Amphibians of Central America [1 ed.] 3936180334, 9783936180336

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%ble l. ?hxono&c composition of the amphibian fama of Central ~merica.

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Introduction

species in life. Some Central American species of amphibians are so distinctive in coloration, as well as body size and shape, that an animal in question often can be identified readily by photographs alone. However, identification keys provide additional information on the morphology andlor coloration of the respective species and should be consulted. Additionally, the distribution maps can be included in the identification process, because many species have very restricted distributions. The keys are dichotomous, meaning that they provide pairs of contrasting alternatives (couplets). Such a key works by using a step-by-step elimination of alternatives until only a single alternative, the solution, remains. It is important to remember when using the identification key that the juveniles of many amphibian species have different coloration and pattern than the adults and might lack characteristics present in the adults. Therefore, in many cases, the keys might not work to definitively identify juveniles. The key to the tadpoles also is challenging to employ, since tadpoles are significantly smaller than the adults of the same species. It is most often necessary to use a hand lens or even a microscope to be able to see the distinguishing features sufficiently well. The technical terms and morphological character designations used in the keys can be unfamiliar to non-specialists, but I am optimistic that anyone willing to invest some effort in learning the terms will be able to use the keys with confidence and success. The glossary included in the book will be helpful in this regard, as will the illustrations accompanying the keys. Abbreviations used are CCL (combined fore and hind limb length); C W C (Costa Rican Amphibian Research Center); HFW (hind foot width); HL (head length); HW (head width); P.N. (Parque National); and SVL (snout-vent length; distance from tip of snout to vent; to distal end of vent in salamanders). Numbers of teeth refer to total number (both sides summed), if not otherwise indicated. The term "limb interval", used in the keys to salamanders, indi-

cates the number of costal folds between adpressed fore and hind limbs; the total count of costal folds includes one each in axilla and groin. For some species-rich taxa (i.e., Bolitoglossa, Oedipina, and Terrarana), I have provided two keys, one that treats the species distributed from southern Mexico to Nicaragua, and the second covering the species known to occur in Nicaragua, Costa Rica, and Panama. Nicaragua is included twice in these keys because zoogeographically, northern Nicaragua belongs to Nuclear Central America (sharing with the northern countries species such as Bolitoglossa mexicana, Ptychohyla hypomykter, Plectrohyla sp., Mesaspis morele tii, Anolis beckeri, Tantillita lin toni, etc.). Southern Nicaragua, on the other hand, has many elements that are otherwise only found in Lower Central America, such as Oophaga pumilio, Dendrobates aura tus, Lepidoblepharis xanthos tigma, Anolis pen taprion, etc.). Thus, Nicaragua, much of which comprises the Nicaraguan Depression, is somewhat "transitional" between Nuclear Central America, and Lower Central America. It would be arbitrary to divide the country and make the split, for example, in central Nicaragua. After the introduction to each major group of Central American reptiles, the following information is provided in the species accounts: the current scientific name with author and year of description (in the case that the author and year of description are enclosed within parentheses, this signifies that the original generic name has been changed to the current one), followed by the citation of the location of the original description of the species and a statement of the type locality; the maximum size (usually SVL), and the known geographic and elevational distribution. Detailed anatomical descriptions are beyond the scope of this book because it is intended for use as a field guide. The recommendations for further reading at the end of each

(nearSan nam6a Be La Fwgen, Hmdia, Costa Rim). Photo: C4. KBhl~r

The index at inhdhgthe

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(19711,h a clb; (3ms(19761,ALTIG (19871,DUELLMAN& CAMPBELL(19921,

be an w u s d addition to a field guide such as thig one, I would be remiss to net

Class3cation of the Amphibians of Central America

ClassXcation of the Amphibians of Central A m h I

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Bolitoglossa (86) Bradytriton (1) Cryptotriton (6) Dendrotriton (8) Nototriton (14) NyctanoLis (1) Oedipina (29) Dseudoeurycea (6

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Family Genus (in parentheses is the number of species that occur in Central America)

claaacation ofthe Amplu'bh of Central America L

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~lophryniscus(1 Atelopus (8) Chaunus (2) Crepidophryne (3) Incilius (22) Rhaebo (1) Rhinella (2

Espadarana (1) Hyalinobatrachium (7: Sachatamia (2) Teratohyla (2)

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miphractus ( Gastrotheca (2

Ameerega (1) Colostgthus (3) Dendrobatm (9) Hyloxalus (1) PhyUobates (2) Phyllodactylus (31

I Agalychnis (6) Anotheca (1) Bromeliohyla (1) Charadrahyla (1) Cruziohyla (1) Dendropsophus (5) Duellrnanohyla (7)

Diasporus ( 6 ) Eleuthe,m&&pJm I

Exerodonta (5)

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Leiupenaae eurodema ( I Engystomops (

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The Environment

The Environment '

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- * Rainfomst The beauty and majesty of a primary tropical rainforest or an old mature , "-

The various mountain complexes that form the physiography of Central America can be divided into two major growth can be breathtaking. Tropical massifs. The northern block includes the rainforest is found in regions with monthMesa Central of Chiapas, the highlands ly temperatures exceeding 18 "C during of central and southern Guatemala, and all months of the year and an annual those of Honduras, El Salvador, and rainfall of more than 2000 mm. northern Nicaragua. These are separated Rainforest soils are typically poor, due to from the southern highlands by the leaching of soluble nutrients. In the Nicaraguan Depression. The southern northern parts of Central America, rainhighlands include the Cordilleras de forest is found mainly in the Caribbean Guanacaste, Central, and Talamanca, as lowlands. In Costa Riea and Panama, it well as the relatively low highlands of also covers large areas of the Pacific verDari6n in eastern Panama. The two large sant. During the day, temperatures in the Nicaraguan lakes (Lagos de Managua tropical rainforest reach 3045°C. During and Nicaragua) are the largest inland bodies of water in Central America, with surface areas of 1035 km2 and 8157 km2, respectively. The diverse landscape of Central America supports very different regional climatic situations (DUELLMAN 1966, STUART 1966). On the Pac5c versant of Nuclear Central America, the dry season extends from January through April. A subhumid corridor, made up predominantly of dry forest or the remains thereof, stretches along the Pacific versant of Central America from the Isthmus of Tehuantepec through northwestern Costa Rica. Generally, the Caribbean versant experiences an equable, tropical climate with relatively mesic conditions throughout the year. Exceptions are the northern part of the Yucath Peninsula, as well as some interior valleys, which experience a more arid climate. The wettest regions of Central America are found in southeastern Nicaragua and northeastern Costa Rica, which receive an excess of 6000 mm precipitation per year. ?

Fig. L. ,iooded rainforest at Rio San Juan, Nicaragua (30 a elevation). Photo: G.Kijhl81'

The h-at Cloud fontst eavyraftemom.

moist forest characterized by frequent mist or clouds at the vegetation level.

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Photo: G.Ktihler

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The Environment streams channel the water on its way to the lowlands. At very high altitudes along exposed ridges, a special sub-type of cloud forest grows, the so-called elfin forest. Subject to low temperatures, high precipitation, and high wind speeds, trees in the elfin forest usually attain less than 1-3 m in height. The fauna of cloud forests tends to be less diverse than that of the lowlands, but there is a high number of endemic species, i.e., species that only occur in one particular area, such as a summit or a mountain chain. Dry forest Dry forests are typical of the Pacific versant of Central America and a few interior valleys of Honduras and Guatemala. The climate is characterized by low Precipitation (500-1200 mm) and long dry

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