shells; British Columbia to Channel Islands; shallow water to 100 m. Hincksina pallida (Hincks, 1884). Plate 442B. See Soule et al. 1995. Encrusting, loosely attached to hard substrates; large opesia, with six pair small lateral spines outside narrow cryptocyst between lateral walls; interzooecial avicularium between transverse zooid walls; ovicell small, with shallow brim, projecting into body cavity of next distal zooid; British Columbia to central California, shallow water to 90 m. Hincksina velata (Hincks, 1882). Plate 442C. See Osburn 1950. Encrusting; opesia large, no spines, small, triangular to curved interzooecial avicularia between lateral walls directed

distolaterally; ovicell endozooecial but visible as small subtriangular distal knob with separate operculum; encrusting shells; British Columbia to ? Colombia; c o m m o n at Monterey, Pebble Beach; shallow water to > 1 2 0 m. Lyrula hippocrepis (Hincks, 1882). See Reginella (Lyrula) hippocrepis. Membranipora fusca Osburn, 1950. Plate 441C. Frontal wall at first a thick, clear membrane, developing heavy dark border, becoming yellowish-brown to black; two distal knobs in older zooids (may belong in genus Conopeum); n o spines, n o avicularia, n o ovicells; encrusting shells, stones; northern, central California; intertidal to about 12 m. Membranipora membranacea (Linnaeus, 1767). Plate 441D. C o m m o n European species, oblong to dumbbell-shaped zooids, small knobs at distal corners may form taller tower cells, may aid colony in water current flow; n o ovicells; heavy encrustations o n giant kelp in northeast Atlantic; transitory if introduced in eastern Pacific, similar to M. serrilamella; see Soule et al. 1995; intertidal to d e p t h of kelp fronds. See Schwaninger, 1999, Mar. Biol. 135: 411-423 (genetics, population structure). Membranipora serrilamella Osburn 1950 (?=M. perfragilis of Osburn, 1950). Plate 441E. See Soule et al.1995. Zooids thin walled, elongate with pair of short, acute, curved spines distally beside base of operculum; a few tiny spinules directed centrally from narrow cryptocyst; may include M. villosa Hincks, 1880, with small chitinous spinules induced o n frontal membrane in early spring, summer by juvenile molluscan predation (Harvell, 1984); c o m m o n o n algae; British Columbia to southern California; shallow water to 30 m, perhaps to bottom of photic zone. Membranipora tuberculata (Bosc, 1802) (?=)ellyella tuberculata Taylor and Monks, 1997). See Soule et al. 1980, 1995. Encrusting oblong zooids with thick, crenulate, widely oval cryptocyst, with two proximal tubercles; in Atlantic specimens, walls thin, tubercles small, spinules small; on floating Sargassum; tropical specimens have heavier walls, m u c h larger tubercles and spinules, if all the same species; central California during El Nino periods; encrusting kelp, other algae; may be reintroduced o n algae o n ships' hulls, surviving in warm bays, harbors temporarily; intertidal to 50 m. Membranipora villosa Hincks, 1880. See Membranipora serrilamella. Micropora coriacea Qohnston, 1847). See Osburn 1950. See Micropora santacruzana. M. coriacea from Britain has n o avicularia, opesiules smaller t h a n in M. santacruzana. Micropora santacruzana Soule, Soule a n d Chaney, 1995 (=M. coriacea of Osburn 1950 in part; ? of Hincksl882; ? of Robertson1908; ? of C. H. and E. O ' D o n o g h u e 1923, 1925). Encrusting, frontal wall with complete perforate cryptocyst, small to medium opesiules at lateral walls proximal to straight aperture, proximal rim flanked by tiny round knobs; small transverse bulbous avicularium with acute mandible between transverse walls; ovicell perforate with apical u m b o ; ? British Columbia to C h a n n e l Islands; shallow water to 168 m. Scrupocellaria cf. califomica Trask, 1857. See Soule et al. 1995. Colony erect, biserial, jointed; opesia about half zooid length; ovicell imperforate, striated; originally described S. califomica has seven to nine zooids per internode, one spine per zooid, scutum a small spine or paddle shaped, on proximal lobe, small vibraculum or none; currently identified "S. califomica," needs new name; has three to four zooids per internode, sometimes u p to nine per internode, opesia a large oval, two to three outer spines, one inner spine; scutum a single prong or oar shaped;

reported from British Columbia, c o m m o n in central California, Baja California; shallow water to > 1 2 0 m. Scrupocellaria diegensis Robertson, 1905. Plate 444F, 444G. See Osburn, 1951. Colony coarse, u p to 12 zooids per internode; opesia large, more t h a n half of zooid length, two outer, three inner spines; scutum paddle shaped; small raised proximal frontal avicularia, large lateral avicularia; ovicells large with small pores, striations; British Columbia, Gulf of California to ? Colombia, o n floats and pilings; shallow water to 20 m - 4 0 m. Scrupocellaria varians Hincks, 1882. Plate 444H, 4441. See Soule et al. 1995. Colony erect, bushy, opesia covering most of zooid frontal area, forked scutum; giant curved lateral avicularium o n outer margin, rostrum troughlike, small frontal avicularium proximal to opesia; dorsal vibraculum small with short bristle, short radicle; ovicell ectooecium bordering imperforate central entooecium; British Columbia, California, ? Gulf of California; shallow water to about 60 m. Scrupocellaria spp. common under rocks, floats, bushy, whitish, greenish or brownish, bristly colonies or feltlike bioturf. Tegella armífera (Hincks, 1880). Plate 443A. Soule et al., 1995; Osburn, 1950 (in part). Colony encrusting, oval zooids with grooves between; lpair tiny spines flanking aperture, one large spine or one proximally directed small avicularium on each side of opesia; ovicell with lucidum slit between ectooecium, entooecium, one pair of sunken pores at ends of slit; large interzooecial avicularium overgrowing ovicell f r o m between transverse walls; Arctic seas, North Atlantic, Alaska, Oregon, California; intertidal in northern waters to > 1 0 0 m in southern California if all are the same species. Tegella cassidata (C. H. and E. O'Donoghue, 1923) (=T. armífera of Osburn, 1950, in part; see also T. laruensis Soule, Soule and Chaney 1995). Zooids ovate, cryptocyst with rolled granular rim; one pair of bulbous acute avicularia flanking aperture raised on conical chambers on gymnocyst; one large spine interior of, proximal to, base of avicularium; ovicell with wider lucidum, strong ectooecial rim, n o lateral pores; small or large raised, transverse interzooecial avicularium, curved distolaterally; encrusting rock, shell; British Columbia, to ? southern California; distribution, depths uncertain due to confusion with other species. Tegella circumclathrata (Hincks, 1881) (=Callopora circumclathrata of Osburn, 1950). Plate 443B. See Soule et al. 1995. Genus Tegella now limited to species with large interzooecial avicularium between transverse walls, avicularium may migrate to top of ovicell; zooids ovate, loosely connected by tubules; opesia large with crenulate rim, large marginal pores, pair of spines flanking aperture, three to four pairs curving over frontal membrane; avicularium with long acute mandible directed proximally in absence of ovicell, directed distolaterally atop ovicell if present; ovicell with gap (lucidum) between ectooecium, entooecium, ovicell n o t closed by operculum; encrusting rock, shell; ? British Columbia to ? Baja California; shallow water to > 1 0 0 m. Tegella hórrida (Hincks, 1880) (=Callopora hórrida). Plate 443C. Colonies encrusting; differs from T. circumclathrata in having contiguous zooids without loose, large, tubular connections; with two to three pairs distal spines, two to three pairs lateral spines; British Columbia, California, ? Galapagos Islands; shallower water in north, to > 6 0 m in Galapagos Islands. Tegella laruensis Soule, Soule and Chaney, 1995 (? = s o m e earlier citations of T. armífera or T. cassidata). Plate 443D. Zooids with ovate opesia, narrower at operculum; one large BRYOZOA

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and one small spine on one side of aperture, one on other; a raised acute avicularium on lateral gymnocyst at mid-opesia, a larger acute interzooecial avicularium between transverse walls raised on pedicel, directed proximally on zooids without ovicell; ovicell raised, ectooecium and entooecium separated by rimmed slitlike lucidum, interzooecial avicularium lying atop ovicell directed distally; central, southern California, encrusting, especially arenaceous worm tubes, shallow to deep waters. Tegella robertsonae C. H. and E. O'Donoghue, 1926. Plate 443E. Species has one to three small spines extending over opesia, no avicularia on lateral wall gymnocyst; very large interzooecial avicularia, acute with raised tip, moving atop ovicells, directed distolaterally; ovicell with slit between ectooecium, entooecium; encrusting shell, sponge, larger algae, tunicates; Alaska, British Columbia, Dillon Beach, Monterey Bay, Channel Islands; intertidal to > 4 5 m. Thalamoporella califomica (Levinsen, 1909). Plate 443G, 443H. See Soule et al. 1980; Soule, Soule, and Chaney 1999. Colonies encrusting, sometimes rising in small, jointed, clubshaped branches; zooids large, vase shaped, paired large opesiules in perforate cryptocystal frontal wall; interzooecial avicularium arched distally to subacute tip, about same length as zooid; large bilobate ovicells common; internal body cavities with tiny calcified, curved caliper-shaped (ice tong) spicules; Pleistocene, southern California; Recent, Monterey Bay and south; on kelp, other algal substrates; intertidal to 15 m. Thalamoporella gothica (Busk, 1856). Plate 4431. Soule et al. 1999. Colonies encrusting, sometimes rising in bilaminar, foliate lobes; zooids large, similar to T. califomica with two opesiules; interzooecial avicularium smaller, with more blunt distal tip; ovicells rare, large; internal spicules both calipers and compasses; on rock, shell; shallow, warmer California waters especially during El Nino years, more common in Gulf of California. Tricellaria circumternata Soule, Soule and Chaney, 1995 (=7ncellaria ternata of Osburn 1950, in part). Plate 444A. Colonies erect in tufts or flaccid branches; three to seven small zooids per internode with light-colored joints; two to three spines on outer margin, one to two on inner margin; scutum a single spine or paddle shaped; a few zooids with a small frontal avicularium, some with large lateral avicularia; ovicells large, imperforate, striate; attached to hydroids, arenaceous worm tubes, erect bryozoan colonies, seaweeds; British Columbia, Dillon Beach and Big Sur, central California; low tide to 50 m. Tricellaria occidentalis (Trask, 1857). Plate 444B, 444C. See Soule et al. 1995. Erect, bushy colonies, internodes usually three zooids, sometimes up to five to six; opesia about half of frontal wall, three smaller spines on inner margin, three larger spines on outer margin, longest spines most distal; scutum a single or bifurcate prong in northern material, multipronged in southern; larger lateral avicularium on outer side, mandible triangular, hooked; ovicell with large pores, sometimes a median suture on brim; common in fouling on boat hulls, other hard substrates, algae; ? British Columbia, California, ? Baja California; intertidal to 40 m. Tricellaria ternata (Solander 1786): Osburn 1950. See Tricellaria circumternata. CRIBRIMORPHINA

Colletosia radiata form innominata (Couch 1844): Osburn 1950. See Puellina (Cribrilaria?) perplexa. 890

BRYOZOA

Puellina (Cribrilaria) californiensis Soule, Soule and Chaney, 1995 (=PueIlina setosa of Osburn, 1950, in part; Colletosia radiata form innominata: Osburn 1950, in part; Colletosia radiata of J. Soule 1959). Plate 446F. Zooids small, shiny, translucent, a small suboral lacuna below proximal apertural rim, five distal spines; frontal shield composed of 13-16 radiate costae with knobs at periphery with marginal buttressed portion slanting upward, five intercostal pores on each side above first costae below lacuna, five to seven on each side between rows of larger costae; gymnocyst wider in young zooids, becoming narrow; acute interzooecial avicularia; ovicells imperforate; encrusting rock, shell; warmer California waters, Channel Islands, Gulf of California; shallow waters to > 1 8 0 m. Puellina (Cribrilaria?) perplexa Soule, Soule and Chaney, 1995 (=Colletosia radiata form innominata of Osburn 1950, in part; not P. (C.) innominata from Britain with fewer costae; see Bishop and Househam, 1987). Plate 446G. Colonies encrusting; zooids small, oval, five distal spines; medium to large suboral lacuna flanked by two smaller pores, three intercostal pores on each side between costal rows one and two, five between other costae, frontal shield composed of 15-17 costae, gymnocyst hardly visible; interzooecial avicularia acute, directed distolaterally; ovicell with pores sometimes obscured by advanced calcification, sometimes umbonate; ? British Columbia to southern California, ? Galapagos Islands, ? Peru; shallow water to 200 m. Reginella (Figularia) hilli (Osburn, 1950). Plate 446E. See Soule et al. 1995. Colony encrusting; zooids large, one fused center proximal costa with two to three pairs of costae; single intracostal pores large, pyriform; aperture wider than high, ovoid; ovicell formed from modified costae, with pair of very large pores, central suture; no spines or avicularia. Monterey Bay, Channel Islands; Baja California; intertidal to > 1 3 0 m. Reginella (Jullienula) hippocrepis (Hincks, 1882) (=Lyrula hippocrepis of Osburn, 1950; =Cribrilina hippocrepis). Plate 446C, 446D. See Soule et al. 1995. Colony encrusting, sometimes raised, bilaminar; zooids large, frontal shield raised, four to six pairs of costae, separated by three to four irregular, dumbbell-shaped intercostal pores, one large intracostal pore at outer end of each costa; large interzooecial avicularia with spatulate mandible directed distally; ovicells small, indistinct, formed of modified costae with two intracostal pores, one median pore; Alaska to southern California; shallow water to 160 m. Reginella (Reginella) furcata (Hincks, 1882). See also Reginella nitida of Osburn 1950; Soule et al. 1995. Plate 446A. Colonies encrusting; six to eight pairs of costae radiating from central suture, four to six intercostal pores, each costa with two small infundibular intracostal pores; aperture bell shaped, flanked by single or weakly bifurcate spines; ovicells porous, sometimes with faint median keel, blending into next distal frontal wall; British Columbia to San Benito Islands off Baja California; shallow waters to > 1 6 0 m. Reginella (Reginella) nitida (Osburn, 1950). Plate 446B. See Soule et al. 1995. Very similar to R. furcata. Colonies encrusting; five to eight pairs of flattened costae, five to seven intercostal pores per rib, three to four smaller infundibular intracostal pores atop each costa; aperture ovate, with or without small lateral projections; ovicell with scattered pores, median suture raised into keel; reported from Puget Sound to San Benito Islands off Baja California, shallow water to > 1 6 0 m.

PLATE 446 Cribrimorphina. A, Regimila {Reginetta) furcata, bell-shaped aperture, ovicell with pores on right; B, Reginetta (Reginetta) nitada, aperture more ovate with scattered pores on ovicell; C, Reginetta (Juliienula) hippocrepis, ovicell on left with two large pores, small median pore; D, Reginetta (Juliienula) hippocrepis , giant avicularium on left; E, Reginetta (Figularia) hilli, ovicells with two large pores, median suture; F, Puellina (Cribrilaria) califomiensis, zooids with median suboral lacuna, imperforate ovicell on right, interzooecial avicularium at top; G, Puellina (Cribrilaria?) perplexa, perforate ovicell bottom left, interzooecial avicularia hypercalcified.

PLATE 447 Ascophorina. A, Microporelloides califomica, suboral ascopore with median labellum, acute lateral oral avicularia; B, Microporelloides catalinensis, with reticulate frontal wall, ovicell pores; C, Microporelloides cribrosa, with suboral cribrate ascopore; D, Microporelloides infundibulipora, with sunken pores, ridged ovicells, suboral umbo proximal to ascopore; E, Microporelloides vibraculifera, avicularia with long, setose mandibles; F, Fenestrulina famsworthi, developing colony with ancestrula (metamorphosed larva) surrounded by spines, frontal wall with marginal pores, central ascopore; G, Fenestruloides blaggae, with imperforate ovicell, frontal wall with pores, ascopore, proximal umbo; H, Fenestruloides miramara, pair of spines on distal rim of aperture or flanking aperture of ovicells, ascopore on umbo, frontal wall pores except for umbo, imperforate ovicells; I, Fenestruloides umbonata, frontal wall with pores, small umbo proximal to small ascopore, ovicell rugose.

ASCOPHORINA

Arthropoma cecilii (Audouin, 1826). Plate 449D. See Osburn 1952. Colony encrusting, white; zooids irregularly hexagonal; frontal wall with many small pores, aperture a semicircle with narrow U-shaped proximal sinus, operculum stem fits in sinus; small suboral umbo in some zooids; ovicell large, irregular, imperforate, leaning over aperture; reported in circumtropical, warm temperate waters; ? British Columbia, California, to ? Costa Rica; intertidal to 80 m. Buffonellaria vitrea (Osburn, 1952) (=Stephanosella vitrea). Plate 451E. See Soule et al. 1995. Colonies porcellanous, encrusting; zooids small, only distinct at growing margins, set off by a few areolar pores; aperture with V-shaped sinus; paired or single suboral frontal avicularia with rounded rostral opesia, narrowed to acute tip, directed laterally, sometimes a larger interzooecial avicularium resting on frontal but set off by areolae; ovicell globose, with large horseshoe-shaped frontal entooecium area bordered by slitlike pores, ectooecium hood thick, imperforate; on shell, rock, worm tubes; Puget Sound and south; shallow water to 170 m. Buffonelaria bolini is a similar species from deep water, with larger zooids, a wider sinus; off Pt. Sur and Santa Rosa Island. Cellepora costazii Audouin, 1826 (=Costazia costazii) See Osburn 1952. Not found in northeastern Pacific. See Celleporina robertsoniae, C. souleae. Celleporaria brunnea (Hincks, 1884) (=Holoporella brunnea). Plate 451A. See Osburn, 1952, Soule et al. 1980, 1995. Forms thick brown or gray encrustations and clumps; colony very irregular, with large interzooecial avicularia having dark brown mandibles, tips curved upward distally; primary aperture symmetrical, rounded distally, almost straight proximally with shelflike condyles almost meeting in center to leave small notch; secondary aperture asymmetrical due to small oval suboral avicularium directed laterally; ovicell a very shallow hood becoming immersed; encrusting algae, stone, shell, Oregon to Ecuador; abundant in shallow water; intertidal to 50 m. Celleporella hyalina (Linnaeus, 1767) (=Hippothoa hyalina). Plate 448C. Genus Hippothoa now limited to species with uniserial colonies. Colonies multiserial with three kinds of zooids: small tapered autozooids with aperture having wide, shallow sinus; female zooids without sinus, sometimes small suboral umbo, large ovicells with large pores; and tiny dwarf male zooids; frontal walls smooth with transverse striations, large, flaring areolae on margins where frontal budding occurs; smaller areolae also present; C. hyalina becomes multilaminar during reproduction. A northern Atlantic species; C. hyalina sensu lato in the eastern Pacific is a complex of species; reported from Miocene of Alaska, Pliocene, Pleistocene of California; Recent, reported from Alaska, San Francisco to Channel Islands; Galapagos Islands; encrusting rock, shell, algae, hermit crabs; from intertidal to > 1 3 0 m. Similar species C. cornuta has a suboral umbo, a U-shaped sinus flanked by notches on autozooids, an imperforate ovicell on female zooids, found from Bodega Bay to Baja California. C. santacruzana colonies remain unilaminar, the latter has a narrow V-shaped sinus, imperforate ovicells. See Morris (1976, 1979, 1980). Celleporina robertsoniae (Canu and Bassler, 1923) (=Cellepora costazi Robertson 1908, in part; Costazia robertsoniae of Osburn 1952, part; Celleporina ventricosa of Morris 1979, in part; see Soule et al. 1995). Plate 45 IB. Colony encrusting; initial zooids recumbent, frontally budded zooids erect, frontal wall with scattered small pores, areolae; primary aperture rounded with deep, V-shaped proximal sinus, flanked by paired lateral, oral,

rounded avicularia on pedestals forming secondary aperture; other small avicularia proximal or distal to aperture; larger shoe-shaped interzooecial avicularia; ovicells raised, globose, ectooecium imperforate, striated, with triangular entooecial frontal area having 12-16 radiating costae; on erect stems of algae, hydroids, seagrasses, bryozoans, wood, shell; Alaska, common at Dillon Beach to Tanner Bank off California-Mexican border; shallow waters to 100 m. Original C. costazi has imperforate frontal wall with small areolae, 16-20 costae on ovicell entooecial face. Celleporina souleae Morris, 1979 (=Costazia robertsoniae of Osburn 1952, in part; see Soule et al. 1995). Plate 451C, 451D. Encrusting, multilaminar from frontal budding; frontal wall with many small pores, becoming reticulate; aperture with shallow, V-shaped sinus flanked by small paired avicularia raised on pedestals sometimes turned toward each other, rare interzooecial avicularia with tan to brown mandibles smaller than in C. robertsoniae; ovicell with large crescentic frontal entooecial area with five to eight costae, ectooecium a shallow imperforate hood, slit between layers; on erect stems; Bodega Head to southern California, Pleistocene of Oregon, California; shallow water to 60 m. Coleopora gigantea (Canu and Bassler, 1923). See Osburn 1952. Encrusting, distinctive yellowish nodules, among largest cheilostome zooids, up to 2 mm in length; perforate frontal wall, high, flaring peristome; ovicell with an arcuate thin entooecial area, roughened, imperforate ectooecial outer layer; Recent, Monterey Bay, Channel Islands, Baja California; Pleistocene of Santa Monica; not common; shallow water to > 2 0 0 m. Costazia costazi (Audouin 1826): Osburn 1952. See Celleporina souleae Morris 1979. Costazia robertsonae Canu and Bassler 1923. Plate 45IB. See Osburn 1952. See Celleporina robertsonae. Cryptosula pallasiana (Moll, 1803). See Soule et al., 1995. Colonies encrusting, thin; apertures bell shaped, frontal wall with reticulate pores extending distal to aperture; sometimes a small, round, suboral avicularium; no spines or ovicells; yellow, pink, orange embryos visible, brooded in body cavity; Alaska to Mexico, Chile; Atlantic from Nova Scotia to Florida, Norway to Red Sea, if all are same species; intertidal to 60 m. 'Dakaria' dawsoni (Hincks, 1883). See Soule et al. 1995. Dakaria type belongs in the genus Watersipora. The species is different from Watersipora and Neodakaria. Its generic status needs to be re-assigned. Colonies encrusting; zooids with distinct lateral walls, transverse walls extending down to middle of aperture, aperture ovate or D-shaped; frontal walls with reticulate pores, no spines or avicularia; ovicell immersed with single rounded opening or with several irregular pores in ectooecium, entooecium may be visible with pores in openings; British Columbia to Channel Islands; shallow water to > 1 3 0 m. Dengordonia uniporosa Soule, et al. 1995; =Smittina bella; Osburn, 1952, part. Plate 450A. Encrusting, zooids large; frontal wall coarsely reticulate, lateral walls indistinct; aperture higher than wide, pyriform margins becoming raised, with median proximal denticle, pronounced lateral condyles, median suboral avicularium; ovicell imbedded, a flap with a single median pore extended from next distal frontal, meeting raised lateral oral margins; British Columbia to southern California; intertidal to 50 m. Eurystomella bilabiata (Hincks 1884). Encrusting; reddish, pink or red-brown; zooids large, hexagonal but rounded distally, aperture resembling profile of derby hat, curved proximally with notches at ends for passage of opercular muscles; BRYOZOA

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PLATE 448 Ascophorina, continued. A, Cryptosula pallasiana, with bell-shaped apertures, median suboral sulcus bearing avicularium in some; B, Hippoporina insculpta, with large frontal pores, ribbed ovicell lower left; C, Celleporella hyalina, with large porous ovicell on right, dwarf male proximal, transverse frontal striations; D, Trypostega claviculata, dwarf zooid left of ovicell, tiny avicularium to right; E, Neodakaria islándico, ovicells with central pores; F, Neodakaria umbonata; G, ISchizoporella cornuta; H, S. cornuta ovicell; I, Schizoporella inarmata.

PLATE 449 Ascophorina, continued. A, Schizoporella unicornis (lectotype, Britain), with very acute lateral oral avicularium, suboral umbo; B, Schizoporella pseudoerrata, rotated 90 degrees left, with sharp oral condyles, paired lateral suboral avicularia; C, Schizoporella pseudoerrata, ovicell typical of genus; D, Arthropoma cecilii, with proximal apertural notch, operculum fill snotch; E, Smittina ovirotula, median lyrula, suboral avicularium, ovicell with wagon-wheel pore pattern; F, Smittina veleroa, with median lyrula bearing avicularium, ovicell with m a n y pores; G, Smittoidea prolifica, ovicells with many pores, four spine bases on zooid without ovicell; H, Schizosmittina pedicellata, with suboral avicularium o n pedistal; I, Raymondcia osburni, with suboral avicularium, upper ovicells developed from distal, lateral flaps, bottom ovicel submerged.

450 Ascophorina, continued. A, Dengordonia uniporosa, ovicell distal flap with single pore; median lyrula bearing avicularium; B, Haywardipora major, slender spines around aperture, median suboral mucro, ovicell small, imperforate, central frontal wall without pores; C, Haywardipora orbicula, raised subterminal aperture with spines, median mucro, frontal wall with pores, ovicell small, imperforate; D, Haywardipora rugosa, with suboral umbo, mid-frontal rugose with marginal pores; E, Porella Columbiana, median lyrula bearing raised avicularium, frontal imperforate with few large areolae, ovicell small, imperforate; F, Porella porifera, median suboral avicularium on umbo set off by pores, frontal wall imperforate with few areolae, imperforate ovicell; G, Lagenicella neosocialis, raised tubular apertures flanked by avicularia, reticulate frontal wall, ovicells with perforate frontal area; H, Lagenicella punctulata, tall peristomes with fused spines flanked by two small avicularia, frontal wall reticulate, ovicell suspended on distal peristome rim, with perforate central area; I, Lagenicella spinulosa, tall peristomes with irregular points topped with spines, avicularia on tall posts, ovicells suspended from distal peristome rim, with central area perforate. PLATE

P L A T E 451 Ascophorina, continued. A, Celleporaria brunnea, with serrate avieularium in aperture, giant spatulate interzooecial avieularium o n right; B, Celleporina robertsoniae, with paired lateral oral avicularia on posts, shoe-shaped interzooecial avicularia, ovicells raised with radiate ribs in central area; C, Celleporina souleae, colony; D, Celleporina souleae, primary aperture lower right with deep sinus, ovicell with radiate ribs; E, Buffonellaria vitrea, with developing and immersed ovicells with imperforate central area set off by slits; many interzooecial avicularia; F, Phidolopora pacifica, fenestrate colony; G, Phidolopora pacifica, developing ovicell, sunken aperture with beaded distal rim, frontal wall imperforate with few areolae; H, Rhynchozoon rostratum, ovicell with central labellum, apertures hidden by avieularium o n umbo; 1, Rhynchozoon rostratum, primary aperture with beaded rim, asymmetrical suboral avieularium.

operculum dark brown; no avicularia or spines; ovicell a subtriangular shallow hood with large median pore; reddish color is a caratinoid, hopkinsiaxanthin, transferred intact to the predator nudibranch Okenia rosacea; Alaska to Tenacatita, Mexico; intertidal to > 2 0 0 m. Fenestrulina farnsworthi Soule, Soule and Chaney, 1995 (^Fenestrulina malusi of Osburn, 1952, in part). Plate 447F. Colony encrusting; zooids small, separated by gymnocystal walls, frontal wall with crescentic ascopore containing branched denticles; aperture curved distally with five to seven spines on young zooids; scattered pores on frontal wall and between ascopore and aperture with denticles that form grid over pores; no avicularia, no ovicell; ancestrula with 12 marginal spines; Pleistocene, southern California; Recent, Channel Islands, La Jolla; ? British Columbia; 15 m-20 m, but may be on intertidal drift algae or shell. Fenestrulina malusii (Audouin, 1826). Species probably restricted to eastern Atlantic, Mediterranean, not an eastern Pacific species; =F. malusi of Osburn, 1952, in part: see Soule et al. 1995. See Fenestrulina farnsworthi, Fenestruloides blaggae, F. eopacifica, F. miramara, F. morrisae, F. unibonata. Fenestruloides blaggae Soule, Soule and Chaney, 1995 (=Fenestrulina malusi of Osburn, 1952, in part). Plate 447G. Colonies encrusting, porcellanous; small zooids irregular in size, shape; young zooids with single row of marginal pores, frontal wall with oval ascopore with median uvulate process, both with serrate rims, in mature zooids two rows of pores between aperture and ascopore; pores increasing in number to fill frontal wall except proximal to umbo below ascopore; pores containing denticles; extra umbones on proximal frontal wall; ovicell imperforate except for marginal areolar pores; two spines flanking aperture of ovicell; Carmel Bay on settling plates, perhaps more widely distributed as part of Osburn's F. malusi; shallow water. Fenestruloides eopacifica Soule, Soule and Chaney, 1995 (=Fenestrulina malusi of Osburn 1952, in part). Colonies encrusting; zooids small; young zooids with single row of marginal pores; frontal pores filled with denticles, one to three rows between aperture and ascopore, older zooids with pores over entire frontal wall; ascopore raised, no other umbo, one to three spines distal to aperture; ovicell imperforate except for marginal areolar pores, a rim separating ovicell from next zooid; ancestrula resembles true Fenestrulina, with single row of marginal and suboral pores; on kelp off San Onofre, probably occurs in other shallow waters as part of "F. malusi" of Osburn. Fenestruloides miramara Soule, Soule and Chaney, 1995 (=Fenestrulina malusi of Osburn, 1952, in part). Plate 447H. Colonies encrusting; zooids small, aperture semicircular with two to three distal spines, two lateral spines; ancestrula and young zooids with one row of marginal pores, pores covering frontal except proximal to umbonate ascopore, ascopore with small uvulate process, denticulate rims, pores denticulate; ovicells large, imperforate except for large marginal pores, aperture flanked by two spines; on drift algae off Montecito (Santa Barbara), beach, probably elsewhere as part of "F. malusi"; shallow water. Fenestruloides morrisae Soule, Soule and Chaney, 1995 (=F. malusi of Osburn, 1952; 387, in part). Colonies encrusting; zooids larger than most species of genus, irregularly hexagonal, without gymnocystal rim; pores with denticles covering frontal wall, ascopore wide, opening between uvulate process and rim narrow, denticulate; ovicell flattened, imperforate except for one to two closed pores, but with marginal pores 898

BRYOZOA

bound by gymnocystal rim; the only Fenestrulina or Fenestruloides with a rare avicularium, acute, at proximal margin of zooid; on shell, stone; Channel Islands, California coast, Revillagigedo Islands off Baja California, Gulf of California, perhaps north elsewhere as "F. malusi"; on shell, stone; shallow water to 100 m. Fenestruloides umbonata (C. H. O'Donoghue and E. O'Donoghue, 1926) (=Fenestrulina malusi var. umbonata of Osburn 1952). Plate 4471. See Soule et al. 1995. Colonies encrusting; zooids hexagonal with little or no gymnocyst rim on margins; frontal wall with numerous denticulate pores, ascopore wide, almost closed by uvulate process, both rims denticulate, a small umbo proximal to ascopore but separate from it; ovicell large, rugose, with ribbed front margin like two spines folded across it, flanked by two spines, marginal pores small, rimmed by gymnocyst; hard substrates; British Columbia to Channel Islands; shallow water to > 1 0 0 m. Haywardipora major (Hincks, 1884) (=Mucronella major of Osburn 1952, in part). Plate 450B. See Soule et al. 1995. Colonies encrusting, zooecia large, up to 1 mm, zooids hexagonal, raised, aperture subterminal with high peristome, spine bases imbedded in peristome, a mucro on median proximal lip extending down as ridge to wide, anvil shaped lyrula in primary aperture; frontal wall with two to four irregular rows of tubular pores; no avicularia; ovicell small, imperforate suspended on distal peristome, becoming recumbent; on rock, shell; British Columbia to southern California, ? Galapagos Islands, identifications confused; shallow water. Haywardipora orbicula Soule, Soule and Chaney, 1995 (=Mucronella major of Osburn, 1952 in part). Plate 450C. Colonies encrusting; zooids large, hexagonal with inflated frontal wall, subterminal peristome tall with 10 long spines forming collar, large pores over entire frontal wall including distal to peristome; hemicylindrical ridge extending down to primary aperture, an inverted triangular median denticle at base of ridge; ovicells small, with imperforate ectooecium, distal to spines, appearing to dangle from peristome; perhaps from Vancouver Island to Baja California; shallow water to > 2 0 0 m. Haywardipora rugosa Soule, Soule and Chaney, 1995 (=Mucronella ventricosa of Osburn, 1952, in part). Plate 450D. Colonies encrusting; zooids ovoid to hexagonal, raised distally, frontal wall rugose, two to three rows of marginal pores with denticles projecting inward, tubules extending beneath secondary calcification up frontal wall; aperture with four large spines, sometimes two small spines flanking proximal rim, two blunt lateral condyles, a low truncate median denticle with suboral umbo; ovicells large, imperforate, recumbent on next zooid, aperture with four stout spines; on hard substrates, other bryozoans; ? Arctic; Puget Sound, Oregon, Channel Islands; shallow water to ? > 4 0 0 m. Haywardipora rylandi Soule, Soule and Chaney, 1995 (=Mucronella major. Osburn 1952, in part). Colonies encrusting, zooids large, irregularly hexagonal, frontal wall raised, with many small pores extending upward from areolae; peristome raised, with eight spines, a sunken median, anvil-shaped denticle; a pointed external suboral mucro or umbo; ovicells small, dimpled, imperforate or with a few scattered marginal pores; Point Barrow, Alaska, possibly to Baja California; distributions uncertain due to confused identifications; shallow water in north to deeper water in south. Hippoporina insculpta (Hincks, 1882) (=Hippodiplosia insculpta of Osburn, 1952, in part). Plate 448B. See Soule et al. 1995. Colonies encrusting; young colonies flat, sometimes raised in fan shapes or yellowish to orange frills; zooids

flattened, reticulate with coarse pores; aperture with low, curved distal rim ending at small upturned condyles, proximal rim a widely curved sinus, large median suboral pore sometimes bearing a tiny avicularium; ovicells with radiate ribs, set off by areolar pores; on rock, shell, algae, bryozoans, hydroids; Alaska to central California, common in shallow water, to > 2 0 0 m. Hippoporina mexicana Soule, Soule and Chaney, 1995 (=Hippodiplosia insculpta of Osburn 1952, in part). Colony encrusting; zooid frontal walls arched, reticulate with large pores; aperture rounded, higher than wide, peristome raised, encloses a suboral pore, sometimes bearing a tiny thin blunt, proximally directed avicularium, down-curved condyles hidden by peristome; ovicells nodular, raised; forming large aperture with peristome; on shell, stone; Channel Islands to Cocos Island off Costa Rica, but if recognized range may overlap that of H. insculpta in central California; shallow water to deep. Hippomonavella longirostrata (Hincks 1882): Osburn. See Pleurocodonellina longirostrata. Hippothoa spp. See Celleporella hyalina. Lagenicella neosocialis Dick and Ross, 1988. See Soule et al., 1995. Not Lagenipora socialis (Hincks, 1877); not Lagenipora socialis of Osburn 1952, nor of C. H. and E. O'Donoghue 1923 or J. D. Soule 1961. Plate 450G. Colonies small, encrusting; zooids flask shaped, frontal wall perforate, reticulate, primary aperture round with spine scars, peristome becoming tall, thick; proximal lip thick, curved, flanked by pair of tiny, acute avicularia raised above peristome; ovicell with distal imperforate ectooecial hood with arcuate, perforate frontal entooecial plate with pores above tubular peristome, aperture flanked by pedicellate avicularia; on algae, rock, shell, bryozoans; intertidal to > 1 2 0 m. Lagenicella ?punctulata (Gabb and Horn, 1862) (=Lagenipora punctulata). Plate 450H. See Soule et al. 1995. Colonies erect, branching, cylindrical; zooids flask shaped, frontal wall coarsely punctate, reticulate; primary aperture circular, becoming obscured by tall imperforate peristome resembling fused spines; with paired low spinules flanking proximal rim, pair of tiny, raised, acute avicularia proximal to spinules or replacing them; ovicell appears hung from side of peristome, ectooecial hood distally imperforate, arcuate frontal entooecium perforate, becoming occluded; no type known for Pleistocene fossil from Santa Barbara, so identity is questionable; Recent, ? British Columbia, California, Baja California, Gulf of California,? Galapagos Islands; shallow waters to 200 m. Lagenicella spinulosa (Hincks 1884) (=Lagenipora spinulosa). Plate 4501. See Soule et al. 1995. Colonies small, encrusting; zooids small, flask shaped, frontal walls reticulate, covered by thick cuticle, peristomes raised, resembling partly fused spines with irregular tips; paired small acute avicularia raised above spines; primary aperture round with three to four spine scars; ovicells with imperforate ectooecial hood distally, arcuate perforate entooecial plate frontally, appearing suspended from side of peristome, paired pedicellate avicularia flank aperture, with large median suboral umbo or shelf; British Columbia, southern California Pleistocene, Recent; Gulf of California; ? Galapagos Islands; intertidal to > 1 2 0 m. Lagenipora spp. See Lagenicella. Lagenipora spp. have imperforate frontal walls and ovicells; apparently not present in eastern Pacific. Lagenicella spp. have perforate frontal walls and ovicells; tall peristomes imperforate, resembling fused spines. Microporelloides (Cribriporella) californica (Busk, 1856). See Soule et al., 2003; =Osburn 1952, in part; see also M. infundibulipora Soule, Soule and Chaney, 1995. Plate 447A.

Colonies encrusting; zooids ovoid, separated by grooves, frontal wall inflated, with numerous reticulate pores containing wheellike sieve plates; aperture curved distally with four spines or spine scars, straight proximally with small condyles part of a dental ledge, a large ascopore with slim uvulate process, both denticulate, separated from proximal lip and from secondary frontal wall calcification; flanked by pair of raised acute avicularia directed distolaterally; ovicells globular, immersed, perforate to reticulate; ? British Columbia; central, southern California; intertidal to 150 m. Microporelloides (Microporelloides) catalinensis (Soule, Soule and Chaney, 1995) (=M. ciliata of Osburn, 1952, in part. See Soule et al. 2003). Plate 447B. Colonies encrusting, yellowish; zooids ovate to quadrate, frontal wall granular with large pores sometimes merging into slits, no pore spicules or plates, circular ascopore proximal to aperture with small uvulate process, both finely denticulate, small umbo proximal to ascopore; aperture rimmed, wider than high, curved distally, straight proximally with small lateral condyles; sometimes one acute avicularium on lateral frontal wall directed outward; ovicell with pores radiating from proximal center of hood, distal area immersed in next distal zooid; on shell, algae; Channel Islands, probably recorded elsewhere in California as "M. californica"-, shallow water to ? 27 m. Microporella ciliata (Pallas 1766). See Osburn 1952; Atlantic species with imperforate ovicells; see Hayward and Ryland 1998, not found in eastern Pacific waters; see Microporelloides catalinensis, M. planata. Microporelloides (Cribriporella) cribrosa (Osburn, 1952) (=Microporella californica Robertson 1908, in part). Plate 447C. See Soule et al. 2003. Encrusting; zooids small, frontal wall raised with many small pores having stellate or cribrate plates at bottom; aperture arched distally, with five to six spines, almost straight proximally, condyles present or worn away; ascopore uvulate process denticles grow to meet marginal denticles forming sieve plate; an umbo proximal to ascopore; avicularia single or paired flanking ascopore, directed distolaterally, acute with setose mandible; ovicell a perforate, ribbed hood with rib on margin, a median umbo on top, aperture flanked by two spines; on rock, shell, algae, pilings; Mussel Point, central California, to Gulf of California; shallow water (pilings) to > 1 2 0 m. Microporelloides (Cribriporella) infundibulipora (Soule, Soule and Chaney, 1995) (=Microporella californica of Osburn 1952, in part). Plate 447D. See Soule et al. 2003. Colonies encrusting; zooids ovoid with deep separating grooves, frontal wall reticulate having large infundibuliform pores with sunken pore plates like spoked wheel, aperture curved distally with five spine scars, straight proximally with tiny condyles, small ascopore proximal to lip with small uvulate process, small denticles on pore rim, umbo sometimes quite large, reticulate; frontal wall proximal to umbo very reticulate; ascopore flanked by paired, bluntly acute avicularia directed distolaterally; encrusting both sides of shells; Pleistocene, Recent of southern California, probably central California; reports of "M. californica" range from British Columbia to Gulf of California, Baja California, Galapagos Islands; M. infundibulipora, described from Channel Island; shallow water to > 1 5 0 m. Microporelloides (Cribriporella) planata (Soule, Soule and Chaney, 1995). See Soule et al. 2003. Colony encrusting; flat, thin, fragile, yellowish; zooids varied in size, aperture curved distally, four fragile spines, almost straight proximally; frontal wall with small pores containing reticulate plates, areolae larger; suboral ascopore small, denticulate, with rim, median BRYOZOA

899

uvulate process, denticulate; avicularia paired, proximolateral to ascopore, directed distolaterally, with acute, setose mandibles; ovicells perforate, ribbed except on central imperforate area, hood margin curved away from frontal wall at lateral wall; on shell, stone; found in collections labeled M. ciliata by Osburn, reported as cosmopolitan; from off Channel Islands; specimens identified in collections from nearshore to > 1 8 0 m. Microporelloides (Cribriporella) setiformis (C. H. and E. O'Donoghuel923:). See Soule et al. 2003. Colonies encrusting; zooids with frontal wall inflated, numerous small frontal pores with deep set cribrate plates, aperture horseshoe-shaped distally, straight proximally, ascopore tiny, with round flat collar, tiny uvulate process, no denticles on either; avicularia paired, small, flanking ascopore, triangular bases, complete hinge bar, short setose mandibles directed distally; ovicell prominent, many small pores, becoming ribbed, pores closed, immersed; shallow water to more than 100 m. Microporelloides (Microporelloides) umboniformis (Soule, Soule and Chaney, 1995) (=MicroporeIla umbonata of Osburn 1952, in part). Colony encrusting; zooids oval, frontal wall inflated with many tiny pores; aperture rounded with five to six distal spine scars, less curved proximal margin, a small ascopore with slender uvulate process, both denticulate; umbo proximal; one or two setose avicularia proximolateral to umbo directed laterally, or no avicularia; ovicell small, rounded with umbo, small pores; on worm tubes; southern California, ? northern California, ? Baja California; shallow water to > 1 0 0 m. M. umbonata (Hincks) has large pores, three umbones; a Puget Sound species, it may occur in northern, central California. Microporelloides (Microporelloides) vibraculifera (Hincks, 1883) (-Microporella vibraculifera of Osburn 1952). Plate 447E. See Soule et al. 1995. Colony encrusting, zooids irregularly hexagonal, with numerous frontal pores; aperture semicircular with five to seven hollow spines; median suboral ascopore small with small median uvulate process, both finely denticulate; avicularium a bulbous chamber proximolateral to ascopore with very long, setose mandible sweeping over adjacent zooids; ovicell raised, with many small pores; British Columbia to Baja California; tolerant of sediment; 5 m to > 1 2 5 m. Mucronella major (Hincks, 1884). See Haywardipora major. Mucronella ventricosa (Hassall, 1842). Osburn, 1952. See Haywardipora rugosa; not M. ventricosa: Hincks 1880; ? C. H. and E. O'Donoghue; ? Kluge 1975. Neodakaria islandica Soule, Soule and Chaney, 1995 (=Dakaria ordinata of Osburn 1952, in part). Plate 448E. Encrusting; zooids quadrate, frontal wall reticulate with large pores, aperture semicircular distally, pushing into next distal zooid, large condyles, proximal lip a shallow curve or straight, not V-shaped; no spines, no avicularia; ovicells with arched subtriangular entooecium with large pores, surrounded by granular ectooecial hood; on rock, shell, algae; Channel Islands, ? northern California to Baja California; shallow water to 50 m. Neodakaria ordinata (C. H. and E. O'Donoghue, 1923) Soule et al. 1995 (=Dakaria ordinata of Osburn, 1952, in part). Encrusting; zooids quadrate to hexagonal, frontal wall reticulate with large pores becoming closed by calcification, aperture arched distally with large condyles, proximal lip a wide, Vshaped sinus; ovicell with frontal triangular porous area, rimmed by rugose ectooecium without pores; on rock, shell, algae; British Columbia, ? to Dillon Beach; intertidal to 70 m. Neodakaria umbonata Soule, Soule and Chaney, 1995 (=Dakaria ordinata of Osburn 1952, in part). Plate 448F. Encrusting pebbles on sandy bottoms; zooids rectangular with 900

BRYOZOA

large frontal wall pores, large marginal areolae, aperture curved distally, a wide shallow curve proximally with strong condyles, a large frontal suboral umbo; ovicells large with large frontal area, large pores, little encroaching rim distally; recognized from Monterey Bay to San Pedro Bay, and Channel Islands; intertidal on pebbles to more than 50 m. Parasmittina collifera (Robertson 1908). See Osburn 1952. Colonies encrusting, becoming nodular, heaped, multilaminar; frontal wall rugose, imperforate with pillars (colli), marginal areolae; aperture rounded with two distal spines on young, with secondary peristomal collar, truncate median denticle, lateral condyles; avicularia small to large triangular, erect, directed distally, very large in older colonies, small to large ovate frontal avicularia directed variously; ovicells with few large irregular pores, ectooecium overgrowing pores with pillars in older zooids; British Columbia to Coranados Islands of Mexico; common intertidally off Oregon, central California, deeper water off Mexico. Parasmittina trispinosa (Johnston): Osburn, 1952. AtlanticBoreal species, P. trispinosa does not occur in eastern Pacific (see P. regularis, D. F. Soule and J. D. Soule, 2002, from off Dillon Beach, P. aviculifera, D. F. Soule and J. D. Soule, 2002, from off Monterey). P. califomica (Robertson, 1908) (see Soule et al. 2002) is a southern California-Baja California species with large serrate avicularia may range north only to Point Dume; on gravel, sponge, shell; shallow water to 100 m. Parasmittina tubulata Osburn, 1952. Encrusting; zooids large, raised, frontal wall finely granular, with large, irregular marginal areolae; aperture with anvil-shaped median denticle, lateral condyles in primary aperture, secondary aperture tubular with sinus, hiding denticle; a large or small spatulate avicularium directed proximolaterally, small acute frontal avicularia directed proximally, small acute avicularia near areolae directed variously; ovicells large, entooecium with many pores, peristome a complete tube in front of ovicell, ovicell becoming immersed with encroaching ectooecium leaving only a small crescent of pores; northern California to Scammons Lagoon, Baja California; shallow water to 150 m. Phidolopora pacifica (Robertson, 1908). Plates 451F, 451G. See Soule et al. 1995. Colony erect, fenestrate, forming large meshwork from rounded base attached to hard substrate by kenozooids; fenestrae ovoid to diamond shaped; zooids all opening on ventral surface, dorsal surface showing outlines of kenozooids with acute avicularium at base of fenestrae; primary aperture rounded with beaded rim distally, small sinus proximally, sometimes flanked by one to two elongate spines, aperture becoming sunken with notch on proximal border; occasional large raised avicularium with hooked rostrum directed proximally, recumbent on frontal wall; ovicell ectooecium imperforate with concentric lines, a frontal uvulate extension sometime hanging down over aperture; British Columbia to Galapagos Islands; shallow water to > 2 0 0 m. Pleurocodonellina longirostrata (Hincks, 1882) (=Hippomonavella longirostrata of Osburn, 1952, in part). See Soule 1961, Soule et al. 1995. Encrusting; zooids elongate with one row of areolar pores, a few other scattered frontal pores; aperture curved distally ending at large down-curved condyles sometimes with two small distal spines, proximal lip a shallow curve connected by sulcus to avicularium either median or skewed laterally, avicularium with V-shaped hinge bar; ovicells with medium sized pores, surrounded by secondary frontal wall of next distal zooid; shallow water to ? 200 m; may be confused with P. califomica Soule, Soule and Chaney, 1995, which has three to five tiny distal spines, frontal wall with three rows of

marginal areolae, leaving only central area imperforate, long or short acute avicularium median or skewed, connected to proximal aperture; ovicell with large pores raised above next zooid; known only from waters 90 m-150 m off southern California. Porella columbiana C. H. and E. O'Donoghue, 1923. Plate 450E. See Soule et al. 1995. Colonies encrusting, thin, shiny, yellowish white; zooids with frontal wall raised, ventricose, imperforate, a few large areolar pores becoming sunken, buttressed; primary aperture rounded distally with four spines, strong lateral condyles, wide median lyrula, becoming hidden by raised lateral, distal lappets, forming peristome, a median, raised, bluntly acute suboral avicularium with two to three small pores at base of avicularium chamber; ovicell imperforate, separated from next distal zooid, with a brim above ovicell opening; British Columbia to southern California, ? Galapagos Islands; intertidal on floating kelp to 110 m. Porella major Hincks, 1884 ('!=Porella acutirostris of Osburn, 1952, Kluge, 1975; Dick and Ross 1988). See Soule et al. 1995. Colony encrusting, light brown; zooids regular, smooth, lateral walls raised with single row of six to 10 areolae; primary aperture rounded distally, with shallow rim, no spines, tiny lateral condyles, a short, wide lyrula; a median suboral avicularium proximal to lyrula, within peristome, originating from one to two lateral areolae, forming raised chamber, with few small pores at base; avicularium bluntly acute, directed distally; ovicell imperforate; on shell; Alaska to southern California; shallow water to > 1 0 0 m. Porella porifera (Hincks, 1884) (=P. porifera of Osburn, 1952, in part; see also Porella taylori). See Soule et al. 1995. Plate 450F. Encrusting; zooids ovate, quadrate, frontal wall smooth, imperforate, with three to four lateral marginal areolae, four frontal pores at base of median avicularium; aperture rounded distally with four thin spines or spine bases, lateral condyles small, proximal rim with small truncate lyrula, aperture becoming sunken, surrounded by peristome; large median avicularium originating from two lateral frontal pores; large and small ovoid interzooecial avicularia set off by areolae on mounds between zooids, sometimes absent; ovicells small, imperforate, set off by brim, becoming immersed; on rock, shell; British Columbia to southern California, ? west coast of Baja Calfornia; intertidal to 250 m. Porella taylori Soule, Soule and Chaney, 1995. See also P. porifera. Encrusting; zooids subhexagonal, frontal wall imperforate, granular; primary aperture rounded to quadrate, becoming sunken within peristome, tiny median lyrula, no visible lateral condyles; median suboral avicularium mostly outside peristome, ovoid, with acute tip directed proximally, chamber raised, with five to six pores around base; tiny avicularia flanking distal corners of aperture directed distolaterally, originating at lateral walls (interzooecial); ovicells imperforate, raised; on shell; only known from Santa Barbara Channel, 69 m-74 m; perhaps unrecognized along California coast. Raymondcia osbumi Soule, Soule and Chaney, 1995 (=Smittina landsborovi [sic] of Osburn 1952 in part). Plate 4491. Encrusting; zooids ovoid to rectangular, primary aperture wider than high, becoming pyriform, distal rim formed by division in transverse wall, lateral, proximal rims bordered by frontal wall; truncate median lyrula, large paired condyles depressed; frontal wall beaded with large pores showing large coarse granules inside, median suboral oval avicularium directed proximally, mostly outside primary rim; ovicells composed of merging segments from adjacent zooid frontal wall, with suture lines, sometimes a small pore, becoming immersed to appear as solid frontal wall

surrounded by areolae; on shell, rock; S. landsborovii Johnston, 1847, is an eastern Atlantic boreal species mistakenly listed by Osburn from Alaska to Galapagos Islands; shallow water to > 100 m. R. osbumi, described from the Channel Islands, may range from Alaska to California, ? Galapagos Islands. Raymondcia macginitei Soule, Soule and Chaney, 1995 (=Smittina bella of Osburn 1952, in part). Encrusting; aperture pyriform, wider distally, composed of flaps from adjacent frontal, distal walls; large median avicularium originating proximal to lip, moving into aperture to rest on lyrula; frontal wall granular with large pores having irregular spicules inside; ovicell level with frontal wall, formed by frontal wall flaps from sides, leaving slit, then merging at sutures with distal flap; on shell, rock; cool water-arctic species, may occur in Washington, Oregon, California; shallow water. Rhynchozoon rostratum (Busk, 1856). See Soule, Soule and Chaney, 1995: includes R. tumulosum (Hincks, 1882). Plate 451H, 4511. Encrusting; zooids irregular, heaped except at growing margins, frontal wall smooth, inflated, with 12-14 marginal areolae, sometimes with ridges between; primary aperture round, beaded, with strong condyles, young with two distal spines, proximal border a sinus, becoming obscured by secondary peristome, a transverse, acute avicularium set to side of aperture forming a secondary sinus, becoming bulbous giving colony honeycomb appearance, other large acute frontal avicularia randomly placed; ovicell imperforate, becoming immersed, with distinct circular frontal entooecium area mostly surrounded by ectooecium hood; on rock, shell, other hard substrates; Alaska to South America if all are the same species; shallow water to 200 m. Schizomavella acuta Soule, Soule and Chaney, 1995. Not a variety of S. auriculata as indicated by Osburn 1952. Encrusting; zooids quadrate with distinct lateral, transverse wall, frontal wall rugose with small pores, sometimes nodular; aperture curved distally, wider than high, shallow sinus proximally, large, cogged condyles; a median, elongate, acute, suboral avicularium directed proximally outside apertural rim, sometimes skewed; ovicells reticulate with pores over entire surface, becoming immersed in next distal frontal wall; on rock, shell; Channel Islands south to Baja, Gulf of California; common; 33 m to more 100 m. Schizomavella auriculata (Hassall, 1842). See Soule et al. 1995; not Robertson 1908; not Osburn, 1952. See S. robertsonae. Original British S. auriculata has pyriform aperture with narrow sinus, suboral avicularium within aperture, small, rounded or elongate directed proximally; ovicell immersed, showing only a crescent of large, irregular entooecial pores, ectooecium immersed in rugose porous frontal of next distal zooid. Schizomavella robertsonae Soule, Soule and Chaney, 1995 (=S. auriculata of Osburn, 1952, in part). Encrusting; zooids irregular, with rugose, porous frontal walls, raised, riblike in center supporting round, proximally directed avicularium; aperture wider than high, with wide, sometimes four spine scars; proximal shallow sinus, blunt condyles; ovicell nodular, small pores becoming hidden, set off by areolae from distal zooid; on shell; Channel Islands to Coronados Islands, 182 m, but "S. auriculata" of Osburn recorded from Oregon to Baja California, Gulf of California, shallow water to deep. Schizomavella triavicularia Soule, Soule and Chaney, 1995 (=S. auriculata of Osburn, 1950, in part). Encrusting; zooids quadrate, lateral walls distinct, frontal wall with numerous pores; aperture round, sometimes with three small spine scars, U-shaped sinus proximally within peristome, incised at lower corners; three small rounded avicularia outside peristome, one BRYOZOA

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suboral directed proximally, two flanking aperture directed proximolaterally; ovicell with crescentic perforate ectooecium, with imperforate ectooecium surrounding distally and laterally, bounded by areolae; on rock, shell; Channel Islands to Galapagos Islands; > 6 0 m, but may range, as S. auriculata: Osburn, from Oregon to Baja California, Gulf of California, shallow water to deep. Schizosmittina pedicellata Soule, Soule and Chaney, 1995 (=Schizomavella auriculata: of Osburn, 1952, in part). Plate 449H. Encrusting; zooids irregular, rugose with large frontal wall pores except on pedestal bearing median suboral avicularium originating outside aperture, directed proximally, aperture rounded with five spine scars distally, a deep, U-shaped sinus proximally, condyles shelf-like; ovicell entooecium with large irregular pores, imperforate ectooecium distally, raised above distal frontal wall, set off by areolae; on rock, shell; recently described from the Channel Islands, but may range from Oregon to Gulf of California; shallow water to deep; new species from Channel Islands; >100 m. ? Schizoporella cornuta (Gabb and Horn, 1862). See Soule et al. 1955: ?=Buffonellaria. Plate 448G, 448H. Encrusting; zooids raised with frontal pores becoming sunken, occluded; primary aperture rounded distally, with strong paired condyles, wide Vor U-shaped sinus, becoming immersed; avicularia absent or one to two acute flanking aperture directed distolaterally, becoming erect (cornuate); ovicell not typically porous schizoporellid, globose, imperforate with central granular entooecium surrounded by thick ectooecial rim and bar across frontal area; on rock, shell, other hard substrates; reported from Pleistocene of Santa Barbara; shallow waters to 200 m. ISchizoporella inarmata (Hincks, 1884). Plate 4481. See Soule et al. 1995. Encrusting; zooids irregular, flattened with large immersed frontal pores, distinct lateral walls; aperture higher than wide, with strong, burred, down-curved condyles, a narrower Vshaped sinus; avicularia absent; ovicell aperture without sinus, ovicell immersed, almost indistinguishable from adjacent porous frontal wall except for sutural lines above transverse walls; on rock, shell; British Columbia to Costa Rica; 3 m-4 m to > 1 2 0 m. Schizoporella pseudoerrata Soule, Soule and Chaney, 1995. Plate 449B, 449C. Encrusting; zooids regularly oriented in first layer, becoming heaped with frontal budding; frontal wall irregularly porous, margins indistinct; aperture wider than high, with thin, sharp condyles, wide, sinus within proximal ledge; avicularia one, two-paired, or absent proximolateral to aperture, raised, acute, directed distolaterally, mandibles not setose; ovicells perforate, sometimes with ribs, becoming immersed; on shell, rock, ships' hulls, pilings; Elkhorn Slough; other distribution uncertain, confused with other species; intertidal, shallow water, sometimes on shells in deeper water. Schizoporella japonica Ortmann, 1890 (=Schizoporella unicornis of northeastern Pacific authors; see Dick et al., 2005). See also Schizoporella pseudoerrata. Plate 449A. Encrusting, spreading in circular patches, often multilaminar; zooids regular, with distinct grooves at lateral walls, frontal wall with many small and large pores, aperture wider than high or rounded with very shallow proximal sinus, condyles small, rounded; avicularia absent, single or paired, acute but not setose, proximolateral to aperture directed distolaterally; ovicells raised, with pores and strongly ribbed; Japanese species introduced with oyster culture (Powell 1970, J. Fish. Res. Bd. Canada 27: 1847-1853; Ross and McCain 1976 Northwest. Sci. 50: 160-171), Plate 449A is of 5. unicornis, similar in general morphology. 902

BRYOZOA

Smittina landsborovii (Johnston 1847). See Soule et al. 1995 See also Smittina veleroa, Raymondcia osburni. Smittina bella (Busk 1860). See Osburn 1952. See Raymondcia macginitei, Dengordonia uniporosa. Smittina ovirotula Soule, Soule and Chaney, 1995 (=?Smittina spathulifera of Osburn 1952). Plate 449E. Encrusting; reddish brown; zooids elongate, reticulate with large pores except in central suboral area around avicularium; aperture rounded with strong median truncate denticle, lateral condyles hooked downward, a suboral avicularium formed outside peristome directed proximally; ovicell with central pores like wagon wheel in entooecium, surrounded by imperforate ectooecium; S. spathulifera (Hincks), originally described from British Columbia has a larger shoe-shaped avicularium lying partly within peristome on lyrula; on hard substrates; S. ovirotula, Channel Islands to Baja and Gulf of California, depths to 150 m. Smittina veleroa Soule, Soule and Chaney, 1995 (=Smittina landsborovii of Robertson 1908, Osburn 1952; Soule and Duff 1957, Soule, 1961). Plate 449F. Encrusting; zooids with numerous frontal pores, becoming heavily calcified, aperture rounded, with large median denticle bearing small median, bluntly acute avicularium directed proximally, tiny condyles, peristome becoming raised, sometimes enclosing avicularium; avicularia in S. landsborovi, described from Ireland, are small, round, outside tall thin peristome, or large, transverse, shoe-shaped suboral avicularium, sometimes both kinds, larger one sometimes further down frontal wall; ovicell shallow, porous, becoming indistinct; on shell, rock; Oregon to ? Galapagos Islands but confused with other species; low tide to deeper waters. Smittoidea prolifica Osburn, 1952. Plate 449G. Colonies encrusting, small white patches; zooids irregularly hexagonal, small, distinct margins, frontal wall imperforate, smooth or granular, single row of marginal areolar pores; aperture rounded distally with large condyles, truncate median denticle, peristomal collar low distally with two to four spine scars; small, rounded, median suboral avicularium, no other avicularia; large ovicells on most zooids, with many pores turning colony pink or yellow when ova are present; on stone, shell, stems; San Francisco Bay, Channel Islands to Baja California; intertidal to > 1 0 0 m. Stephanosella biaperta (Michelin, 1845): Osburn 1952. Not that species, described from Miocene of France. See Buffonellaria vitrea. Stomachetosella condylata Soule, Soule and Chaney, 1995. Not 5. sinuosa (Busk, 1860, an Arctic-boreal species; ?=S. sinuosa (Hincks, 1884); =S. sinuosa of Osburn, 1952, in part; ?=S. sienna Dick and Ross, 1988). Encrusting, rose-colored to purple patches; frontal wall raised, rugose, with marginal areolae plus a few frontal pores; aperture almost circular, with transverse walls meeting proximal to distal curve, proximal lip almost straight with U-shaped sinus, wide shelf-like condyles not present in 5. sinuosa; no spines, no avicularia; ovicells immersed, set off only by areolae, a single central pore, becoming occluded; on shell, rock; Alaska to Channel Islands; shallow water to > 1 2 5 m. Trypostega claviculata (Hincks, 1884). Plate 448D. Encrusting; three kinds of zooids: quadrate to hexagonal autozooids, larger female zooids with very large ovicells and small zooids beside ovicells, possibly males; frontal walls with large pores over all surface including distal to aperture; aperture rounded with rocker-shaped proximal rim ending at sharp condyles directed proximally; small interzooecial avicularia (zooeciules of some

PLATE 452 Ascophorina, continued. A, Watersipora arcuata (A, B, from Soule and Soule 1975).

subtorquata,

authors) with single row of frontal pores, spatulate mandible directed distally; ovicells large, raised, with many pores; on shell, rock; south to Morro Bay; shallow water to 180 m. 'Watersipora subtorquata (d'Orbigny, 1852). Plate 452A. An often abundant orange-red to black bryozoan, occurring both as crusts and (in quiet water) forming very large foliaceous masses (60 cm and more in length, and 30 cm and more in height) on floats and pilings in estuaries and harbors along the California and Oregon coasts. Handling fresh colonies of this species will stain the hands orange. Opercula black or dark brown. Watersipora arcuata Banta, 1969 (plate 452B) occurs in southern California, and the two species may co-occur. They are distinguished by the shape of the lower border of the aperture: in W. subtorquata, the lower border of the aperture is curved outward, whereas in W. arcuata the lower border of the aperture is curved inward. The species-level taxonomy of Watersipora remains to be worked out, and a number of additional names are in use, including W. cucullata and W. subovoidea. Note also the analysis of invasion patterns of W. subtorquata and W. arcuata by Mackie et al. (2006, Mar. Biol. 149; 285-295).

References For more extensive references see Soule et al. 1995. Bishop, J. D. D., and B. C. Househam. 1987. Puellina (Bryozoa; Cheilostomata; Cribrilinidae) from British and adjacent waters. Bulletin of the British Museum (Natural History), Zoology 53: 1 - 6 3 . Boardman R. S., A. H. Cheetham, D. B. Blake, J. Utgaard, O. L. Karklins, P. L. Cook, P. A. Sandberg, G. Lutaud, and T. S. Wood. 1983. Treatise on Invertebrate Zoology. Part G. Revised, Vol. 1. Geological Society of America, Boulder, Colorado, and University of Kansas, Lawrence, Kansas. 625 pp. Cohen, A. N., and J. T. Carlton. 1995. Biological Study. Nonindigenous Aquatic Species in a United States Estuary: A Case Study of the Biological Invasions of the San Francisco Bay and Delta. A Report for the United States Fish and Wildlife Service, Washington, D.C., and The National Sea Grant College Program, Connecticut Sea Grant, NTIS Report Number P B 9 6 - 1 6 6 5 2 5 , 2 4 6 pp. Cook, P. L. 1964. Notes on the Flustrellidae (Polyzoa, Ctenostomata). Annals and Magazine of Natural History (13) 7: 2 7 8 - 3 0 0 . Dick, M. H., J. R. Freeland, L. P. Williams, and M. Coggeshall-Burr. 2000. Use of 16S mitochondrial ribosomal DNA sequences to investigate sister-group relationships among gymnolaemate bryozoans, pp. 1 9 7 - 2 1 0 . In Proceedings of the Eleventh International Bryozoology Association Conference. A. Herrera Cubilla and J. B. C. Jackson, eds. Smithsonian Tropical Research Institute, 448 pp. * = Not in key.

from St. Thomas, West Indies; B,

Watersipora

Dick, M. H., and J. R. P. Ross. 1988. Intertidal Bryozoa (Cheilostomata) of the Kodiak vicinity, Alaska. Occasional Paper 23, 133 pp. Western Washington University, Center for Pacific Northwest Studies, Bellingham, Washington. Dick, M. H., A. V. Grischenko, S. F. Mawatari. 2005. Intertidal Bryozoa (Cheilostomata) of Ketchikan, Alaska. Journal of Natural History 39: 3687-3784. Gordon, D. P. 1993. Bryozoan frontal shields: Studies on umbonulomorphs and impacts on classification. Zoologica Scripta 22: 2 0 3 - 2 2 1 . Gordon, D. P., and P. D. Taylor. 1997. The Cretaceous-Miocene genus Lichenopora (Bryozoa), with a description of a new species from New Zealand. Bulletin of the Natural History Museum, London 53: 7 1 - 7 8 . Gordon, D. P., and E. Voigt. 1995. The kenozooidal origin of the ascophorine hypostegal coelom and associated frontal shield, pp. 8 9 - 1 0 7 . In Proceedings of the Tenth International Bryozoology Association Conference, Bryozoans in Time and Space. D. P. Gordon, A. M. Smith, and J. A. Grant-Mackie, eds. NIWA, Wellington, New Zealand, 442 pp. Hayward, P. J. 1985. Ctenostome Bryozoans. Synopses of the British Fauna (new series), No. 33, 169 pp. The Linnean Society of London. Hayward, P. J., and J. S. Ryland. 1985. Cyclostome Bryozoans. Synopses of the British Fauna (new series), No. 34, 147 pp. The Linnean Society of London. Hayward, P. J., and J. S. Ryland. 1998. Cheilostomatous Bryozoa. Part I. Aetoidea-Cribrilinoidea. No. 10 (2nd ed.), 3 6 6 pp. The Linnean Society of London. Hayward, P. J., and J. S. Ryland. 2002. Cheilostomatous Bryozoa. Part 2. Hippothoidea-Celleporoidea. No. 14 (Second Edition), 4 1 6 pp., The Linnean Society of London. Hughes, R. S., A. Gomez, P.J. Wright, D. Lunt, G. R. Carvahlo,J. M. Cancino, and H. I. Moyano G. 2 0 0 4 . Phylogeography and sibling speciation in Celleporella hyalina. Boletin de la Sociedad de Biología de Concepción 74: 70. Hyman, L. H. 1951.The Invertebrates: Acanthocephala, Aschelminthes and Entoprocta.Vol. 3, 5 7 2 pp. New York: McGraw-Hill Book Co. Hyman, L. H. 1959. The Invertebrates: Smaller Coelomate Groups. Vol. 5. 784 pp. New York: McGraw-Hill Book Co. Jackson, J. B. C. and A. H. Cheetham. 1990. Evolutionary significance of morphospecies: A test with cheilostome Bryozoa. Science 248: 521-636. Kluge, G. A. 1962. Bryozoa of the Northern Seas No. 76: 1 - 7 1 1 . Moscow: Zoological Institute, Academy of Sciences (in Russian; 1975, English translation). McKinney, F. K., and J. B. C. Jackson. 1989. Bryozoan Evolution, 2 3 8 pp. Boston: Unwin Hyman. Morris, P. A. 1976. Middle Pliocene temperature implications based on the Bryozoa Hippothoa (Cheilostomata-Ascophora). Journal of Paleontology 50: 1 1 4 3 - 1 1 4 9 . Morris, P. A. 1979. Pacific coast Celleporina Gray (1848): fossil and Recent, pp. 4 6 7 - 4 9 0 . In Advances in Bryozoology. G. P. Larwood and M. B. Abbott, eds. The Systematics Association Spec. Vol. 13: 639 pp. London: Academic Press. Morris, P. A. 1980. The bryozoan family Hippothoidae (CheilostomataAscophora) with emphasis on the genus Hippothoa. Monograph BRYOZOA

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series of the Allan Hancock Foundation No. 10: 1-1 IS. Allan Hancock Foundation and Institute for Marine and Coastal Studies. Los Angeles: University of Southern California. Nitsche, H. 1869. Beiträge zur Kenntniss der Bryozoen. Zeitschrift für wissenschaftliche Zoologie 20: 1-36. O'Donoghue, C. H., and E. O'Donoghue. 1923. A preliminary list of Bryozoa (Polyzoa) from the Vancouver Island region. Contributions to Canadian Biology, new series (10): 145-201. O'Donoghue, C. H., and E. O'Donoghue. 1925. List of Bryozoa from the vicinity of Puget Sound. Publications of the Puget Sound Biological Station 5: 91-108. O'Donoghue, C. H., and E. O'Donoghue. 1926. A second list of Bryozoa (Polyzoa) from the Vancouver Island region. Contributions to Canadian Biology and Fisheries, new series, 3: 49-131. Osburn, R.C. 1950. Bryozoa of the Pacific Coast of America. Part 1, Cheilostomata—Anasca. Allan Hancock Pacific Expeditions 14(1): 1-270. Los Angeles: University of Southern California Press. Osburn, R. C. 1952. Bryozoa of the Pacific Coast of America. Part 2, Cheilostomata-Ascophora. Allan Hancock Pacific Expeditions 14(2): 271-612. Los Angeles: University of Southern California Press. Osburn, R. C. 1953. Bryozoa of the Pacific Coast of America. Part. 3, Cyclostomata, Ctenostomata, Entoprocta, and Addenda. Allan Hancock Pacific Expeditions 14(3): 613-843. Los Angeles: University of Southern California Press. Pinter, P. 1969. Bryozoan-algal associations in southern California waters. Bulletin of the Southern California Academy of Sciences 68:199-218. Robertson, A. 1903. Embryology and embryonic fission in the genus Crista. University of California Publications in Zoology 1: 115-1256. (based on species from Land's End, San Francisco). Robertson, A. 1905. Non-incrusting chilostomatous Bryozoa of the west coast of North America. University of California Publications in Zoology 2: 235-322. Robertson, A. 1908. The incrusting chilostomatous Bryozoa from the west coast of North America. University of California Publications in Zoology 4: 253-344. Robertson, A. 1910. The cyclostomatous Bryozoa of the west coast of North America. University of California Publications in Zoology 6: 225-284. Ryland, J. S., and J. S. Porter. 2006. The identification, distribution and biology of encrusting species of Alcyonidium (Bryozoa: Ctenostomatida) around the coasts of Ireland. Biology and Environment: Proceedings of the Royal Irish Academy 106: 19-33. Soule, D. F., H. W. Chaney, and P. A. Morris. 2003. New taxa of Microporellidae from the northeastern Pacific Ocean. Irene McCulloch Foundation Monograph Series, No. 6:1-38. Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Soule, D. F., H. W. Chaney, and P. A. Morris. 2004. Additional new species of Microporelloides from Southern California and American Samoa. Irene McCulloch Foundation Monograph Series, No. 6A: 1-15. Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Soule, D. F., and J. D. Soule. 1975. Species groups in Watersiporidae, pp. 299-309. In Proceedings of the Third International Bryozoology Conference. Bryozoa 1974, Lyon, France: Documents Sciences de Lyon, Université Claude Bernard, H.S. 3(1), 690 pp. Soule, D. F., and J. D. Soule. 2002. The eastern Pacific Parasmittina trispinosa complex (Bryozoa, Cheilostomatida): New and previously described species. Irene McCulloch Foundation Monograph series No. 5, 1—40. Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Soule, D. F., J. D. Soule, and H. W. Chaney. 1992. The genus Thalamoporella worldwide (Bryozoa, Anasca). Morphology, evolution and speciation. Irene McCulloch Foundation Monograph Series, No. 1: 193. Los Angeles: Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Soule, D. F., J. D. Soule, and H. W. Chaney. 1995. The Bryozoa. In Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and Western Santa Barbara Channel, Vol. 13: 1-344. Santa Barbara, CA: Santa Barbara Museum of Natural History.

904

BRYOZOA

Soule, D. F., J. D. Soule, and H.W. Chaney. 1999. New species of Thalamoporella (Bryozoa) with acute of subacute avicularium mandibles and review of known species worldwide. Irene McCulloch Foundation Monograph Series, No. 4: 1-57. Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Soule, D. F., J. D. Soule, and P. A. Morris. 2001. Changing concepts in species diversity in the northeastern Pacific, pp. 299-306. In Bryozoan Studies, Proceedings of the Twelfth International Bryozoology Association Conference, Trinity College, Dublin, Ireland. Lisse: Swets and Zeitlinger. Soule, D. F., J. D. Soule, and P. A. Pinter. 1975. Phylum Ectoprocta (Bryozoa), pp. 579-608. In Light's manual: intertidal invertebrates of the central California Coast. 3rd ed. R. I. Smith and J. T. Carlton, eds., 716 pp. University of California Press. Soule, J. D. 1953. Order Ectoprocta, Suborder Ctenostomata. In Bryozoa of the Pacific Coast of America, Part 3. R.C. Osburn, ed. Allan Hancock Pacific Expeditions, 14(3): 726-755. Los Angeles: University of Southern California Press. Soule, J. D. 1957. Anascan Cheilostomata (Bryozoa) of the Gulf of California. Results of the Puritan-American Museum of Natural History Expedition to Western Mexico, No. 6. American Museum of Natural History Novitates No. 1969: 1-54. Soule, J. D. 1961. Ascophoran Cheilostomata (Bryozoa) of the Gulf of California. Results of the Puritan-American Museum of Natural History Expeditions to western Mexico, No. 13. American Museum of Natural History Novitates. No. 2053: 1-66. Soule, J. D. 1963. Cyclostomata, Ctenostomata (Ectoprocta) and Entoprocta of the Gulf of California. Results of the Puritan-American Museum of Natural History Expeditions to western Mexico, No. 18. American Museum of Natural History Novitates No. 2144: 1-34. Soule, J. D., and M. M. Duff. 1957. Fossil Bryozoa from the Pleistocene of southern California. Proceedings of the California Academy of Sciences (4) 29: 87-146. Soule, J. D., and D. F. Soule. 1969. Systematics and biogeography of burrowing bryozoans. American Zoologist 9: 791-802. Soule, J. D., and D. F. Soule. 1976. Spathipora. Its anatomy and phylogenetic affinities, pp. 247-253 in Proceedings of the Third International Bryozoology Conference. Bryozoa 1974, Lyon, France: Documents Sciences de Lyon, Université Claude Bernard, H.S. 3(1), 690 pp. Soule, J. D., D. F. Soule, and D. P. Abbott. 1980. Bryozoa and Entoprocta: The Moss Animals, pp. 91-107. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie. Stanford University Press. Soule, J. D., D. F. Soule, and H. W. Chaney. 1998. Two new tropical Pacific species of Cribralaria (Bryozoa: Cribrilinidae) and a review of known species. Irene McCulloch Foundation Monograph Series. No. 3: 1-24. Los Angeles: Hancock Institute for Marine Studies, University of Southern California. Taylor, P. D. 2000. Cyclostome systematics: Phylogeny, suborders and the problem of skeletal organization, pp. 87-103. In Proceedings of the Eleventh International Bryozoology Association Conference, Smithsonian Tropical Research Institute. Todd, J. A. 2000. The central role of ctenostomes in bryozoan phylogeny. pp. 104-135. In Proceedings of the Eleventh International Bryozoology Association Conference, Smithsonian Tropical Research Institute. Taylor, P. D., and N. Monks. 1997. A new cheilostome bryozoan genus pseudoplanktonic on molluscs and algae. Invertebrate Biology 116: 39-51. Wood, T. S., and M. Lore. 2003. The higher phylogeny of phylactolemate bryozoans inferred from 18S ribosomal DNA sequences. Boletín de la Sociedad de Biologia de Concepción 74: 126. Woollacott, R. M., and W. J. North. 1971. Bryozoans of California and northern Mexico kelp beds. Nova Hedwigia 32: 455-475. Zimmer, R. L., and R. M. Woollacott. 1977. Structure and classification of gymnolaemate larvae, pp 5 7-89 in R. M. Woollacott and R. L. Zimmer, eds., Biology of Bryozoans, New York: Academic Press.

Chaetognatha (Plates 453 and 454)

ERIK V.THUESEN

More than 35 species of chaetognaths (arrow worms) are found in the eastern north Pacific Ocean. Eight species are treated here, including the six most likely to turn up in short surface tows made nearshore with small plankton nets from small boats or piers. The two shallow-living benthic chaetognaths known from southern California are also included. Although the West Coast of the United States has no known tide-pool chaetognaths, small benthic chaetognaths are collected in tide pools in Japan and other locations. Their unique mating dance has been studied in detail (Goto and Yoshida 1985). It is possible that tide pools of the West Coast harbor benthic chaetognaths, and the two species of benthic chaetognaths are included here in the hopes that more records of these interesting animals will be forthcoming. Temperature and salinity affect morphological characteristics of chaetognaths during development, and the identification of chaetognath species is more difficult as a result of various intraspecific ecotypes. Most studies of chaetognaths are undertaken on preserved specimens, but the fragile external structures of chaetognaths preserve poorly. Living mature specimens are the easiest to identify, but these are often absent in samples. Extent of ovaries, shape and position of seminal vesicles, relative length of the tail section to total body length, and the shape and position of the fins and extent of fin rays are all important characteristics used to identify chaetognaths. The use of vital stains (e.g., aniline blue or rose bengal) and various lighting angles under the microscope highlight these characteristics and make chaetognaths easier to identify. The shape of eye pigmentation and the number of hooks and teeth have often been used as identification characteristics, but these often overlap between species and can change with maturity. The general body aspect of juvenile specimens often matches the adult, even though important distinguishing features have not yet developed fully. The degree of transparency is another identifying characteristic, but this is often dependent on the condition of the specimen. Chaetognaths quickly lose transparency if damaged during collection. The key is best used with mature living specimens that have been collected carefully to preserve their fragile body structures.

The taxonomic outline of Bieri (1991) is followed throughout this section, and a complete list of chaetognaths is available online at http://academic.evergreen.edU/t/thuesene/ chaetognaths/chaetognaths.htm. Descriptions and illustrations of other Pacific chaetognaths can be found in Alvarino (1967), Yamaji (1980), and Chihara and Murano (1997). Reviews of specific aspects of the biology and ecology of chaetognaths are found in Bone et al. (1991). The general anatomy of chaetognaths is presented in plate 453A.

Key to Some Common Nearshore Chaetognaths 1.

—

2. — 3.

— 4. — 5.

— 6.

Heavy transverse musculature along the trunk segment gives opaque appearance, small ( < 1 0 mm), one pair of lateral fins, benthic or epibenthic, often attached to algae or other substrates Spadellidae 2 No transverse musculature along the trunk segment, transparent, size can exceed 20 mm, two pairs of lateral fins, planktonic Sagittidae 3 Without adhesive organs, body length to 6.5 mm (plate 453B) Spadella bradshawi With adhesive organs, body length to 3.8 mm (plate 453C) Paraspadella pimukatharos Inner edges of grasping spines with small serrations (400x), seminal vesicles with anterior nipple, matures at 14 mm17 mm (plate 453D) Serratosagitta bierii Grasping spines without serrations, no anterior nipple on seminal vesicles 4 Fins with complete rays 5 Fin rays very sparse or only filling outer edges 6 Two rows of eggs in each ovary extend as far as or further than the middle of the anterior fins, collarette extensive, seminal vesicles with terminal knobs when fully mature, body length to 26 mm (plate 453E) Sagitta bipunctata Ovaries do not reach the anterior fins 7 Ovaries may extend past the leading edge of the posterior fins; sperm usually forms a heavy "V" pattern in the tail section, whereby the anterior and central portion of the tail section is devoid of sperm, seminal vesicles are simple bulbs, total body length when mature is > 1 5 mm (plate

905

anterior teeth grasping spines posterior teeth eye

ciliary sensory fans

_

- mouth collarette

-

ventral ganglion 1 mm anterior fin

ovary

posterior fin

seminal receptical .

testes -

- trunk/tail septum

seminal vesicle — tail fin

0.1 mm J

• >

E2

PLATE 453 A, General anatomy of a sagittid chaetognath; B, Spadella bradshawi; C, Paraspadella pimukatharos; Dl, D2, Serratosagitta bierii; El, E2, Sagitta bipunctata (A, Thuesen; B, from Bieri, revised by Thuesen; C-E, from Alvarifio, with permission of the Biological Society of Washington, University of Hawaii Press, and Scripps Institution of Oceanography, respectively).

PLATE 454 A, Flaccisagitta enfiata; B, Mesosagitta minima; CI, C2, Parasagitta euneritica; D, Parasagitta eìegans (A, B, from Alvarino with permission of the Scripps Institution of Oceanography; C, from Alvarino with permission of the University of Hawaii Press; D, Thuesen).

454A) Flaccisagitta enflata Ovaries shorter than the length of the posterior fins with a few large ova, highly transparent with buoyancy sac mesenteries often visible, seminal vesicles are very simple, total mature body length < 1 0 mm (plate 454B) Mesosagitta minima 7. Anterior fins, seminal vesicles, and posterior fins may all be touching in alignment, collarette-type tissue extends the length of the body, mature body length of 8 mm-16 mm (plate 454C) Parasagitta euneritica — Posterior fins not touching seminal vesicles, mature body length of 24 mm-48 mm (plate 454D) Parasagitta elegans —

List of Species Sagittoidea SPAOELLIDAE Spadella bradshawi Bieri, 1974. Point Loma south in 25 m 100 m, may occur shallower further north; prefers course sand; also on silt. Chestnut-colored markings on body and brilliant green eyes visible in living specimens (see Bieri 1974, Bieri et al. 1987).

Paraspadellapimukatharos (Alvariño, 1987). Reaches densities over 3,500 individuals m~ 2 at Catalina Island ( - 1 0 m depth); most abundant on sediment with coralline algae fragments. Coloration pattern unknown. Possible indicator of El Niño (see Alvariño 1987).

SAGITTIDAE Flaccisagitta enflata (Grassi, 1881). Mesosagitta minima (Grassi, 1881). Parasagitta elegans (Verrill, 1873). Boreal species with southern limit ~40°N, indicative of northern intrusions of cold water south of this point (see Terazaki and Miller 1986). Obvious ammonia-filled buoyancy sacs in fresh-caught specimens (see Bone et al. 1991). Parasagitta euneritica (Alvarino, 1961). Dominant chaetognath in the California Current (see Bieri 1959, as Sagitta friderici, and Alvarino 1966) and nearshore waters, including Bodega Bay (see Renshaw 1962), Monterey Bay (see Bigelow and Leslie 1930, as Sagitta bipunctata), Santa Barbara Channel (see Thuesen and Childress 1993), Anaheim Bay (see Felts 1973), Newport Bay (see Kinoshita 1981) and San Diego (see Michael 1911, as Sagitta bipunctata). Possibly synonymous with S. friderici. CHAETOGNATHA

907

Sagitta bipunctata Quoy and Gaimard, 1827. Off California; this species has been described as Sagitta califomica (see Michael 1913, Bieri 1959). Serratosagitta bierii (Alvarino, 1961). C o m m o n coastal species off California (see Bieri 1959, as Sagitta sp., and Alvarino 1966), usually further offshore than P. euneritica. Serrations appear as bright sheen on inner side of hooks under a dissecting microscope but seen clearly under a compound microscope.

References Alvarino, A. 1961. Two new chaetognaths from the Pacific. Pac. Sci. 15: 67-77. Alvarino, A. 1966. Zoogeografia de California: Quetognatos. Rev. Soc. Mex. Hist. Nat. 27: 199-243. Alvarino, A. 1967. The Chaetognatha of the NAGA Expedition (1959-1961) in the South China Sea and the Gulf of Thailand. I. Systematics. Naga Reports. 4: 1-197. Alvarino, A. 1987. Spadella pimukatharos, a new benthic chaetognath from Santa Catalina Island, California. Proc. Biol. Soc. Wash. 100: 125-133. Bieri, R. 1959. The distribution of planktonic Chaetognatha in the Pacific and their relationship to the water masses. Limnol. Oceanogr. 4:1-28. Bieri, R. 1974. A new species of Spadella (Chaetognatha) from California. Pub. Seto Mar. Biol. Lab. 21: 281-286. Bieri, R. 1991. Systematics of the Chaetognatha. In The Biology of Chaetognaths. Q. Bone, H. Kapp, and A. C. Pierrot-Bults, eds. Oxford: Oxford University Press, pp. 122-136. Bieri, R., M. Terazaki, E. V. Thuesen, and T. Nemoto. 1987. The colour pattern of Spadella angulata (Chaetognatha: Spadellidae) with a note

908

CHAETOGNATHA

on its northern range extension. Bull. Plankton Soc. Japan 34: 83-84. Bigelow, H. B., and M. Leslie. 1930. Reconnaissance of the waters and plankton of Monterey Bay, July, 1928. Bull. Mus. Comp. Zool. Harvard 70: 427-581. Bone, Q„ H. Kapp, and A. C. Pierrot-Bults, eds. 1991. The Biology of Chaetognaths. Oxford: Oxford University Press, 173 pp. Chihara, M., and M. Murano, eds. 1997. An illustrated guide to marine plankton in Japan. Tokai University Press, Tokyo, 1574 pp. Felts, R. W. 1973. Seasonal distribution and abundance of the chaetognaths from Anaheim Bay, California, and the adjacent waters. MA thesis, California State University, Long Beach, 118 pp. Goto, T., and M. Yoshida. 1985. The mating sequence of the benthic arrowworm Spadella schizoptera. Biol. Bull. 169: 328-333. Kinoshita, P. B. 1981. Population structure, vertical migration and feeding of the chaetognath Sagitta euneritica in Newport Bay, California. MA thesis, California State University, Fullerton, 72 pp. Michael, E. L. 1911. Classification and vertical distribution of the Chaetognatha of the San Diego region. Univ. Calif. Publ. Zool. 8: 20-186. Michael, E. L. 1913. Sagitta califomica, n. sp., from the San Diego region. Univ. Calif. Publ. Zool. 11: 89-126. Renshaw, R. W. 1962. The Chaetognaths of the Dillon Beach area and their possible use as indicators of water movements. MA thesis, University of the Pacific, Stockton, California, 71 pp. Terazaki, M., and C. B. Miller. 1986. Life history and vertical distribution of pelagic chaetognaths at Ocean Station P in the subarctic Pacific. Deep Sea Res. 33: 323-337. Thuesen, E. V., and J. J. Childress. 1993. Enzymatic activities and metabolic rates of pelagic chaetognaths: Lack of depth-related declines. Limnol. Oceanogr. 38: 935-948. Yamaji, I. 1980. Illustrations of the Marine Plankton of Japan. Osaka, Japan: Hoikusha Publishing Company, 369 pp.

Hemichordata (Plate 4 5 5 )

KEITH H. WOODWICK A N D CHRISTOPHER B. CAMERON

The Enteropneusta (acorn worms) are soft-bodied worms found intertidally most commonly in sand and mud. They also occur in subtidal and deeper waters. The first enteropneust was identified as a sea cucumber, but later findings of gill slits and structures similar to a notochord and a dorsal hollow nerve cord led to investigation of chordate relationships. Most workers consider enteropneusts to be a class of Hemichordata (Hyman 1959, Ruppert 1997, Cameron et al. 2000, Cameron 2005), but Nielsen (1998) supported his earlier elevation of Enteropneusta to phylum status. He placed them close to chordates and separated them from echinoderms and pterobranchs. Enteropneusts vary in size in extremes from 2.5 cm to 2 m, but most specimens are 10 c m - 4 0 cm in length. They have three body divisions: proboscis, collar, and trunk (plate 455A). The trunk may have as many as four distinct regions: branchiogenital, esophageal, hepatic, and intestinal. The straight gut begins with an anterioventral mouth at the interphase of the muscular proboscis and the cufflike collar; it ends in a terminal anus. The branchiogenital region has a few to hundreds of pairs of small gill pores or eternally visible gill slits. Gonads appear as surface bumps, ridges, or genital wings (plate 455E, 455F5) or lappets (plate 455D4). Some genera have external sacculations (caeca) in the hepatic region. They are finger- or ear-shaped. In the field enteropneusts can be found in sandy mudflats by utilizing surface clues and shoveling up clods of substratum. Worms may leave fecal strings or coils at the openings of their burrows. Some extend their proboscis and collar to the surface to deposit feed utilizing mucus and ciliary action (Barrington 1965). Several species collect food from the water by filter-feeding using the gill slits in the pharynx (Cameron 2002). At this time body colors of red, orange, to light yellow may reveal their presence; however, many forms are drab in color (Hyman 1959). More complete specimens may retain the hepatic region with its brown and green pigment. Clods of substratum can be hand-processed, but enteropneusts are fragile and it is difficult to collect complete specimens. The proboscis, collar, and anterior trunk are least fragile and are the body parts most often taken in the field, found in museum collections, and utilized here in the key. Specimens in the substratum are covered with mucus and sediment and contain ciliary collected sediment

(food) in their digestive tract. Fixation in this condition increases the difficulty of appropriate processing of specimens for identification and morphological and other studies. When possible, live specimens should be sorted from the sediment. Sometimes breaking the sediment into large pieces will reveal the burrow and the organism, and further careful breaking will free the specimen. Live specimens should then be placed in large containers of clean seawater to permit evacuation of the gut. Several changes of seawater may be needed and surface sediment may be released with their movement or removed with a camels hair brush or forceps. Clean specimens should be fixed by holding them at the posterior end with a pair of forceps and dipping them in a tall jar of fixative (e.g., Bouin's fluid). Gravity will assist in straightening the specimen as fixative is added to the posterior end and allowed to flow down into the jar. When fixation is complete, release the specimen into the jar and store on its side for several days. Transfer specimens to 50% alcohol and then wash several times in 70% alcohol (not water) to clear the picric acid (Galigher and Kozloff 1971). Specimens can then be stored or run through an alcohol, toluene, paraffin series for embedding. Prepared paraffin blocks are then serially sectioned at 10 |xm-15 n,m and slide sections stained with Harris's Hematoxylin and Eosin Y. The anatomy is reconstructed from microscopic study of the serial cross and sagittal sections. Most published descriptions have included labeled drawings of critical diagnostic features and areas (Woodwick 1996, pp. 252-253). In addition to the external features emphasized here, the nature of and presence and absence of internal structures are important in placing specimens in family, genus, and species (Spengel 1893, Horst 1939, Dawydoff 1948, Hyman 1959, Benito and Pardos 1997).

Classification of Enteropneusta Characteristics important to the key and field observations are listed first.

Harrimaniidae Proboscis short, conical, or elongate; trunk has four enlarged genital lappets or lacks genital lappets or wings; proboscis lacks 909

G

M'

B

s

-

- / / y .

/

PLATE 455 A, Saccoglossus; of Balanoglossus;

B, Schizocardium;

G, Glossobalanus

C, cross-section of Schizocardium;

D, Stereobalanus;

E, Balanoglossus;

F, cross-section

(1, proboscis; 2, collar; 3, trunk; 4, genital lappets; 5, genital wing).

cauliflower organ and vermiform process; peripharyngeal cavities and neurocord nerve roots of the collar not present; trunk lacks parabranchial ridges, synapticules, and hepatic caeca; development direct, eggs large (150 y m - 4 0 0 pm).

GENERA: HARRIMANIA, PROTOGLOSSUS, STEREOBALANUS, XENOPLEURA

SACCOGLOSSUS,

STEREOBALANUS Proboscis short, conical; collar shorter than broad, usually with two proboscis pores; paired dorsal and ventral genital lappets; lappets partially cover dorso-ventral gill slits that open directly to the exterior; lappets not in esophageal region; longitudinal muscles of proboscis form radial pattern.

SACCOGLOSSUS

Spengeliidae

Proboscis elongate, cylindroid, one proboscis pore; collar broad as long; genital pores medio-dorsal; gonads simple; longitudinal proboscis muscles in concentric rings.

Proboscis short, ovate; collar shorter t h a n broad; hepatic caeca present in some genera; proboscis muscle includes thick layer of circular muscle encompassing homogenously

910

HEMICHORDATA

arranged longitudinal fibers; stomochord with a vermiform process; pericardium and glomerulus with paired anterior diverticula more or less developed; chondroid tissue well-developed; eggs small, development indirect, tornaria larva.

G E N E R A : GLANDICEPS, WILLEYIA

SCHIZOCARDIUM,

SPENGELIA,

SCHIZOCARDIUM Hepatic caeca present and finger-shaped; esophageal pores present, both single and paired; long vermiform process; gill slits almost equaling the pharynx in depth so the ventral nonpharyngeal part of the pharynx is reduced to a mere groove, long gill bars with synapticles and a narrow hypobranchial area; gonads lateral only.

List of Species

Ptychoderidae Proboscis short, conical; collar as long as broad with nerveroots; trunk external regionation pronounced; ventral part of pharynx large and sometimes more or less separated from branchial part by parabranchial ridges; genital wings extend into esophageal region; hepatic caeca ear-shaped; cauliflower organ may be present; proboscis muscle radial pattern of bands; gill bars short, curved, with synapticules; parabranchial ridge present; longitudinal ciliated intestinal grooves; eggs small, development indirect, tornaria larvae (Hadfield 1975).

G E N E R A : BALANOGLOSSUS, PTYCHODERA

Saccoglossus pusillus Proboscis creamy white; collar brick red to reddish orange; 60 or more pairs of gill pores; four to six pairs of esophageal pores; eggs ca. 250 (im Saccoglossus bromophenolosus 3. Enlarged genital lappets or genital wings absent (plate 455B, 455C) Schizocardium — Enlarged genital lappets or genital wings present 4 4. Four enlarged genital lappets extend above and below branchial openings; lappets not present in esophageal region (plate 455D) Stereobalanus — Ventro-lateral wings only, extend below branchial openings; wings present in esophageal region 5 5. Genital wings well-developed; genital openings near branchial pores (plate 455E, 455F) Balanoglossus — Genital wings not well-developed; genital openings on margin of genital wings (plate 455G) Glossobalanus

—

GLOSSOBALANUS,

BALANOGLOSSUS Proboscis may be very small, partially enclosed by collar; genital wings long, well-developed; genital openings near branchial pores, branchial pores small; lack cauliflower organ; hepatic caeca not regularly arranged posteriorly; intestinal grooves paired. GLOSSOBALANUS Proboscis as long as wide and mainly free of collar; genital wings not well-developed; genital openings on margin of genital wings; lack cauliflower organ; hepatic caeca in two regularly arranged rows; intestinal groove on left only.

For subtidal and deeper water forms see Woodwick, 1955, Allan Hancock Pac. Exped. 19:166-167; Woodwick 1996; Holland et al. 2005, Nature 434: 374-376.

Harrimaniidae Saccoglossus sp. Newport, Half Moon Bay; see Bullock, 1944, J. Comp. Neur. 80: 355-367. Saccoglossus pusillus (Ritter, 1902) Duxbury Reef (Bolinas Bay) at base of seaweeds; southern and Baja California (e.g., San Pedro, Newport, San Diego in sand or mud, Ensenada), north to British Columbia; see Ritter and Davis 1904, Univ. Calif. Publ. Zool. 1: 171-210 and Davis 1908, Univ. Calif. Publ. Zool. 4: 187-226 (reproduction and development); Evans 1919, Pomona Coll. J. Ent. and Zool. 11: 28-33 (general morphology); Horst 1930, Vidensk. Medd. Dansk Nat. Foren. 87: 135-200 (includes original description of species by Ritter, pp. 154-156); Bullock 1944, and Bullock 1945, Quart. J. Microsc. Sci. 86: 55-111 (nervous system); Smith et al. 2003, Can. J. Zool. 81.131-141. (molecular biogeography of Pacific Northwest saccoglossids). Saccoglossus bromophenolosus King, Giray, and Kornfield, 1994. Washington (Willapa Bay sandy mudflats), Oregon; see King, Giray, and Kornfield 1994, Proc. Biol. Soc. Wash. 107:383-390 (original description and biochemical systematics); Giray and King 1996, Proc. Biol. Soc. Wash. 109: 430-445 (table of 14 species of Saccoglossus); Smith et al. 2003, Can. J. Zool. 81:131-141. (molecular biogeography of Pacific NW saccoglossids). Stereobalanus sp. Newport, San Diego; Spengel, 1893 (described only known species); Reinhard 1942, J. Wash. Acad. Sci. 32: 3 0 9 - 3 1 1 (described complete, live specimen).

ACKNOWLEDGMENTS This section is dedicated to Professor Theodore H. Bullock, who kept alive the hope for further study of West Coast enteropneusts.

Spengeliidae Schizocardium sp. Morro Bay; see Bridges and Woodwick, 1994, Acta Zool. 75: 371-378. (hepatic caeca); Spengel 1893 (described the two known species).

Key to Enteropneusta 1. — 2.

Proboscis elongate (plate 455A) Saccoglossus 2 Proboscis not elongate 3 Proboscis orange, collar darker orange; 60 or less pairs of gill pores; one pair of esophageal pores; eggs 145 pm-155 pm

Ptychoderidae Balanoglossus sp. Newport, Laguna, Mission Bay, also Puget Sound and Baja California; see Bullock 1944 and 1945. HEMICHORDATA

911

Glossobalanus sp. La Jolla; see Bullock 1 9 4 4 and 1945; also found at Moss Beach, Shelter Cove and Puget Sound. Glossobalanus berkeleyi (Willey, 1931). See Willey 1931, Trans Roy. Soc. Can. 25: 1 9 - 2 8 (original description; collected at Nanaimo, British Columbia, but more abundant at Penrose Point, Puget Sound).

References Barrington, E. J. W. 1965. The Biology of Hemichordata and Protochordata. Freeman, San Francisco, 176 pp. Benito, J., and F. Pardos. 1977. Hemichordata. In F. W. Harrison and E. E. Ruppert, eds. Microscopic Anatomy of Invertebrates. 15. New York: Wiley-Liss, pp. 15-101. Cameron, C. B. 2005. A phylogeny of the hemichordates based on morphological characters. Canadian Journal of Zoology 83: 196-215. Cameron, C. B. 2002 Particle retention and flow in the pharynx of the enteropneust worm Harrimania planktophilus: the filter feeding pharynx may have evolved prior to the chordates. Biological Bulletin 202:192-200. Cameron, C. B., B.J. Swalla, and J. R. Garey. 2000. Evolution of the chordate body plan: New insights from phylogenetic analysis of deuteros-

912

HEMICHORDATA

tome phyla. Proceedings of the National Academy of Sciences 97: 4469^474. Dawydoff, C. 1948. Stomochordes. In P. Grasse, ed. Traité de Zoologie. Masson, Paris, pp. 367-532. Galigher, A. E., and E. N. Kozloff. 1971. Essentials of practical microtechnique. 2nd ed., Lea and Febiger, Philadelphia, 531 pp. Hadfield, M. G. 1975. Hemichordata. In Reproduction of marine invertebrates. 2. A. C. Giese and J. S. Pearse, eds. London: Academic Press, pp. 185-240. Horst, C. J. van der. 1939. Hemichordata. In Bronn, Klassen und Ordnungen des Tierreichs. 4, 737 pp. Hyman, L. H. 1959. Phylum Hemichordata. In The invertebrates 5. New York: McGraw-Hill, pp. 72-207. Nielsen, C. 1998. Origin and evolution of animal life cycles. Biological Reviews 73: 125-155. Ruppert, E. E. 1997. Introduction: Microscopic Anatomy of the Notochord, Heterochrony, and Chordate Evolution. In Microscopic anatomy of invertebrates. 15. F. W. Harrison and E. E. Ruppert, eds. New York: Wiley-Liss, pp. 1-13. Spengel, J. W. 1893. Die Enteropneusten des Golfes von Neapel. Fauna und Flora des Golfes von Neapel. 18, 757 pp. Woodwick, K. H. 1996. Phylum Hemichordata, Class Enteropneusta. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. 14. J. A. Blake, P. H. Scott, and A. Lissner, eds. Santa Barbara, CA: Santa Barbara Museum of Natural History, pp. 251-259.

Echinodermata (Plates 4 5 6 - 4 7 5 )

Introduction JOHN S. PEARSE AND RICH MOOI

The Echinodermata (echino = spiny; derm = skin) is a phylum of deuterostome macroinvertebrates sharing morphological features not found in any other phylum. The phylum includes the CRINOIDEA (sea lilies and feather stars), ASTEROIDEA (sea stars or starfishes), O P H I U R O I D E A (brittle stars), ECHINOIDEA (sea urchins, heart urchins, and sand dollars), and HOLOTHUROIDEA (sea cucumbers) in addition to a less familiar assemblage of fossil groups. A sixth, somewhat controversial group, the CONCENTRICYCLOIDEA (sea daisies), with three species known from sunken wood in the deep sea, may be highly derived asteroids. Echinoderms are entirely marine and extremely intolerant of fresh water. Most echinoderms have pelagic larvae with bilateral symmetry, but following a drastic metamorphosis, during which the left side comes to predominate in the adult, they develop into bizarre forms with unusual symmetries. The adults typically have pentaradial (five-sided radial) symmetry with a water-vascular ring that encircles the esophagus. This ring canal gives off five radial canals along which are arranged tube feet (podia) used for locomotion, respiration, and feeding. Within the body wall are the ossicles (spicules, plates, spines) of the internal skeleton (stereom), composed of closely aligned, magnesium-rich, fenestrated crystals of calcium carbonate. In most echinoderms, five series of paired ambulacral columns of ossicles form an axial skeleton that supports the radial canals; other ossicles fill in between these columns to form the extraxial skeleton. The growth and organization of the skeletal ossicles in large part determines the form of the adults: feathery, star-shaped, or globular or flattened discs. In contrast, sea cucumbers lack spines and are generally soft-bodied, wormlike animals with only tiny ossicles in the body wall and a calcareous ring around the esophagus. Echinoderm adults range in lifestyle from pelagic holothurians to infaunal burrowers and inhabit nearly every marine environment, from sandy beaches and coral reefs to the greatest depths of the sea. The phylum has left a relatively complete and detailed fossil record of more than 13,000 species stretching back 500 million years to the Cambrian. Crinoids are not found in shallow waters off the California and Oregon coasts, and therefore we treat them here only briefly. In asteroids and ophiuroids, the axial skeleton forms

five or more arms (rays). These distinctive, starlike animals are mainly active predators, scavengers, or detritivores of the benthos, and together form the most species-rich group of echinoderms considered here. Echinoids lack arms and have a rigid test of tightly fitted plates and movable spines. About 14 species occur along the shores of California and Oregon, but only three—two sea urchins and one sand dollar—are commonly found in the intertidal and shallow subtidal, and these can be important herbivores and planktivores. Holothuroids are also represented by about a dozen species along Oregon and California shores, but the few that are commonly found in the intertidal and shallow subtidal are usually inconspicuous.

References Binyon, J . 1972. Physiology of Echinoderms. Oxford: Pergamon Press, 2 6 4 pp. David, B., and R. M o o i . 1 9 9 6 . Embryology supports a new theory of skeletal homologies for t h e phylum Echinodermata. Comptes Rendus de l'Academie des Sciences, Paris, 3 1 9 : 5 7 7 - 5 8 4 . Giese, A. C., J . S. Pearse, and V. B. Pearse, eds. 1 9 9 1 . Reproduction of Marine Invertebrates, Volume VI, Echinoderms a n d Lophophorates. Pacific Grove: Boxwood Press, 8 0 8 pp. Harrold, C., and J . S. Pearse 1 9 8 7 . The ecological role of echinoderms in kelp forests. In Echinoderm studies 2. M. J a n g o u x and J. M. Lawrence, eds., Balkema, Rotterdam, 1 3 7 - 2 3 3 pp. J a n g o u x , M., and J . M. Lawrence, eds. 1 9 8 2 . Echinoderm Nutrition. Balkema, Rotterdam, 6 5 4 pp. Lawrence, J . 1 9 8 7 . A Functional Biology of Echinoderms. J o h n s Hopkins University Press, Baltimore, 3 4 0 pp. Mooi, R. 2 0 0 0 . Not all written in stone: Interdisciplinary syntheses in echinoderm paleontology. Canadian Journal of Zoology, 7 9 : 1 2 0 9 - 1 2 3 1 . Mooi, R., and B. David. 1 9 9 7 . Skeletal homologies of echinoderms. T h e Paleontological Society Papers, 3 : 3 0 5 - 3 3 5 . Moore, R. C., ed. 1 9 6 6 . Treatise on Invertebrate Paleontology. Part U. Echinodermata 3. Geological Society of America, New York, 6 9 5 pp. Moore, R. C., ed. 1 9 6 7 . Treatise o n Invertebrate Paleontology. Part S. Echinodermata 1. Geological Society of America, New York, 6 5 0 pp. M o o r e , R. C., a n d C. Teichert, eds. 1 9 7 8 . Treatise on Invertebrate Paleontology. Part T. E c h i n o d e r m a t a 2. Lawrence: University of Kansas Press, 1 0 2 7 pp. Readers c a n also consult t h e proceedings volumes of t h e International Echinoderm Conferences, and t h e following websites: T h e California Academy of Sciences Echinoderm Webpage: http:// www.calacademy.org/research/izg/echinoderm/ 913

The Echinoderm Portal: http://www.nrm.se/researchandcollections/ zoology/invertebratezoology/research/researchprojects/sabinestohr/ echinodermata/echinodermportal.4.Sfdc727fl0d795blc6e800011488 .html The University of California Museum of Paleontology: http://www. ucmp.berkeley.edu/echinodermata/echinodermata.html

University of California Museum of Paleontology: http://www.ucmp. berkeley.edu/echinodermata/crinoidea.html

Echinoidea J O H N S. PEARSE A N D RICH M 0 0 I (Plates 4 5 6 - 4 6 2 )

Crinoidea J O H N S. PEARSE A N D CHARLES G. MESSING

The class Crinoidea includes the most exquisite members of the Echinodermata. Moreover, they have the longest fossil record, dating back almost 500 million years, and once were dominant forms in shallow seas. They differ from other echinoderms by having (1) the oral surface with both mouth and anus facing away from the substrate, (2) five flexible, usually branched, featherlike rays that extend into the water and gather food using tube feet, and (3) a cuplike body (calyx) that contains most of the viscera. Most of the fossil forms were sessile, stalked forms known as sea lilies; only a small fraction remain today, all in deep water. Nearly all living crinoids shed their stalks at an early age and cling to the bottom using small, hooklike appendages (cirri). These are called feather stars or comatulids. Some swim short distances by undulating their rays. There are approximately 540 living species of feather stars and about 95 sea lilies. Though found in all oceans, feather stars are especially abundant and diverse in the shallow tropical western Pacific and Indian Oceans, as well as in the deep sea. Only one is common along the coast of the eastern Pacific, the feather star Florometra serratissima (A. H. Clark, 1907). A second species, F. asperrima (A. H. Clark, 1907) is probably a synonym. It is often abundant along the outer continental shelf and slope to about 1,500 m. Although occurring in < 3 0 m depths in a few places in British Columbia, often attached to kelp, it lives in deeper water off California and Oregon. Several other species, including sea lilies, have been observed and collected much deeper (500 m-3,000 m) in the eastern Pacific, but these are very poorly known.

References Clark, A. H., and A. M. Clark. 1 9 6 7 . A m o n o g r a p h o n the existing crinoids, 1(5). Bulletin of the U.S. National Museum 82, 8 6 0 pp. McEdward, L. R., S. F. Carson, and F.-S. Chia. 1 9 8 8 . Energetic content of eggs, larvae, and juveniles of Florometra serratissima and the implications for the evolution of crinoid life histories. International Journal Invertebrate Reproduction and Development 13: 9 - 2 2 . Meyer, D. L., and D. B. Macurda, Jr. 1 9 7 7 . Adaptive radiation of the comatulid crinoids. Paleobiology 3: 7 4 - 8 2 . Mladenov, P. V. 1 9 8 7 . Phylum Echinodermata, Class Crinoidea. In: Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast, M. F. Strathmann, ed. Seattle: University of Washington Press, pp. 5 9 7 - 6 0 6 . Rasmussen, H. W., and H. Sieverts-Doreck. 1978. Articulata Classification. In Treatise o n invertebrate paleontology. R. C. Moore and C. Teichert, eds. Part T, E c h i n o d e r m a t a 2(3), Geological Society of America, Boulder, CO, p p . T 8 1 3 - T 9 2 8 . Roux, M., C. G. Messing, and N. Ameziane. 2 0 0 2 . Artificial keys to the genera of living stalked crinoids (Echinodermata). Bulletin of Marine Science 70(3): 7 9 9 - 8 3 0 .

Websites Charles Messing's Crinoid Pages: http://www.nova.edu/ocean/messing/ crinoids/index.html 914

ECHINODERMATA

Echinoids are rounded to flattened echinoderms encased in an interlocking endoskeleton of calcareous plates covered with spines. Tube feet extend through ambulacral plates, arranged in five paired columns from the mouth on the oral surface to the opposite, aboral or apical pole. On each side of each ambulacral column is a column of interambulacral plates; these dominate the body wall, and together the ambulacral and interambulacral plates form a rigid "test" upon which are movable spines and pedicellariae. Most echinoids have an intricate jaw apparatus, Aristotle's lantern, with five teeth that aid in the ingestion of food. The opposite, aboral side of the animal carries the apical ring of small plates, including the genital plates with gonopores and the madreporite; in sea urchins, these plates surround the periproct with the anus. The anus is shifted to one side in sand dollars and heart urchins, forming a "posterior" end; in most heart urchins, the mouth is shifted to the opposite "anterior" end of the animal. Heart urchins also do not have a jaw apparatus. Most echinoids are omnivorous grazers and scavengers, scraping algae and encrusting animals off hard surfaces, or ingesting detritus and debris caught from the water or other organic material in soft substrates. The nearly 1,000 species of echinoids were traditionally divided into two groups: rounded "regular" echinoids that generally occur on hard surfaces (sea urchins) and flattened or heart-shaped "irregular" echinoids that occur on or within soft substrates (sand dollars, cake urchins, heart urchins). Only the latter group is today considered a natural taxonomic assemblage. The class is currently divided into three subclasses: perischoechinoidea (an ancient stock with no living representatives), cidaroidea (pencil-spine urchins occurring mainly in the tropics, deep sea, and Antarctic, plate 456), and euechinoidea (including all the other living echinoids divided among 14 orders, plates 457-462). The shores of central California and Oregon are relatively poor in species of echinoids, with only three species of sea urchins (Strongylocentrotus purpuratus, S. franciscanus, and S. droebachiensis, the last found as far south as southern Oregon) and one species of sand dollar (Dendraster excentricus) commonly found. However, additional species occur in southern California that could occasionally be found along these shores, especially as general global warming continues. In addition, other species found subtidally may be cast ashore, either live or as empty tests, from time to time. All these species are included in the following key and annotated list.

Key to Echinoidea 1.

Body flattened, diameter several times greater than thickness 2 — Body not flattened, nearly spherical, rounded, or heartshaped 4 2. Six holes or marginal slots (lunules) penetrate flattened test (plate 459E, 459F) Encope micropora — Test without lunules 3

PLATE 456 Cidaroida, Diadematoida, Arbacioida: A, Eucidaris thouarsii; B, Centrostephanus denuded test.

3.

Gray-lavender, brown, or purple color; apical system offcenter and in posterior half of test; anterior ambulacral petaloid ("petal") conspicuously larger than other four (plate 459A, 459B) Dendraster excentricus

Pale yellow or tan; apical system nearly central; ambulacral petaloids all nearly same size (plate 459C, 459D) Dendraster terminalis 4. Body strongly bilaterally symmetric, heart-shaped 5 — Body nearly rounded; not asymmetrical and heart-shaped 10 5. Test elongate with conspicuous long spines articulating on deeply sunken large tubercles (plate 462B) Lovenia cordiformis — Test not elongate; covered with spines of nearly the same length 6 6. Petaloids deeply sunken, band of minute spines encircling petaloids (peripetalous fasciole), on either side of the periproct (anal fasciole) and forming a ring below the periproct (subanal fasciole) 7 Petaloids not deeply sunken, fascioles not like above 8 Width of posterior petaloid < 1 1 % length of the test (plate 461A) Brisaster latifrons

D, Arbacia

stellata,

—

Width of posterior petaloid > 1 1 % length of the test (plate 461B) Brisaster townsendi

8.

Test outline nearly round, not indented anteriorly or posteriorly, both peripetalous and subanal fascioles (plate 462A) Brissopsis pacifica Test indented anteriorly or posteriorly, subanal fasciole only 9 Deep anterior indentation (plate 460) Spatangus californicus No anterior indentation, slight posterior indentation (plate 462C) Nacospatangus laevis Primary spines not covered by living epidermis, eroded, usually encrusted with coralline algae, sponges, bryozoans, and other organisms (plate 456A) Eucidaris thouarsii Primary spines covered with epidermis, not encrusted with other organisms 11 Primary spines long, black, hollow, covered with forwardpointing imbricating spinelets, and easily broken (plate 456B) Centrostephanus coronatus

—

— 7.

coronatus; C, Arbacia stellata;

— 9. — 10.

— 11.

—

Primary spines otherwise, if black, not hollow or easily broken 12 ECHINOIDEA

915

PLATE 457 Echinoida. A, Strongylocentrotus purpuratus, living specimen with tube feet fully extended (photo courtesy of Ralph Buchsbaum); B, Strongylocentrotus franciscanus, living specimen lifted from tide pool (photo courtesy of Ralph Buchsbaum); C, Strongylocentrotus fragilis; D, Strongylocentrotus fragilis, denuded test; E, Lytechinus pictus; F, Lytechinus pictus, denuded test.

12. Periproct with four to five large plates around anus; apical portion of ambulacral plates conspicuously devoid of spines (plate 456C, 456D) Arbacia stellata — Periproct with m a n y small plates; test uniformly covered with spines 13 916

EC HI N O D ERM ATA

13. Color of test and spines yellow or pale tan, often with blotches of grey or pale purple; ambulacral plates with single primary spine and n o secondary spines (plate 457E, 45 7F) Lytechinus pictus — Color of test and spines green, pink, red, purple, or nearly

A

B

PLATE 458 Tubercle morphology of Strongylocentrotus: A, oblique view of denuded primary spine tubercle of S. droebachiensis; B, same view of tubercle from S. purpuratus.

14.

— 15.

—

16. — 17.

—

black; ambulacral plates with single primary and several secondary spines 14 Color of test and spines pale orange-pink; spines and test very fragile and easily broken (plate 45 7C, 45 7D) Strongylocentrotus fragilis Color of test and spines not pale orange-pink; spines and test not easily broken 15 Primary spines nearly as long or longer that half test diameter, and colored orange, red, maroon, or nearly black; peristome never green, orange in the smallest animals (plate 45 7B) Strongylocentrotus franciscanus Primary spines m u c h shorter, often stubby looking and colored green or purple; peristome often green, especially in juveniles 16 Primary spines purple Strongylocentrotus purpuratus (in part) Primary spines green 17 Primary spine tubercles with distinct neck undercutting mammelon (area articulating with spine) (plate 458A) Strongylocentrotus droebachiensis Primary spine tubercles rounded, without distinct neck below m a m m e l o n (plates 45 7A, 458B) Strongylocentrotus purpuratus (in part)

List of Species CiDAROIDA CIDARIDAE

Eucidaris thouarsii (Valenciennes, 1846). Slate-pencil urchin; a southern species c o m m o n in rocky low intertidal to 140 m in t h e Gulf of California south to the Galapagos Islands. Rarely f o u n d in southern California; fossils known from central California; see Glynn et al. 1979, Science 203: 47-49 (feeding o n corals).

DIADEMATOIDA DIADEMATIDAE

Centrostephanus coronatus (Verrill, 1867). Long-spined, black sea urchin; a southern species occasionally c o m m o n from southern California to t h e Galapagos Islands. Mainly rocky subtidal to 110 m; see Kennedy and Pearse 1975, J. Exp. Mar. Biol. Ecol. 17: 323-331 (lunar reproductive cycle), Vance 1979, Ecology 60: 537-546 (grazing effects).

ARBACIOIDA ARBACIIDAE

Arbacia stellata Gmelin, 1872. Sharp-spined, black sea urchin; a southern species c o m m o n in rocky low intertidal to 90 m in the Gulf of California south to Peru. Rarely found in southern California. ECHINOIDA TOXOPNEUSTIDAE

Lytechinus pictus (Verrill, 1867). White sea urchin; c o m m o n in embayments and rocky-sandy areas of southern California and Mexico, shallow subtidal to 300 m; occasionally found subtidally below 20 m in Monterey Bay. L. anamesus H. L. Clark, 1912, is a synonym for the ecoform that has longer spines and is generally found in deeper, open-coast water; see Dean et al. 1984, Mar. Biol. 78: 301-313 (grazing effects), Zigler and Lessios 2004, Evolution 58: 1225-1241 (speciation). STRONGYLOCENTROTIDAE

Strongylocentrotus droebachiensis (O. F. Müller, 1776). Green sea urchin; an Arctic and circum-boreal species extending into n o r t h Atlantic and n o r t h Pacific, south to Cape Blanco in southern Oregon; low rocky intertidal to 300 m. Although there are n o confirmed records of this species from California, it is easily confused with juveniles of S. purpuratus, which are also green; see Scheibling and Hatcher in Lawrence, 2007, pp. 353-392 (ecology, mainly in North Atlantic). Strongylocentrotus fragilis Jackson, 1912. Pink sea urchin; an a b u n d a n t deep-water species o n rocky a n d fine sand bottoms, often occurring in large n u m b e r s f r o m 30 to more t h a n 1,200 m. The m o n o t y p i c genus Allocentrotus Mortensen is a b a n d o n e d because it leaves Strongylocentrotus paraphyletic (Biermann et al. 2003). Strongylocentrotus franciscanus (A. Agassiz, 1863). Red sea urchin; large, over 100 m m in diameter, with long spines. Reported presence in Japan almost certainly misidentification of sister species, S. nudus. U n c o m m o n in crevices and pools of low intertidal; mainly subtidal in or near kelp forests, but extending to 125 m. Main species of commercial fishing industry in northeast Pacific; see Rogers-Bennett in Lawrence 2007, pp. 393-425 (natural history and commercial harvest), Rogers-Bennett et al. 2003, Fish. Bull. 101: 614-626 (growth and longevity). Strongylocentrotus purpuratus (Stimpson, 1857). Purple sea urchin; generally smaller echinoid (usually 50 m m diameter or ECHINOIDEA

917

PLATE 459 Clypeasteroida: A, Dendraster excentricus, lower (oral) and upper (aboral) surfaces of dead, denuded tests as they would appear washed up on the beach (anterior end is towards top of page (photo courtesy of Ralph Buchsbaum); B, Dendraster excentricus, living specimens from a subtidal population (photo courtesy of Ralph Buchsbaum); C, Dendraster terminalis, aboral surface; D, Dendraster terminalis, oral surface; E, Encope micropora, aboral surface; F, Encope micropora, oral surface.

PLATE 4 6 0 Spatangoida: A, General features of a heart urchin as shown by a denuded test of Spatangus

less) than S. franciscanus, with short spines. Often common in crevices, pools, and mussel beds in mid- to low-intertidal, extending subtidally to 90 m. Action of teeth and spines can erode hollows in soft rock, within which animals nestle. Sometimes dense subtidal populations graze areas of most macroalgae, forming "barrens." A model organism for genome sequencing (see http://www.ncbi.nlm.nih.gov/genome/ guide/sea-urchin); see Rogers-Bennett in Lawrence 2007, pp. 393-425 (natural history), Behrens and Lafferty 2004, Mar. Ecol. Prog. Ser. 279: 129-139 (diseases); Pearse 2006, Science 314: 940-941 (ecology). Note: Species of Strongyiocentrotus readily hybridize in lab, and hybrids are likely to occur in field. Lab-reared hybrids of 5.

franciscanus

x S. purpuratus have varied appearances—some look like either parent or only a little different from either; they would be difficult to

califomicus.

or sandy-mud of inlets and embayments, and subtidally along open coast to 90 m; dead tests frequently encountered on beaches. In higher currents, embeds anterior end into sand to stand "upright"; see Cameron and Rumrill 1982, Mar. Biol. 71: 197-202 (recruitment), Morin et al. 1985, Mar. Ecol. Prog. Ser. 27: 163-185 (subtidal aggregations), Mooi 1997 (systematics, distribution, and overview). Dendraster terminalis (Grant & Hertlein, 1938). Southern sand dollar; subtidal species found in sandy areas of southern California and the West Coast of Baja California, 6 m-55 m depth. Reaches sexual maturity at smaller sizes ( < 2 0 mm test length) than any other Dendraster, leading to its being mistaken for miniaturized forms in a completely different suborder (Mooi 1997).

distinguish in the field Q. S. Pearse and M. E. Steele, pers. obs.). MELLITIDAE

CLYPEASTEROIDA DENDRASTERIDAE

Dendraster excentricus (Eschscholtz, 1831). Common sand dollar; locally abundant low intertidal-shallow subtidal in sand

Encope micropora L. Agassiz, 1841. Keyhole sand dollar; southern species found in intertidal and subtidal to 30 m, sandy areas from Baja California to Peru. Rarely encountered in southernmost California; see Ebert and Dexter 1975, Mar. Biol. 32: 397-407 and Dexter 1977, Bull. Mar. Sci. 27: 5445-551 (natural history of related species). ECHINOIDEA

919

PLATE 461 Spatangoida: A, Brisaster latifrons, aboral, oral, and side views; B, Brisaster townsendi, aboral view.

SPATANGOIDA

BRISSIDAE

SCHIZASTERIDAE

Brissopsis pacifica (A. Agassiz, 1898). Southern heart urchin; subtidal species burrowing in sandy-mud bottoms from south-

Brisaster latifrons (A. Agassiz, 1898). C o m m o n heart urchin; subtidal species burrowing in sandy-mud bottoms, 35 m - 1 , 8 0 0 m, see Hood and Mooi 1998 (systematics, evolution).

ern California to the Galapagos Islands, 9 m - 7 5 m.

Brisaster townsendi (A. Agassiz, 1898). Very similar to B. latifrons, especially young individuals, several measurements from several specimens usually required to distinguish these species; 3 5 m - 1 , 9 0 0 m; see Hood and Mooi 1 9 9 8 (systematics, evolution). 920

ECHINODERMATA

LOVENIIDAE Lovenia cordiformis (A. Agassiz, 1872). Sea porcupine; southe m species extending from southern California to t h e Galapagos; burrows just below the surface of sand from t h e low intertidal to 1 4 0 m.

PLATE 462 Spatangoida: A, Brìssopsis pacifica, gus laevis, aboral, oral, and side views.

aboral, oral, and side views; B, Lovenia cordiformis,

aboral, oral, and side views; C,

Nacospatan-

SPATANGIDAE

Nacospatangus laevis (H. L. Clark, 1917). Sea mouse; southern California to Gulf of California, 5 m - 4 1 0 m. The nomenclature for this species is greatly confused. Although listed in some works as Gonimaretia laevis or Pseudomaretia laevis, studies suggest that Nacospatangus, Gonimaretia (under the name Goniomaretia) and Pseudomaretia should all be submerged under the oldest n a m e Nacospatangus. Without formal revision, we assume that Nacospatangus depressus Clark, 1917 is a junior synonym of N. laevis. Spatangus califomicus H. L. Clark 1917. Santa Barbara County to Gulf of Mexico, 5 m - 3 0 0 m.

References Biermann, C. H., B. D. Kessing, and S. R. Palumbi. 2003. Phylogeny and development of marine model species: strongylocentrotid sea urchins. Evolution and Development 5: 360-371. Durham, J. W., C. D. Wagner, and D. P. Abbott. 1980. Echinoidea: The sea urchins, pp. 160-176, In R. H. Morris, D. P. Abbott, and E. C. Haderlie, Intertidal Invertebrates of California, Stanford University Press. Grant, U. S. IV, and L. G. Hertlein. 1938. The west American Cenozoic Echinoidea. Publ. UCLA Math. Phys. Sci. 2: 1-225. Hood, S., and R. Mooi. 1998. Taxonomy and phylogenetics of extant Brisaster (Echinoidea: Spatangoida), pp. 681-686. R. Mooi and M. Telford, eds. Echinoderms: San Francisco, A. A. Balkema: Rotterdam. Jensen, M. 1974. The Strongylocentrotidae (Echinoidea), a morphologic and systematic study. Sarsia 57: 113-148. Lawrence, J. M., ed. 2007. Edible sea urchins: biology and ecology. 2nd Edition. Ansterdam: Elsevier, 529 pp. Lee, Y.-H. 2003. Molecular phylogenies and divergence times of sea urchin species of Strongylocentrotidae, Echinoida. Mol. Biol. Evol. 20: 1211-1221. McCauley, J. E., and A. G. Carey, Jr. 1967. Echinoidea of Oregon. J. Fish. Res. Bd. Canada 24: 1385-1401. Mooi, R. 1997. Sand dollars of t h e genus Dendraster (Echinoidea: Clypeasteroida): phylogenetic systematics, heterochrony, and distribution of living species. Bulletin of Marine Science, 61: 343-357. Mortensen, T. 1928-1951. A Monograph of the Echinoidea. 5 vols. Copenhagen: C. A. Reitzel. Pearse, J. S., and R. A. Cameron. 1991. Echinodermata: Echinoidea, pp. 513-662, In Reproduction of marine invertebrates. Vol. VI, Echinoderms and Lophophorates. A. C. Giese, J. S. Pearse, and V. B. Pearse, eds. Pacific Grove, CA: Boxwood Press.

Asteroidea CHRISTOPHER MAH

tertidal and subtidal interactions of m a n y species, such as t h e ochre star Pisaster ochraceus. Interspecific interactions between asteroids a n d o t h e r invertebrates were reported by Mauzey et al. (1968) a n d Birkeland (1974); Harrold a n d Pearse (1987) reviewed t h e role of asteroids and other echin o d e r m s in kelp forest ecosystems. Wobber (1975) docum e n t e d interspecific behavioral interaction between certain California sea stars. Jangoux (1982) and Sloan (1980) provided comprehensive reviews of asteroid diet and feeding behavior. As a group, sea stars feed opportunistically (Jangoux 1982). Some species are predators o n specific prey, such as Solaster dawsoni, which feeds u p o n other asteroids (Van Veldhuizen and Oakes 1981); others, such as Patiria miniata, are omnivores or detritivores. Since t h e previous edition of this book, there have been several comprehensive summaries of northwest Pacific Asteroidea. Feder (1980) reviewed most California shallow-water species and provided brief summaries of each species' biology, ecology, and natural history. Lambert (2000) provided a key and short accounts of biology and ecology for asteroids of British Columbia, and Kozloff (1987) provided a key to t h e shallow-water Asteroidea of Washington a n d Oregon. Brusca and Brusca (1978) listed asteroid species f r o m n o r t h e r n California. Hopkins and Crozier (1966) provided a key to a n d natural history of southern California asteroids. Among t h e earliest t a x o n o m i c m o n o g r a p h s of Pacific coast asteroids is t h a t of Verrill (1914). Fisher (1911, 1928, 1930) remains t h e authoritative m o n o g r a p h for asteroids f r o m this region. Asteroid identification is based primarily on endoskeletal characteristics. The elements of the endoskeleton, known as ossicles or plates, form regular series and complex arrangements that are often decorated with spines, granules, or other armam e n t or accessories. In most cases, observation with a dissection microscope or h a n d lens is all that is required for recognizing characteristics. Analysis of more subtle characters (e.g., valves of pedicellariae, plate form) may require minor preparation with sodium hypochlorite (common household bleach) for proper identification. Preservation in ethanol is best for observation of soft characters such as tube feet; however, most skeletal characters are best displayed in dry specimens. For many, the color of t h e living animals is the most useful diagnostic tool, but unfortunately color quickly fades in preserved specimens. Some species, such as Solaster stimpsoni and Solaster dawsoni, are immediately recognizable w h e n alive but are more difficult to distinguish w h e n preserved.

(Plates 4 6 3 - 4 6 6 )

Asteroids, also known as starfishes or sea stars, are familiar inhabitants of intertidal and subtidal California and Oregon. The asteroid fauna of the northeast Pacific is a m o n g the most diverse in the world, including m a n y endemic species, such as the well-known sunflower star Pycnopodia helianthoides. Two of the largest sea stars in the world, Pycnopodia helianthoides and Pisaster brevispinus, are found in our area, with adults reaching radii of 35 c m ^ O cm. Clark (1962) summarized general biology and diversity. Hyman (1955) remains a dependable account of functional morphology. Blake (1989) reviewed functional morphology, classification, and phylogeny. Feder (1980) provided excellent coverage of most shallow-water California and Oregon sea stars. Because of t h e i m p o r t a n t role sea stars play in m a r i n e ecosystems, there is an extensive literature concerning in-

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ECHINODERMATA

Terminology and Glossary The mouth-bearing or "bottom" side is referred to as the actinal, or oral, surface and the nonmouth-bearing, "top" side is the abactinal or aboral surface. Terms such as "dorsal" and "ventral" are discouraged in adult echinoderms owing to the incorrect suggestion of homology with t h e larvae or other bilateral animals. Actinal and abactinal also refer to structures located o n those surfaces. Thus, granules on the mouth-bearing side are referred to as actinal, or oral, granules. "R" and "r" refer to standard descriptive measurements used in reference to the body: R, the major radius, from the center of the disk to the arm tip; r, the minor radius from the disk center to t h e interradial edge (plate 463A).

PLATE 4 6 3 A, B, a b a c t i n a l (aboral) surface of g e n e r a l i z e d sea star.

Glossary Terminology follows Lambert (2000) and Clark and Downey (1992). Useful glossaries of terms may also be found in Spencer and Wright (1966). AMBULACRUM Midradial groove on lower surface of arm containing radial elements of water vascular system. Also referred to as a tube-foot groove (plate 464). ACTINAL INTERMEDIATE OSSICLES Area of a c t i n a l surface be-

tween marginals and adambulacrals (plate 464).

AMBULACRAL OSSICLES One of a paired series of plates within the ambulacrum, forming an arched channel for the radial water vessel, and between which the tube feet are extended (plate 463B). ADORAL CARINA One or more pairs of contiguous adambulacral behind each pair of mouth angle ossicles (plate 466C). ADAMBULACRAL OSSICLES One row on each side of the ambulacrum between and articulating with two successive ambulacral plates, defining the edge of the furrow (plates 463 B, 464). ASTEROIDEA

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PLATE 464 Actinal (oral) surface of generalized sea star.

PLATE 4 6 5 A, abactinal view of paxillae of Astropecten verrilli; B, C, sessile pedicellariae on a tabulate ossicle (B) and tabulate ossicles (C) of D, Crescentic abactinal ossicles of Patiria miniata; E, abactinal plates of Henricia leviuscula (original; E, from Verrill, 1914, plate 8 7 , la).

Mediaster aequalis;

ADAMBULACRAL S P I N E S Spines that sit upon adambulacral ossicles that project into the ambulacrum. These arrays are comprised of several spines in comb or forklike arrangements. ARM (=RAY) Radial part of sea star distal to disk (plate 463A). COMET Term referring to either a newly regenerated or postfissiparous sea star in which all but one partially or fully formed arm is attached to the disk, giving a cometlike appearance. This term is used particularly in reference to ophidiasterids, such as Linckia columbiae. D I S K Central part (body) of sea star from which arms project distally (plate 463A). FURCATE PEDICELLARIAE A type of stalked pedicellariae specific to Pisaster (plate 466B). INFEROMARGINAL OSSICLES ( = INFRAMARGINAL PLATES) T h e

lower of the two marginal ossicle series. Defines the ambitus of the actinal surface (plates 463B, 464). MADREPORITE (=SIEVE PLATE) A specialized, perforated, i n -

terradial plate on the abactinal surface of the disk, forming a sievelike opening for the water vascular system (plate 463A). MARGINAL PLATES: The two horizontal series of plates (ossicles), inferomarginal and superomarginal, usually defining the ambitus. Often larger and more regularly aligned than the other series of plates extending to the terminal plate (plates 463A, 463B, 464).

MOUTH ANGLE OSSICLE One of the pair of plates opposite the mouth at the apex of each lower interradius. PAPULAE Respiratory finger or glovelike pockets of the coelom that protrude through the body wall. PAXILLA(E) A columnar plate with the base usually expanded and the top crowned with a cluster of spinelets or granules. Found in sand or mud-dwelling sea stars such as Luidia or /Utropecten. They are believed to inhibit clogging of papulae and act as protection from predators (plate 465A). PEDICELLARIA(E) Small pincerlike organ on body surface, variously modified in shape and number of component valves. Plates 465B, 466A, and 466B show different types of pedicellariae. A review of pedicellarial form and function can be found in Jangoux and Lambert (1988). See also sessile, furcate, and stalked pedicellariae. PSEUDOPAXILLAE Superficially resemble paxillae, but the top crowned with spines which are extensions of the plate rather than articulated with the paxillae. Household bleach applied to the latter will remove the tissue articulating the spines to the paxillae. Found in Solaster. S E S S I L E OR BIVALVE PEDICELLARIAE Pedicellariae of two tonglike valves, sitting in a pit nearly flush with the asteroid surface or on tabulae, or paxillae. Found on tabulae and actinal surface of Mediaster (plate 465B). ASTEROIDEA

925

2.

—

3.

mouth angle ossicles

adorai carina

—

adambulacrals

4. —

5. PLATE 466 A, crossed pedicellariae of Leptasterias aequalis; B, furcate pedicellariae of Pisaster ochraceus; C, adoral carina of Orthasterias koehleri (A, from Fisher, 1930, plate 46, fig. 3a,b; B, from Fisher, 1930, plate 73, fig. 8a; C, from Fisher, 1928, plate 65, fig. 9).

—

6. STALKED (=CROSSED OR FORCIPULATE) PEDICELLARIAE Pedicellariae composed of two wrench-shaped valves that articulate at the base (plate 466A). Stalked pedicellariae are sheathed by epithelium and attached to the body surface with a stalk and frequently occur in wreaths or batteries around spines. Forciform pedicellariae are a form of stalked pedicellariae (plate 466B).

— 7.

SUPERMARGINAL PLATES ( = SUPRAMARGINAL PLATES) T h e

upper of the two marginal plate series. These plates define the ambitus of the abactinal/aboral surface (plates 463A, 464). SUPRADORSAL MEMBRANE Membrane found only in Pteraster tesselatus and other pterasterids. A second membrane suspended by pseudopaxillae over the abactinal surface, forming a tentlike cavity between the two surfaces. TABULAE Columnar structures, similar to paxillae. Crowned with prismatic or blunt spines rather than narrow stellate ones (plate 465C). TUBE FEET Two to four rows of tube feet occupy the tube foot groove along the radii of the underside, or actinal surface, of the sea star (plate 463B). Tube feet may be suckered or pointed. The latter are found only in the sand- or mud-inhabiting paxillosidan asteroids such as Luidia or Astropecten.

—

8.

—

9.

Key to Asteroides Species in the key and species list are those encountered in the intertidal to 2 m. Some subtidal species are included in the species list but not keyed out. Excellent color photographs are found in Gotshall (1994). 1. Eight to 24 or more arms 2 — Five to six arms (as a result of injury and regeneration, individuals with other than the normal number of arms also 926

E C H I N O DERM ATA

—

10.

occur) 4 Four rows of tube feet; with stalked or crossed pedicellariae (plate 466A) arranged in prominent rosettes around spines; pseudopaxillae absent; disk and arms, soft, fleshy, and flexible; typically 20-24 arms; color in life pink, purplish, or brown, less often red, orange, or yellow Pycnopodia helianthoides Two rows of tube feet; pedicellariae absent; pseudopaxillae present; disk and arms firm, not fleshy, and rigid; typically eight to 13 Solaster 3 Typically 10 arms (exceptionally nine or 11); arms long and slender; color in life red/orange with dark blue, purplish-gray strip radiating from disk along arms Solaster stimpsoni Typically 12-13 arms (exceptionally eight to 11); arms short and stocky; color in life solid brown to gray-yellow and occasionally red or orange Solaster dawsoni Tube feet suckered; paxillae absent on surface 5 Tube feet pointed, lacking a flaring disk; abactinal surface of body covered with paxillae (plate 465A); large marginal plates bearing short, stout spines Astropecten armatus Four rows of tube feet; stalked (=crossed or forcipulate) pedicellariae (plate 466A) never sessile; pedicellariae in wreaths around spines; adoral carina present in adults (plate 466C) 6 Two rows of tube feet; pedicellariae sessile or absent, never stalked (=crossed or forcipulate); adoral carina absent 12 Typically with six rays; in California adults not greater than R = 4.0 cm (Washington, Oregon, and northerly species of Leptasterias can be larger); R = 3r to 5r; with brooding embryos Leptasterias 7 Typically five rays; adults easily with R > 4.0 cm; R = 5r to lOr; no brooding embryos or eggs 8 Abactinal skeletal ossicles in distinct radial rows, midradial row conspicuous (denuding of abactinal spines may be necessary for observing the midradial ossicle series); arms stouter, thicker at base Leptasterias aequalis Abactinal skeletal ossicles not in distinct radial rows, midradial row not conspicuous, arms more slender Leptasterias pusilla Abactinal spines blunt or low in irregular series; adambulacral spines with pedicellarial clusters; arms thick and relatively short, R = 5.0-6.0r; relatively wider at base; larger central disk than above 9 Prominent sharp abactinal spines in regular series; adambulacral spines without attached pedicellariae; arms slender and deciduous; R = 6.0-10.0r; base of arms relatively slender; with small disk 11 Two to three adambulacral spines with clusters of pedicellariae; pedicellariae not furcate; abactinal spines neither blunt nor clublike, never in regular series; irregular reticulations over abactinal surface; arms more slender, R = 4.5-8.Or; color in life extremely variable Evasterias troschelii Single adambulacral spines; furcate pedicellariae (plate 466B); arms more stout, R = 2-5r; blunt, clublike abactinal spines sometimes forming regular series Pisaster 10 Midradial row of spines typically distinct, straight; spines on lateral and abactinal surfaces of arms not forming reticulated pattern (except rarely); color in life consistently whitish pink to deep pink sometimes mottled with graygreen or maroon purple Pisaster brevispinus

— Spines o n lateral and abactinal surfaces of arms very short and blunt, forming extensive irregular, reticulated pattern, or separate convex, curved groups at arm tips; distinct midradial row of spines not typically present, or at least n o t straight; color in life uniform orange, yellow, brown to reddish purple Pisaster ochraceus — Abactinal (aboral) spines typically blunt, club-shaped, relatively large, surrounded at base by rings of flesh (blue in life), with ring of pedicellariae outside fleshy ring; spines dense but typically not arranged in distinct radial or concentric rows; color in life yellow to gray with blue rings around bases of spines/pedicellariae Pisaster giganteus 11. Inferomarginal plates with two spines, each of which possesses clusters of crossed pedicellariae (plate 466A); color in life bright red/brick red-orange, often with yellow to white banding or mottling on arms Orthasterias koehleri — Inferomarginal plates with two spines, only one of which possesses a cluster of crossed pedicellariae; color in life bluebased spines and bright orange tips; surface is mottled graygreen to brown with distinct dark bands across the arms Astrometis sertulifera 12. Slender arms with small disk 13 14 — Body with large disk and broad, triangular arms 13. Surface covered with coarse hemispherical granules; two madreporites (exceptionally one, three, or four); variable number of blunt, cylindrical rays; fissiparous-occasionally f o u n d in "comet" stage; brooding absent; adambulacral spines, rounded-granular; color in life red with yellow to orange spots Linckia columbiae — Surface covered with reticulate network covered by fine spination (plate 465E); single madreporite; typically five slender arms; nonfissiparous; brooding present or absent; adambulacral spines needlelike; color in life bright red, light orange to dark brown with mottled tan-cream (see species description for explanation of quotation marks) Henricia spp. 14. Abactinal skeleton composed of crescentic-shaped plates forming a chain-maillike mesh (plate 465D); papulae emerge through mesh; abactinal surface with minute bifurcate or trifúrcate spines; n o distinctive odor; color in life highly variable, red-orange, blue, purple to cream or purple with light or dark mottling and blotches Patiria miniata — Surface almost completely smooth to t h e touch, covered with a velvety skin; papulae present in widespread patches over surface; n o pedicellariae; p u n g e n t garlic-sulfurous odor; color in life red to orange with gray-red imbrications Dermasterias imbricata — Surface covered with tabulate plates (plate 465C); with prominent marginals, covered by large prismatic granules, forming border around perimeter of body; sessile pedicellariae present o n tabulae (plate 465B); color in life bright red-orange Mediaster aequalis

List of Species PAXILLOSIDA A S T R O P E C T I N I DAE

Astropecten armatus Gray, 1840 (=A. brasiliensis armatus). Southern California species extending south from San Pedro. Shallow water (0-1 m) to subtidal depths. Frequently mistaken

for A. verrilli but possesses short, stout spines on superomarginal plates. An infaunal predator o n sand to m u d bottoms. Diet includes sea pansies, sand dollars, m u d snails, and jackknife clams. See Hopkins and Crozier (1966) and Segal 1988, Bull. So. Cal. Acad. Sci. 87: 35-38. Morin et al. (1985) treats interaction with other sand c o m m u n i t y inhabitants and ectoparasitism by the eulimid gastropod Polygireulima rutila. *Astropecten verrilli deLoriol, 1899 (=A. califomicus Fisher). Gotshall (1994) treats this species as a synonym of A. armatus, but the two are retained as distinct here. U n c o m m o n , poorly known; primarily subtidal. An infaunal predator occupying sandy bottoms; see Morin et al. (1985). LUIDIIDAE

*Luidia foliolata Grube, 1866. U n c o m m o n ; occurs on sandy bottoms at subtidal depths. Abactinal surface with subquadrate paxillae and long, straplike arms (R = 7.1-8.7r). A burrowing predator of infaunal invertebrates, mostly bivalves, but also ophiuroids, echinoids, holothurians, scaphopods, bivalves, polychaetes, and crustaceans (Sloan and Robinson 1982, Jangoux 1982). The brittle star Ophiura liitkeni displays a strong escape response f r o m this species (Lambert 2000). Pettibone (1953) reports two commensal polynoids, Arctonde pulchra and A. vittata.

VALVATIDA ASTERINIDAE

Patiria miniata (Brandt, 1835) (=Asterina miniata; see Clark 1983, Bull. Br. Mus. Nat. Hist. (Zool). 45; 359-380). This species was reassigned to Patiria by O'Loughlin and Waters 2004, Mem. Mus. Victoria 61: 1-40. "Bat stars" or "sea bats." Comm o n from low intertidal to subtidal depths. Bat stars are omnivores/predators, consuming echinoids, algae, sponges, bryozoans, tunicates and bryozoans (see Harrold and Pearse 1987). The worm Ophiodromus pugettensis is a commensal (Pettibone 1953). See Wobber (1975) (ecological interaction with asteroids); Schroeter et al. 1983, Oecologia 56: 141-147 (ecological interaction with t h e echinoid Lytechinus anamesus); Rumrill 1989, Mar. Ecol. Prog. Ser. 56: 37-47 (growth, reproduction and population biology); Leonard 1994, J. Exp. Mar. Biol. Ecol. 179: 81-98 (effect on recruitment of kelp Macrocystis). GONIASTERIDAE

Mediaster aequalis Stimpson, 1857. C o m m o n in the intertidal to subtidal depths. Sloan and Robinson (1983) report M. aequalis as a microphagous feeder with a very broad diet. Diet includes encrusting sponges, bryozoans, and sea pens (Mauzey et al. 1968, Birkeland 1974); also scavenges dead animals (Hopkins and Crozier 1966). See Birkeland, Chia, and Strathmann 1971, Biol. Bull. 141: 99-108 (development and growth). OPHIDIASTERIDAE

Linckia columbiae Gray, 1840. C o m m o n intertidally to subtidally in southern California; absent north of San Pedro. Possesses developed regenerative abilities, but seldom are individuals observed with all five rays perfectly intact, and frequently found as * = Not in key. ASTEROIDEA

927

"comets." Fisher (1911) provides extensive morphological evaluation. Food and feeding behavior are u n k n o w n , but possibly a particulate suspension feeder (Anderson 1960, Biol. Bull. 119: 371-398); other species of Linckia are substrate film feeders and microherbivores (jangoux 1982). Digestive morphology is described by Anderson 1962, Amer. Zool., 2: 387. See McAlary 1993, pp. 233-248, Third CA Islands Symposium (population structure).

boldt County) (Brusca and Brusca 1978). See Mauzey et al. (1968) (general diet); Van Veldhuizen and Oakes (1981) (escape response from S. dawsoni); two commensal scale worms, Arctonoe pulchra and A. vittata (Pettibone, 1953).

PORANIIDAE

Henricia spp. In b o t h shallow and deep waters; c o m m o n intertidally. This genus forms a puzzling complex o n the Pacific northwest coast, and the systematics of species along the California and Oregon coasts require revision. Fisher (1911) treated Henricia from California as H. leviuscula (Stimpson, 1857), but also noted that this n a m e may n o t be applicable to California populations. He also (Fisher 1911) described six distinct "varieties" of Henricia leviuscula from California. Some of these morphotypes may be separate species (D. Eemisse and M. Strathmann, pers. comm. 2005). Diet includes encrusting invertebrates (Mauzey et al. 1968), particulate suspension feeding (Anderson 1960; Rasmussen 1965) and detritus (Hopkins and Crozier 1966). Morphology of the digestive system is reported by Anderson (1960, Biol. Bull. 119: 371-398). See Lambert (2000) and Feder (1980) for reproductive biology. Brooding in Fisher's variety "F" is described by Chia (1966, as H. leviuscula).

Dermasterias imbricata (Grube, 1857). The leather star. Common, intertidal to 91 m (Maluf 1988). Ricketts et al. (1985: 285) note that D. imbricata is most numerous in the northern half of its range and that specimens " . . . found in Puget Sound are gigantic (diameter u p to 25 cm) by comparison with those in the tide pools of t h e protected outer coast." Leather star diets vary with region; feeds o n sponges, hydroids, bryozoans, colonial tunicates, algae, pennatulids, holothurians, echinoids, and even other asteroids (Jangoux 1982, Harrold and Pearse 1987). Elicits a dramatic escape response from actinarian sea anemones; see Dalby et al. 1988, Can. J. Zool. 66: 2484-2491; Elliott et al. 1989, Biol. Bull. 176: 73-78 (Stomphia) and Elliott et al. 1985, Can. J. Zool. 63: 1921-1929 (Urticina). Potentially mutualistic relationship with t h e polynoid worm Arctonoe vittata (Wagner et al. 1979, J. Exp. Mar. Biol. Ecol. 39: 205-210). *Poraniopsis inflata (Fisher, 1906). Primarily subtidal, seldom encountered. White to orange; pointed spines with a fleshy surface texture. Probably feeds on sponges. See Anderson and Shimek 1993, Zool. Biol. 12: 499-503 (diet and feeding habits in aquaria). Poraniopsis jordani Gotshall, 1994, is a nomen nudum and should be removed from use.

VE LATI DA PTERASTERIDAE

*Pteraster tessellatus Ives, 1888. Subtidal depths, seldom encountered. Stellate (R = 1.6-1.6r) along most of its range with t h e more pentagonal subspecies (R = 1.44r). Very thick, fleshy species with unique supradorsal membrane. Color a cream/tan with dark mottling. Pteraster tessellatus arcuatus Fisher, 1928, in Monterey Bay is a probable synonym. Utilizes mucus as a defense mechanism against predators (see Nance and Braithwaite 1979, J. Exp. Mar. Biol. Ecol. 40: 259-266; 1981, J. Exp. Mar. Biol. Ecol. 50: 21-31). McEdward 1992, Biol. Bull. 182: 177-187; McEdward 1995, Biol. J. Linn. Soc. 54: 299-327 (evolution of pelagic direct development); Harley et al. 2006, Biol. Bull. 211: 248-262 (color polymorphism). SOLASTERIDAE

Solaster dawsoni Verrill, 1880. U n c o m m o n . Largely subtidal, rarely very low intertidal; primarily northern. Feeds o n asteroids, preferentially o n its congener Solaster stimpsoni (Van Velduizen and Oakes 1981). Feder (1980) reports that S. dawsoni also feeds on holothurians and, in the laboratory, elicits escape responses from the nudibranch Tritonia. See Lambert (2000) for commensal polynoids Arctonoe fragilis and A. vittata. Solaster stimpsoni Verrill, 1880. U n c o m m o n . Predominantly subtidal, but in the low intertidal of northern California (Hum* = Not in key. 928

ECHINODERMATA

SPINULOSIDA ECHINASTERIDAE

FORCIPULATIDA ASTERIIDAE

Astrometis sertulifera (Xantus, 1860). Rare in southern California. Brusca (1980) reports that in t h e Gulf of California smaller specimens often occur in the low intertidal zone, apparently migrating offshore as they mature. Larger specimens are always found subtidally. The smaller individuals are considerably less flexible t h a n their larger, older kin. This species is considered a "voracious predator" of gastropods, pelecypods, and barnacles (Brusca 1980). Further prey items include chitons, the ophiuroid Ophiothrix spiculata and occasionally sea urchins (Feder 1980). Small crabs and even fishes as large as the sea star itself can be held by pedicellariae for feeding (Jennings 1907, U.C. Publ. Zool. 4: 43-185, but misidentified there as ,4sterias forreri (=Stylasterias forreri)). Evasterias troschelii (Stimpson, 1862). Intertidal to 70 m; n o t south of Monterey. Frequently mistaken for Pisaster. Fisher (1930) describes variation in E. troschelii and considered it as a m o n g the most variable of sea stars. Lambert (2000) noted that it displaces Pisaster ochraceus in sheltered inlets. Mauzey et al. (1968) report that the diet varies with the relative abundance of prey, which includes bivalves, limpets, snails, brachiopods (Terebratalia), barnacles (Balanus glandula), a n d tunicates. See Christensen 1957, Limnol. Oceanogr. 2: 180-197 (feeding on bivalves); Young 1984, Echinodermata, Proc. 5th IEC, 577-583 (feeding o n ascidians). The polynoid Arctonoe fragilis is a commensal, occurring in the ambulacral groove and o n the body surface (Feder 1980). See also Patterson et al. 1978, J. Exp. Mar. Biol. Ecol. 33: 51-56. Leptasterias spp. A species complex exists o n the northwest Pacific coast. See Foltz 2001, Mar. Biol. 139: 475-483 and references therein. Papers pertaining to biology of Leptasterias (mostly L. hexactis) include Chia 1966, Biol. Bull. 130: 304-315; Chia 1968, Acta Zool. 49: 321-364; Menge 1975, Mar Biol. 31:

87-100, Menge and Menge 1974, Ecol. Monogr. 44: 596-600 (competition with P. ochraceus) Leptasterias aequalis (Stimpson, 1862). In the previous edition as L. hexactis; see Foltz et al., 1996, Can. J. Zool. 74: 1275-1283. Common, south to San Simeon, CA. MacGinite and MacGinitie 1968, Nat. Hist. Marine Animals, 2nd ed., notes eggs brooding in February and March. Pearse and Beauchamp 1986, Intl. J. Inv. Reprod. Develop. 9: 289-297 report photoperiod relative to feeding and reproduction. Leptasterias pusilla (Fisher, 1930). The validity of this species is unclear. See Foltz 2001 (cited above). A predator on small snails and limpets (Feder 1980). See also Smith 1971, Ph.D., Biological Sciences, Stanford University, 229 pp. Orthasterias koehleri (de Loriol, 1897). Rainbow star. An uncommon, chiefly subtidal species (to 250 m), but occasionally found in the low intertidal (Ricketts et al. 1985). Diet extremely varied but predominantly composed of bivalves, as well as limpets, barnacles, chitons, snails, tunicates, and brachiopods (Terebratalia). Mauzey et al. (1968) suggest an ontogenetic diet shift. Lambert (2000) reports breeding from June to August. The polynoid polychaete Arctonoe fragilis is a commensal (Lambert, 2000). Pisaster brevispinus (Stimpson, 1857). Pink sea star. Common, intertidal to 102 m. Sandy to muddy bottoms; a highly specialized predator on infaunal bivalves and gastropods and able to extend the central tube feet into the substrate to capture prey for a distance roughly equal to the radius of the arm (Van Veldhuizen and Phillips 1978, Mar. Biol. 48: 89-97). Diet also consists of sand dollars Dendraster excentricus (Farmanfarmaian et al. 1958) and the olive snail Callianax biplicata (Feder, 1980). Both of these species display escape responses to P. brevispinus. On hard substrate, this species also preys upon barnacles (Balanus spp.), mussels (Mytilus spp.), and tube-dwelling annelids (Feder 1980). See Wobber (1975) (agonistic bouts) and Farmanfarmaian et al. (1958) (reproductive cycles). Pisastergiganteus (Stimpson, 1857). Intertidal to 374 m depth. Only exceptionally found north of San Francisco; although recorded as far north as Vancouver Island by Fisher (1930), this has not been confirmed in recent years (P. Lambert, pers. comm., 1999). Fisher (1930) recognized a southern subspecies Pisaster gigantean capitatus, which possesses more clublike abactinal spines. P. giganteus is a predator with a broad-based diet consisting primarily of gastropods, bivalves, barnacles and detritus (Harrold and Pearse 1987). See also Landenberger 1968, Ecology 49: 1062-1075 (feeding), and 1969, Physiol. Zool. 42: 220-230 (distributional ecology); Stubbs 1998, pp. 293-297, in Echinoderms: Proc. 9th, Intern. Echinoderm Conf. (diurnal behavior patterns); Farmanfarmaian et al.1958; Pearse et al. 1988 (reproductive biology). Pisaster ochraceus (Brandt, 1835). Ochre star. Among the most studied sea stars on the Pacific coast. Feder (1980) provides an older review. For morphological variation see Fisher (1930). See Menge 1975, Ecology 31: 87-100; Menge and Menge 1974, Ecology 44: 189-209 (competition with Leptasterias); Palumbi and Fred 1988, Ecology 69:1624-1627 (agonistic interactions); Miller 1986, Veliger 28: 394-396 (interaction with gastropods); Feder 1970, Ophelia 8:161-185 (feeding and ecological interaction with the mussel, Mytilus); Patton et al. 1991, Bull. Mar. Sci. 48: 623-634 (ecology, interaction with Corynactis califomica); Paine 1976, Ecology 57: 858-873 (role of P. ochraceus as a "keystone species" affecting distributional patterns); Abed and Crawford 1986, J. Morphology 188: 239-250 (development and growth). Harley et al. 2006, Biol. Bull. 211: 248-262 (color polymorphism). *Sclerasterias heteropaes Fisher, 1924. A rarely encountered, poorly known species. Subtidal from Monterey to southern

California. Co-occurs with Astrometis sertulifera. Relatively large with R = 10 cm. Oral surface is pale with lack of color on spines. Found in deeper kelp beds among rocks and holdfasts (Hopkins and Crozier 1966). 'Stylasterias forreri (de Loriol, 1884). Subtidal. Can approach considerable arm radius (R = 20 cm-25 cm). Catches motile prey such as fish with its pedicellariae. See Robilliard 1971, Syesis 4: 191-195; Chia and Amerongen 1975, 53: 745-755. Reproductive biology in Pearse et al. (1988). PYCNOPODIIDAE

Pycnopodia helianthoides (Brandt, 1835). The sunflower star. Low intertidal to 435 m. Below 100 m depth, this species is frequently confused with Rathbunaster californicus Fisher. In Baja California/Mexico P. helianthoides is confused with Coronaster marchennus Ziesenhenne. Prey of P. helianthoides includes gastropods, but also chitons, pelecypods, barnacles, and echinoids. This species often elicits alarm responses in other invertebrates (e.g., Weightman and Arsenault 2002, Can. J. Zool. 80: 185-190. Feder (1980) provides a summary of the biology; see also Shivji et al. 1983, Pac. Sci. 37: 133-140 (feeding and distribution); Sloan and Robinson (1983); Harrold and Pearse (1987, prey in Alaska, Canada, and central California); McClintock 1989, Comp. Biochem. Phys. A, Comp. Phys. 93: 695-698 (growth); Wobber 1975 (agonistic bouts with other sea stars), Lawrence 1991, Mar. Behav. Phys. 19: 39-44 (alarm response to other P. helianthoides); Mladenov et al. 1989, Biol. Bull. 176: 169-175; Wilkie et al. 1995, pp. 137-146 in Proc. 4th European Echinoderms Colloquium, (autotomy).

ACKNOWLEDGMENTS

Thanks to John Pearse, Gil Van Dykhuizen, Rich Mooi, James Watanabe, Steve Lonhart, Jon Flowers, Dave Foltz, and Megumi Strathmann for assistance, and Patricia Liu, CAS-Education, who provided line drawings for plates 465A and 466.

References Anderson, R. C., and R. L. Shimek. 1993. A note on the feeding habits of some uncommon sea stars. Zoo Biology 12: 499-503. Birkeland, C. 1974. Interactions between a sea pen and seven of its predators. Ecological Monographs 44: 211-232. Blake, D. B. 1989. Asteroidea: Functional morphology, classification and phylogeny. Echinoderm Studies 3: 179-223. Brusca, G. C., and R. C. Brusca. 1978. A Naturalist's Seashore guide: common marine life of the northern California coast and adjacent shores. Mad River Press, Eureka, CA, 205 pp. Brusca, R. C. 1980. Common intertidal invertebrates of the Gulf of California. 2nd ed. University of Arizona Press, 513 pp. Chia, E S. 1966. The development of two brooding sea stars, Henricia leviuscula and Leptasterias hexactis. American Zoologist 5: 3 3 1 - 3 3 2 (abstract). Clark, A. M. 1962. Starfishes and their relations. London, British Museum (Nat. Hist.) 119 pp. Clark, A. M., and Downey, M. E. 1992. Starfishes of the Atlantic. Chapman and Hall, London, 794 pp. Farmanfarmaian, A., A. C. Giese, R. A. Boolootian, and J. Bennett. 19S8. Annual reproductive cycles in four species of west coast starfishes. Journal of Experimental Zoology 138: 355-367. Feder, H. M. 1980. Asteroidea: The Sea Stars, pp. 117-135. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie, eds., 690 pp. Stanford University Press. * = Not in key. ASTEROIDEA

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Fisher, W. K. 1 9 1 1 . Asteroidea of the North Pacific and adjacent waters. Part 1. Phanerozonia and Spinulosa. Bulletin of the United States National Museum 76, 4 1 9 pp. Fisher, W. K. 1 9 2 8 . Asteroidea of the North Pacific and Adjacent Waters, Pt. 2: Forcipulata (Part). Bulletin of the United States National Museum 76, 2 4 5 pp. Fisher, W. K. 1930. Asteroidea of the North Pacific and Adjacent Waters, Pt. 3: Forcipulata (Concluded). Bulletin of the United States National Museum 76, 3 5 6 pp. Gotshall, D. W. 1 9 9 4 . Guide to Marine Invertebrates: Alaska to Baja California. Sea Challengers Press, Monterey, CA, 105 pp. Harrold, C., and J. S. Pearse. 1 9 8 7 . The ecological role of echinoderms in kelp forests. Echinoderm Studies 2: 1 3 7 - 2 3 3 . Hopkins, T. S., and G. F. Crozier. 1 9 6 6 . Observations on the asteroid echinoderm fauna occurring in the shallow water of southern California (intertidal to 6 0 m). Bulletin of the Southern California Acade m y of Sciences 6 5 : 1 2 9 - 1 4 5 . Hyman, L. H. 1 9 5 5 . The Invertebrates: Vol. IV. Echinodermata. McGrawHill, 1 - 7 6 3 . Jangoux, M. 1 9 8 2 . Food and feeding mechanisms: Asteroidea, pp. 1 1 7 - 1 5 9 . In Echinoderm nutrition. M. J a n g o u x and J. M. Lawrence, eds. Rotterdam: A. A. Balkema. Jangoux, M., and A. Lambert. 1 9 8 8 . Comparative a n a t o m y and classification of asteroid pedicellariae, pp. 7 1 9 - 7 2 3 . In Echinoderm biology. R. D. Burke et al., eds. Rotterdam: Balkema. Kozloff, E. N. 1987. Marine Invertebrates of the Pacific Northwest. University of Washington Press, 5 1 1 pp. Lambert, P. 2 0 0 0 . The Sea Stars of British Columbia. British Columbia Provincial Museum Handbook 3 9 . 1 8 6 pp. Maluf, L. Y. 1988. Composition and distribution of the Central Eastern Pacific Echinoderms. Natural History Museum of Los Angeles County Technical Report No. 2. 1 - 2 4 2 . Mauzey, K. P., C. Birkeland, and P. K. Dayton. 1 9 6 8 . Feeding behavior of asteroids and escape responses of their prey in the Puget Sound region. Ecology 149: 6 0 3 - 6 1 9 . Morin, J. G., J. E. Kastendiek, A. Harrington, and N. Davis. 1 9 8 5 . Organization and patterns of interactions in a subtidal sand c o m m u nity o n an exposed coast. Marine Ecology Progress Series 2 7 : 163-185. Pearse, J. S., D. J. McClary, M. A. Sewell, W. C. Austin, A. Perez-Ruzafa, and M. Byrne. 1 9 8 8 . Simultaneous spawning of six species of echinoderms in Barkley Sound, British Columbia. Invertebrate Reproduction and Development 14: 2 7 9 - 2 8 8 . Pettibone, M. H. 1 9 5 3 . Some scale-bearing polychaetes of Puget Sound and adjacent waters. University of Washington Press, Seattle, 8 9 pp. Rasmussen, B. 1 9 6 5 . On t a x o n o m y and biology of the North Atlantic species of the asteroid genus Henricia Gray. Medd. Danm. Fisk.Havunders 4: 1 5 7 - 2 1 3 . Ricketts, E. F., J. Calvin, J. W. Hedgpeth, and D. W. Phillips. 1 9 8 5 . Between Pacific Tides. 5 t h ed. Stanford University Press, 6 5 2 pp. Sloan, N. A. 1 9 8 0 . Aspects of the feeding biology of asteroids. Ocean. Mar. Biol. Ann. Rev. 18: 5 7 - 1 2 4 . Sloan, N. A., and S. M. C. Robinson. 1 9 8 3 . Winter feeding by asteroids o n a subtidal sandbed in British Columbia. Ophelia 22: 1 2 5 - 1 4 0 . Spencer, W. K., and C. W. Wright. 1 9 6 6 . Asterozoans, Part U: Echinodermata In R. C. Moore, ed. Treatise o n Invertebrate Paleontology 3(1): U 4 - U 1 0 7 . Lawrence: University of Kansas Press. Van Veldhuizen, H. D., and V. J. Oakes. 1 9 8 1 . Behavioral responses of seven species of asteroids to the asteroid predator, Solaster dawsoni. Oecologia. 4 8 : 2 1 4 - 2 2 0 . Verrill, A. E. 1 9 1 4 . Monograph of the shallow-water starfishes of the North Pacific coast from the Arctic Ocean to California. United States National Museum, Harriman Alaska series 14, 4 0 8 pp. Wobber, D. R. 1975. Agonism in asteroids. Biological Bulletin 1 4 8 : 4 8 3 - 4 9 6 .

Ophiuroidea GORDON HENDLER (Plates 467-470)

As a general rule, ophiuroids are more numerous and diverse, more agile, and frequently more colorful and attractive than other echinoderms. In central California and Oregon, intertidal species represent a minor but resilient subset of much 930

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more populous, wide-ranging, subtidal ophiuroid populations. This is also the case worldwide, as the number of ophiuroid species is typically higher in comparatively stable deeper-water environments than in shallow water. Intertidal species are a relatively small component of total ophiuroid biodiversity. Of more than 2,000 species of ophiuroids that have been described, only one well-studied species, the subtropical and tropical Ophiocoma scolopendrina (Lamarck, 1816), is clearly adapted to the intertidal zone. Although the first account of eastern Pacific ophiuroids was published more than 150 years ago, they have not been extensively studied, and their representation in museum collections and coverage in the scientific literature is limited. A better appreciation of their natural history will emerge with further investigation, and future research will reveal previously unreported and undescribed species along the Pacific coast. The present section provides updates and revisions since the previous edition in 1975. For example, the ophiuroids referred to as Amphiodia sp. and Ophionereis eurybrachiplax H. L. Clark, 1911, in past editions are now Amphiodia akosmos Hendler and Bundrick, 2001, and Ophionereis diabloensis Hendler, 2002. Ophiopholis aculeata var. kennerlyi is accorded species-level status as Ophiopholis kennerlyi (Lyman, 1860). In addition, Ophionereis eurybrachiplax and Amphiodia urtica (Lyman, 1860) are expunged from the list of the intertidal fauna from central California and Oregon. Ophiuroids are identified in different languages by vernacular names, which bear little relation to their classification or phylogeny. In English, ophiuroids with unbranched arms are called brittle stars, and sometimes serpent stars or snake stars. The attribution "brittle" refers to the ability of ophiuroids to voluntarily cast off (autotomize) their arms when adversely stimulated. However, the propensity to do so varies widely among different species. During autotomy, which is under nervous control, the mutable connective tissue linking the arm joints abruptly deteriorates, and the arm immediately disarticulates at the weakened junctures. Pieces of the arm that separate from the disk can remain active for many hours. The stump of arm remaining attached to the disk forms a new growing tip and may eventually regenerate to its original length. Moreover, some ophiuroids, chiefly in the family Amphiuridae, can autotomize a portion of the disk as well as the arms. Afterwards, they regenerate the body wall, gonads and digestive tract from remnants of the body. The English term for ophiuroids with branching arms is basket stars, a name based on the tendency of individuals pulled from the water to coil and compact their arborescent arms into a massive knot, creating the appearance of a woven basket. Individuals in the two families that have branching arms, Gorgonocephalidae and Euryalidae, begin life with five simple arms. During development, the arms bifurcate, and the sister branches may continue to subdivide dichotomously, the pattern of branching nodes depending on the species. The rings of microscopic hooks that encircle the distal arm tendrils of gorgonocephalids are used to secure the zooplankters on which they feed, and to hold the animals fast to rocky reefs. Gorgonocephalus eucnemis (Müller and Troschel, 1842) is the only local basket star species. Off the California coast, it inhabits deep water, but it thrives in greater numbers in the frigid shallow water of the north Pacific. Many ophiuroid species are cryptic, particularly those in shallow waters. They occupy shelter afforded by inanimate objects and sessile biota, often tucked in inaccessible and virtually undetectable crannies. As they increase in age and body size, many ophiuroids, including California and Oregon intertidal species,

migrate from one microhabitat to another. Most large intertidal ophiuroids live in bedrock, beneath boulders and cobbles. The smallest species, and juveniles of larger species, occur among fronds, holdfasts, and rhizomes of plants, and in protective clumps of bryozoans, hydroids, worm tubes, echinoid spines, and so on. A search among fouling communities on pilings, buoys, and marina floats will also often produce smaller species. Burrowing species remain loosely or deeply covered in sediment. Although ophiuroids are almost exclusively marine, a few species tolerate brackish environments, and to varying degrees, intertidal species can tolerate freshwater runoff and rain, sedimentation, pollution, and desiccation. They generally avoid anoxic conditions, and for that reason ophiuroids flourish where water circulation is relatively unobstructed, such as beneath rocks that rest loosely on coarse sediment. Species inhabiting sponges depend on water currents created by the host, and those that burrow in fine sediment create currents that irrigate their burrows. Many echinoderms are so incredibly slow-moving that their behavior is clearly perceptible only in a time-lapse recording. However, some ophiuroids defy that rule, and their intricately jointed and muscled arms execute lithe, rapid feeding and escape responses. It is commonly presumed that, excepting basket stars and related species, ophiuroids are capable of moving their arms only in a horizontal plane. However, numerous species can conform their arms to the irregular dimensions of crevices, lock their arms rigidly when disturbed, nimbly flex their arms during locomotion, and deftly coil their slender, distal arm tips. Brittle stars can gallop by sweeping their arms in rowing strokes, or crawl by combining dragging and pushing efforts. Long-armed species often employ a combination of tube-foot and muscular whole-arm movements. Small and juvenile ophiuroids, and the adults of some species, advance solely by flexing their tube feet, much as a centipede uses its legs. Further, certain species respond to sudden suspension in the water column by reflexively folding the arms above the disk, to minimize drag and maximize the rate of sinking. Although none of the ophiuroids discussed in the manual can swim, there are specialized, highly active species with that capability. Ophiuroids have been mischaracterized as strict deposit feeders with a monotonous diet and a limited repertoire of feeding behaviors. However, all ophiuroids are to some degree selective feeders, and various species are specialized to pursue and capture other animals, collect particles of sediment and debris, and scavenge plant and animal remains, offal, and feces. Macrophagous ophiuroids ensnare edible items in coils of their arms, which like an elephant's trunk convey food to the mouth. Microphagous species, whether suspension or deposit feeders, entangle particles in the mucus on their arm spines and tube feet. The tube feet compact particles into a bolus, which is passed down the arm and transferred to the mouth. Ophiuroids can open their mouths to a surprising extent, and their flexible disks can be distended to a considerable degree, permitting large masses of particulate material or bulky prey to be accommodated within the gut. After material is processed in the stomach, it is expelled from the mouth and may then be conveyed out along the arm by the tube feet. In addition to ingesting solid food, ophiuroids can extract dissolved nutrients from seawater and obtain soluble organic material from symbiotic bacteria living within their tissues. The sensory abilities of ophiuroids are exceedingly acute. Sensitive chemoreceptors enable them to detect and rapidly respond to minute quantities of waterborne chemicals liberated

by food. Touch receptors enable them to deftly manipulate minute particles, and trigger escape reactions in response to potential predators and physical disturbance. It is unlikely that ophiuroids can locate prey visually, but species in the photic zone typically rely on photoreception to find shelter. Their preference for shadow and shelter is related to the avoidance of predation by fish, crustaceans, asteroids, and other benthic predators. Different species show contrasting responses to illumination. Epifaunal ophiuroids may "freeze" in response to shadow, and cryptic ophiuroids preferentially move away from bright light. Photoreceptors appear to be situated within the skeleton, which in some cases is modified and acts in concert with chromatophores to concentrate and direct light. The details of reproductive biology have been elucidated for relatively few ophiuroid species. Although it is presumed that most ophiuroids have planktonic feeding larvae, few such species have been reared through metamorphosis. Referred to as an ophiopluteus, the planktotrophic larva is bilaterally symmetrical, with up to eight arms supported by a glassy calcite skeleton, and bears a single, sinuous band of cilia used for locomotion and feeding. In some cases, the ophiopluteus resorbs the larval arms prior to metamorphosis and transforms into an irregularly ellipsoidal, secondary larva with transverse rings of cilia positioned between the developing appendages of the ophiuroid rudiment. Species with planktonic, nonfeeding larvae have reduced, yolky larvae resembling the armed ophiopluteus or the secondary larva. The planktonic larvae develop from eggs that are released in the water and fertilized externally. Brooding species hold the eggs and embryos in internal bursae. Brooders are usually hermaphroditic, and at least one species is capable of self-fertilization, whereas broadcast-spawning ophiuroids generally have separate sexes that are superficially indistinguishable. Nonfeeding larval development can take as few as three days, but feeding larvae may require several months to complete metamorphosis. Ophiuroid life spans have not been documented with precision, but depending on the species, individuals may mature, reproduce, and die within one or two years, or live several decades and longer. Longevity is particularly difficult to pinpoint among the small number of species that reproduce asexually while larvae, or as adults in a process termed fissiparity. The fissiparous species generally have six arms and split across the disc to produce two genetically identical brittle stars that have part of a disk and three arms. The animals regenerate the missing components of arms and disk and thereafter are capable of further fissiparity and of perpetuating a prolific, longlived clone.

Morphology and Terminology The critical structures for the identification of ophiuroids are the superficial skeletal elements, but to appreciate ophiuroid biology it is necessary to "lift the hood" and study their internal structures. Further, the present account is tailored to the identification of a small number of species and barely suggests the profound anatomical adaptations that have evolved in the ophiuroid body plan. The literature cited below may be consulted for more extensive, detailed information on morphology. Plate 467 should be referred to for illustrations of anatomical structures and also bolded terms, and their abbreviations in parentheses in this section. Despite the common misconception that they have an "exoskeleton," the skeleton of ophiuroids is internal, consisting of OPHIUROIDEA

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P L A T E 4 6 7 Ophiuroid anatomy illustrated with scanning electron micrographs, integument is removed from structures to reveal the skeleton: Al, A2, juvenile Ophioplocus esmarki labeled to show structures of the dorsal surface (Al), ventral surface (A2) of the disk and arms; B, distal tip of the arm of Ophiactis simplex with intact soft tissue structures, showing integument covering the skeleton and the extended tube feet; small arrows, tube foot papillae; arrowhead, terminal bulb of tube foot; a pore through which the terminal tube foot can be extended is visible at the tip of the terminal plate; C1-C3, sections of the arm of Amphiodia occidentalis, with tube feet removed, showing structures of the ventral surface (CI), lateral surface (C2), dorsal surface (C3), with several dorsal arm plates removed to reveal the vertebrae within the arm joints; C2, arrowhead arm-spine articular surface on the lateral arm plate; C3, arrowheads in intervertebral muscle tissue; D-G, details of the oral structures of Ophiactis simplex (arrowhead, hydropore of madreporite) (D); Amphiodia occidentalis (E); Ophiopteris papillosa (F); Ophiothrix spiculata (G), labeled to show the arrangement of oral papillae, dental papillae, and infradental papillae in several types of oral armament. Abbreviations: ads, adoral shield; aj, arm joint; as, arm spine; bs, bursal slit; cp, central plate; dap, dorsal arm plate; dp, dental plate; dpa, dental papilla; ipa, infradental papilla; j, jaw; lap, lateral arm plate; m, mouth; mad, madreporite; opa, oral papilla; ors, oral shield; pp, primary plate; rp, radial plate; rs, radial shield; sc, scale; t, tooth; tf, tube foot; tp, terminal plate; tpo, tentacle pore; ts, tentacle scale; vap, ventral arm plate; v, vertebra; vir, ventral interradius.

O S S I C L E S that are each composed of a single calcite crystal enveloped in a thin layer of integument. The names used for specific ossicles are inconsistent, even in English, and descriptive terms like plate, shield, scale, spine, and papilla are somewhat arbitrary. The nomenclature adopted here is widely but not universally in use (below, some common alternative expressions are presented parenthetically). Also, be aware that the key features of an ophiuroid, including its overall appearance, color, and the numbers and shapes of specific ossicles, change markedly as an individual grows.

The ophiuroid body consists of a central hub, the DISK, from which radiate five or more A R M S (plate 467A). The P R O X I M A L direction is toward the center of the disk, and the DISTAL direction is toward the tips of the arms. The arms are composed of numerous A R M J O I N T S (aj), also called segments, that are generated at the distal tip of the arm. Those nearest the disk are the oldest and largest, as they increase in girth as the animal grows. On the V E N T R A L (=oral) surface of the animal, which usually faces the substrate, are a star-shaped M O U T H ( M ) at the center of the disk and pairs of tube feet that emerge along the length of the arm (plate 467A2, 467B). The opposite side of the animal is referred to as D O R S A L (=aboral). The joints are composed of a protective ossicle on each principal surface, including a D O R S A L A R M PLATE (dap), a V E N T R A L A R M PLATE (vap), and a pair of LATERAL A R M PLATES (lap), which surround a V E R T E B R A ( V ) that superficially resembles one of the bones of a spinal column (plate 467C). The vertebrae each have articulating protuberances and attachment surfaces for the intervertebral muscle, ligament, and connective tissue that link the arm joints. The dorsal arm plate may be a large solitary plate (plate 467C3), or consist of a dominant plate associated with one or more minute ACC E S S O R Y D O R S A L A R M P L A T E S at its edges (plates 468D1, 469C1), or it may be composed of a mosaic array of associated plates (plate 468C1). The lateral arm plates typically bear one or more moveable ARM SPINES (as) that are used for protection, locomotion, and feeding (plate 467C). The first ventral arm plate is positioned at the edge of the mouth, and the most distal arm ossicle is the cylindrical TERM I N A L PLATE (tp) (plate 467A1, 467B), through which projects a terminal tube foot. In addition, there are two T U B E F E E T (tf) (=podia, tentacles) per arm joint, and each protrudes through a T E N T A C L E P O R E (tpo) situated between a lateral arm plate and the ventral arm plate on the ventral surface of each arm joint (plate 467A2, 467C1). Protecting the retracted tube foot are one or more small ossicles, T E N T A C L E S C A L E S (ts), which arise from the lateral or ventral arm plate and overlap the tentacle pore. The tube feet are appendages of a W A T E R - V A S C U L A R S Y S T E M , an organ system found exclusively in echinoderms and composed of flexible, muscular, fluid-filled tubes. It consists of a circular canal within the disk, and a radial canal in each arm from which the tube feet branch. They are used as sensory and respiratory structures and may function in feeding and locomotion. Particularly in suspension feeding species, tube feet are equipped with microscopic PAPILLAE rich in sensory structures and mucus secreting glands (plate 467B). Those of deposit feeders have a smooth shaft lacking papillae, and a T E R M I N A L B U L B with secretory glands (plate 46 7B). The disk develops in the ophiuroid larva, beginning as a series of six ossicles that consist of a C E N T R A L PLATE (cp) and five concentrically arranged RADIAL PLATES (rp), which are referred to collectively as P R I M A R Y P L A T E S (pp) (plate 467A1). Depending on the species, they may comprise most of the dorsal surface of the adult disk, be barely discernible, or be entirely

resorbed in the adult. Generally, the primary plates are separated or entirely supplanted by the numerous intercalary ossicles called S C A L E S (sc), which may be large and robust, or small and delicate. And often the disk scales and plates are overlain by an armament of microscopic ossicles, such as slender sharp S P I N E S (plate 469A1) or blunt P A P I L L A E , short S T U M P S , spherical G R A N U L E S (plate 468A1, 468B1), or large T U BERCLES. In some cases, the scales themselves take the form of spines, tubercles, or nearly invisible granules that are resorbed and incorporated in the connective tissue of the body wall, RADIAL S H I E L D S (rs) are frequently the most conspicuous ossicles on the dorsal disk surface (plate 467A1). They consist of a pair of mirror-image ossicles at the base of each arm, and together with an inconspicuous series of internal ossicles, they fasten the disk and arms together. On the ventral surface of the disk are triangular JAWS (j) that extend inward from between the bases of the arms and work to open and close the centrally located mouth (plate 467A2). Each jaw is composed of modified vertebrae (ORAL PLATES) and carries two pairs of tube feet (ORAL TENTACLES) that project into the mouth, manipulate incoming food, and disperse outgoing waste. Most of the digestive tract is a blind, pouch-shaped stomach that fills the disk and opens at the mouth. Ophiuroids lack an anus. The most basal arm joints are connected to the jaws and disk, and the wedge of disk between pairs of arms is referred to as a V E N T R A L I N T E R R A D I U S (vir) (pi. interradii). The outer edges of the interradius are creased alongside the base of the arms, and in each crease an orifice, the B U R S A L S L I T (bs), opens into a B U R S A (=respiratory bursa, genital bursa). The edge of the slit may bear rounded granules or minute, blunt spines (GENITAL PAPILLAE). The bursa itself is a thin pouch, an inpocketing of the disk integument, which is inserted within the disk between the stomach and the body wall. The ciliated walls of the bursa (pi. bursae) circulate seawater for respiratory exchange, and the gonoducts discharge gametes near the bursal slit. In viviparous species, embryos develop within the bursa, and the eggs and embryos absorb nutrients from the surrounding tissues. A vertical column of T E E T H (t) extends dorsally into the mouth, along the proximal edge of each jaw, attached to an inconspicuous DENTAL PLATE (dp) (plate 467D). In most ophiuroids, a series of small scale- or spine-shaped ossicles, the ORAL PAPILLAE (opa), are attached to the edge of each jaw, nearly flush with the ventral surface of the disk (plate 467D-467F). Instead of or in addition to oral papillae, some species have structures at the apex of the jaw, ventral to the teeth. They are called I N F R A D E N T A L P A P I L L A E (ipa) if they are a pair of blocklike ossicles (plate 467E) and are called DENTAL PAPILLAE (dpa) (=tooth papillae) if they consist of a close-set group of blunt ossicles (plate 467F, 467G). A trio of conspicuous ossicles lies between the jaw and the ventral interradius, composed of an ORAL S H I E L D (ors) flanked on each side by an A D O R A L S H I E L D (ads) (plate 467D-467G), the latter ossicle usually connecting the jaw and arm. One of the oral shields serves as a M A D R E P O R I T E (mad) and may often be distinguished by its relatively large size and sometimes by the presence of one or more H Y D R O P O R E S that open into the water vascular system (plate 467D).

Classification Several major classification schemes and phylogenies have been proposed for the living Ophiuroidea, of which more than 2,000 species have been described. According to a dominant OPHIUROIDEA

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PLATE 4 6 8 Disk and basal portion of the arm of: A l , Ophiopteris papillosa, dorsal; A2, ventral; B l , Ophioncus granulosus, dorsal; B2, ventral, arrowheads point to divided bursal slit; C I , Ophioplocus esmarki, dorsal; C2, ventral; D l , Ophionereis diabloensis, dorsal; D2, ventral; in D l , a pair of accessory dorsal arm plates (arrowheads) is distal to the lateral arm plate.

nineteenth century school of thought, a distinction was drawn between Euryalae (basket stars and related ophiuroids with unbranched arms) and Ophiurae (the other brittle stars) based on the nature of the vertebral articulation, arm spine position, integument histology, and the reduction and loss of principal skeletal elements. Beginning in the twentieth century, insights into the significance of internal structures such as genital, oral, and dental plates allowed for the discrimination of the order Ophiurida, consisting of three subgroups, from the order Phrynophiurida, which combined the thick-skinned family Ophiomyxidae and the "Euryalae." In addition, there is evidence, open to question, that one "living fossil" species represents an ancient sister-group to all other extant ophiuroids. That controversy aside, the most inclusive, contemporary, cladistic classification divides the class Ophiuroidea into the order Euryalida, equivalent to the classical Euryalae, and the order Ophiurida. The prime division within the latter group segregates Ophiomyxidae from five other major clades (infraorders) that do not readily lend themselves to recognition by their general appearance. Even in this scheme, relationships among the clades of Ophiurida are not clearly resolved by the available morphological and molecular data, possibly because they all evolved relatively contemporaneously during the early Mesozoic. The approximately 20 ophiuroid families have been somewhat more taxonomically stable than the higher taxa, and that will probably remain the case until the genera are critically revised.

Collection, Preservation, and Examination Any method devised to extract invertebrates from benthic substrates can yield ophiuroids. Because they are rarely found in clear sight, a thorough survey of ophiuroids requires disruptive or destructive techniques, which should be performed in a manner that minimizes environmental damage. Looking between and below loose-set rocks and sifting the sediment beneath them can be productive. A chisel-tipped geologist's pick can provide useful leverage, and patches of soft sediment may be shoveled and sieved to find burrowing forms. Small animals, which are frequently the most unusual and interesting, are extracted by washing rocks overgrown with plants and animals, clumps of sessile invertebrates, or plants in a container of seawater; carefully examining and discarding the cleaned substrate; and sorting the remnants under low magnification. Ophiuroids may also be found by dissecting sponges and kelp holdfasts. Individuals can be prevented from autotomizing if they are handled carefully and not lifted by their arm tips. In the field, ophiuroids are best maintained in containers of clean seawater with some pebbles or a bit of sediment, and preferably kept in the dark. The containers can be transported in an insulated box, to which a sealed bag of ice may be added. Examining living animals is indispensable for an understanding of the organism, but microscopic observations are most easily made on anesthetized or preserved individuals. Ophiuroids can be rapidly relaxed by transferring them to a magnesium chloride solution (74 g per liter of fresh water), epsom salts solution (200 g per liter of fresh water), or by placing them in a minimal amount of seawater and gradually adding small amounts of epsom salts. Afterward, they may be revived by placing them in fresh seawater or preserved for further study. That is accomplished by straightening the arms of a relaxed specimen, laying it flat in a tray of alcohol for several minutes to "harden," and storing it in a container of al-

cohol. Because natural color deteriorates after preservation, it is advantageous to photograph the living animal or add notes on color to the sample label along with date and locality information. Preservation and storage in 70%-95% ethyl alcohol is generally preferred, as it permits the study of soft tissue and skeleton and DNA extraction. Preserved specimens may be partially or completely dried to facilitate identification and examination of the skeleton. Bear in mind, however, that ophiuroids directly removed from seawater and dried eventually disintegrate because of the hygroscopic salts remaining in their tissues. Taxonomic specimens are vulnerable to acidic fixatives that dissolve the skeleton, and for that reason storage in formalin must be avoided. Cotton should not be used as a cushioning material because the fibers invariably damage delicate structures. However any specimen, no matter how badly damaged, is potentially informative and useful for identification. Preservation for electron microscopy or histology requires toxic fixative solutions that must be handled using special procedures discussed elsewhere in the literature. Adult individuals of the intertidal species of California and Oregon can be distinguished using the key, photographs, and comments provided. However, keys to ophiuroids are virtually useless for the identification of small and juvenile individuals because the shape and number of crucial characters drastically change during ontogenesis (e.g., compare plates 467A and 468C). Thus, accurate identification may require additional information gleaned from the primary literature and museum specimens, or the advice of an expert. In the descriptions of ophiuroid species, standard measurements of body size include disk diameter (dd) measured from the outer edge at the radial shields to the distal periphery of the opposite interradius, and arm length (AL) from the distal tip of the arm to the edge of the disk. Dimensions provided herein are representative of large individuals. These data and other information summarized in the following list of species are based on the author's personal observations and the literature cited. Note that the pigmentation described is that of living animals, unless otherwise specified. The term s t r i p e refers to a pigment pattern running the length of the arm, and bands are patterns that run across the arm. References to numbers of arm spines and tentacle scales refer to the greatest number found on one lateral arm plate near the base of an arm, and counts of oral papillae refer to the number on one side of the jaw. The specimens photographed are from the collections of the Natural History Museum of Los Angeles County.

Key to Ophiuroidea 1. Number of arms five 2 — Number of arms six; fissiparous (plate 469D) Ophiactis simplex 2. Dorsal arm plate is composed of a mosaic of ossicles (plate 468C) Ophioplocus esmarki — Dorsal arm plate is single; accessory dorsal arm plates are present 3 — Dorsal arm plate is single; accessory dorsal arm plates are absent 4 3. One accessory dorsal arm plate between each lateral arm plate and the dorsal arm plate (plate 468D) Ophionereis diabloensis — Numerous accessory dorsal arm plates surround the dorsal arm plate (plate 469C) Ophiopholis kennerlyi OPHIUROIDEA

935

4. —

—

5. — 6. — 7. — 8.

—

9. —

Disc scales bear spherical granules (plate 468A1, 468B1) 5 Disc scales bear serrated or cylindrical spines, or tall cylindrical granules (plate 469A1, 469B1); jaws bear dental papillae but lack oral papillae (plate 467G) 6 Disc covered by naked scales (plate 470A1); jaws bear paired infradental papillae and oral papillae (plate 467E) 7 Dorsal surface of disk smooth; two bursal slits in each interradius (plate 468A) Ophiopteris papillosa Dorsal surface of disk bumpy; four bursal slits in each interradius (plate 468B) Ophioncus granulosus Arm spines with jagged edges (plate 469A) Ophiothrix spiculata Arm spines smooth (plate 469B) Ophiothrix rudis Most distal oral papilla considerably enlarged, middle oral papilla diminutive (plate 470A2, 470B2) 8 Most distal oral papilla and middle oral papillae similar in size and shape (plates 467E, 470C2, 470D2) 9 Arm spines with bulbous base, short and abruptly tapering; primary plates absent (plate 470A) Amphipholis squamata Arm spines gradually tapering; longest spines have slender shaft and may have a bulbous tip; primary plates usually present (plate 470B) Amphipholis pugetana Moderately large species, with two tentacle scales (plates 467C, 467E, 470D) Amphiodia occidentalis Small species, with single elongated tentacle scale (plate 470C) Amphiodia akosmos

List of Species AMPHIURIDAE

Amphiodia akosmos Hendler and Bundrick, 2001. Previous editions of this manual treated this small species (dd = 4.2, AL = 24 mm) as an unnamed "ovoviviparous species" or a "variety of A. occidentalis." White to pale beige, with some disk scales and arm plates a contrasting gray or brown. Distinguished from similar juveniles of Amphiodia occidentalis, together with which it can occur, by the single, relatively elongate tentacle scale, prominent wedge-shaped scales separating the radial shields, and the absence of primary plates. Individuals suspended in the water swiftly retract their arms into a tightly coiled mass atop the disk. Known only from the intertidal at Monterey Peninsula, Santa Cruz County, and Farallón Island. Lives under rocks that rest on coarse sand. It is the only Amphiodia species known to bear live young. See Hendler and Bundrick 2001. Amphiodia occidentalis (Lyman, 1860) (=Diamphiodia occidentalis). Large, with long, slender arms and small disk (dd = 12, AL = 220 mm). Dorsal surface tan or yellow, densely variegated with gray, brown, red, and cream; ventral surface of arms dark gray. Distinguished from A. akosmos by two tentacle scales, and dorsal arm plates two and a half to three times wider than long. Adults burrow in sediment beneath rocks and seagrass, often in protected tide pools. Extend their arms to deposit feed and possibly to gather suspended material. Suspended individuals behave similarly to A. akosmos. Broadcast yolky eggs that undergo rapid development within a benthic fertilization envelope. Reports of the species from deep water and south of central California are suspect. See May 936

ECHINODERMATA

1924, Austin and Hadfield 1980, Rumrill and Pearse 1984, Hendler and Bundrick 2001, Emlet 2006. Amphiodia urtica (Lyman, 1860) (=Amphiodia barbarae). Moderately small, with long slender arms (dd = 4.0, AL = 50 mm). Disk red-brown with dark primary plates, radial shields gray with pale distal tips, arms red gray with red medial stripe. Allied with other California species in the subgenus Amphispina, which have hyaline, barbed disk scales and proximally curving arm spines beneath the disk. Reported from the intertidal and at scuba-accessible depths, but reliable central California and Oregon records are strictly for the subtidal where populations may attain densities up to several thousand per square meter. Its larva is a planktotrophic ophiopluteus. The parasitic nauplius stage of a thespesiopsyllid copepod can be found within its stomach. The species is monitored as an indicator of water quality. See H. L. Clark, 1911, Nielsen 1932, Barnard and Ziesenhenne 1961, Bergen 1995, Hendler 1996, Maurer and Nguyen 1996, Ho et al. 2003. Amphipholis pugetana (Lyman, 1860). Small (dd = 5.8, AL = 32 mm). Disk red-brown, red-gray, or gray, radial shields brown or gray-brown with white mark at distal tip; arms paler t h a n disk, blotched with red-brown, green, gray, pale brown, or cream. Large individuals distinguished from adult Amphipholis squamata by arm spines longer than arm joint; middle arm spine longest, up to one and half times length of joint, with slender shaft between the base and the thickened or bulbous tip. A putative difference in relative arm length that has been suggested to distinguish between individuals of A. pugetana and A. squamata is unreliable. The two species have often been misidentified, and small individuals may be impossible to identify with certainty. A. pugetana rarely occurs intertidally, despite reports to the contrary; nearly all reliable records are for depths from 15 m - 6 0 0 m. The large number and small size of orange eggs found in the ovaries of ripe individuals indicate that the larva is planktonic. See H. L. Clark 1911, Nielsen 1932, Strathmann and Rumrill 1987, Hendler et al. 1995, Hendler 1996. Amphipholis squamata (Delle Chiaje, 1828) (=Axiognathus squamatus). Diminutive, rarely reaching dd = 4.1, AL = 21 mm. Widely characterized as worldwide in distribution, but molecular evidence indicates that it may consist of several cryptic taxa. However, individuals from wide-ranging localities are luminescent, viviparous, and hermaphroditic. Some populations are capable of self-fertilization as well as outcrossing. California individuals white, gray, or tan in color, with pale patch at distal tip of radial shield, often with several thin black bands on arms. Adults distinguishable from Amphipholis pugetana by arm spines bulbous at base, abruptly tapering, and n o longer than an arm joint. Symbionts of A. squamata, sensu lato, include an orthonectid, a turbellarian, a polychaete, external copepods, internal copepod parasites that may castrate the host, and bacteria that play a role in host nutrition. Although references to its biology are too numerous to list in full, see Austin and Hadfield 1980; Emson and Wilkie 1982; Radner 1982; Rumrill and Pearse 1984; A. M. Clark, 1987, Bull. Zool. Nom. 44: 246-247 (nomenclature); Strathmann and Rumrill 1989; Hendler et al. 1995; 0stergaard and Emson 1997; Poulin et al. 1999; Sponer and Roy 2002; Fauville et al. 2003.

OPHIACTIDAE

Ophiactis simplex (Le Conte, 1851). Fissiparous, usually with three to six regenerating arms. Usually very small, but some

PLATE 469 Disk and basal portion of the arm of: Al, Ophiothrix spiculata, dorsal; A2, ventral; B l , Ophiothrix rudis, dorsal; B2, ventral; C I , Ophiopliolis kennerlyi, dorsal; C2, ventral; arrowheads indicate accessory dorsal arm plates surrounding the dorsal arm plate; D l , Ophiactis simplex, dorsal; D2, ventral.

PLATE 470 Disk and basal portion of the arm of: Al, Amphipholis squamata, dorsal; A2, ventral; B l , Amphipholis pugetana, dorsal; B2, ventral; C I , Amphiodia akosmos, dorsal; C2, ventral; D l , Amphiodia occidentalis, dorsal; D2, ventral. Primary plates (arrowheads point to the central and a radial plate) and modified, bulbous tipped arm spines (arrow) are indicated in B l ; compare the most distal oral papillae (arrowheads), which are considerably enlarged in B2, but not so in D2; compare the single, elongated tentacle scale in C2 and the small, paired tentacle scales in D2 (small arrows). Tube feet (asterisks) remain visible in the specimens preserved in alcohol (C2, D2).

individuals reach moderate size (dd = 7.1, AL = 25 m m ) and may have five arms. Variegated with patches of brown, greenbrown, and tan pigmentation; arms distinctly banded. Tube feet of living specimens red, presumably from hemoglobin-containing coelomocytes. First discovered in Panama, it has been considered identical to Ophiactis orstedii Liitken, 1856, and Ophiactis arenosa Liitken, 1856, which were originally found in Costa Rica and Nicaragua. Ophiactis simplex was long known from as far north as the Channel Islands, California, and was unexpectedly recorded in central California (Lonhart and Tupen 2001). Cause of the apparent range extension is unresolved (Schiel et al. 2004). Moreover, it appears to occur in Texas and may be identical to Ophiactis rubropoda Singletary, 1973, first described from Florida. Distinguished from Ophiactis savignyi (Miiller and Troschel 1842), a related tropicopolitan species found in southern California, by the single oral papilla and relatively small radial shields that are completely separated by small scales. Can be exceedingly abundant in sponges, algae, and around serpulid tubes. Capable of absorbing dissolved organic material from seawater. See Lyman 1865, Nielsen 1932, Stephens and Virkar 1966, Christensen and Christensen 2003, Christensen and Dean 2003, and Christensen 2004.

u n c o m m o n and usually small. Distinguished by densely granulated disk, prominent dental and oral papillae, arm spine closest to dorsal arm surface small and scalelike, lower arm spines long, dorso-ventrally compressed, smooth. Coloration black to pale brown or red, with darker bands o n the arms; sometimes variegated with cream-colored splotches or bands; distal ends of arms sometimes yellow. Very active, readily autotomizes, and shows rapid escape behavior in response to predators, which include sea stars, fish, crabs, and lobster. Individuals suspended in water assume a teardrop shape, with the arms extended vertically above the disk and pressed together, which facilitates rapid descent. Carnivorous, using arm spines to tear apart material held in the mouth; also able to feed on suspended material. Adhesive tube feet enable it to climb glass surfaces. Spawns in winter, releasing minute eggs of a size and number characteristic of species with planktotrophic ophiopluteus larvae. See May 1924, Austin and Hadfield 1980, Wallerstein 1982, Rumrill and Pearse 1984, Yee et al. 1987, and Pomory 2001.

Ophiopholis kennerlyi Lyman, 1860 (=Ophiopholis aculeata var. kennerlyi). First described based o n a specimen from Puget Sound collected by Caleb Kennedy, naturalist and surgeon of the United States Northwest Boundary Survey, w h o died during the voyage. Afterward, taxonomically merged with Ophiopholis aculeata (Linnaeus, 1767) and assigned an infrasubspecific name, which is today taxonomically unavailable. Individuals from California are here tentatively accorded specific rank as O. kennerlyi to distinguish t h e m from other eastern Pacific species of Ophiopholis. Uncommon in California and appreciably smaller (dd = 8.5, AL = 38 m m ) than conspecifics from Alaska. Disk granule-covered, with few dorsal naked plates and lacking dorsal spines; six to 10 relatively large, angular, accessory dorsal arm plates per joint; arm spines usually shorter than arm joint, broad at the base, blunt. Coloration highly variable and attractive; disk and arms often red to pink, with contrasting mottling, marbling, and bands of black, brown, cream, and green hues. Slowmoving, it lives under rocks intertidally or in varied substrates subtidally. Spawns in summer, producing an ophiopluteus larva. The numerous publications on O. aculeata, sensu lato are not cited herein, as the biology of O. kennerlyi must differ to some degree from O. aculeata, but see H. L. Clark 1911; May 1924; Nielsen 1932; LaBarbera 1978, 1982; Austin and Hadfield 1980; Hart 1982; Strathmann and Rumrill 1987; and Balser 1998.

Ophioncus granulosus Ives, 1889. Small species (dd = 7.1, AL = 17 mm), rarely encountered intertidally. Distinguished by bursal slits divided into two parts; disk distinctly lumpy, granule covered. Resembles the juveniles of large Ophioderma species that occur south of central California. Light gray, cream, or pale yellow-brown; disk sometimes with several black or brown marks, arms often with several brown to pale yellow-brown bands. Crawls using the rowing motions of laterally positioned arms. Individuals suspended in midwater quickly fold the arms in a concentric pattern atop the disk, and sink like a pebble.

Ophiopholis bakeri McClendon, 1909. The previous edition of this manual suggested intertidal occurrence, but it is reliably reported only at depths from 18 m-902 m. Individuals are similar in size to O. kennerlyi (dd = 10.5, AL = 67 mm). Distinguished by the disk covered with pointed granules and short, slender spines with several terminal spikes; accessory dorsal arm plates separated from one another, small, and often with one or two sharp spikes. Red or orange-brown to pink with some gray, cream, or brown markings; arms banded but disk not boldly patterned with sharply contrasting colors. Typically associated with holdfasts and sessile animals on outcrops of hard substrate. See McClendon 1909, H. L. Clark 1911, and Hendler 1996.

OPHIOCOMIDAE Ophiopteris papulosa (Lyman, 1875). Reaches moderate size (dd = 19, AL = 70 m m ) in the subtidal; intertidal individuals

OPHIODERMATIDAE

OPHIOLEPIDIDAE Ophioplocus esmarki Lyman, 1874. Reaches moderate size (dd = 22, AL = 60 mm), although individuals are smaller and less numerous in the intertidal t h a n the subtidal. Distinguished by the dorsal arm plates composed of small plates arranged in a mosaic pattern. General coloration gray or brown-pink, redbrown, or brown, finely stippled with a contrasting darker hue; arm tips often pale. Slow-moving, relatively unresponsive, and loath to autotomize. Adhesive tube feet are used to climb smooth surfaces, and to transport and ingest small prey and food particles. Reproductive w h e n approximately 10 years old. Females produce yolky eggs, and large individuals brood more t h a n 1,500 embryos. Restricted dispersal of the juveniles results in genetic differences a m o n g populations. See Austin and Hadfield 1980, Gaarde and McClenaghan 1982, Rumrill and Pearse 1984, and Medeiros-Bergen and Ebert 1995.

OPHIONEREIDIDAE Ophionereis diabloensis Hendler, 2002. A considerably smaller species (dd = 6, AL = 17 mm) than Ophionereis eurybrachiplax, with which it has been confused. Differs from 0. eurybrachiplax by its conspicuous, rounded disk scales, absence of genital papillae, absence of a patch of dark brown pigment distal to oral shield. In addition, distinguished from a much more similar, southerly species Ophionereis amphilogus (Ziesenhenne, 1940) by its coarser disk scales, more robust arms, and oral shield with truncate proximal tip. Disk predominantly brown and green-brown with dark brown and cream-colored patches; arms green-brown with dark OPHIUROIDEA

939

brown bands and cream patches. Occurs in low intertidal algal turf on rock substrate. Known solely from Diablo Cove, San Luis Obispo County, although in the first half of the twentieth century, it was collected at the Monterey Peninsula. Broods crawlaway juveniles. See Hendler 2002. Ophionereis eurybrachiplax H. L. Clark, 1911. Moderately large (dd = 25, AL = 2 1 5 mm). Contrary to information in previous editions of this manual, it is strictly subtidal, in depths 5 3 m 45 m. Disk brown with black and cream mottling, or rusty brown with white spots; radial shields orange-brown with white distal edge; dorsal surface of arms orange-brown with mottled bands of cream, brown, and mottled gray, often with a pale discontinuous medial stripe; ventral side of arms sometimes a salmon color.

OPHIOTRICHIDAE

Ophiothrix rudis Lyman, 1874. Moderately small (dd = 10, AL = 5 0 mm). Distinguished by large, naked radial shields and smooth, somewhat dorso-ventrally compressed arm spines; disk armament, depending on the individual, consisting of smooth-sided cylindrical granules, stumps, or spines. Disk green, tinged reddish or bluish; radial shields sometimes with red or orange spots; arms green or yellow with narrow dusky and broad red bands. In alcohol, specimens become blue, and thin dark bands are apparent across and distal to each dorsal arm plate. Lives under rocks, in coarse sand, and associated with seagrass rhizomes. May occur together with Ophiothrix spiculata. Females with ripe eggs in summer. See McClendon 1909, Nielsen 1932, Austin and Hadfield 1980. Ophiothrix spiculata Le Conte, 1851. Moderately small (dd = 15, AL = 85 mm). Distinguished by serrate or conspicuously prickly spines on the disk and arms. Pigmentation and color patterns extraordinarily variable; frequently green, greenbrown, or green-yellow, and more or less extensively marked with white, gray, orange, red, garnet, maroon, brown, pink, or gray. Alcohol preserved specimens turn blue, as do many ophiotrichid species. The species occupies a wide range of substrates, and in current-swept habitats it can occur " . . . in almost unbelievable n u m b e r s . . . The bottom in deeper water may be covered to depths of an inch or more by millions of these active animals" (Limbaugh 1955). Prone to autotomize. Individuals extend several arms rigidly from crevices to capture microscopic particles using mucus-coated arm spines and tube feet, or gracefully flex the arm tips to secure larger particles. Broadcast immense numbers of minute eggs in the spring, which develop into planktotrophic ophiopluteus larvae. See: May 1924, Nielsen 1932, and Austin and Hadfield 1980.

ACKNOWLEDGMENTS

Specimens, personal observations, opportunities for field work, and comments on the manuscript were offered by Shane Anderson, William Austin, Michael Behrens, Karin Boos, Carla Bundrick, Ana Christensen, Paula Cisternas, Cathy Colloff, Dimitri Deheyn, Richard Emlet, J o h n Engle, Constance Gramlich, Cathy Groves, Florence Nishida, Steven Rumrill, Freya Sommer, Richard Strathmann, Anne Richmond, Jeffery Tupen, Waldo Wakefield, and James Watanabe. Giar-Ann Kung, William Ormerod, and Michelle Schwengel helped prepare the plates. Curatorial staff at the California Academy of Sciences, Museum of Comparative Zoology, National Museum of Natural History, and Santa Barbara Museum of Natural History pro940

ECHINODERMATA

vided access to specimens and data. I am grateful to all w h o provided assistance and am indebted to Capt. F. C. Ziesenhenne, who established the collection of eastern Pacific ophiuroids, now in the Natural History Museum of Los Angeles County, on which much of this contribution is based.

References Austin, W. C., and M. G. Hadfield. 1980. Ophiuroidea: The brittle stars. In Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E.C. Haderlie, eds., pp. 146-159, figs. 10.1-10.12. Stanford, CA: Stanford University Press. Balser, E. J. 1998. Cloning by ophiuroid echinoderm larvae. Biol. Bull. 194: 187-193. Barnard, J. L., and F. C. Ziesenhenne. 1961. Ophiuroid communities of southern Californian coastal bottoms. Pacific Nat. 2: 131-152. Bergen, M. 1995. Distribution of brittlestar Amphiodia (Amphispina) spp. in the southern California Bight in 1956 to 1959. Bull. Southern Calif. Acad. Sci. 94: 190-203. Boolootian, R. A., and D. Leighton. 1966. A key to the species of Ophiuroidea (brittle stars) of the Santa Monica Bay and adjacent areas. Contr. Sci. Los Angeles County Museum 93: 1-20. Byrne, M. 1994. Ophiuroidea. In Microscopic anatomy of invertebrates, Vol. 14. Echinodermata. F. W. Harrison and F.-S. Chia, eds., pp. 247-343. New York: Wiley-Liss. Christensen, A. B., and E. F. Christensen. 2003. Molecular comparison of a Texas population of ophiactid brittle star with Ophiactis simplex and Ophiactis rubropoda. In Echinoderms. Miinchen. T. Heinzeller, and J. H. Nebelsick, eds., p. 574. Balkema, Leiden. Christensen, A. B., and D. K. Dean. 2003. Population structure in a fissiparous ophiactid brittlestar possessing hemoglobin, http://sicb.org/ meetings/2003/schedule/abstractdetails.php3?id=245. Christensen, A. B. 2004. A new distribution record and notes on the biology of the brittle star Ophiactis simplex (Echinodermata: Ophiuroidea) in Texas. Texas J. Sci. 56: 175-179. Clark, H. L. 1911. North Pacific ophiurans in the collection of the United States National Museum. Bull. U.S. Natl. Mus. 75: 1-302. Clark, H. L. 1915. Catalog of Recent ophiurans: Based on the collection of the Museum of Comparative Zoology. Mem. Mus. Comp. Zool. Harvard 62: 265-338, pis. 1-8. Emlet, R. B. 2006. Direct development of the brittle star Amphiodia occidentalis (Ophiuroidea, Amphiuridae) from the northeastern Pacific Ocean. Invertebrate Biol. 125: 154-171. Emson, R. H., and I. C. Wilkie. 1982. The arm-coiling response of Amphipholis squamata (Delle Chiaje). In Echinoderms: Proceedings of the International Conference, Tampa Bay. J. M. Lawrence, ed., pp. 11-18. Rotterdam: Balkema. Fauville, G., S. Dupont, and J. Mallefet. 2003. Comparison of mechanically and chemically induced luminescence in the brittle star Amphipholis squamata. In Echinoderm research 2001. J.-P. Feral and B. David, eds., pp. 189-192. Balkema: Lisse. Fell, H. B. 1960. Synoptic keys to the genera of Ophiuroidea. Zool. Pubis. Victoria Univ. Wellington 26: 1-44. Gaarde, W. A., and L. R. McClenaghan Jr. 1982. Genetic variability, dispersal, and differentiation of two species of ophiuroids from southern California. Southwestern Nat. 27: 255-262. Hart, M. W. 1982. Particle captures and the method of suspension feeding by echinoderm larvae. Biol. Bull. 180: 12-27. Hendler, G. 1991. Echinodermata: Ophiuroidea. In Reproduction of marine invertebrates. Vol. VI. Echinoderms and Lophophorates. A. C. Giese, J. S. Pearse, and V. B. Pearse, eds., pp. 3 5 5 - 5 1 1 . Pacific Grove, CA: Boxwood Press. Hendler, G. 1996. Class Ophiuroidea. In Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. Vol. 14-Miscellaneous taxa. J. A. Blake, P. H. Scott, and A. Lissner, eds., pp. 111-179. Santa Barbara, CA: Santa Barbara Museum of Natural History. Hendler, G. 2002. Account of Ophionereis diabloensis, a new species of brittle star, and of O. amphilogus, with information on their brooding reproduction and distribution (Echinodermata: Ophiuroidea: Ophionereididae). Proc. Biol. Soc. Wash. 115: 57-74. Hendler, G. 2004. An echinoderm's eye view of photoreception and vision. In Echinoderms. Miinchen, T. Heinzeller, and J. H. Nebelsick, eds. pp. 3 3 9 - 3 4 9 . Balkema: Leiden.

Hendler, G., and C. J. Bundrick. 2001. A new brooding brittle star from California (Echinodermata: Ophiuroidea: Amphiuridae). Contr. Sci., Los Angeles County Natural History Museum 486: 1-11. Hendler, G., J. E. Miller, D. L. Pawson, and P. M. Kier. 1995. Sea stars, sea urchins, and allies. Echinoderms of Florida and the Caribbean. Smithsonian Institution Press, Washington, 390 pp. Ho, J.-S., M. Dojiri, G. Hendler, and G. B. Deets. 2003. A new species of Copepoda (Thaumatopsyllidae) symbiotic with a brittle star from California, U.S.A., and designation of a new order Thaumatopsylloida. J. Crust. Biol. 23: 582-594. Kyte, M. A. 1969. A synopsis and key to the Recent Ophiuroidea of Washington State and southern British Columbia. J. Fish. Res. Board Can. 26: 1727-1741. LaBarbera, M. 1978. Particle capture by a Pacific brittle star: Experimental test of the aerosol suspension feeding model. Science. 201: 1147-1148. LaBarbera. 1982. Metabolic rates of suspension feeding crinoids and ophiuroids (Echinodermata) in a unidirectional laminar flow. Comp. Biochem. Physiol. 71A: 303-307. Limbaugh, C. 1955. Fish life in the kelp beds and the effects of kelp harvesting. Univ. of California, Inst. Mar. Sci. IMRRef. 55-9:1-158, 20 figs. Lonhart, S. I., and J. W. Tupen. 2001. New range records of 12 marine invertebrates: The role of El Nino and other mechanisms in southern and central California. Bull. Southern California Acad. Sci. 100: 238-248. Lyman, T. 1865. Ophiuridae and Astrophytidae. 111. Cat. Mus. Comp. Zool. Harv. 1: 1-200, pis. 1-2. Maurer, D., and H. Nguyen. 1996. The brittlestar Amphiodia urtica: a candidate bioindicator? P.S.Z.N.I: Mar. Ecol. 17: 617-636. May, R. M. 1924. The ophiurans of Monterey Bay. Proc. Calif. Acad. Sci.. Ser. 4, 13: 261-303. McClendon, J. F. 1909. The ophiurans of the San Diego Region. Univ. Calif. Pubis. Zool. 6: 33-64. Medeiros-Bergen, D. E., and T. A. Ebert. 1995. Growth, fecundity, and mortality rates of two intertidal brittlestars (Echinodermata: Ophiuroidea) with contrasting modes of development. J. Exp. Mar. Biol. Ecol. 189: 47-64. Nielsen, E. 1932. Ophiurans from the Gulf of Panama, California, and the Strait of Georgia. Vidensk. Medd. fra Dansk naturh. Foren. 91: 241-346. 0stergaard, P., and R. Emson. 1997. Interactions between the life histories of a parasitic copepod, Parachordeumium amphiurae, and its brittle-star host, Amphipholis squamata. J. Crust. Biol. 17: 621-631. Pomory, C. M. 2001. An escape response behaviour in the brittle star Ophiopteris papillosa (Echinodermata: Ophiuroidea). Mar. Fresh. Behav. Physiol. 34: 171-180. Poulin, E.J.-P. Feral, M. Florensa, L. Cornudella, and V. Alva. 1999. Selfing and outcrossing in the brood protecting ophiuroid Amphipholis squamata. In Echinoderm Research 1998. Proceedings of the Fifth European Conference on Echinoderms, Milan, Italy, 7-12 September 1998. M.D. Candia Carnevali and F. Bonasoro. eds., pp. 147-150. Rotterdam: Balkema. Radner, D. N. 1982. Orthonectid parasitism: effects on the ophiuroid, Amphipholis squamata. In Echinoderms: Proceedings of the International Conference, Tampa Bay. J. M. Lawrence, ed., pp. 395-401. Rotterdam: Balkema. Rumrill, S. S., and J. S. Pearse. 1984. Contrasting reproductive periodicities among north-eastern Pacific ophiuroids. In Echinodermata. B. F. Keegan and B. D. S. O'Connor, eds., pp. 633-638. Balkema, Rotterdam. Schiel, D. R., J. R. Steinbeck, and M. S. Foster. 2004. Ten years of induced ocean warming causes comprehensive changes in marine benthic communities. Ecology 85: 1833-1839. Smith, A. B., G. L. J. Pateron, and B. LaFay. 1995. Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives. Zool. J. Linn. Soc. 114: 213-243. Sponer, R., and M. S. Roy. 2002. Phylogeographic analysis of the brooding brittle star Amphipholis squamata (Echinodermata) along the coast of New Zealand reveals high cryptic genetic variation and cryptic dispersal potential. Evolution 56: 1954-1967. Stephens, G. C., and R. A. Virkar. 1966. Uptake of organic material by aquatic invertebrates. IV. The influence of salinity on the uptake of amino acids by the brittle star, Ophiactis arenosa. Biol. Bull. 131:172-185. Strathmann, M. F., and S. S. Rumrill. 1987. Phylum Echinodermata, Class Ophiuroidea. In: Reproduction and development of marine invertebrates of the northern Pacific coast, M. F. Strathmann, ed., pp. 556-573. Seattle: University of Washington Press, Seattle, Washington. Wallerstein, M. C. 1982. An examination of the roles of predation and

competition in determining the distributions of the ophiuroids Ophiothrix spiculata Le Conte, 1851 and Ophiopterus [sic] papillosa (Lyman, 1875) in a shallow marine community. Ph.D. Dissertation. University of Southern California, 142 pp. Warner, G. 1982. Food and feeding mechanisms: Ophiuroidea. In Echinoderm nutrition. M. Jangoux and J. M. Lawrence, eds., pp. 161-181. Rotterdam: Balkema. Yee, A., J. Burkhardt, and W. F. Gilly. 1987. Mobilization of a coordinated escape response by giant axons in the ophiuroid, Ophiopteris papillosa. J. Exp. Biol. 128: 287-305.

Holothuroidea PHILIP LAMBERT (Plates 4 7 1 - 4 7 5 )

Sea cucumbers have a soft body wall containing circular and longitudinal muscles and a vestigial skeleton made up of isolated calcite particles, called ossicles, and a calcareous ring around the oesophagus. Typically, a sea cucumber is an elongate cylinder lying on its side with the mouth at one end and the anus at the other. It has five longitudinal rows of tube feet, which are part of a closed hydraulic network called the water vascular system. One or two circles of feeding tentacles surround the mouth. Tube feet, or podia, usually consist of a cylindrical shaft with a sucker at the tip. The three ventral rows tend to be more robust than the two on the dorsal side, but they can be quite variable. Leptosynapta albicans, for example, has n o tube feet, and on the dorsal side of Parastichopus californicus, the tube feet are modified into pointed warts, or papillae. The feeding tentacles, being part of the water vascular system, are extended and retracted by hydraulic pressure. Sea cucumbers have four types of tentacles (plate 471). Treelike, dendritic tentacles (plate 471 A) pick up small suspended particles on a coating of mucus; the tentacle is then placed in the mouth and "licked" clean. Detritus feeders, like Parastichopus californicus have moplike, peltate tentacles (plate 471C), which when pressed onto the substratum pick up particles and transfer them to the mouth. The digestive system processes the organic matter, and the bits of shell and sand particles pass through the gut. Sea cucumbers that burrow push sediment into the mouth with fingerlike, digitate (plate 471E) or pinnate (plate 471B) tentacles. Species with dendritic tentacles have a thin-walled "neck" region just behind the tentacles called the introvert. Five internal retractor muscles pull the introvert and tentacles into the body cavity to prevent predatory fish from nipping them. Plate 4 7 1 D shows the internal anatomy of a generalised Cucumaria. To dissect a sea cucumber, determine the dorsal side (usually slightly darker or with tube feet less well-developed) and make a lengthwise incision to the left of the midline with sharp-pointed scissors. This will leave the dorsal mesentery intact. The digestive tract in this genus is two or three times the length of the body. The anterior part of the intestine hangs from the mid-dorsal body wall by a transparent sheet of tissue, or mesentery. Other mesenteries connect the next part of the intestine to the left side and finally to the ventral body wall. The position of these mesenteries varies in different groups of sea cucumbers and this arrangement is an important character in classification. Five bands of longitudinal muscle, and in taxa with an introvert the tentacle retractor muscles, are plainly visible. The rest of the body wall consists of a layer of circular muscles, connective tissue, and skin. The contraction of these circular and longitudinal muscle layers produces a wormlike or peristaltic action. Imagine a long thin, water-filled balloon. W h e n you squeeze HOLOTHUROIDEA

941

calcareous ring

B

haemal ring polian vesicle dorsal mesentery genital duct

circular muscles retractor muscle radial long, muscle

ventral mesentery intestine

1"*-'* I *~l

genital tubule

ventral haemal vessel transverse haemal vessel body wall

dorsal haemal vessel

respiratory tree muscle fibers

PLATE 471 A, dendritic tentacles; B, pinnate tentacles; C, peltate tentacles; D, internal a n a t o m y of a generalized cucumarid sea cucumber; E, digitate tentacles.

one end the other extends forward. Some species use these waves of contraction to move along the ocean floor or through the mud. Respiratory trees are the "lungs" of a sea cucumber. These hollow, branched organs lie inside the body cavity on either side of the posterior intestine. The base of the tree connects to a muscular cavity, or cloaca. Circular muscles, or sphincters, close each end of the cloaca. A sea cucumber "breathes" by expanding the cloaca to draw oxygenated water in through the anus. The posterior sphincter then closes, then cloacal muscles contract to force water up into the respiratory trees. Oxygen is transferred across the thin membrane into the fluids of the body cavity. When the oxygen is depleted, the main body wall contracts to squeeze water out of the trees. The ring canal circles the oesophagus just behind the mouth and may have saclike extensions called polian vesicles. They are thought to function as expansion chambers for the system. One or more stone canals, calcified tubes with a perforated swelling at the end, called the madreporite, also attach to the ring canal. The function of stone canals is not clear but it may have something to do with maintaining the fluid levels in the water-vascular system. The number and position of stone canals is another useful taxonomic character. Five radial canals emerge forward of the ring canal sending branches to the tentacles, then curve back to run the length of the body between the longitudinal and the circular muscle layers. Short branches go to the tube feet and a small sac, or ampulla, marks the internal end of each tube foot. W h e n contracted, these ampullae force fluid into the tube foot, causing it to extend. In some species like Parasti942

ECHINODERMATA

chopus californicus, the base of each feeding tentacle also has an ampulla. The calcareous ring is one of the few obvious, internal hard parts of a sea cucumber. It is comprosed of a series of plates, usually 10, joined side by side like a collar around the oesophagus. The tentacle retractor muscles attach to this structure. The plates vary in shape in different species, some plates having long tails and others having anterior projections. The shape of the ring is important in the classification of sea cucumbers. For example, those that have long posterior tails on the ring are placed in the same family. Each plate may be a solid piece or in some species, a mosaic of smaller segments. Being one of the few hard structures in a sea cucumber, the calcareous ring is often the only part that fossilises, thus providing a way of relating extinct and living forms. The rest of the sea cucumber skeleton is represented by isolated pieces of calcite, embedded in the outer layers of skin (plate 472). These microscopic ossicles are complex and varied in shape and along with the calcareous ring are important in verifying the identity of a species. A description or illustration of them is an important part of a scientific account. The reproductive organs of a sea cucumber consist of one or two tufts of tubules in the forepart of the body cavity. They combine into a single duct leading to an external gonopore near the tentacles. Most sea cucumbers have separate sexes, but the sex is difficult to determine by examining external features. Sea cucumbers usually spawn annually, either by broadcasting eggs or sperm into the surrounding water, or by brooding the fertilized eggs. An environmental cue, such as a certain temperature, consecutive sunny days, or a plankton bloom,

PLATE 472 Scale line = 100 pm: Skin ossicles of A, Pseudocnus curatus; B, Cucumaria pseudocurata; cumaria piperata; E, Pentamera montereyensis; F, Pentamera charlottae.

C, Pseudocnus

lubricus; D, Cu-

may cause m a n y individuals to spawn simultaneously, thus increasing the chance for successful fertilisation. A female Cucumaria miniata releases clusters of green eggs as a buoyant pellet. Males release sperm nearby and fertilization takes place by chance in midwater. The pellet of eggs eventually breaks apart and each egg develops into a swimming larva. The larva develops and grows for days or weeks in the plankton and then settles on rocky areas inhabited by the adults.

2.

—

3.

A few species retain their eggs, rather t h a n releasing them. As the eggs emerge, the female collects and holds t h e m underneath her body. Sperm shed by nearby males fertilize the eggs. The larvae develop for a few m o n t h s until the juveniles are large enough to crawl away. Cucumaria pseudocurata, Pseudocnus lubricus, and Pseudocnus curatus all reproduce this way during the winter. Leptosynapta broods its young internally.

—

Preparation of Ossicle Slides

5.

If, after using t h e key, you are still unsure of t h e identification, use the following procedure to isolate skin ossicles to compare with the more detailed descriptions in Bergen (1996) or Lambert (1997). It is a relatively simple procedure to isolate ossicles, but you will need access to a microscope and, if you want to prepare a permanent slide, some m o u n t i n g medium. You need some household bleach, a glass slide, a coverslip, and a small dropper or pipette. Simply cut a small piece of skin (about 2 m m square) from the mid-dorsal side between the rows of tube feet. On the slide, cover the skin sample with a drop of bleach. The flesh will dissolve away in about five minutes, leaving the ossicles behind. Placing a fine-tipped pipette at the edge of the drop, carefully draw off the bleach. An alternative method is to let the bleach and ossicles dry on the slide. The ossicles will then stick to the slide and the bleach crystals can be redissolved with water. For a good, permanent preparation, it is crucial to wash the ossicles with water at least three times to remove bleach crystals. This part is tricky because it is easy to suck u p t h e ossicles while removing the water. Swirl the slide quickly in tight circles to cause the ossicles to collect in the center, making it easier to draw t h e water off. Using the alternate method of drying first, the sample should be flooded with water several times until n o bleach crystals are left behind when the slide is dried. If you only want to confirm your identification with a temporary wet mount, place a coverslip o n the water-covered ossicles and view t h e m under the microscope. For a permanent slide, remove the last wash water and let it air dry or, if available, use a slide warmer to speed u p t h e process. Once the water has evaporated, place two small drops of m o u n t i n g medium (Canada Balsam or any synthetic substitute) o n the sample, apply a coverslip, and place on a horizontal surface to set. The following key was modified from the one in the third edition by James Rutherford. With the exception of plate 473D by Richard Hermann and plate 475A by Shane Anderson, all other drawings and photographs were produced by Royal BC Museum staff—James Cosgrove (plate 473C), Gerald Luxton (plate 471), and all others by the author.

Key to Holothuroidea 1. Tube feet absent — Tube feet present, scattered or in rows 944

ECHINODERMATA

2 3

4.

—

—

6.

—

Wormlike, delicate, white or semitransparent; five muscle bands visible through the skin in live specimens (plate 473A) Leptosynapta albicans Stout body tapering to a wormlike tail; color in life purplish gray to dark brown with an opaque, smooth, wrinkled skin (plate 473B) Paracaudina chilensis Obvious tube feet only o n ventral surface; ventrum easily distinguished from dorsum by form and color 4 Tube feet on all sides of body; ventral surface n o t sharply defined from dorsal 7 Large cylindrical species (up to 50 cm) with tube feet in rows on the ventral side and fleshy papillae or warts o n the dorsum; short feeding tentacles like mops; crawls o n the sea bottom 5 Small species (