The New Precambrian [2 ed.] 9783000478710

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Uwe-M. Troppenz

THE NEW PRECAMBRIAN No „boring“, but bustling billions in a succession of evolutions and catastrophes

“You must be able to follow your feelings, you must be free in your thoughts but without fantasizing and you must always stay curious.” (Abderrazak El Albani, University of Poitiers)

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Tetrada

© 2017 Tetrada Verlag, Parchim second edition 2017 ISBN 978-3-00-047871-0 updated and complemented text translated by Anita Müller, Karlstein 115 pictures and two chronological tables printed by Power Design & Druck, Parchim reprints only with the permission of the author photos, drawings, graphics: chapter “The revolution of the Gabonionta” Abderrazak El Albani (unless otherwise indicated) chapter “A new picture of the Precambrian” and “From the war between the creatures to the apocalypse“ Regina Troppenz (unless otherwise indicated) contact: www.palaeontologie-troppenz.de or [email protected] The cover picture shows fossils from the Franceville biota (big photo: A. El Albani) and fossils of the three big Precambrian biotas (photos: A. El Albani, France, Thomas Kapitany, Australia, Tomonori Kikushi, Japan)

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Inhalt 4

Preface The revolution of the Gabonionta Two billion years before our time Who is Professor El Albani? Hundreds of life witnesses in clay shale Franceville biota - pros and cons What are the Gabonionta? Chinese scientists: conserved cells! Next proof: multicellular organisms in India

A new picture of the Precambrian Gabonionta and the consequences Life after the hail of meteorites Creative catastrophes “Bustling billion” - no „boring billion” Strings of beads and hairpins A paradise explodes

From the war between the creatures to the apocalypse Ediacaran in the Cambrian? The traces are leading into a new world Two times Burgess: "Time capsules of life" Chengjiang: clearance sale of predators Astonishing structures in the Västervik basin The almost exact dating of the end of the world

Acknowledgements Some feedback from scientists Book review Literature

7 8 10 14 18 24 28 31 35 35 40 46 52 56 81 90 90 92 97 103 108 111 120 121 123 126 74/75

Chronological tables

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Preface One of my theses in the first volume of my book “Wohin die Spuren führen” (“Where the traces are leading to”) postulates the existence of the Montana biota before the Ediacara biota. This thesis has now been supported in an impressive way. On 12 March 2014, a fossil exhibition opened in the Museum of Natural History in Vienna, displaying the “Gabonionta” - exhibits that drew a completely new picture of the Precambrian! According to scientists, the Gabonionta represent the first known ecosystem of the Earth. They were discovered in a 2.1-billionyear-old stratum near the city of Franceville in Gabon, Africa. On the one hand, this hitherto oldest example of biodiversity shows that complex life did indeed not originate only about 600 million years ago. On the other hand, it contradicts the theory of the great “emptiness” before that time, in which solely unicellular bacteria existed, which caused the reef-formation of the “stromatolites”. This premise had been the basis of any evaluation of the Precambrian world. Well, there seem to be quite some changes ahead. Still in 2014, the joint publication “Lebensspuren im Stein” (Rothe et al.) described life at that time to have been limited to “microbes, that is to say organisms with a relatively simple structure and of a low organisational level”. It continues: “It was not until the final stages of the Precambrian that fossils first provided evidence of organisms with somewhat more complex structures.” Today, however, we know: there has been complex life for at least 2.1 billion years. The Franceville biota, followed by the Montana biota and eventually the well-known Ediacara biota, which gradually disappeared with the “Cambrian explosion”. As described in my book (mentioned above), the individual eras of the Earth’s history are limited by catastrophes that largely erased previous biospheres and created new animate worlds. This also applies to the time of the Gabon biota, which was marked by complete glaciation, big impacts and an oxygen collapse. The Franceville biota in Gabon was discovered by Prof. Abderrazak El Albani, a FrenchMoroccan scientist at the University of Poitiers, and his international team. In an exchange of letters, Prof El Albani expressed his agreement with the “Montana biota” with its living beings such as Horodyskia, which followed the Gabonionta. It was definitely conceivable as an era of transitory biota (“intermediate stages of life"), he wrote.

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Professor Abderrazak El Albani at the finding place north-west of Franceville in Gabon - the story of life has to be re-written. The discovery of a world populated by diverse living beings at a time for which science had ruled out complex life altogether, throws all theories overboard. And this does not happen with much “palaeopoetry”, but with clear “palaeofacts” - namely with “the fossil in one’s hand”, as Dr Z. Gába, a Czech geologist, once put it. Photo: Gabon Expression

Almost exactly 100 years previously: Charles Doolittle Walcott (left) with his wife and daughter in 1913 in the world-famous Cambrian Burgess Shale in Canada, which he had discovered in 1909. By 1924, he had collected as many as 65,000 fossils. He used them to present to the marvelling world a completely new picture of life in the Cambrian, which had been much more diverse than previously thought. Photo: Wikimedia Commons

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So it seems that the prehistory of life - from the Earth’s formation to the “Cambrian Explosion”, introducing the modern era with its well-known fossils and recent living beings - must be rewritten. As far as I am concerned, this discovery makes El Albani even surpass Charles Walcott (18501927). At the beginning of the past century, Walcott discovered the midCambrian black shale sediment (“Burgess Shale”, 505 m years) near Fields, British Columbia, Canada. This discovery with its fossils with soft parts enabled Walcott to provide evidence of a considerably more diverse habitat at that time than previously thought. Proof of complex life in the Mesoproterozoic and Paleoproterozoic: Charles Darwin would have been happy, for he was definitely aware of the large gaps in his Theory of Evolution. In his work “On the Origin of Species” (1859), he admitted with self-critical candour that he did not know why absolutely no fossils could be found from the days before the Cambrian. He had absolutely no solution to the problem of “why do we not find beneath the Cambrian system great piles of strata stored with the remains of the progenitors of the Cambrian fossils?” So where do the creatures of the “Cambrian Explosion”, that seemed to appear all of a sudden, come from? This question has now fairly been answered. On the other hand, we witness here a certain weakness in Darwin’s theory. After all, he wrote in the same paper that “I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Cambrian system was deposited”. Nevertheless, the 2.1-billion-year-old Gabon fossils do indeed represent a full biosphere in all its diversity, something which certainly nobody would have suspected. So where does t h i s diverse life come from, if Darwin was to be proved right? The “Cambrian Explosion” was, after all, the starting signal for a new age, that began 540 million years ago and led to human beings, who shape the world today. Whether we are going to be up to this great responsibility remains to be seen. But don’t worry - should the “Human Catastrophe” present itself on Earth, there will certainly be a successor biota at hand... Uwe-M. Troppenz, Parchim 2016

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The revolution of the Gabonionta And once again, everything turns out to be completely different than previously assumed. But actually, this palaeontological revolution was sheer coincidence. The French Embassy was the one to spark the revolution, originally intending to enrich the partnership with the West-African state Gabon on a scientific level. Thus, it suggested to send a group of scientists into the Franceville region with its bedrock of Precambrian clay shale. Franceville, with its roughly 43,000 inhabitants, is Gabon’s third largest city and provincial capital of Haut-Ogooué. In recent years, it has experienced a significant economic upturn owing to the exploitation of manganese and uranium. Gabon is well-known for its special geological and mineralogical characteristics. The area around Franceville, for instance, is the type locality for nine minerals: Bariandite, Chervetite, Curienite, Francevillite, Lenoblite, Metavanuralite, Mounanaite, Schubnelite and Vanuralite. Of fossils, however, there was no mention... Nevertheless, in 2008, Professor Abderrazak El Albani, geologist and sedimentologist at the University of Poitiers, set out for Franceville; he was accompanied by his colleague Paul Sardini and his Gabonese student Frantz Ossa Ossa. With little financial means, as the undertaking did not appear in any research programme, a great deal of idealism was necessary. In his portrait on the website of the French University of Poitiers (27 September 2013), Prof El Albani explains in an extremely modest understatement: “In the end, the credit for our discovery belongs to the embassy, as it took a marvellous initiative. My only contribution was that I reacted positively to their offer, leaving aside certain dogmas... However, a great deal of curiosity was involved, because we knew from experience that there was no chance of finding any life forms in that region - many explorers and researchers had been there in the course of the foregoing 25 years...” His comment about the regrettably low funds: “If you are not enthusiastic about it, then this profession is not the right thing for you anyway.”

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Two billion years before our time With this attitude, one can really move mountains. And this is exactly what El Albani did. In an area where there seemed to be no hope of finding any traces of ancient life, the Albani team made a find. And what is more: they did not find microbial mats or stromatolites, but best preserved multicellular and complex fossils of living beings, physically handed down in clay shale - apparently a whole marine ecosystem and the very first example of biodiversity. Its age: 2.1 billion years! “In 2010, a report from the professional journal ‘Nature’ came as a bombshell” said a press release of the Museum of Natural History in Vienna on 11 March 2014. The reason being: “This 2.1-Gyr-old find revolutionized our ideas about the history of life on Earth.” (Press release of the University of Poitiers on 23 June 2014.) Even some newspapers described the situation with similar words in the year of the „Nature“ publication. This description, however, stems partly from understandable wishful thinking, and partly from journalistic dramatization. In reality, the experts looked up only briefly from their beloved tomes, squinted over the top of their glasses and raised their eyebrows in slight uncertainty, only to comfortably go on delving into the traditional and established views. Some activists at least made the effort to try to refute the findings, in order to put in its place the unruly attack to a once established and apparently consistent world view. But we come to that later. The “bombshell” ended in a silent “ploff” and, by and large, a dark veil of silence was drawn over the subversive discovery. Professor El Albani regretted this. During our exchange of letters, he wrote on 30 August 2014: “I take the liberty to say that the international scientific community is very ‘hesitant’. Certain scientists are trapped in a dogma and do not want to see that there was a life before Ediacara. Our research has demonstrated the opposite.” It is certainly not easy, continues El Albani, to accept completely new circumstances in view of the established theories. But there are simply new scientific facts.

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The finding place of the fossils lies north-west of the city of Franceville (photo below) in south-east Gabon. Images: Wikimedia Commons

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Who is Professor El Albani? On its website, the University of Poitiers calls him “a researcher beyond the usual - curious by nature, but eternally dissatisfied”. Professor Abderrazak El Albani sees himself as a team player and likes attributing success to others. His passion for research and his unconventional ideas combine with the courage to make something apparently absurd a subject of discussion - willingly against the prevailing opinion. He is particularly annoyed by dogmas, blinkers, a lack of flexibility and insufficient willingness to accept new ideas. The worst for him is when facts are being ignored in favour of sustaining outdated visions. In that case, he may even criticize colleagues, as he did for instance in the CNRS journal on 25 June 2014: “To be honest - it is very difficult for certain colleagues of the scientific community to admit that such early macrofossils might exist!” As a boy, he wanted to become a fighter pilot. He says that geology “seduced him only very late”. But then it did! “When the scientific fever hit me for the first time, I didn’t want to do anything else anymore.” Abderrazak El Albani was born in Marrakesh, Morocco - according to El Albani “the most beautiful city in the world”. He is the youngest of a total of ten siblings. Today, he is himself father of a ten-year-old son. From Marrakesh, El Albani went to France to go to university and his geological dissertation was accepted in 1995. After his doctorate, he spent three years to Kiel in Schleswig-Holstein, Germany (from 1996 to 1998), and finally signed on in 1999 at the laboratory for hydrogeology and soil science of the University of Poitiers, which is part of the “Centre national de la recherche scientifique” (CNRS), the national centre for scientific research. Its slogan: “Advancing the frontiers”. The title of professor followed in 2010, in the year in which his research results from Gabon were published. In the following months, little happened in the scientific world and almost nothing in public, so El Albani took the initiative. He saw to a public exhibition of the fossils. After all, they represent a kind of paradigm shift, that is to say a transformation of basic conditions for the geology and palaeontology of the Precambrian and with that a complete reorientation regarding the early development stages of life and the evolution of the earthly biosphere itself.

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Deep insights into a hitherto completely unknown and more than 2-billion-yearold world: The research team led by Abderrazak El Albani (above, photo: CNRS) found in Gabon fossils with sizes between 2 cm and 17 cm in completely different manifestations: the “Gabonionta”... All images in this chapter: A. El Albani - unless otherwise indicated.

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Once again, it was a French embassy that acted as a facilitator - this time the one in Austria. It came in handy that the NHM, the Museum of Natural History in Vienna celebrated its 125th anniversary in 2014. A sensational exhibition served the interests of both, the museum and Professor El Albani. And so it happened that from 12 March to 30 June 2014, the most impressive “Gabonionta” were presented to the public for the first time ever. According to a press release of the museum on 11 March, “the fossils of Gabon had never before been publicly accessible despite their importance in the evolution of life”. Two display cases now showed the best preserved specimens “in order to document the diversity of this most ancient known complex ecosystem”. Videos showed virtual three-dimensional reconstructions of several individuals. The animations were based on micro-CT data and allowed amazing insights into the organisms. The University of Poitiers contributed a 40-minute-film (with the help of the University of Innsbruck for the German translation) that presented interviews with experts, but also pictures of the finding place. On 11 March, a press conference was held in combination with an exhibition tour, which was attended by Prof Abderrazak El Albani, the discoverer, Prof Christian Köberl, the museum’s general director, and Dr Matthias Harzhauser of the NHM’s Geological-Palaeontological section. They made it clear to the media representatives that “the discovery of macroscopic multicellular organisms living in colonies that were found in 2.1-billion-year-old sediment revolutionizes” the past general belief (“common sense") that there had not been any multicellular, colonial, complex life before Ediacara. The courageous advance paid off: the Gabonionta started to become well-known in public and this time, the scientific world was forced to change its ways. It could not “dwell” for years on its results and analyse them over and over all by itself, just to discover one day that new findings were produced, which would again stay trapped within the university walls - no, this time, the path was followed in the opposite direction: The public learned of apparently established research findings, which the scientific world can now take note of, assess and discuss. Thus, El Albani also “advanced the frontiers” in the way of proceeding.

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Historic fossils in the Museum of Natural History in Vienna: below the display cases with the Gabonionta, to the right a rock slab with numerous individuals - image width 30 cm. Photos: NHM

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Hundreds of life witnesses in clay shale The exhibits on display in the showcases in Vienna’s Museum of Natural History had been recovered laboriously by the El Albani team in several excavation campaigns in Gabon between 2008 and 2014. North-west of the provincial capital Franceville, roughly 450 increasingly impressive fossils from 45 different horizons have been excavated; sometimes more than 40 individuals in one cubic metre! It is further assumed that the clayey sediment contains many more surprises. “The area is extraordinary!” As El Albani put it. What is the reason? While Precambrian strata elsewhere were severely disturbed by erosion, ablation, folds, tectonic movement and other geological processes in the course of billions of years, we find an “incredible stability” (El Albani) in the Franceville basin. The fossil-rich strata are part of the “Franceville group”, which in turn belongs to a well-known rock system and spreads out over roughly 35,000 square kilometres in southeast Gabon. It reaches a maximum thickness of around 2,500 m. This rock system is composed of five not metamorphic, unchanged and not deformed rock strata, with the fossiliferous stratum being termed FB2. The lithofacies analysis showed the complete absence of microbial mats. 2.1 billion years ago, multicellular organisms existed in an oxygen-enriched and calm shallow water - probably in colonies on the seabed in a depth of 30 to 40 metres. They formed an ecosystem comprising macroorganisms and microorganisms (acritarchs). During the first excavation, about 250 macrofossils with sizes between 2 cm and 12 cm were found. They had very different forms: round, oblong, segmented... El Albani and his team published the first report in 2010 in „Nature“, an English weekly journal. It treats mainly topics from scientific disciplines. „Nature“, next to „Science“, is the world’s most renowned journal for the natural sciences. The international and interdisciplinary group of authors even made it to the front cover. The group consisted of scientists from France, Sweden, Denmark, Canada, Belgium and Germany. They went immediately in medias res: “Here we report the discovery of centimetre-sized structures from the 2,1-Gyr-old black shales of the Paleoproterozoic Francevillan B Formation in Gabon, which we interpret as highly organized and spatially discrete populations of colonial organisms.”

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Above: The geological map of the Franceville basin and the lithostratigraphy of the Paleoproterozoic strata there. The finding place is marked with an asterisk. The fossils stem from the FB2 layer. Below: Professor El Albani (left) with colleagues during the sighting and first estimation of the current findings on site. Owing to the completely undisturbed stratigraphic sequence, the ancient fossils are exceptionally well preserved.

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El Albani had good reason not to write about the fossils all by himself with just some colleagues, but to commit an interdisciplinary group of authors from different scientific fields such as palaeontology, biology or chemistry. He rightly feared that somewhat more inflexible and conservative palaeontologists object to his research findings, clinging to traditional views as if to say: “This confuses our world view and ruins laboriously established hypotheses.” Blinkers, however, are foreign to the young French-Moroccan professor the best prerequisite for new findings. A portrait of the University of Poitiers from 27 September 2013 quoted him as follows: “You must be able to follow your feelings, you must be free in your thoughts - but without fantasizing - and you must always stay curious.” Naturally, he employs the latest technology to study the fossils, to make absolutely sure. It is not clear yet, whether the fossils represent different species or just one variable species. The outward appearance, however, suggests that they are indeed very different species. But morphology is really only one side of the coin - the other is the internal structure. To find out more about the internal structure, the objects are examined using a micro-CT scanner. The three-dimensional reconstruction allows insights into the structural design - which seems to be the same in all Gabonionta specimens. The observed foldings obviously result from a post-mortal deformation of the gelatinous central body. El Albani inferred that this complex structure represents the oldest geological indication for coordinated growth and intercellular communication. In „Nature“ (2010), the team of authors wrote: “The Gabon fossils, occurring after the 2.45–2.32-Gyr increase in atmospheric oxygen concentration, may be seen as ancient representatives of multicellular life, which expanded so rapidly 1.5 Gyr later, in the Cambrian explosion.” The end was soon near: One hundred million years after the Gabonionta’s heyday, the oxygen levels fell again radically, resulting in a new oxygen event, but this time vice versa. Donald Eugene Canfield, professor of ecology at the “Syddansk Universitet”, and Abderrazak El Albani, professor of geology, discovered in 2013 clear indications for this event in the sea sediment of the Franceville basin. In 2009 already, the professors Robert Frei (University of Copenhagen) and Donald E. Canfield as well as other authors ascertained in „Nature“, after an analysis of specimens from all

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This specimen was one of the first findings. It was on the cover of the scientific journal „Nature“ in 2010 (to the right). The German newspaper „Frankfurter Rundschau’“ called the first signs of life of an unexpected primeval world “ear-shaped biscuits”. Above: Positive and negative original version of the macrofossil, below the CT image.

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over the world, that the oxygen content had suddenly dropped 2 billion years ago reaching the same low levels as were present before the ”Great Oxydation Event” (GOE). Franceville biota - pros and cons Naturally, there have been doubts right from the start. The first findings nourished these doubts, as they were relatively shapeless or similar to mineral processes. There was talk about already known symbiotic communities of unicellular bacteria, of pyrite concretions, ovoidly growing microbial mats, colonies of unicellular fungi, etc. The German palaeontology professor Franz T. Fürsich of the Geo-Centre in Erlangen (part of the University of Erlangen) was involved in the finds’ handling and the interpretation. In an interview with the German newspaper „Frankfurter Rundschau“ of 4 August 2010, he explained: “These organisms that existed as early as 2.1 billion years ago and grew in a coordinated way, are comparatively large, which really surprised us.” However, he also conceded: “Cellular structures were regrettably not preserved in the fossils.” By the time of the interview, about 250 specimens had been found and roughly 100 fossils studied. The first opposing party were the Christian creationists. Of course they felt attacked by the reports about multicellular fossils, which were supposed to be 2.1 billion years old! On 15 July 2010 already - that is shortly after the „Nature“ publication - Shaun Doyle, a young environmental scientist at the University of Queensland (Brisbane/Australia), wrote on a website “creation.com”: “There is no evidence of cell differentiation, such as different tissue structures, in the Gabon fossils.” Multicellular organisms were presupposed simply because of the fossils’ size. Essentially, Doyle argued that the findings were at best an accumulation of communicating cells, which had not reached the organism-level. Not even El Albani et al. would claim a connection with other fossils of the Precambrian and Cambrian, which means that these findings do not even serve Darwin and the evolution theorists. Doyle concluded: “Therefore we are left with fossils that have modern analogues (today’s bacteria colonies), but with no links to something else.” However, the creationists were not the only adversaries of the Gabonionta

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The fossil above and to the left is one of the first finds. Creationists like to take it as an example that the Gabonionta “resemble rather a bacteria colony than truly multicellular life.” But there has also been criticism from other sides... Hardly or not at all pyritized macrofossils (to the right) of round morphotype. - Similar: the roughly same-sized problematic specimen from the Lower Cambrian glacial erratic boulders (below). Photo: Regina Troppenz

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discoverers. There were certainly also more secular scientists, like Prof Adolf Seilacher (1925-2014), who was regarded as one of the most prominent and innovative palaeontologists worldwide. Although he himself originally advanced rigid frontiers with sensational finds and bold interpretations, he did eventually adapt to conventional wisdom and in his book “Trace Fossil Analysis” (2007), he ruled out multicellularity more than 800 million years ago. His argument: the „biogenic (metazoan) interpretation is in conflict with the radiometric ages of the host rocks“. This means that not presumably biogenic results relocate the beginning of complex life further into the past, but that the age of the finds contradicts the biogenic interpretation. This stance really forestalls new insights. Logically, Seilacher classified his worm burrows, “hairpin structures” and also the “string of beads” Horodyskia as “Pre-Ediacaran dubiostructures” from a time significantly before Ediacara (see also next chapter). The same argument was put forward in connection with the Gabonionta. „Nature“ reported online (2010): „The palaeontologist Adolf Seilacher at Yale University in New Haven, Connecticut, instead interprets them as aggregations of the mineral pyrite that grew in different shapes depending on the changing state of the surrounding sediment.” “Pyrite suns” is the term being used. The report quoted Seilacher’s retraction as follows: "I now firmly believe that my own so-called first animals were pseudo-fossils, too.” In 2010, the „Frankfurter Rundschau“ also asked the question about loose cell aggregations as a symbiotic association of unicellular organisms. Professor Fürsich, as one of the authors of the „Nature“ article, conceded in the interview the missing cellular structure in the specimens found by 2010. This is why I had to ask him directly: Was it not possible that a cellular structure could not be expected at all or did any of the findings made between 2010 and 2014 maybe show this structure? Franz Fürsich made it plain to me: “Since the first publication of the ‘Gabonionta’, I have not dealt with them anymore and therefore, I do not know if any subsequent finds allow additional statements.” I asked the same question to Dr Matthias Harzhauser, Head of the Geological-Palaeontological department of the Museum of Natural History in

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This specimen from the black shales of Franceville is 12.5 cm big.

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Vienna, where the Gabonionta exhibition had just been closed. In a press release on 11 March 2014, Harzhauser wrote among other things: “Even in cyanobacteria, simple forms of multicellularity, in which individual cells communicate with each other, have been documented. Although multicellularity has thus been known since the early Proterozoic, it has been common sense to place the leap into the macroscopic world of multicellularity ... about 580 million years ago.” Loose cell aggregations alone, however, do not form complex living beings. So are there any cells distinguishable in the Gabonionta macrofossils? Harzhauser wrote to me in October 2014: “Cellular structures are not really to be expected” in these shales. And how does the Gabonionta discoverer Professor Abderrazak El Albani himself respond to this? His answer took some time. He seems to be a passionate workaholic. Even his university’s profile states: “If you cannot find Abderrazak in his lab at the University of Poitiers, best go looking for him in Gabon or in any of the other four corners of the world.” Finally, he answered - from a train on his way back to Poitiers from a palaeontological mission and adding “I will soon be abroad again.” In between times, he dealt with his e-mails on his laptop. He also admited: “Indeed, there are actually no fossilized cellular structures.” But: “This is the case in most fossils, even in the younger ones.” Moreover: “Pyritization preserves the overall morphology very well, but scarcely the cells.” This means, that the detected biogenic nature of the specimens in combination with their size and shape has to justify the assumption of the Gabonionta’s integrally working multicellularity. In the „Nature“ report of 2010 already, the team of authors led by Professor El Albani wrote that the geochemical analysis suggested that the sediment had been deposited in oxygenated water. The examination of the carbon and sulphur isotopes revealed data suggesting definitely biogenic structures. The fossils contained, for instance, a significantly higher accumulation of organic carbon than the surrounding sediment. All in all, this was considerably too complex to be of inorganic origin. The team of authors continued: “The growth patterns deduced from the fossil morphologies suggest that the organisms showed cell-to-cell signalling and coordinated responses, as is commonly associated with multicellular organization.”

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This specimen is about 3 cm big (above: original fossil). At first glance, it could be mistaken for a pyrite concretion or something similar. In my opinion, the image below taken from a micro-CT scan says something completely different...

Below: two unpyritized (!) macrofossils of 2014 from the same stratigraphic plane. This ensemble of two different morphotypes has a diameter of about 8 cm. The positive and the negative side are depicted.

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Dr Gisela Gerdes from Wilhelmshaven, Germany, a biologist and marine scientist specializing in biofilms, microbial mats and stromatolites, had certain reservations. Upon my request, she answered on 5 February 2015 in a very balanced way: 1. Gabonionta occur on bedding planes and in three dimensions. However, this also applies to bacterial aggregations, which are certainly not always embedded in sediment and still display biofilm formation. 2. Gabonionta are sometimes described as spherical central bodies surrounded by radial fringes. Analogous structures are produced with gas bubbles in microbial mats and stromatolites. They leave spherical cavities surrounded by palisades of calcite spicules. However: The elasticity conveyed in the Gabonionta’s micro-CT images in this type of structure is much less frequent in microbial mats, the recent structures observed are considerably smaller and the regularity of this Gabonionta’s form, size and distribution on bedding planes cannot be observed in microbial mats. 3. Gabonionta show clear signs of coordinated growth and cellular communication, but this is also found in mat-forming cyanobacteria. 4. When talking about Gabonionta, size is mentioned as a criterion. A slime-stabilized surface and floating biofilms may also generate large, seemingly complex forms. But on the other hand: recent forms like these are often unstable and would be reshaped in the embedding process quite irrespective of synsedimentary mineral formation, which would also have to be taken into account. Gerdes: “By no means do I wish to contradict the theory that the Gabonionta were remnants of multicellular eukaryotes. I simply wish to qualify the theoretical exclusion of bacterial growth structures.” What are the Gabonionta? On 25 June 2014, the joint project of Professor El Albani and 27 other scientists from several countries was published in “PLOS ONE”, an international online journal: “The 2,1 Ga Old Francevillan Biota: Biogenicity, Taphonomie and Biodiversity”. By today, about 450 fossils have been discovered. More than ever before, they make us aware of the Gabonionta’s great variety and diversity and allow us further insights into this Paleoproterozoic biosphere. Apart from pyritized and partly unpyritized macrofossils, also microfossils (acritarchs) have been found.

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Oblong and round specimens from the Franceville basin in Gabon. Above the record holder in terms of size: a 17-cmlong pyritized macrofossil. Scale for the specimens below to the left: 1 cm. Below to the right a round morphotype (approx. 3 cm). Post-mortal deformation is quite possible.

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El Albani et al. finally commited themselves: “Overall, the Francevillian biota represents an exceptional Paleoproterozoic oxygenated ecosystem comprising several types of macroscopic organisms”. They clarified once again that there are pyritized as well as partly pyritized and unpyritized fossils. This also rendered the claim, the Gabonionta were merely pyrite concretions, null and void, a fact that had already been excluded after the analyses. Likewise: “Lithofacies analysis indicates the absence of bedding-parallel microbial mats throughout the entire fossiliferous sequence.” This means that the structures cannot have been produced by random manifestations of biomats, but must have a different origin. The book „Les origines de la vie - une nouvelle histoire de l’évolution“ (A. El Albani et al.) published in 2016 in Paris says it unambiguously: “An intriguing discovery was made: Fossils with complex structures, more than 2 billion years of age. The fossils represent the oldest form of multicellular organisms.” So what actually are the Gabonionta? This is not an easy question to answer. These fossils occupy a unique position in the chronology of life, incomparable with other animate worlds, not emerging from one of them and not leading to one of them. This is at least what we know today. Purely from their outward appearance, we may feel reminded of fossils from the Lower Cambrian such as brachiopod moulds or medusiform moulds, lobopodians, or even crinoids. But this has to remain on a speculative level. Comparing certain Gabon fossils with fungi colonies is also being discussed. Dr Joachim Scholz from the Senckenberg research institute wrote in a personal note of 5 October 2014: “By the way, from their morphology, the Gabonionta resemble fungi colonies growing in agar dishes. I should not be surprised by their age of 2 billion years. They are the only eukarya that can (almost) be a match for bacteria, as far as the diversity of the extreme habitats they populate is concerned.” Fungi as eukaryotic living beings constitute a kingdom of their own next to animals and plants. Their cells contain mitochondria as well as a cytoskeleton. Except for the unicellular yeasts, multicellularity is the norm with fungi. Today, fungi are positioned closer to animals than to plants, because they use enzymes to dissolve organic nutrients from their surroundings, for example, for inges-

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Above a slate plate with several round fossils (each approx. 3 cm) - with central body and radial structures at the fringes. They are compared to yeast colonies in agar dishes (below to the right, source: www.mikrobiologischer-garten.net). Below to the left an image taken with a scanning electron microscope (SEM) provided by Dr Gisela Gerdes: a vertical section through a recent, purely biogenic microbial mat, e.g. with cut filiform cyanobacteria, which appear “segmented” (cell colonies).

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tion. They do not perform photosynthesis and the cell walls are mostly made of chitin, which is not the case in plants. Are the Gabonionta fungi? Why not? But here again: These are interpretations and assumptions. Deducting from appearance and size, we could just as well pursue the trace of Dactyloidites ottoi, comparable with the feeding behaviour of today’s lugworm Arenicola marina (Wilmsen & Niebuhr 2014), or else Atollites italicum (Serpagli 2005). Prof Joachim Reitner of the University of Göttingen, president of the German „Paläontologische Gesellschaft“ („Palaeontological Society“), also considers the Gabonionta as highly problematic. “Multicellularity is not proven”, he wrote to me on 22 October 2014. On the other side, he relented: “We cannot prove it anyway, we are only assuming...” This last statement is certainly right and I could not agree more. However, I think that the Gabonionta have gone beyond the mere speculative. Chinese scientists: conserved cells! In contrast to the Franceville biota, scientists now found 167 specimens of 1.56-billion-year-old fossils with conserved cells! They belong to the next biota, the Montana biota. Shixing Zhu, Maoyan Zhu, Andrew H. Knoll, Zongjun Yin, Fangchen Zhao, Shufen Sun, Yuangao Qu, Min Shi & Huan Liu published their discovery on 17 May 2016 in Nature Communications (Nature Commun. 7: 11500; doi: 10.1038/ncomms11500). They wrote: „Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1.560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ~10?µm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain.“ And they continued: „The new fossils provide the strongest evidence yet

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Above you see fossils of Yanshan/China: 1.56 billion years old. It is a sensation: In contrast to the Gabonionta, the cells are visible! Photo: Zhu et al., fig. 3 and 7

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that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion.“ It could be expected that there would be some disagreement. It was the „Guardian“ (18 May 2016) who summarized the pros and cons of this sensational discovery. Phil Donoghue, a professor of palaeobiology at the University of Bristol, described the discovery as a “big deal”. “They are not the oldest eukaryotes, but they are certainly the oldest demonstrably multicellular eukaryotes,” he said. The „Guardian“: „But other experts were more sceptical. ‘There is nothing here to suggest that the specimens are eukaryotic, as opposed to bacterial,’ said Jonathan Antcliffe, a senior researcher in the University of Oxford’s department of zoology. Bacteria are, by definition, unicellular, and do not have distinct nuclei containing genetic material. Antcliffe suggested the fossils were more likely corresponded to colonies of bacterial cells, rather than a single complex organism. Truly multicellular creatures display three-dimensional form in which only some cells are in direct contact with the environment. This was ‘critically important for function because it introduces transport problems for oxygen, nutrients and signalling molecules’ needed by the internal cells, Andrew Knoll of Harvard University explained in an article reviewing scientific literature on the origins of complex life.“ Even Abderrazak El Albani has doubts. He said, the level of detail in the study was “absolutely insufficient to tell us if these organisms were multicellular, eukaryotes or complex”. But to give proof of conserved cells in such old fossils would help to verify his own discovery from Gabon, I think. Professor Maoyan Zhu is convinced of „his“ multicellular organisms. On 19 December 2016, he wrote me an e-mail comparing the fossils of Gabon and China: „In the community, very few believe these structures are individual organisms. In contrast, our Gaoyuzhuang fossils preserved as carbonaceous imprints exhibit regular morphology as shown by morphometric data.“ I asked him to comment the view of the sceptics. He did. „Both skeptics do not have any experience with carbonaceous fossils“, he wrote to me (20 March 2017), „and do not know how it would look like if any bacterial

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colony is fossilized. I doubt whether Jonathan Antcliffe read our paper.“ A problem I know very well myself... Zhu continued: „Gaoyuzhuang fossils not even are preserved as carbonaceous imprints, but also display regular shapes and distinct margins as supported by statistical analyses of morphology. These features are similar to some sea grasses in present oceans and absent in the bacterial colony.“ Be that as it may: Things are in a state of flux. No boring billion at all. The old textbooks must urgently be redesigned. Prof Maoyan Zhu agrees: „I would say the 'boring billion’ is not that boring, more new discoveries and information are waiting for us. It is necessary to rewrite the textbook about early evolution of eukaryotes." Next proof: multicellular organisms in India Now that scientists have started to conduct their research without any prejudice regarding a layer’s age, they have been making one spectacular discovery after another. So Prof Stefan Bengtson, Swedish Museum of Natural History at Stockholm, discovered the next multicellular organisms, this time in India! His main research interests are the origin and early evolution of animals, and he worked together with Prof. Abderrazak El Albani. He and his team published a very detailed and revealing illustrated paper („PLOS biology“, 14 March 2017, http://dx.doi.org/10.1371/journal.pbio.2000735) with the title: Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae. The ~1.6 Ga Tirohan Dolomite of the Lower Vindhyan in central India (see p. 66 f) contains phosphatized stromatolitic microbialites. Bengtson et al. report from there uniquely well-preserved fossils interpreted as probable crown-group rhodophytes (red algae) and they gave them scientific names. The filamentous form Rafatazmia chitrakootensis n. gen, n. sp. has uniserial rows of large cells and grows through diffusely distributed septation. Each cell has a centrally suspended, conspicuous rhomboidal disk interpreted as a pyrenoid. The septa between the cells have central structures that may represent pit connections and pit plugs. Another filamentous form, Denaricion mendax n. gen., n. sp., has coinlike cells reminiscent of those in large sulfur-oxidizing bacteria but much

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more recalcitrant than the liquid-vacuole-filled cells of the latter. There are also resemblances with oscillatoriacean cyanobacteria, although cell volumes in the latter are much smaller. The wider affinities of Denaricion are uncertain. Ramathallus lobatus n. gen., n. sp. is a lobate sessile alga with pseudoparenchymatous thallus, “cell fountains”, and apical growth, suggesting florideophycean affinity. If these inferences are correct, Rafatazmia and Ramathallus represent crown-group multicellular rhodophytes, antedating the oldest previously accepted red alga in the fossil record by about 400 million years. Stefan Bengtson wrote in his summary: „The rocks mainly consist of calcium and magnesium carbonates, but the microbial mats and the fossils are preserved in calcium phosphate, letting us view the cellular and subcellular structures in three dimensions with the use of synchrotron-radiation X-ray tomographic microscopy.“ I asked Maoyan Zhu, whether his discovery and the discovery of Stefan Bengtson would be comparable and proofs for multi-cellular organisms in the Mesoproterozic. He answered (email 21 March 2017): „Indeed it is very interesting to see the new discovery from India by Prof Bengtson and his colleagues. Here in Nanjing, our colleagues had an intense discussions on the fossils. We think that the fossils are definitely the multicellular organisms with excellent preservation of cell structures.“ But he continues: „All India fossils do not show any difference both in preservation and morphology from the Ediacaran Doushantuo fossils of South China. In this regard, we think that the age of India fossils may be wrong because of the complicated tectonic history of these Proterozoic rocks without good age constrain in India. It urgently needs stratigraphic confirmation and repeat of the work. If confirmed, the India fossils would be very significant.“ Faced with these doubts, professor Bengtson at once refuted the objections of his Chinese colleague (email 21 March 2017): „We have of course considered this possibility, but I regard it as extremely unlikely, for the reasons we gave at some length in the paper. All available modern radiochronometric evidence points to the older age.“ Furthermore Bengtson declares forcefully: „Even disregarding the proposed correlation with the Son

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Rafatazmia chitrakootensis n. gen., n. sp., SRXTM renderings. (A–D) NRM X4251, surface, volume, slice. (E–G) NRM X5572, surface, volume, slice. (H–J) NRM X5562, surface, volume, slice. Legend: ec, external coating; db, diagenetic boundary; sw, septal wall; tw, thick wall. Scale bars 50 µm except where otherwise noted. Photos: Bengtson et al., fig. 4 33

Valley sequence, from where the most exact dates have been obtained, we have radiometric dates directly of the fossiliferous phosphorites as well as of glauconite in the same sequence, with no possibility of stratigraphic mixup. I don't see what correlational value would lie in the preservational similarities between these two phosphoritic deposits, nor in the morphological similarities of the very general kind of the rhodo-phyte-like thalli.“ He is sure of his interpretation of the Indian fossils. Unless stratigraphically meaningful Ediacaran-Cambrian fossils can be found in the Tirohan („we have been looking for ten years“), the only argument he can see for an Ediacaran age is "rhodophytes cannot be as old as 1.6 Ga". Here he argued ironical and refered to my criticism on Adolf Seilacher (see p. 65, below). I think the two sensationel discoveries of professor Zhu and professor Bengtson with their teams both have an enormous significance for drawing a new picture of the Precambrian period, verifying the existance of multicellular organisms in the Mesoproterozoic („Montana biota“).

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A new picture of the Precambrian Naturally, the existence of a proper biotope of complex multicellular organisms more than 2 billion years ago had enormous consequences for all previous assumptions about the Precambrian. The Precambrian was a period that lasted roughly seven times the Phanerozoic, which began with the "Cambrian Explosion" 542 million years ago. The term Precambrian, which has actually become outdated, is still used here as the overall term for the time before the Cambrian. For the time before the beginning of the bustling Ediacara 635 million years ago, merely single "occurrences" like Grypania spiralis or Horodyskia have been the topic of discussion. Grypania spiralis is a filiform structure that also existed from 2.1 billion years ago and up to the Mesoproterozoic. It has been found in India, China and North America and is presumed to be a eukaryotic alga. Horodyskia has been found in roughly 1.5-billion-year-old strata in Montana („Montana biota“) and Australia; it is possibly an early fungus. Apart from that, the Precambrian has been regarded as relatively empty, as far as life is concerned, if we do not take those prokaryotic unicellular organisms into account that were responsible for the formation of the stromatolites. Gabonionta and the consequences Let's follow the assumption that already in the Paleoproterozoic, there were unicellular organisms with a nucleus (i.e. eukaryotes), which joined to form not only loose communicating cell aggregations, but multicellular complex living beings. In that case, the chronology of prokaryotes (without nucleus) and eukaryotes has suddenly become wrong. As a result, we have to ask ourselves the question, whether the Precambrian was full of evolutionary islands or, alternatively, whether the developments had been connected to each other for billions of years and possibly all over the world. In the first volume of my book "Wohin die Spuren führen" ("Where the traces are leading to") I had two central theses: 1) Multicellular life is more than twice as old as hitherto assumed. Examples: Horodyskia (documented as a multicellular complex living

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being), worm traces and other objects that cannot be thought of as inorganic occurrences. Key word: Montana biota (approx. 1.8 to 0.8 billion years). 2) Evolution does not take place continuously and consistently to reach a higher state, as Darwin's spearhead Ernst Haeckel suggested with his infamous depiction of a tree of life with humans as the crown of their own evolution. Evolution rather takes place in between catastrophic and devastating events, which largely eradicate the prevailing animate world and create new biospheres. Simply put: a succession of evolutions and global catastrophes. Most dramatic examples: the sudden end of the Palaeozoic animate world at the end of the Permian about 250 million years ago or the sudden end of Mesozoic life at the end of the Cretaceous about 65 million years ago. There are always connections between the successive biospheres. Key word: interval model. The existence of the Gabonionta over 2 billion years ago has supported this thesis in an impressive way. Now, there is no more question whether there could have been multicellular life 1.5 billion years ago or whether that was impossible simply because it contradicted the doctrine. The Montana biota between the Franceville biota and the Ediacara biota has therefore not only become possible, but logical. Prof El Albani explained on 25 June 2014 in "Le journal" of the French scientific research centre CNRS (motto: "Making sense of science"): "The first big oxygen peak lasted only 200 to 300 million years and dropped about 2 billion years before our time. The oxygen levels decreased considerably and for about one billion years, the Earth was transferred into a state, which possibly triggered the eradication of the Franceville biota and the return to a merely microbial life." In our exchange of letters, Abderrazak El Albani qualified this statement. I had sent him my book "Wohin die Spuren führen" ("Where the traces are leading to"), volume 1, and approached him directly about the Montana biota. On 30 August 2014, he wrote to me: "As far as the forms before Ediacara you are quoting are concerned, I completely agree that they have their place in the biological register. Maybe they represent intermediate stages of life", namely between Franceville and Ediacara. The Franceville biota integrates smoothly into the succession of "creative

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This is how it all once started even "in our case": Powerful radiation of "newly born" stars - extremely bright stars in the emission nebula NGC1748, which is located within the "Large Magellanic Cloud" - in immediate vicinity to the Milky Way, namely "only" about 170,000 light years from us. In total, there are about 15 billion stars in the "Large Cloud". The "gas bubble" around the arising star has a diameter of 25 light years = 237 billion km. Photo: Hubble Space Telescope

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catastrophes" and the development of new animate worlds. Before the Franceville biota, we find not only the first oxygen catastrophe ("Great Oxydation Event" GOE), which "poisoned" almost all microbial life, but also the "Huronian glaciation". This massive spell of cold weather was named after stratigraphic sequences in the area of Lake Huron, through which the border between the USA and Canada runs. These stratigraphic sequences allow a reconstruction of the glacial movements at the time. The Ediacara biota, in turn, was initiated by a second "Great Oxydation Event" and several successive and partly total - ice ages ("Iceball Earth"). There is a connection. Higher oxygen levels correlate with cooler climate. According to a study in "Nature" (2009), more oxygen in the hydrosphere and the atmosphere makes organisms consume more carbon dioxide. Professor Robert Frei (Copenhagen/Denmark), Professor Donald E. Canfield (Odense/Denmark) and other authors inferred that it subsequently turned colder, because the greenhouse gas levels decreased. This fauna was terminated by the sudden rapid drop of oxygen concentrations, associated with major impacts roughly 2.025 billion years ago (South Africa) and 1.850 billion years ago (Canada), which certainly had an influence on climate and life. One proof for a connection between the animated worlds - as the heart of a new biota, as it were - is for example the fossil Grypania spiralis, which has been interpreted as a eukaryotic alga. Before the oxygen backlash, it existed in the Franceville biota (2.1 billion years ago/Michigan) and afterwards in the Montana biota (1.3 billion years ago/China). The succession of catastrophes and developments has been a crucial earmark of the history of the Earth right from the beginning. In 1992 already, Prof Gero Hillmer and Dr Joachim Scholz, both at the University of Hamburg at that time, wrote in the magazine "GEO": "There is no gradual, linear transition from one state into another. A spell of fine weather is followed by a sudden and catastrophic collapse (and then by a new beginning)." If the worst case presents itself, no adaption will help, no matter how perfect it might be. Stephen Jay Gould, a US palaeontologist, brought up the

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A constant hail of meteorites (similar to this modern Orionid meteor shower) and violent volcanism characterized the seething planet, the slowly solidifying crust of which was ruptured and melted over and over again. Images: NASA (above) and Wikimedia Commons (below)

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example of the fish: They may be perfectly adapted to life in the water but if all lakes dry up, they will still all perish. Connections of the individual "evolutions" between the catastrophes do exist: the ancient "regulator genes". They can be found in similar forms in all animals and in all multicellular organisms. Prof Christiane NüssleinVollhard, a biologist and Nobel Prize laureate, called them in 2004 "Hox genes", actually Homeobox genes. They regulate embryonic development. Klaus Foppa, psychology professor in Bern with an interest in evolutionary biology and the development of humanity and culture, wrote in his book "Jenseits von Darwin" ("Beyond Darwin") in 2011: "The common regulator genes for evolutionary processes show close relations between certain groups that would not have been suspected at all to be related, as they simply have different morphologies." Life after the hail of meteorites At the beginning, there was the catastrophe: Roughly 100 million years after the formation of the Earth, a collision with an asteroid led to the separation of the moon and almost to the Earth's destruction. After this event, the planet was seething for a long time and its slowly solidifying surface was repeatedly ruptured by a veritable hail of meteorites. Professor Joachim Reitner (Göttingen) expressed it in 2008 as follows: "This period is characterized by a continuous re-melting of the Earth's crust, caused by a high impact frequency of large cosmic bodies such as comets, asteroids and small meteorites." He quantified the impact frequency as "1000 times higher than today". However, the bombardment did not only entail destruction, but also all ingredients for the "primordial soup" of life. The gaseous and liquid components of the comets and meteorites brought large quantities of water, carbon dioxide, carbon monoxide, ammonia, nitrogen, methane and many other simple, "but also complex organic compounds like amino acids to Earth", says Reitner. The building blocks of life are in fact largely "extraterrestrial"... For a nutritious soup, however, it is certainly not enough to merely collect the necessary ingredients. They have to be cooked to become a proper meal. And here lies the problem, because nobody knows, how it all once started.

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One possibility - that the soup brew itself - has often been claimed and even "proved" - for instance in 1953 by the US chemists Stanley Miller and Harold C. Urey. In a laboratory, they produced an environment similar to the presumed prebiotic conditions. With the supply of energy, the inorganic compounds water, ammonia and hydrogen as well as methane turned into more complex organic compounds. Today however, this experiment is heavily criticized, as both the prerequisites and the results do not conform to modern scientific knowledge any more. In the Hadean, at any rate, traces of life and biological marks were still "extremely rare, although all prebiotic processes must have taken place at that time", emphasized Professor Reitner. After all, the Hadean carbon isotope values "represent a definite biological mark". Some kind of methane metabolism must have taken place already at that time. Reitner did not answer the question whether these processes were still regulated by enzymes or already by cells. According to Prof Reitner, 3.9 to 3.5 billion years ago - that is in the Lower Archaean - "methanogenesis" took place. This means that the metabolism of microbial organisms, so-called "methanogens", converted carbon dioxide and hydrogen into methane. This important process is contributed to archaea. Next to bacteria and eukaryotes, they form one of the three domains that classify all cellular organisms. Reitner: "The processes of primary cell formation remain largely unknown." As a result, we see the outcome, but not the causes, nor the exact beginning of the actual birth of life on Earth. According to current findings, archaea can be found in all ecosystems, but they have the advantage of being capable to adapt to extreme habitats (e.g. heat, acids, volcanic soil) and of possessing special metabolic characteristics such as the production of methane. Like bacteria, archaea are prokaryotes, that means, for example, they have a nucleus, - but interestingly, "the central molecular information-processing systems ... are very similar to those of eukaryotes", says an online introduction of the University of Duisburg-Essen of 24 January 2013 ("Aquatic Microbiology"). To put it all in a nutshell: the Archaean provides proof of some kind of traceable life. On the Akilia island in southwestern Greenland, which harbours the apparently oldest known sediment strata with an age of 3.85 billion years, also the oldest signs of life

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seem to have been found in a rock formation in 1997. The graphite parts contain carbon of organic origin. However, the signs of life found in the Greenstone belt are controversial. The Greenstone belt is part of the Isua gneiss, also in Greenland, which is roughly 3.8 billion years old. Here, analyses have shown the same results as on the Akilia island since the 1970s. One day, however, a study carried out by Dr Marc A. van Zuilen from the Netherlands and other scientists (2003) revealed that this was metamorphic rock. Apparently, mineral and chemical processes played the main role. Soon after that, in 2005, however, Dr Iain McDonald from Great Britain found that in other deposits than the previously examined, an organic origin of certain findings caused by methane production and photosynthesis does have to be taken into consideration. He named primarily conglomerates and banded iron formations. In any case unquestionable are the Australian stromatolite deposits with as many as 3.43 billion years of age making them part of the Palaeoarchaean era (image on the next page). They are among the oldest fossils, as it were, and come from the Strelley Pool Formation in the Pilbara region. Stromatolites are rock-like structures formed by colonies of cyanobacteria (formerly called "blue-green algae"). They are surrounded by a slimy film, in which limestone from the ground is bound. In this way, several layers are formed. Today, stromatolites can still be found in Australia. They are also referred to as "living rocks" and grow approximately 1 mm per year. The formation of oxygen on Earth is attributed to their existence. However, we differentiate between oxygenic and anoxygenic photosynthesis. In oxygenic photosynthesis, molecular oxygen is produced, while in anoxygenic photosynthesis, inorganic substances other than oxygen may be produced, for example elemental sulphur. Nonetheless, nature headed from the archaea's anaerobic methanogenesis towards the "oxygen catastrophe"... Supposing the Franceville biota existed roughly between 2.1 and 2.0 billion years ago, then we also have to rethink the theories about eukaryotes, which are - with their nucleus - prerequisites for the metazoa. Multicellular beings like the Gabonionta can hardly be imagined without eukaryotes. Not only the scientists led by Professor Abderrazak El Albani

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The problematic specimen Diskagma buttonii RETALLAK 2013 (to the left) is 2.2 billion years old, was found in South Africa and would be the first multicellular organism even before the Franceville biota (Images: Wikimedia Commons). To the right an image of the finding place of the oldest stromatolites from the Strelley Pool Formation, Western Australia (Photo: Tom Kapitany, Victoria/Australia). They are nearly 3.5 billion years old. Below a cut and polished specimen (Troppenz collection). Size: 8x5 cm. All images in this chapter: R. Troppenz - unless otherwise indicated.

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are sure about the multicellularity of the Gabonionta. Dr Bettina Schenk, for example, who is a microbiologist in Vienna, also wrote in 2014 in the publication "Fossilien - Journal für Erdgeschichte" ("Fossils - Journal for Geolo-gical History") that the Gabonionta are "probably the oldest multicellular organisms". Consequently, the former idea about the origin of eukaryotic cells roughly 1.5 billion years ago, can probably not be right any more. The assumption had been that a prokaryote was ingested by another cell to become an "intracellular organelle" (most recently Gray & Doolittle 1982); this is referred to as the "endosymbiotic theory". According to this theory, this would mark the evolutionary origin of eukaryotes. If this was true, then it must have happened at a considerably earlier stage. Prof Hans D. Pflug at the University of Gießen, Germany, estimated the origin of eukaryotes at about 3.8 billion years! This means even before the origin of the prokaryotes - thus contradicting the "endosymbiotic theory". Apparently, Professor Pflug and other scientists had found as early as 1979 yeast-like organisms in metamorphic rock near Isua/Greenland. Since then, this discovery has been disputed. On the one hand, the banded iron formations found there indicate that at the time, the atmosphere contained little oxygen - but it was not completely free of oxygen. On the other hand, however, more recent palaeontological and geochemical studies revealed that these alleged fossils were not of organic material, as the German magazine "Spektrum der Wissenschaft" reported in 1999. A more appropriate dating of eukaryote origin to 2.7 billion years was given by Professor Reitner at the University of Göttingen in 2008. According to his research, "well preserved sediment" with an age of 2.7 billion years "contained first signs of aerobic photosynthesis" by cyanobacteria. At the same time, the first appearances of steranes (organic hydrogen molecules) were recorded - "a biomarker pointing to the occurrence of eukaryotic metabolism." However, this report was "highly problematic". In eukaryotes, an oxygen metabolism is actually supposed to take place, but the "Great Oxidation Event" did not start until 2.6 billion years ago (El Albani speaks of 2.45 billion years). In my opinion, though, "exact" dating has always been problematic and not clearly defined by scientific means. Nevertheless, Reitner reproduced microbial structures and eukaryote

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cells from 2.2-billion-year-old "Gunflint chert" stromatolites (Lake Superior/Canada). The period of the Franceville biota seems to be safe for the origin of eukaryotes. Even prokaryotes without nucleus are suspected of potentially producing complex multicellular life. If that was true, there is nothing left to inhibit the Precambrian biota. We could even speculate that there might have been animate worlds even before the Franceville biota from Gabon, which are yet to be discovered or which have literally vanished "without a trace" as a result of geological processes in the course of billions of years. Prokaryotes may not have a nucleus, but their DNA lies freely in the cytoplasm, the basic substance of the cell. Apart from that, these cells are also capable of connecting and exchanging information. We know this for example from myxobacteria (photo on p. 43), which predominantly live on the soil on decaying organic material and move actively by gliding. They form swarms of thousands of communicating cells and are kept together by means of messenger substances (intercellular signals). Myxobacteria are currently in a transition phase from unicellular to multicellular organisms! The association of a great number of cells presumably facilitates nutrition, as the concentration of digestive enzymes is then increased. It is fantastic: When nutrients become scarce, the cells surge towards each other and about 100,000 bacteria form a fruiting body with a size of only 1/10 mm. In this fruiting body, cells turn into spores - but the majority is used to nourish the group and help it survive... Myxospores are especially well protected against dehydration and show only little metabolic activity. They can remain in this stage and wait patiently until the supply of nutrients improves - by change of location or with the help of hosts or wind. These microorganisms' way of living is similar to that of eukaryotic slime moulds, and thus an example of convergent development. For other prokaryotes, something similar has already been proven for the time period in question. Dr Bettina Schirrmeister, an evolutionary biologist from Zurich, established in 2011 together with some colleagues that in the course of the Earth's history, cyanobacteria have undergone the development from unicellular organisms to multicellular organizations several times. The existence of cyanobacteria for the time period 2.5 billion years ago was established. According to Bettina Schirrmeister, fossil findings

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showed that the first multicellular differentiated cyanobacteria were there already about 2.3 billion years ago (!). This was closely connected to the Great Oxydation Event, she continues, because the oxygen-producing multicellular organisms had a more efficient metabolism than the unicellular ones. Consequently, anaerobic types of bacteria were suppressed and the multicellular cyanobacteria could make use of the now vacant ecological niches (University of Zurich, press release, 15 January 2013). Are cyanobacteria possible candidates for complex multicellular organisms? Bettina Schirrmeister's PhD supervisor Prof Homayoun Bagheri was wondering about why this had apparently not happened. A publication by the University of Zurich (14 March 2011) quotes him as follows: "It remains an unsolved mystery for us why cyanobacteria did not eventually manage to develop into higher life forms as did eukaryotes, although they are even capable of forming differentiated cells." A slightly different opinion has Dr Joachim Scholz of the Senckenberg research institute in Frankfurt, who is responsible for invertebrates/bryozoology. He wrote to me on 10 November 2014: "I do not entirely share Prof Bagheri's opinion, because the cyanobacteria did indeed develop into higher life forms. As chloroplasts, they are part of plants, something not only Lynn Margulis had discovered, but long before her also Constantin Mereschkowsky." Lynn Margulis was a US biologist and geoscientist and presented her theses to the public in 1967/70. As early as 1905, the Russian biologist Constantin Mereschkowsky had similar ideas. And here we are back to the subject: What is really new? Former theses are often unearthed and adapted to current findings, because they had not been wrong altogether - as happened with the catastrophe theory, which has long been regarded as obsolete. Regarding the chloroplasts, the German botanist Professor Andreas Schimper had expressed similar theories to those of Margulis and Mereschkowsky already in 1883! So more than 2 billion years ago, everything was ready for a biosphere of complex multicellular living beings. Creative catastrophes The starting point of the new animate world was a double catastrophe: First, there was the Great Oxydation Event (GOE) with an oxygen level fatal for anaerobic organisms (about 2.5 to 2.3 billion years ago). Second,

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Cell filaments of Nostoc sp. (large image), a cyanobacteria genus, and fruiting body of Myxococcus xanthus (small image below). Myxobacteria can be found in the transition phase from unicellular to multicellular life (both images Wikimedia Commons)

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there was the "Huronian glaciation" (about 2.4 to 2.2 billion years ago), which was probably connected to the GOE. We are talking about a ten-fold increase of the oxygen concentration in the atmosphere, namely from 0.2 to 0.3 per cent up to 2 to 3 per cent; a value deadly enough for a significant part of the existing micro world. The resulting niches are occupied by oxygen-friendly organisms like cyanobacteria. This transformation to an aerobic atmosphere paved the way for a first biosphere that was more differentiated than had been there on Earth before: the Franceville biota - at least this will remain the supposition until further discoveries are made! The multicellular, complex, colonial and diverse biota described in the previous chapter now started to develop, although it is not said that it was unique in geographical and biological terms. The Gabon findings were a great coincidence, as nothing comparable had been expected, and the strata had been left amazingly undisturbed over billions of years. It is definitely conceivable that in other regions with comparable prerequisites similar discoveries are made, or even that older or younger findings show similar signs of evolution. - Admittedly, this hope is limited. Not only because of this unparalleled situation in the Franceville basin, but also because of the temporal limitation. The ice age ended about 2.2 billion years ago and glacial erosion probably carried minerals into the ocean, causing a boost in nutrients. The fossil findings come from a period 2.1 billion years ago. According to the scientists' conclusions on site, the oxygen concentration in the atmosphere dropped already about 2 billion years ago reaching again values comparable to those before the GOE. The end of the Franceville biota! Additionally, two further major impacts did certainly not remain without consequence. They are among the largest in the history of the Earth. The first occurred as early as 75 million years after the bloom of the Franceville biota, namely 2.023 billion years ago (give or take 5 million years). It was an asteroid with a likely diameter of 20 km creating the Vredefort crater in South Africa - a crater with multiple rings, up to 320 km long and 180 km wide. The impact originally produced a hole in the Earth's crust with a depth of 40 km and a diameter of 100 km. The distinct drop in oxygen levels could be connected to this impact. (El Albani in 2014: "The first large oxygen peak ... abated about 2 billion years before our time. The oxygen levels dropped considerably...")

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As early as about 3 billion years ago, an asteroid impacted in the area of what today is Greenland. The original crater diameter is estimated at 500 to 600 kilometres. The crater was discovered in 2012 by a research team led by Adam A. Garde at the Geological Survey of Denmark and Greenland (GEUS). Above computer graphics by Carsten E. Thuesen, GEUS. The Vredefort crater in South Africa (to the right, photo: NASA) is roughly 2 billion years old and has a diameter that is hardly half as big.

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Professor El Albani assessed the situation as follows (message of 29 December 2014): "The most famous asteroid - the largest that has ever been described - impacted about 2 billion years ago. It took place close to the time and place in our focus of attention." This impact was bound to be important. Corresponding literature, though, has been scarce. If we start out from the assumption that this event has been proven, says El Albani, we consider it a momentous impact "not only with reference to oxygen, but also to other gases - not to mention the repercussions on the palaeo-environment". In any case, this matter still "has to be studied thoroughly" according to El Albani. The scientists led by Dr Donald Canfield have not only found signs for a decreasing oxygen content in the Franceville deposits, but also examples in Western Australia and Canada, which reflect extremely low oxygen concentrations 1.89 billion years ago. The second major impact took place 1.852 billion years ago (+4/-3 million years), when a roughly 15-km-big asteroid struck today's Canadian province of Ontario and created a crater with a diameter of 200 to 250 km. This is known as the Sudbury impact. With regards to the time frame, we can say that this catastrophe took place close to the end of the Franceville biota and the beginning of the subsequent Montana biota. In order to visualize the huge consequences of these impacts, we can think of the impact at the K-Pg boundary between Cretaceous and Paleogene. This event contributed to one of the largest mass extinction events in the history of the Earth, with the dinosaurs among the extinct species. In the end, it paved the way for the new biosphere of the mammals. Another example is the Chicxulub crater: 66 million years ago, a 10- to 14km-large asteroid hit the Gulf of Mexico with the five-billion-fold force of the atomic bomb on Hiroshima and a speed of just under 72,000 kilometres per hour. It created a crater with a depth of 10 km and a diameter of 200 km. As it were, this event is responsible for the transition from the Mesozoic era to the Cenozoic era. Thus, it forms a highly important geological and palaeontological cardinal point. The asteroid of the K-Pg boundary was considerably smaller than the two Precambrian specimens. However, borehole studies from the impact area (Keller 2004 and Harting 2004) showed that the Chicxulub crater is probably 300,000 years older than hitherto assumed, so that it does not qualify as the single cause of the catastrophe at the end of the Cretaceous. This has been a topic of discussion for quite some time - but the impact theory is of course nice and

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Stromatolites, or in other words several layers of microbial mats on top of each other, were not the only ones to shape life in the Precambrian, as we have come to know - the blue stromatolite at the very top is 1 billion years old (azurite as petrification medium, 8x4 cm); it comes from Areyonga/Australia. 2 billion years ago, the green stromatolite above from Kolmården near Nyköping/Sweden formed (4x3 cm). The grey stromatolite Acaciella australica (9.5x4 cm) from Ross River near Alice Springs/Australia, is only 800 million years old. Troppenz collection

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easy to imagine, especially for the media. Today, several impacts of asteroids and comets within a short period of time are being discussed as an alternative explanation, but other aspects like climate changes resulting from increased volcanism certainly play a role as well. This is not necessarily a suddenly occurring catastrophe, but rather a catastrophic process with several causes and over a long period of time which, in geological terms, still equals just a blink of an eye. Doubtless, the Chicxulub crater has played a significant role. So if an event inferior to the Precambrian impacts destroys an entire era with a complete megafauna, then more massive events of this kind can hardly have inferior consequences. "Bustling billion" - no "boring billion" At any rate, the end of the Franceville biota is characterized by a sudden drop in oxygen levels reaching values comparable to the time before the GOE as well as the impact of a very large asteroid. Considering the acquired data, the Franceville biota probably developed at the end of the ice age 2.2 billion years ago and came to an end with the devastating major impact and the drastic drop in oxygen levels roughly 2.025 billion years ago. This would sum up to an existence of 175 million years at most. In the following period, the oxygen concentrations proved to have risen again slightly (Frei/Canfield, "Nature" 2009). We are talking here about a gradually developing oxygen levels of up to 4 per cent; today the oxygen levels amount to roughly 21 per cent. In any case, the avid unicellular stromatolite producers went on about their business using photosynthesis... Up to approximately 1 billion years ago, they were very abundant in almost all shore waters, but then started to suffer considerable losses in terms of biodiversity and prevalence. They are presumed to have been grazed by the score and forced out by multicellular eukaryotes. In general, the period between 1.8 and 0.8 billion years ago has been referred to as "boring billion". Again and again, scientists have been searching for an explanation for this phenomenon, because they cannot imagine why life did not make any progress for such a long time. Also in 2014, at the University of Tasmania in Australia, where geology professor Ross Large conducted seabed analyses and blamed the lack of vital trace metals at that time for the "boring wasteland". Quite unnecessarily! Why searching for the reasons of a "boring billion", if proof of multicellular life

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at that time has long since been around? Quite to the contrary, the "boring billion" offers rather exiting prospects. Not least the discovery of the Gabonionta showed that anything is possible. Though you must be exceptionally lucky and highly idealistic to stumble upon undisturbed strata from that period, which even give account of life in that era. How did Professor El Albani put it? Yes indeed, there had been a transitory biota. Even he himself was at first convinced that after his Franceville biota and before the Ediacara biota there was a major setback to unicellularity and that multicellular life took a second run-up, so to speak. Simply "boring billion". The Gabonionta, however, did by no means reschedule multicellular biosphere to 1.5 billion years earlier, as press releases of the University of Poitiers and the Museum of Natural History in Vienna outlined. They were merely the (what we know today) beginning of multicellular life, which developed after a catastrophic event for the old world and seemed to vanish with another catastrophe in order to take on new forms - during the period of the "bustling billion". The Franceville biota lasted about 175 million years, the Ediacara biota as little as 70 million years or even less. In between, there were 1000 million years, which should not have produced anything despite a renewed increase in oxygen levels? There are some multicellular organisms, which I presented in my previous book, and which belong to this period of time: the "Wellenwurm" (worm trace?) from the glacial erratic boulders of Endeholz in Lower Saxony/Germany (Swedish Dala sandstone) and another problematic specimen (traces?) found in the same region and originating in the period of about 1.3 billion years ago; the problematic specimens also from the Upper Precambrian of Dalarna/Sweden; Adolf Seilacher's "Pre-Ediacaran dubiostructures" - the worm trace Manchuriophycus (later interpreted as torn biomat, 1.8 Ga); the Australian "hairpins" Myxomitodes stirlingensis (1.8 Ga); the Indian "Chorhat worm burrows" (1.1-1.5 Ga) and the "string of beads" Horodyskia sp., identified as macroorganism in 2013 and first found in Montana/Canada (therefore "Montana biota") and then in Western Australia (1.2-1.5 Ga). Additionally, there are several individual fossils with an age reaching into

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the "bustling billion", such as the aforementioned alga Grypania spiralis, found for example in Michigan/USA (2.1 Ga) and in Gaoyuzhuang/China (1.3 Ga), or the Ediacaran fossil Cyclomedusa, discovered also in one-billion-year-old sediment in Siberia - and, by the way, even lasting up to the Cambrian. Or the red alga Bangiomorpha pubescens from the Canadian Arctic (1.2 Ga)... The reason, why the yield is still very small, is that "it contradicts the doctrine". Finds beyond Ediacara have just not been taken seriously. Professor Seilacher's crucial argument against Manchuriophycus (2008): "Alone considering its age (1.8 billion years) is its interpretation as worm trace impossible." In the face of the Franceville biota, this argument has finally lost its value. Nobody really dared accepting an animate world before Ediacara, analysing the fossils correspondingly and publishing the results. It cannot be held against any scientist that they prefer the supporting wave of "political correctness" and respect generally recognized principles, lest they run the risk of ruining their reputation... At the same time, a thousand million years is such an enormous period of time - after all nearly twice as long as the Phanerozoic - in which surely there must be ample palaeontological rewards hiding. The above-mentioned geological processes certainly present another problem. Most rock from the Precambrian is of plutonic or igneous origin. Plutons are magmas intruding from deep layers of the Earth into higher ones, solidifying already on the way. Numerous porphyries and granites from that time, that were found for example in Nordic glacial erratic boulders, give evidence of a highly restless Earth's crust. Other phenomena, such as rock metamorphism, erosions and folds did their part in disturbing the strata, disguising them or even destroying them. Plus: By now, Rodinia has become uncontested in principle - the supercontinent, formed between 1300 and 900 million years ago by tectonic and igneous processes, was surrounded by the ocean Mirovia, and eventually broke up into its individual parts after about 150 million years. Actually, undisturbed situations like the one found by the unorthodox professor El Albani in Gabon to his own surprise are completely unlikely. But they do exist! Maybe in view of these new findings, these sediment strata and their possible contents will now be purposefully searched for something which has been refrained from up to now (see above). As a result, specimen of presumably multicellular organisms found in lower

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Banded iron formations (to the left) are oxygen indicators. This piece (section) from the banded iron formation (BIF) of Western Australia is 2.6 billion years old. A little later, the "Great Oxidation Event" (GOE) took place... (Troppenz collection) - Below: Grypania spiralis counts as eukaryotic alga; it was found in 2.1- and 1.3-billionyear-old strata. (Photo: Wikimedia Commons)

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and medium strata of the Proterozoic are controversial at best. At any rate, the Montana biota from the "bustling billion" between about 1.8 and 0.8 billion years ago does have an evidential representative: Horodyskia sp. with the species H. williamsii (Western Australia) and H. moniliformis (Montana/USA). H. minor, an Ediacaran species found in three different places in China (Dong et al. 2008) is only interesting to that extent that Horodyskia apparently outlived the sharp break between the Montana biota and the Ediacara biota. Shen Bing, Lin Dong and others, for instance, wrote in 2007 in the "Journal of Palaeontology": "Thus, at least some Ediacaran organisms may have a deep root because Horodyskia also occurs in Mesoproterozoic successions." Strings of beads and hairpins There is a nice calendar slogan: "Using new investigation techniques, you will continually succeed in opening new chapters in the history of the Earth. The proceedings will sometimes remind you of a detective's work, sometimes of endless jigsaw puzzles, and the results are often surprising and bizarre." How true! Of course, I am not quoting a conventional household calendar, but the calendar of the "Deutsche Gesellschaft für Geowissenschaften", DGG („German Society for Earth Sciences“) for the year 2015. This quote refers to surprising and often seemingly bizarre new research results in conflict with their interpretations. So what kind of organisms were there during this "bustling billion" and how many? The Montana biota was a topic in my previous book, but in the following, I will present further aspects, more scientific results and new finds: The first "string of beads" Horodyskia sp. was found in the 1980s by Robert J. Horodyski (geological department of Tulane University, New Orleans) in Montana to the south of the border with Canada. In his honour, the fossil was later named after him. The fossil stands out due to its wide distribution in terms of area and time: Montana/1.48 Ga, Western Australia/1.47-1.07 Ga, Tasmania/1.3-0.8 Ga, three Chinese territories/0.65-0.51 Ga as well as Northern India/0.51-0.42 Ga, this means it existed from the Mesoproterozoic until the Phanerozoic.

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Påskallavik porphyry ... is an igneous rock with large alkali feldspar phenocrysts. It is a bedrock at the east coast of southern Sweden near Oskarshamn. Age: approximately 1.8 billion years. The large slab shows a cut piece of glacial erratic boulder from Czech Silesia (photo: Z. Gába jun.), the specimen below is a glacial erratic boulder from Heiligendamm, Mecklenburg-West/Germany (approximately 7.5x3.5 cm, Troppenz collection).

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This also means that Horodyskia outlived several catastrophes, "Iceball Earth" for example. Interpretations as to the nature of the fossil have been abundant: excrement line of a multicellular organism (1985), brown alga (1990), pseudo-fossil (1992), dubiofossil (1993), sponge (2001 by the same scientist originally identifying Horodyskia as pseudo-fossil), moss animal colony (2002), prokaryotic colony (2006), foraminifera (2008), fungus (2013). The certainly very simple morphology makes it difficult to determine what it really is - but "we cannot prove it anyway, we can only assume..." (Reitner). At any rate, there are hardly any doubts left regarding the nature of the fossil as a multicellular organism. Horodyski's colleagues Ellis L. Yochelson (Palaeobiology Department of the Smithsonian National Museum of Natural History, Washington/USA) and Mikhail A. Fedonkin (Geological Institute of the Russian Academy of Sciences, Moscow) wrote in 2002 in the "Smithsonian Institution Press": „We are convinced the specimens are biogenic and have placed them within Linnaean nomenclature as Horodyskia moniliformis". An apt description of the locally abundant fossils is "string of beads." On each string, the beads are of nearly uniform size and spacing (...) They may not be related to any other known fossil. We judge they were multicellular, tissue-grade, colonial eukaryotes (the cells have a nucleus). They lived on the seabed. Their energy source is obscure. [We assume] that Horodyskia likely lived primarily by ingesting chemosynthetic bacteria (energy from inorganic compounds)." Together with Kathleen Grey and David Martin at the "Geological Survey of Western Australia", the Western Australian occurrences are published in 2010 in the journal "Precambrian Research". Horodyskia williamsii, the new species, was also a macrofossil of the Middle Proterozoic, they claim. During the annual meeting of the Geological Society of America (GSA) in 2012, however, doubts were raised by Roy Rule of the Department of Geological Sciences of the University of Saskatchewan. Horodyskia has nothing to do with eukaryotic algae or tissue-grade, he contended, but with chemical processes. He mentioned the finds in India and China and classified them as simply a worldwide (inorganic) phenomenon of the Precambrian. "Despite the possible role of organic matter in its formation, Horodyskia belongs in the realm of pseudofossils", according to Roy Rule.

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Horodyskia williamsii, Ashburton/ Western Australia, in three fossil states: to the right as hollow forms (Troppenz collection), below to the right as positive protrusions, below to the left in connection with the "string of beads". (Images below: Tom Kapitany, Victoria/Australia.) This creature was a complex multicellular organism from the Montana biota - but apparently prevalent all over the Earth and through several geological eras.

The illustration to the left shows one of the animals (or fungi?) living in the colony; they were connected by tubular structures. These produce Horodyskia's shape of a string of beads. Image: Wikimedia Commons

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Today we know, that the finds from India and China are not a Precambrian phenomenon, but one that reaches far into the Phanerozoic. During an annual meeting in Vancouver/Canada, Rule fetched two combatants from his university and changes his arguments slightly: not "string of beads" were found, but rather "isolated beads". His conclusion: "We assume that the beads formed as a result of clay flocculation and joined with the support of microbial activity." However, we have to take into consideration that when a "string of beads" disintegrates in a natural way, several "individual beads" remain. Rule does not comment on the tubular connections between the "beads", which form the "string of beads" in the first place. In 2013, Gregory J. Retallack at the Department of Earth Sciences at the University of Oregon/USA as well as Kimberley L. Dunn and Jennifer Saxby at the University of Southampton ("Ocean and Earth Science") affirmed the nature of Horodyskia as Middle-Proterozoic fossil. As reported in "Precambrian Research", they themselves had found and thoroughly studied Horodyskia fossils in the 1.48 billion-year-old strata of Glacier National Park in Montana. Some grinding work on the fossils revealed that the individual "beads" were connected by a tube system; these organisms seemed to be sessile on the bottom of the sea. The new observations also refuted a number of explanations for Horodyskia: pseudo-fossil, dubiofossil, prokaryotic colony, foraminifera, mould, brown alga, sponge, cnidaria, moss animal colony, excretions of multicellular organisms. "Our working hypothesis is that Horodyskia is comparable to the modern fungus Geosiphon pyriformis." The fungus uses a bladder to incorporate free cyanobacteria, which it then uses for its own metabolism. In my opinion, Roy Rule will not manage to lead the considerable number of international and interdisciplinary scientists, who are sure about Horodyskia, into wonderland... With his book "Trace Fossil Analysis" (published in 2007), Professor Adolf Seilacher (1925-2014) at the University of Tübingen/Germany presented "Pre-Ediacaran dubiostructures" such as the "Chorhat worm burrows" (India) and the "hairpins" of the Stirling biota. Ten years previously, Seilacher had written in the German journal "Fossilien" („Fossils“) about burrows of vermiform animals with an "age of more than one billion years". In his last years, he withdrew his interpretations completely: They

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were all pseudo-fossils - because they existed in the wrong time... The palaeontologist, who had actually been known as an unconventional avant-gardist and who was awarded the Crafoord Prize in 1992 (a kind of Nobel Prize for his innovative research) revised himself. Please do not mistake my meaning. Adolf Seilacher and many palaeontologists have achieved great things in their respective areas of expertise. Not in the slightest do I presume to question their accomplishments. But what I do criticize is their overall approach, which in my opinion, has often been wrong, uninspired and all too conventional. It has spoiled many perspectives, which might have led to something completely new had it been replaced by constant curiosity and undogmatic freedom of thought (El Albani). All the while, there are hardly any doubts left about the biogenic nature of the above-mentioned traces - as far as this can be said for sure, anyway, for traces with an age of a billion years... To give an example: the "hairpins" from the Stirling quartzite of Western Australia as an interpretation of flatworm traces. Just like in Horodyskia, the structures are composed of "beads". The real sensation came from the journal "Science" in 2002. "Discoidal Impressions and Trace-Like Fossils More Than 1200 Million Years Old" was the headline of a report by four scientists - geologists, geophysicists and palaeozoologists of the University of Western Australia and of the Swedish Museum of Natural History in Stockholm. The geologist Professor Birger Rasmussen and the palaeozoologist Professor Stefan Bengtson gave account of macrofossils from a stratum between 1215 and 2016 million years of age! "Although nonbiological origins for the discoidal impressions cannot be completely discounted", they were still sure: "The structures resembling trace fossils clearly have a biological origin and suggest the presence of vermiform, mucus-producing, motile organisms." These fossils have a size of roughly 1-2 cm and are distributed irregularly in the rock. They always have the same appearance - roughly samesized parallel burrows or ridges forming a U. Adolf Seilacher, too, emphasized explicitly in 2007 that they contradicted a physical cause. In the same year, Bengtson and Rasmussen took the next crucial step together with Bryan Krapez (University of Western Australia): They gave the hairpin fossils an internationally valid trace fossil name: Myxomitodes stirlingensis. At the same time, they refined their former statements. They

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claimed the fossils were 1.8 to 2 billion years old and came from sediment formed under the influence of storms, longshore currents, and tidal currents. They continued: "Sandstones contain a megascopic fossil biota represented by discoidal fossils similar to the Ediacaran Aspidella (cf. Cyclomedusa, author's note) as well as ridge pairs... The ridges run parallel or nearly parallel for most of their length, meeting in a closed loop at one end". By the way, Zhe Chen and Chuanming Zhou (2013) at the Chinese Academy of Sciences as well as five other Chinese and US colleagues found very similar traces in strata of the Upper Ediacara of South China, namely in the Three Gorges Reservoir Region of the Yangtze River. They show "animal activity" below and above the "biomat" and can easily be compared to those from the Paleoproterozoic. On 2 October 1998, Adolf Seilacher, University of Tübingen and Yale University, Pradip K. Bose (Jadavpur University in Calcutta) and Friedrich Pflüger (Yale University) commented self-confidently on the "Chorhat worm burrows" in "Science": "Some intriguing bedding plane features that were observed in the Mesoproterozoic Chorhat Sandstone are biological and can be interpreted as the burrows of wormlike undermat miners. These burrows suggest that triploblastic animals existed more than a billion years ago." The description of the "animal activities" corresponds exactly to those of the "hairpins" from Australia... This time, the media suspected a "sensation" and react. Already in October, the German periodical "Der Spiegel" published an article about the Indian traces: "Without noticing, farmers had been stomping over the signs on the ground for hundreds of years. Two years previously, a group of land surveyors were the first to wonder about these features. Their discovery allured Adolf Seilacher, a geologist from Tübingen in Germany. He travelled to Chorhat, made rubber casts of the brownish weathered rock and took some samples, hoping to solve the riddle of the ridges. "According to radiometric investigation, the Chorhat rock was reported to be 1,1 billion years old. It contained remains of blue-green alga mats, which used to cover the bottom of a prehistoric sea in this place. The periodical continued: "Seilacher interprets the ducts as burrows of wormlike creatures that used to feed their way through the blue-green algae at the time. There was 'no other explanation'." Seilacher postulated an "era of burrow worms (triploblastic animals)."

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A. Seilacher and his wife at a conference in Berlin in 2009 - he described strange structures in strata from the Middle Precambrian: Worm traces from the Indian Chorhat sandstone (above, approx. 15 cm) and "hairpins" from the Australian Stirling quartzite (to the right, 2 cm). Despite Seilacher's denial, Rasmussen and Bengtson confirmed in 2007 the biological origin of the "hairpin" structures and called them Myxomitodes stirlingensis. They even described a whole macroscopic ecosystem including parallel worm (?) tunnels that meet in a closed loop while digging under and through microbial mats on their way. The same phenomenon was found in the Upper Ediacara of South China (below a section, Zhe Chen et al. 2013 in "Precambrian Research").

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In December, the "Zeit Online" uses similar words: "How does a scientist react, when he finds something that contradicts all conventional theories? He starts looking for an obvious explanation. If there is none, he examines the next hypothesis, and so on. In case all these attempts remain unsuccessful, then the scientific concept of the world must be wrong however unlikely this may seem. If this happens, the scientists speak of a paradigm shift." These trace fossils - apparently produced by multicellular organisms in such an ancient era and found in the village of Chorhat in Central India - will challenge the established evolutionary theory. Professor Birger Rasmussen (Australia), Professor Subir Sarkar (India) and four other colleagues ascertained in "Geology" in 2002 that using state-of-the-art methods, they were able to determine for certain the age of the Chorhat sandstone (lower Vindhyan) to the time period "between 1628 (+/- 8) million and 1599 (+/- 8) million years". Assuming that the bedding-plane markings be interpreted as burrows of burrow worms, "these structures were regarded as the oldest fossil evidence for metazoan life." As far as the biological origin of the traces is concerned, Rasmussen and the other authors requested that the studies be continued. Doubts are permitted and necessary for scientific progress. Hans J. Hofmann at the McGill University in Montreal/Canada shared these doubts. In 2005 in the "Journal of The Palaeontological Society of India", he took up the "Paleoproterozoic dubiofossils" once more and mentioned the new age dating: approximately 1.6 billion years. Hofmann mentioned mudcracks, suggested subsequently produced reticulate patterns ("chemoglyphs"), but argued mainly with the "molecular clock", which positions most ancient life to 1.1 billion years ago. This would have been consistent earlier, but with the new dating, it no longer was. According to Hofmann, "the existence of complex macroscopic organisms producing branching tunnels at 1.6 Ga is difficult to reconcile with molecular clock data and the absence of a record of animal burrows during a 1 billion year interval." This is the same circular reasoning, in which also the great Adolf Seilacher got trapped. They cannot be complex organisms, because the strata, in which they are deposited, are simply too old (instead of thinking the other way round), thus not matching the molecular clock. It is irritating that nobody even considers questioning the time this clock shows. According to Francisco José Ayala (a US geneticist, evolutionary

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biologist and philosopher at the University of California) there are several clocks and all of them show different times. The reason behind this is that scientists use different organisms and genes, resulting in the fact that the molecular clocks are still too imprecise, even despite more exact analyses and better data than before. In the opinion of Professor Ayala, scientists have not understood the clock speed yet. Different premises - different results. Perfectly logical. The hypothesis that there had been almost nothing there for a period of one billion years - the infamous "boring billion" - is not true either, after all. It seems that the fossil record is assumed to be identical to the reality of life at that time. By the way, Hofmann himself had backed down in another case: In 1992, he called Horodyskia from the "boring billion" a "pseudo-fossil", only to let it pass as a sponge after all in 2001. "Proterozoic carbonaceous remains from the Chorhat Sandstone: oldest fossils of the Vindhyan Supergroup, Central India." This is the title of an article published in 2006 for "Geobios", an international palaeontology journal based at the University of Lyon/France. The article is authored by Professor Purnima Srivastava and Professor Rameshwar Bali at the Indian University of Lucknow. They reported about new finds that presented "not only the oldest, but also the only reliably dated fossil record of the Vindhyan Supergroup" (about 1.63 billion years). The new fossils represent a biota assemblage with Chuaria and Tawuia (discoidal structures) as well as other remains of uncertain biologic affinities. Macroscopic they may be, but the fossils are still very small: only up to 3.5 mm. At that time, Professor Seilacher had not yet abandoned his previous definitions. One year later, in his book "Trace Fossil Analysis" (2007), he also surmised biological traces despite his designation of "dubiostructures" at the time: Horodyskia was "certainly biogenic, but difficult to explain", the hairpin structure "defied any physical interpretation", the Chorhat worm burrows would pass "in younger rock as worm burrows - simply because of their radiometric age, a nonbiological cause must be assumed". The Franceville biota of Gabon finally makes the profound error in this thinking apparent. Once again, the Chorhat sandstone was examined for its age and it did

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not turn out younger, but even a little older: 1.65 billion years. In 2008, Rafat Jamal Azmi, an employee at the "Rajiv Gandhi Institute of Petroleum Technology" wrote a paper on Cambrian fossils, which he had found in an allegedly undisturbed direct superposition of Chorhat sandstone. An international team of scientists from Sweden and Australia set about verifying this assertion and determined the Paleoproterozoic age of the fossils in an integrated palaeontologic-geochronologic investigation of new samples from the corresponding strata. Professor Stefan Bengtson, palaeozoologist, Professor Martin Whitehouse, geologist, Veneta Belivanova, specialist for microfossils, all at the "Swedish Museum of Natural History" in Stockholm as well as Professor Birger Rasmussen, sedimentologist from Australia, published their research results in 2009 in the journal "Proceedings of the National Academy of Sciences" (PNAS/USA). Their hypothesis was: "either the radiometric dating consistently reflects inherited dates not related to sedimentation, as suggested by Azmi and coworkers, or Cambrian-like fossils occur in rocks that are a billion years older than the Cambrian." They come to the following conclusion: The radiometric dating is correct, but part of the fossil record is correct, too! How does this match? It seems that some of the "fossils" are not what they pretend to be. For instance, spherical forms are interpreted as gas bubbles in the biomats of the cyanobacteria, other structures do not at all correspond to the apparent Cambrian fossils, like annulated and segmented tubes reminding of Spirogyra, which are filamentous green algae. Today, it lives in calm waters, floating freely. However, precisely these kinds of tubes as well as a "morphologic diversity of apparently biogenic objects" do exist, and they are perfectly preserved. The authors name "the low level of metamorphism, and (...) the presence of sedimentary phosphate, both unusual for rocks of this age" as the main factors responsible for this degree of preservation. Phosphatization (similar to pyritization) is often responsible for exquisite preservation of soft parts. At first, there were only "microbial fabrics, strings of concatenated cells" but the microfossils are accompanied by a range of macroorganisms representing "distinct forms in the Lower Vindhyan" as far as their appearance is concerned. In this context, the following fossils from the Ediacaran and the Cambrian are mentioned: Vindhyanitubulus semriensis (tubular specimen), Olivooides multisulcatus (coralloid), Orbisiana (chain-like fos-

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sil), Konglingiphyton (alga) and Flabellophyton strigata (alga). This means that there must have been similar fossils more than 1.5 billion years ago. Bengtson and his colleagues said it clearly: "the Vindhyans have a long history of megafossil discoveries that sometimes have had difficulties getting into the mainstream literature because of uncertainties about the age, sometimes also because the reports themselves have not been convincingly documented." But: "All these forms are highly significant for our understanding of biotic diversity in the Lower Vindhyan" and the early evolution of multicellular eukaryotes. This biota is of Paleoproterozoic and not of Ediacaran-Cambrian age. This permits the conclusion that Chorhat worm burrows occur in MidPrecambrian sequences, in which great varieties of microfossils and macrofossils seemed to be abundant - in fact, in a stratum of the CentralIndian Vindhyan basin, deposited "under moderate climate conditions" (S. Paikaray, University of Bayreuth, and colleagues of IIT Bombay, 2008). Another dubiofossil from that time is the "Wellenwurm" („worm on waves“) from Endeholz, south of Lüneburg Heath in Germany. I found this specimen in 2012 on a pile of stones right next to a potato field. The reddish brown Dala sandstone with wave-formed ripples comes from the Mid-Swedish province Dalarna and is supposed to have been deposited 1.2 to 1.35 billion years ago in floodplains of rivers, at least in the shallow water area. Around 135,000 years ago, at the peak of the Saale glaciation, these erratic boulders were transported by glaciers right up to the south of Bremen, Hanover and Berlin. Here and there, they show mudcracks or wave-formed ripples like they tend to form on beaches. They are early red beds indicators of free oxygen in the atmosphere. In the present case, there is a wound tube, similar to a worm trace, on top of a "wave crest" on a wavy Dala sandstone. So far, general opinion has been that there were no fossils in Dala sandstone. After all, this sandstone is more than 1 billion years old - and if there had been any similar phenomena, they were interpreted in a different way: as desiccation cracks or remains of shrunk and torn biomats (e.g. "Manchuriophycus" in Seilacher's "Fossil Art", 2013). Both phenomena occur, but then they

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stretch over the entire surface. The same applies to the pseudo-fossils named ladder ripples, which may form by the wind moving the standing water located between the large wave ripples at low tide. Here as well, they occur all over the surface, like a pattern, and diagonally in between the large wave-formed ripples, but not on top of them and not oriented in the same direction. In case of the "Wellenwurm" from Endeholz, there is just the only one recognizable trace on an otherwise "empty" boulder with ripple marks. As far as I am concerned, there is no need to discuss how this can be produced without the digging activities of living beings, just because we are allegedly talking about the wrong era. Let's rather try to work out what organism might have been responsible for this trace - after all, we have compiled sufficient examples of multicellular and diverse life from this time that was definitely not a "boring billion". Today, the digging activity of a worm on a Mesoproterozoic wave ridge, for example, has become perfectly conceivable. In 2013, I sent an e-mail with photographs of the boulder to the trace expert Dr Sören Jensen (Universidad de Extremadura in Badajoz/Spain), asking him for his opinion. He was not enthusiastic about it. Morphologically simple structures like these were not easy to interpret, he wrote. He favoured filled cracks in the sediment as a more plausible explanation. The whole thing was just "too poor". That reminded me of Professor Seilacher, who wrote in "Trace Fossil Analysis" (2007): "In the Precambrian, however, even the poorest trace becomes important as a testimony for the presence and activities of a multicellular animal." Another curiosity is the "Fleckenstein" („spotted stone“) from Eschede in Lower Saxony, a Dala sandstone discovered by Kläre Troppenz in 2012 on a pile of stones. It does not display the usual discolouration spots, as one might think at first sight, but it is penetrated by a system of yellowish tunnels and spherical structures in the reddish brown glacial erratic boulder. The rock shows glacial striations bearing witness to the transport with the ice advancing from the north to the Lüneburg Heath region 300,000 to 120,000 years ago. It is furthermore a ventifact showing that the receding ice left behind a low-lying countryside with ground moraines of fertile glacial till, surrounded by terminal moraines. Over a very long period of

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“Wellenwurm“ from Endeholz Below an image by Sören Jensen (1997), showing a "younger" specimen of a "Wellenwurm" from the Lower-Cambrian Mickwitzia sandstone, Sweden.

The "Wellenwurm" (10.5x8x2 cm, trace at the left edge) is by no means one of the mudcracks or ladder ripples (below, 17 cm long), that cover the entire surface. The geologist Z. Gába assumes a biological origin of the spherical and cylindrical structures on the Dala sandstone to the left (9x5x3.5 cm). Photo below: Stefan Meng, DAG Greifswald

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time, sand and wind vigorously shaped the stony heritage of the glaciers in their very own ways. The structures in this glacial erratic boulder from Eschede (incidentally close to Endeholz) are hard to interpret. Discolouration spots are not eligible, so they must have another cause. Dr Zdenek Gába, a geologist v from Šumperk/Czech Republic, has a detailed opinion on this. He was interested in this specimen and wrote to me in September 2014: "This 'two-tone' Dala sandstone is certainly a most interesting phenomenon. These structures are by no means discolouration spots of inorganic origin." He saw three possible explanations. In the first place, he mentioned "animal traces". Animal bodies he considers unlikely. "Remains of plants, possibly 'discolouration traces' around plant remnants" could also be possible. Early evidence of multicellular body fossils came from Sweden, namely from the home region of the "Wellenwurm" - from Dalarna. As far as I know, the following fossils have not been a topic for discussion since 1953/54: the "Mångsboderna fossils" from the „Jotnian“ era. This era of 1.2 to 1.4 billion years ago is called „Ectasian“ today. There has been only one opinion - of Professor Ehrhard Voigt (1972), Hamburg. He interpreted the structures as rolled-up biomat shreds. Gerhard Schöne, who is in charge of the library of the „Gesellschaft für Geschiebekunde“, GfG ("Glacial Erratic Boulder Society") at the University of Hamburg, hinted at the publications by Pontus Ljungsgren and Ragnar Lannerbro in "Geologiska Föreningens Förhandlingar" (GFF), Stockholm. An exciting view into the treasure chest of lost knowledge - because it contradicts the doctrine... The news of the amazing fossils from the "Jotnian" of Dalarna came hesitantly. Already at that time, discoverers did not really have the courage to go public with their discoveries. Regardless of whether the "fossils" will be confirmed or not (that is, if they can still be found in Stockholm and if they are investigated with state-of-the-art technologies) - in my opinion, this shows the unpleasant pressure, that is so obstructive for a new understanding, but that palaeontology researchers are apparently subject to. No wonder that some scientists prefer to avoid this pressure instead of putting up their theses for discussion, contradicting the "zeitgeist". To give an example: Not until ten years later did Ragnar Lannerbro find the courage to present to the public the Precambrian dubiofossils he had found

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In 1954, Ragnar Lannerbro described rolled up, conical and club-shaped types of fossils from the "Jotnian sandstone" near Mångsboderna all of them several centimetres large. The images are taken from his article for "Geologisk Förenigens Förhandlingar", Stockholm.

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in 1944 on the pastures of Mångsboderna south-west of Älvdalen/ Dalarna. There, the sandstone has reddish and yellowish layers, interspersed with thin layers of grey and red clay. It was located in a depth of four metres in a very narrow zone. The thin interstratifications contained desiccation cracks, wave-formed ripples and fossil-like structures - as in the "Wellenwurm" from Endeholz. At first, he termed the "enigmatic structures" "pseudo-fossils". Alternatively, they could also be impressions of organisms from the "Jotnian era", wrote Lannerbro in the GFF issue 1/54. To be on the safe side, he left the term "fossil" in inverted commas... There were "many different types", said Lannerbro, among them conical (6-8 cm!), cylindrical, triangular, radial and some with irregular shapes. Lannerbro probably found the courage to publish his findings after his colleague Pontus Ljunggren had published similar findings from western Dalarna, south of Malung in the GFF issue 3/53. The Precambrian sandstone there showed numerous clayey horizons containing wave-formed ripples and desiccation cracks - and "fossils of an unknown type with a length of up to 90 mm and a width of 5 to 10 mm. They are long, slim, regularly shaped or slightly conical. Their cross sections are more or less oval." Seemingly, there had not been any hard parts - otherwise an erroneous dating would also have to be considered. Ljunggren did have the courage: "These early fossils were preserved by a clayey deposit in connection with their habitat in the sand." Apparently, they had lived buried in the sand with only their uppermost part reaching above the sand surface. I admit that I was first surprised by the size of the presumed fossils. More than one-billion-year-old multicellular fossils already with a size of up to 9 cm? Horodyskia and the other fossils of the Montana biota are rather small, after all. The "transitory biota" between Franceville and Ediacara acknowledged by El Albani has been so low in evidence, because nobody really wanted to admit it. But it is precisely these finds in Gabon made by El Albani with fossils of up to 17 cm from an even earlier time that are the reason why large multicellular organisms seem possible even in the "bustling billion". Adolf Seilacher, for his part, had argued in two directions: On the one hand, he argued that even the tiniest sign of multicellular life in the

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Precambrian was of paramount importance. On the other hand, however, he claimed that it was absolutely necessary to recognize "pseudo-fossils" as such and not take them into account. In between, there are the "dubiofossils", the nature and classification of which are doubtful. At any rate, research remains to be done in order to determine whether the depicted "Gotland enigma" of red sandstone with a circular bright structure, surrounded by a dotted circle, is a pseudo-fossil or a dubiofossil. The bright impression on the reddish background has a diameter of roughly 2 cm. This specimen was found in 2014 by Heiko Koch from Bredstedt, who also owns a house on Gotland. Within the course of many years, he has certainly collected more stones than there is room for them inside his house. As Gotland is a Silurian coral island, in a manner of speaking, his coral skeletons, trilobites, brachiopods, crinoids and shells come from this era. But: there are also local glacial erratic boulders! Heiko Koch sent me his find from Kovik at the west coast of Gotland with the note that it might be a jellyfish, possibly from the Lower Cambrian. This would not even be very surprising, as jellyfish are sometimes preserved on more coarse material. One of my display cases contains a jellyfish-like being with delicate structures, about 10 cm in size, from the Cambrian of Wisconsin/USA. The good news is that the find is more than twice as old. The bad news, however, is that the "jellyfish" must be questioned. After some research had been done, it turned out that it was "Jotnian" red sandstone with medium-sized coarse grains and small mica particles. This bedrock can be found in the Baltic Sea between Stockholm and Gotland, hence opposite the west coast, not far off the submarine deposits of brown Baltic quartz-porphyry. In Germany, this can be found as glacial erratic boulders. There, it is called "Trebus sandstone" after Trebus, the important finding place in Brandenburg. In this rock, wave-formed ripples and desiccation cracks can often be found, too. Its age: 1.3 to 1.4 billion years. Both, Dala sandstone and Trebus sandstone, are said to contain no fossils at all. In the past, this had also been said about the Precambrian as far as multicellular organisms are concerned. But now that we know better with regards to the Precambrian and cannot tell for certain any more with regards to the Dala sandstone - what justifies this possibly misleading premise with regards to Trebus sandstone? This rock sometimes displays rounded clay

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Mesoproterozoic

Cambrian

541-485.4

Ediacaran

635-541

Ediacara biota

Cryogenian

850-635

Varanger ice age („Iceball Earth“)

Tonian

1,000-850

Stenian

1,200-1,000

Ectasian

1,400-1,200

Cambrian Explosion

e s

Proterozoic

Neoproterozoic

previous view

eukaryotes Calymmian 1,600-1,400

Paleoproterozoic

Statherian

1,800-1,600

Orosirian

2,050-1,800

Rhyacian

2,300-2,050

Siderian

2,500-2,300

Archaean

Huronic ice age oxygen catastrophe

Neoarchaean

2,800-2,500

Mesoarchaean

3,200-2,800

Paleoarchaean

3,600-3,200

Eoarchaean

4,000-3,600

banded iron

prokaryotes

hail of meteorites

Hadean

4,550-4,000 moon catastrophe

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S t r o m a t o l i t

The Precambrian

The Precambrian

Proterozoic

Neoproterozoic

Mesoproterozoic

Cambrian

542-485.4

Ediacaran

635-542

Cryogenian

Cambrian Explosion Pannotia desintegrates

Ediacara biota 2. oxygen enrichment (NOE)

850-635

Tonian

1,000-850

Stenian

1,200-1,000

Ectasian

1,400-1,200

ice ages (“Iceball Earth“) supercontinent Rodinia

Montana biota

Calymmian 1,600-1,400

Paleoproterozoic

Archaean

actual findings

Statherian

1,800-1,600

Orosirian

2,050-1,800

Rhyacian

2,300-2,050

Siderian

2,500-2,300

Neoarchaean

2,800-2,500

Mesoarchaean

3,200-2,800

Paleoarchaean

3,600-3,200

Eoarchaean

4,000-3,600

big impacts / oxygen backlash

Franceville biota cyanobacteria multicellular Huronic ice age 1. oxygen catastrophe (GOE) banded iron (BIF) eukaryotes?

prokaryotes / stromatolites

eukaryotes? Akilia / Isua methanogenesis hail of meteorites

Hadean

4,550-4,000 moon catastrophe

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galls as inclusions, as can also be found in red sandstone. Light pale spots are typical of Trebus sandstone. But is it that easy? David Schmälzle is a former geological preparator at the Freie Universität Berlin, a petrographer and trace collector. He answered: "Rather yes. However - I have never seen this kind of dotted circle around a discolouration spot before." Dr Sören Jensen at the Universidad de Extremadura in Badajoz/Spain immediately thought of a pale spot: "I would estimate that it was some kind of reduced halo, as you are suggesting, but I don't have a good answer for the peripheral dots. Sometimes, such a discolouration can be caused by adhesion or a decay of a modern organism, but I am not sure this has happened with your rock slab." Prof Roland Vinx, Elmshorn, pointed at "a very nice zoned pale halo in the Jotnian sandstone of Dalarna", described by Sven Hjelmqvist in 1966. The concentric rings, however, might be described as a kind of "discolouration in phases" and do not really match the outer dotted circle of this specimen. Dr Markus Bertling at the University of Münster reasoned similarly: "I would like to thank you for this new enigma from the world of glacial erratics. The structure really reminds me of pale halos, I totally agree with you there, but I have not seen this kind of outer circle before, either. Nevertheless, I find it too irregular to be some kind of organic remnant. A trace was conceivable - but to make this decision, two perpendicular cuts using a saw would have to be made into the rock, with subsequent polishing." We'd rather spare this unique specimen of this procedure, though. Meanwhile, my circular to different experts was even answered from afar. Despite his stay on a different continent, Prof Hillmer took the time to send me a short e-mail: "Judging from this far away, the photograph seems to be a kind of a trace cross section; the structures at the edge could be some kind of wall covering. Very cautious regards from South East Asia." The geologist Dr Gába from Šumperk/Czech Republic goes a bit further. In a short message from 7 January 2015 he wrote: "The red sandstone certainly contains an organic structure, most probably an alga. Even an ichnofossil might be thinklable." In a letter from 20 January 2015 he added: "We can rule out an inorganic origin - the structures are too regular. Morphologically, this problematic specimen has a great resemblance to a plant, for example an alga. I am

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Two "Gotland enigmas" from the west coast of the island. Experts are confronted with a mystery: Are these enigmas biogenic or not? The dimensions of the rock above are 9x4.5 cm, of the rock below: 11x6 cm. Photos of the finding place: Heiko Koch

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thinking of Ordovician algae or the microscopic genus of Pachytheca. This would then be the contour, the impression." The interpretation as a trace of life considered Gába as "unlikely" - again because of the regularity. However, he eventually quoted the "Treatise (W)" (Häntzschel, 1975) and lists the following as comparable specimen: Atollites, Lorenzinia and Rotamedusa. In my opinion, Asterichnites would also qualify. Dr Gába's résumé: "I consider the find in the sandstone as highly interesting. Palaeobotanists should have a closer look at it." With "actualistic palaeontological" eyes, we might compare it to the remnants of a starfish, as can be seen in the deep sea nowadays (Hollister et al. 1975 in "The Study of Trace Fossils", published by Robert W. Frey). Although, when looking at completely differently organized and composed primeval worlds with intervals of billions of years in between, "actualistic palaeontology" is rather way off. Not least of all, the structure does resemble the coronavirus just from the morphological perspective... It is certainly true that no definite scientific conclusion can be made simply on the basis of a photography. Still, I find it very exciting how differently the experts judge this fossil structure. Until the stone itself has been thoroughly examined and scientifically investigated, a lot of possibilities of interpretation will remain. Once again, Heiko Koch visited Kovik beach to take some pictures of the finding place of his "jellyfish". As chance would have it, he found yet another reddish medium-grained sandstone with mica particles, some glauconite and some cobbles. He recognized it immediately: In the middle, there was a circular bright structure with a diameter of about two and a half centimetres and surrounded by a "dotted circle". This time, it was three-dimensional - with the circle set back in the stone. The "dots" were holes. A very special problematic specimen is the following possibly spectacular old find - a red-white layered sandstone. It comes from the glacial erratics of Gusow in the Oderbruch region/Germany, not far away from Trebus ("Trebus sandstone") and has a size of about 7x4x4 cm (opposite page). The rock suggests an origin in Dalarna/Sweden, meaning that a Precambrian time determination would be appropriate. This thinking is supported by a couple of scientists I consulted. They were sent a picture showing the specimen from the side. The trace specialist Dr Sören Jensen (Badajoz/Spain), however, instantly qualified his evaluation in a

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Finder: David Schmälzle Collection: Uwe-M. Troppenz Photo of quarry: Roland Vinx

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private note: "It is quite possible, that it is Dala sandstone, but if there were any signs of fossils in this block, you would have to look for the Lower Cambrian." And indeed, on the topmost reddish surface, there are two crossing traces with crescent structures. Even at the sides, similar shapes can be seen, oddly enough. Professor Roland Vinx from Elmshorn is a rock expert and author of the textbook "Gesteinsbestimmung im Gelände" ("rock classification in the outdoors"). He hypothesized merely on the basis of the rock and notes the following: "I have seen these interchanging deposits from your rock especially in northern Dalarna. They occur occasionally in local glacial erratic boulders and are downright characteristic of Jotnian sandstone (Dala sandstone) from the quarry of Mångsboderna and other disused quarries in its vicinity." The name of this quarry is certainly interesting considering the the old finds mentioned above. According to Roland Vinx, however, a possibly different origin can definitely not be ruled out. Conclusion: It seems to be certain that the Franceville biota was terminated by a sudden drop in the oxygen levels of the atmosphere and the hydrosphere, which subsequently started to increase again. Thus, it would be conceivable that living beings existing roughly between 1.5 and 1.8 billion years ago did not have great chances to develop. This is also the presumption of the professors Purnima Srivastava and Rameshwar Bali at the geological department of Lucknow University in the state of Uttar Pradesh/India. In their work on the Chuaria-Tawuia biota association in the Chorhat sandstone more than 1.6 billion years ago ("Geobios", issue 6/2006), they stated that the size of the fossils (0.02-3.5 mm) showed a transitional phase of evolution from microorganisms to macroorganisms. "Low oxygen levels may have induced small size." As early as in 2007, Xian-Guang Hou and his team of authors commented on the development of early life on Earth in "The Cambrian Fossils of Chengjiang, China": "There are (...) much older trace-like fossils from Western Australia, where parallel pairs of ridges, straight or curved, occur in rocks dated as more than 1,200 million years old (Rasmussen et al. 2002). Intriguingly, these traces are associated with discoidal imprints that are possibly of biogenic origin (...). This discovery serves to illustrate the fact that new finds of Proterozoic fossils are being reported at an everincreasing rate, and it is clear that scenarios for the evolution of

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Precambrian life are facing continuing modification as these new data appear." The eukaryotic fungi mentioned in the previous chapter as a possible part of the Franceville biota did certainly occur already in the Montana biota. In the journal "Fossilien", issue 2/2015, Prof Helmut Keupp at the Freie Universität Berlin reported that, in molecular biological terms, the fungi's existence can be dated "far back into the Precambrian". Fungal hyphae (filamentous cells), described as Tappania, could be found in the Mesoproterozoic "Roper Group" of Australia - with 1.43 billion years of age (Butterfield, 2005). The Tappania deposits of the "Kamo Group" in Siberia are of Mesoproterozoic age as well (Nagovitsin, 2009). In this huge time period that I am describing as "bustling billion" and Montana biota, numerous new discoveries are certainly awaiting and many an enigmatic occurrence will doubtless have to be discussed. But: If you want to find something, you will have to go looking for it in the first place... A paradise explodes It happened for the second time. Let's think back. The initial impulse for the first multicellular biota on this earth was triggered over 2 billion years ago by the "Huronian glaciation" and the Great Oxydation Event (GOE). As far as the second impulse is considered, there were probably four ice ages involved in the period between 780 and 580 million years ago. At times, these ice ages covered the entire terrestrial globe, producing the "snowball", as it is referred to, or more appropriately, the "Iceball Earth". Once again, the end of these glaciation events is connected with a strong increase in oxygen levels in the atmosphere, reaching values up to 15 per cent; this equals about three quarters of today's values. This second GOE is called "Neoproterozoic Oxygenation Event" (NOE). The effect on the animate world was the same as 1.5 billion years before: Macrofossils of the Ediacara biota first appeared 580 million years ago! Obviously, this seemes to be another "creative catastrophe". It initiated an incredible, paradise-like submarine world, in which there were neither hunters, nor hunted, neither feeding, nor being fed. Of course, all of this has been hotly debated. If we were sure, no exciting book would be written about it. What were the words Professor Reitner at

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the University of Göttingen had used? "We cannot prove it anyway, we are only assuming..." There may be no proof, but there are certainly numerous pieces of circumstantial evidence in the rocks to help draw conclusions. To give an example: It is assumed that there were four ice ages in the Upper Proterozoic (among others Gradstein 2012): Kaigas glaciation (780-735 Ma.), Sturtian glaciation (720-660), Marinoan glaciation (650-635) and Varanger or Gaskiers glaciation (582-580). The Sturtian and the Marinoan glaciation are suspected to have been possibly global ("Iceball Earth"). The allegedly so desolate and boring billion has not only produced multicellular life, but was very eventful, also from a geological point of view. The formation of "Rodinia" is one example of these geological events. It was formed by orogenic, mountain-forming, tectonic processes between 1300 and 900 million years ago. This supercontinent broke up about 740 million years ago - presumably because of a "superplume" below Rodinia. In a superplume, hot rock material rises in form of a thin tube from deep layers of the Earth's mantle and spreads in a form of a mushroom underneath the rigid Earth's crust. It has a diameter of thousands of kilometres! The resulting elongated rift valleys and violent volcanism were likely to have caused the disintegration of the supercontinent and a global warming that was probably responsible for the end of the Kaigas glaciation. The pieces then collided about 650 million years ago, forming „Pannotia“, the second Neoproterozoic supercontinent, which existed only until about 540 million years ago: throughout the Ediacara period until the "Cambrian Explosion" - just to disintegrate into the four continents of Laurentia, Baltica, Siberia and Gondwana precisely in this "event" of life. The reason being: The collisions producing Pannotia were of a rather "grinding" nature and the individual continents still showed active "rifting", shoving past each other. The Ediacara biota, too, was thus an evolutionary period between catastrophic - in any case transformational - events of climatic and tectonic kinds. Additionally, the "biota of peace" was confronted with the "Cambrian Explosion" (also "Cambrian Radiation") with creatures well equipped with carapaces and attacking apparatuses, which killed this biota off in no time - only few remained to live in the Cambrian. What were the Ediacara living beings, anyway? On 11 October 2005, the "Frankfurter Rundschau" put it in very illustrative and memorable words: "One of the

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Nearly complete glaciations and considerable plate-tectonic events, such as the disintegration and new formation of a supercontinent ,as well as the increase in oxygen levels in the atmosphere mark the end of the Montana biota and the beginning of the Ediacara biota. Both images: Wikimedia Commons

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marine symbiotic communities of the Ediacara was resident in deep waters. The beings living there resembled ostrich feathers, fern fronds, leaves or Christmas trees. They were moving gently with the currents. Other creatures with the shape of a spindle lay flat on the soft sand that would once become the rugged cliffs of Avalon, a peninsula of Newfoundland." In fact, as early as 1868, the first Ediacara fossil - as would turn out later - was found on Newfoundland by the Scottish geologist Alexander Murray. In 1872, the Canadian palaeontologist Elkanah Billings described it as Aspidella terranovica (synonymous of or similar to Cyclomedusa). However, it was certainly not a medusa, but rather the appressorium of a sessile living being. The term Ediacara, by contrast, comes from the finds of Reginald Claude Spriggs, a geologist who explored the Ediacara hills north of Adelaide/Australia in 1946. On the relatively coarse quartzite and sandstone slabs, he found numerous different imprints of soft organisms - the biota of the Precambrian was discovered for the first time. Later on, finds in almost all parts of the world followed - for example in Namibia, Russia, in the Ukraine, China, Canada and in the USA. Apparently, the biota prevailed all over the world. It was not until 2004, however, that the final part of the Proterozoic, in which this third Precambrian biota developed, was named "Ediacara". This was officially done by the International Commission on Stratigraphy (ICS) and confirmed by the International Union of Geological Sciences (IUGS). At that time, most beings were fixed to the ground. They included sponges (Porifera), hydrozoans, scyphozoa, anthozoans, protomedusae, hardly classifiable „vendians“, and many other living beings. However, apparently mobile organisms were found, too. Trace fossils indicate lively digging activities in the seabed. Even fossils with hard parts emerged, which had not been expected among the soft animal biota of the Ediacaran. Glaessnerina (an organism reminding of fern fronds with a length of up to 70 cm!), Dickinsonia, Cyclomedusa, Spriggina, Charniodiscus, Nemiana, Kimberella or Cloudina are well-known names in the fossil record. The reason why Cloudina is so important is because it is the oldest shellbearing creature and consists of several funnel-shaped tubes stacked into each other; these tubes can be as a long as 3.5 cm. The big sensation was that these living beings had regular round boreholes. Was this the

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Dickinsonia costata (above, approx. 13 cm, photo: Wikimedia Commons), Nemiana simplex (centre, one animal approx. 1 cm, Troppenz collection) and Kimberella sp. (below, 3.5 cm, photo: Tomonori Kikushi, Troppenz collection).

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oldest proof of a predatory organism penetrating the shells? These occurrences are well-known in later eras. They were usually caused by boring sponges, snails or shells. Apparently, the murderous principle ("feeding or being fed") loomed already before the "Cambrian Explosion" - right in the middle of this peaceful Ediacara biota consisting of soft tissue organisms without any feeding apparatus or carapace, which filter food from the water or live as sediment feeders ingesting algae, bacteria or mineralised substances at the bottom of a body of water. This is why no bite marks or other traces of attacks could be detected on the fossils. Except for Cloudina and its enemies... Two scientists - three opinions. Although the Ediacara biota has become a constant on the geological and palaeontological scale, although it can be proved with ample finds, although it is not questioned, there are still enough starting points for scholarly dispute. The dating is clear, in principle, but the exact boundaries are not. While the end of this period is defined with the beginning of the Cambrian, there are disputes about the beginning of the Ediacaran. Sometimes it is scheduled at 635 million years before our time, sometimes at 600 million and sometimes at 580 million years. To me, the last dating seems most probable, as it coincides with the end of the Varanger glaciation. In Newfoundland/Canada, the first macroscopic fossils that are to be interpreted as the first appearance of the Ediacara biota, can be found directly on top of the regionally occurring Varanger glaciation. It is true that the beginning of the Ediacaran era was laid down at 635 million years before our time, but the biota does not seem to have developed until 580 million years ago. The nature of the Ediacara animals is definitely another topic for debate. "As with any new discovery, scientists have differing opinions about the nature of the animals, and even if they were true animals." This is how the website of the Queen's University (Ontario/Canada) described the "Ediacarian fossils". And indeed: In 1983, Professor Adolf Seilacher from Tübingen compared the organisms to "water-filled, quilted air mattresses". With regards to evolutionary history, he classified the "unicellular dinosaurs" not as animals or plants, but as "Vendian biota" (after "Vendian Period", the former designation of the Ediacaran). In 2013, in the German issue of "Fossil Art", he still adhered to his opinion describing the "serially segmented Vendians" as "huge, but multinucleated unicellular organisms related to the foraminifera". He conceded that next to the so-called

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The sponge-like and reef-building archaeocyatha (above, matrix 10 cm wide, Troppenz collection) are among the survivors of the Precambrian; here are cross-sections and longitudinal sections from the Lower Cambrian from Labrador/Canada. - To the left a form of feeding trace left by Treptichnus pedum, which counts as evidence of the Precambrian/Cambrian boundary - but was also found in the Upper Ediacaran! It could have been caused by a priapulid worm, which presumably had Precambrian ancestors (Bromley 1999).

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Vendian biota, "there were indeed complex multicellular living beings, but they were completely overshadowed by the unicellular dinosaurs". Just like the small mammals of the Mesozoic were overshadowed by multicellular dinosaurs later on... Mark A. McMenamin, a US geologist, wrote in 2000 that these organisms were neither plant nor animal. Our ancestors were probably responsible for their eradication... Also Professor Joachim Reitner, the palaeontologist from Göttingen, indicated to the "Frankfurter Rundschau" (No. 236/2005) that "80 to 90 per cent of the Ediacara biota had the typical pneu structure". Reitner: "These beings were certainly not animals." Dr Richard Jenkins, an Australian palaeontologist at the University of Adelaide, is of a totally different opinion. The university harbours one of the largest collections of Precambrian soft fossils. He found out that the fossils had heads, intestinal tracts, delicate skin flaps for breathing, tentacles, gonads, etc. Why didn't the other palaeontologists see this? The Ediacara organisms were embedded in a coarser sediment than the Cambrian fossils, thus making more detailed features very difficult to detect and easy to overlook. Jenkins complained already in 1992: Some colleagues simply seem to ignore today's basic knowledge about zoology and genetics. These were unmistakably early forms of corals, ringed worms (annelids) and jellyfish. According to Jenkins, there was a continuous line from the Ediacara biota to modern organisms. In 2003, Prof Matthew E. Clapham, Dr Guy M. Narbonne and Prof James G. Gehling at the Queen's University in Ontario/Canada came to the same conclusion. Studying the Canadian Ediacara biota, they ascertained that the deep sea at that time was quickly colonized by complex organisms. "Species richness, abundance, and diversity values, as well as levels of intraspecific interaction, all fall within the typical range observed in modern slope communities." Gregory J. Retallack (2012), professor at the University of Oregon/USA and director of the local Museum of Natural and Cultural History, had the unusual idea that they might be some kind of lichen plants. Be that as it may, the "compromise" was insinuated by Adolf Seilacher: Apart from the "quilted air mattresses", other forms of complex multicellular life did exist, after all, and Joachim Reitner's "pneus" do leave 10 to 20 per cent of the biota for further theories... A unique biota - for sure, but

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here again, there were bridges to what had existed before and to what came afterwards. One role in the farewell of Ediacaran could have been played by the disintegration of the supercontinent Pannotia towards the end of the Proterozoic Period. This break-up dramatically changed the appearance of the Earth - the distribution of land and water surfaces, marine chemistry, currents, continental shelf areas, habitats, hence the entire ecology. At any rate, the end of the peaceful Ediacara biota coincided with the "Cambrian Explosion", when more or less suddenly living beings with teeth, claws and grip arms as attack apparatuses emerged, as did on the other hand hard-shelled and spiky beings that knew how to defend themselves. The Vendian biota with its soft parts, that probably fed on algae, bacteria and freely available nutrients, eventually had no chance to survive and was easy prey for the first hunters. Their basis of life - the biomat, on which they colonized and grazed - was probably destroyed by the more mobile organisms. The US Professor David J. Bottjer at the University of Southern California called this "The Cambrian Substrate Revolution" (in "GSA Today", 2000). Living beings gently swaying with the currents - sadly, this had now ended for good.

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From the war between the creatures to the apocalypse Nearly simultaneously, - within a very short interval of maybe 10 million years, which is actually hardly worth mentioning in geological terms representatives of almost all of today's animal phyla started to appear in the Lower Cambrian. We are talking about 540 to 530 million years ago and it started with the "small shelly fauna". The mineralised fossils show that the arms race had begun. Whoever could not save themselves from the carnivorous marine predators by digging themselves in, had to use hard parts to make life as difficult as possible for them. These hard parts were produced using the calcium and silicon available in the sea water. On the other hand, the hunters "invented" claws to grab their prey, teeth to crush and chew the hard parts or other apparatuses to etch and pierce the shells. The invention of the "eye" made a "predator" capable of recognizing and pursuing its prey - but it also made the prey able to recognize its pursuer and escape. Ediacaran in the Cambrian? The "small shelly fauna" can be found not only in rock strata of the Lower Cambrian, the Tommotian, but already in Upper-Ediacara strata, which leads to the conclusion that the system of predators and prey had developed a bit earlier. On the other hand, quite a few members of the Ediacara biota apparently "survived" the fiasco of the "Cambrian Explosion" and seemed to prevail even until the Upper Cambrian, although the biota itself disappeared. The claim of Dr Richard Jenkins, Adelaide/Australia, that there has been a continuous line from the Ediacara biota to today's organisms, is certainly not tenable. However, we have observed transitions through all catastrophic turning-points. The German magazine "Der Spiegel" wrote in its issue no. 34/1998 that Jenkins felt vindicated "by the most recent finds, because they show that the animate worlds of the soft-skinned Ediacara creatures and the hard-shelled animals of the Cambrian did overlap in time". Researchers led by the palaeontologist Sören Jensen, for example, found Ediacara fossils in clearly Cambrian slices of rock - "evidence that the Ediacara biota did indeed extend into the era of the Cambrian Explosion".

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In June 1998, the scientists Dr Sören Jensen, at that time in Cambridge/Great Britain, Professor James ("Jim") Gehling from Australia and Professor Mary L. Droser from the USA published an article in "Nature" with the title: "Ediacara-type fossils in Cambrian sediments". They ascertained that in South Australia, typically rounded Ediacara fossils were found together with Cambrian traces "in unequivocally Cambrian-aged sediments". This unusual occurrence "bridges the apparent divide between the terminal Proterozoic and Cambrian fossil assemblages". They name archaeocyatha and sponges as well as the following fossils as exemplary "survivors": Charniodiscus, Conumedusites, Cyclomedusa, Ediacaria flindersi/Ediacaria booleyi (similar to Cyclomedusa/Aspidella), Kullingia, Nimbia, Tirasiana, Stromatoveris psygmolena or Praecambridium, possibly an early arthropod, but this is only one interpretation. There have in fact been several interpretations, but the systematic classification of Ediacara beings remains controversial, anyway. In our exchange of e-mails in early 2015, Professor Jean-Bernard Caron mentioned the Ediacara fossil Kimberella. Caron is a French-Canadian scientist and professor at the University of Toronto. He discovered the second Burgess finding place, but we will come to that in more detail later on. According to Caron, Kimberella "is reminiscent to Odontogriphus from the Burgess Shale and I think might be part of an ancient lineage of proto molluscs", that means mollusc ancestors, which probably came from the depths of the Precambrian (e-mail of 15 January 2015). The simultaneous presence of predominantly sessile Ediacara fossils and obviously free-moving animals, which have been documented as trace fossils, already hints at the "nature-made" catastrophe. Once, the cyanobacteria's oxygen production had been toxic for most unicellular organisms. This time, the organisms' life and way of living was fundamentally changed by the opposition of immobility and mobility in combination with tectonic processes and a break in the global distribution of the stable carbon isotope carbon-13 (just like in the case of the transition to the Proterozoic and of "Iceball Earth"). With reference to the carbon-13 anomaly, the study of zircons in volcanic ash strata in Oman helped to determine the beginning of the Cambrian to 542 (+/-0.3) million years ago. This scenario resembles that from the beginning of the Franceville biota 2.2 to 2.1 billion years ago: increased supply of oxygen, glaciation, global warming, rise of the sea level, supply of nutrients and minerals through

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glacial erosion. The great supply of calcium carbonate, main component of sedimentary limestone, was probably highly useful for the "armament" of the new living beings in the oceans. The traces are leading into a new world In the beginning, there was a trace: Treptichnus pedum, probably produced by a priapulid worm. Anette Högström at the Arctic University of Norway, Tromsø, recounted a mission in northern Norway in a blog post of August 2014: "The hunt for the Precambrian-Cambrian boundary is on. Treptichnus pedum is a trace fossil distinctly Cambrian and wherever it appears we know the boundary is close." Anette Högström's work is characterized not only by a purely rational approach, but she is also emotionally involved, as we can gather from further statements on her website „sciencenordic.com“: "This is one of the most exciting periods in the evolution of life, huge functional changes happen and animals more similar to the ones we know from today emerge in the oceans. Animals leaving behind a multitude of traces on these shallow marine bottoms, traces we are looking for roughly 550-540 million years later..." A diversity of trace fossils tells the story of a different animate world than had been known before, both in Sweden and correspondingly also in the Nordic glacial erratic boulders. Whatever beings produced those traces is unknown in most cases or guessed at best, as in case of Treptichnus. With Gabavermis annulatus (TROPPENZ 2013), a presumed annelid from the Hardeberga sandstone of the early Lower Cambrian, and with Xenusion auerswaldae (POMPECKJ 1927), a presumed lobopodian (similar to the recent onychophora) from the Kalmarsund sandstone of the late Lower Cambrian, are preserved as bodily impressions. Gabavermis annulatus was also a special for PD Roger Schallreuter, as he had contributed greatly in its first description and the following publications. PD Schallreuter from the University of Greifswald was the founder and long-term director of the "Gesellschaft für Geschiebekunde", GfG ("Glacial Erratic Boulder Society") and of its journal "Geschiebekunde aktuell" (Ga). Claims that this designation might not be valid were contradicted by Prof Ingelore Hinz-Schallreuter at the University of Greifswald (press release of 10 November 2014): "My husband published your arti-

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Xenusion auerswaldae (POMPECKJ 1927) from the late Lower Cambrian (8.5 cm long, photo: Museum of Natural History in Berlin) and Gabavermis annulatus (TROPPENZ 2013) from the early Lower Cambrian (above to the right, 6 cm long). PD Roger Schallreuter (1937-2013) had the wish to deposit the original of Gabavermis at the University of Greifswald in the "Deutsches Archiv für Geschiebeforschung" ("German Archives of Glacial Erratic Research"). This wish was fulfilled. All images in this chapter: R. Troppenz - unless otherwise indicated.

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cle in 'Ga', which means that it became valid in accordance with the international rules of zoological nomenclature." After Treptichnus, many more similar pieces of evidence of life followed, for example resting structures (cubichnia), locomotory tracks (repichnia), feeding and grazing traces (pascichnia), more disruptive feeding traces (fodinichnia) or dwelling structures (domichnia). Sweden has been wellknown for its bedrock from the Lower Cambrian with large blocks, on or inside which numerous traces of this era can be found. Unfortunately, this extensive bedrock from the Precambrian and Lower Cambrian is located below sea level - between the east coast of Stockholm and the west coast of Gotland. These ancient sedimentary rocks can be found as local glacial erratic boulders; besides the Gotland west coast, they can also be found on Öland. In 2014, Claus Friis wrote in "Steinkern", the German online fossil forum: "My collection area for trace fossils is located at the west coast of northern Öland... At Djupvik beach, the Cambrian sediment can be found just below the waterline, but it is overlaid with beach gravel. In this gravel, the attentive collector will find the most varied fossil traces and marks... The collection area extends over an approximately 100-metre-long beach. The continuous wave movements of the Baltic Sea erode rock fragments from the Cambrian bedrock under water. During stormy weather and high water level, they will then be washed to the shore." We can discover many of these traces in the northern-German glacial erratic boulders, for example in the Lower-Cambrian Hardeberga sandstone, which originated in Scania/southern Sweden and was shoved to this place by the glaciers of the last ice age. There are structures like the parallel Skolithos burrows, the fan-shaped Syringomorpha, the vertical Monocraterion with funnel and the U-shaped Diplocraterion, also Psammichnites, Plagiogmus or Arcuatichnus, just to mention a few wellknown ichnofossils. They thoroughly permeated and burrowed the sea floor. After these, the traces of more complicated fossils followed: trilobites. They are represented by resting traces (Rusophycus), creeping and striding traces (Cruziana) as well as quicker striding traces (Diplichnites). These originators are well-known today, because they possessed a special protective shield: their exoskeletons, which were reinforced with calcite to form a carapace. Naturally, this made their fossilization and eventually their discovery by palaeontologists much easier...

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Skolithos tibia (HINZSCHALLREUTER& SCHALLREUTER 2003), 45x27x14 cm, Lower Cambrian, Brandenburg/Germany, photo: J. Evers, Schmälzle collection, Berlin

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Detail of Skolithos linearis from Brandenburg

A slant trace (40x15 cm) in a Lower Cambrian glacial erratic boulder from Wulfersdorf/Prignitz, Germany. Finder: David Schmälzle, Troppenz collection. (To compare with the trace on p. 79, in the middle!)

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Apart from trilobites, which belong to the arthropods, the ocean was now alive with almost all modern animal phyla: sponges (Porifera), reef-building sponge-like archaeocyatha, jellyfish (cnidaria), moreover brachiopods, shells and snails (molluscs), precursors of sea urchins, starfish and sea lilies (Echinodermata), other phyla of invertebrates - as well as the first progenitors of vertebrates, the Chordata. These were eel-like creatures without jaws and fins, comparable to today's lampreys. Some of the above-mentioned animals existed already in the Cambrian. Hence, it would be worth considering to place the beginning of radiation, that means the diversification of organisms, into the Ediacaran. The only thing missing in the Cambrian are the bryozoa. We will have to wait for them until the Ordovician. The reason why the "Cambrian Radiation" turned into and "explosion" are of course the organisms' hard parts, which had now developed and which determined the situation of the finding place. Soft parts are seldom contained in the fossil record, and it is remarkable that soft fossils, their impressions and traces are still preserved, sometimes even in fairly coarse sandstone. The term "explosion" for an in fact rather "short" period of time, geologically speaking, is therefore indeed appropriate. The entire scope of this event, however, did not become clear until the discoveries of entire soft animal habitats in Walcott's Yoho Burgess Shale, in the Chengjiang claystone and most recently also in the Kootenay Burgess Shale: a new beginning, that has an effect to the present day. Furthermore, we must not forget the Sirius Passet biota association that was discovered in 1984 on Peary Land in northern Greenland (Simon Conway Morris 1987, 2008). Roughly 10,000 fossils have been gathered in the course of the years. In chronological terms, they have to be placed close to Chengjiang. The following living beings have been described: annelids, arthropods, trilobites, lobopodians and a phylum of uncertain classification - Halkieria evangelista, first denoted as primordial mother of the annelids or brachiopods, subsequently as a mollusc (Vinther/Nielsen 2005). Two times Burgess: "Time capsules of life" Thousands upon thousands of soft fossils from the above-mentioned finding places have opened the door to an animate world in the Lower and Middle Cambrian, which we had never thought possible. Now, there was

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proof that numerous new animal phyla, a plethora of new genera and species and even completely indeterminable bizarre fossils populated the oceans 525 to 505 million years ago. Probably even much earlier and up until much later - although we have not found reliable evidence of this at the finding places we know today. It was in late August 1909, when Charles Doolittle Walcott, a US palaeontologist, whose main field of expertise was the Cambrian, was riding his horse on the Burgess Pass through the Canadian Rocky Mountains, accompanied by his wife Helena. On its way down, Helena Walcott's horse tripped over a rock on a steep path between Mount Wapta and Mount Field. Charles Walcott smashed this piece of rock and found the first Burgess fossil: Marrella. This is at least how the story goes. Regrettably, there is no evidence that this nice story really happened, not even in Walcott's diary. The diary, however, does mention that he and his wife were collecting fossils in the Stephen Formation on 31 August 1909. Among these fossils was a "remarkable phyllopod". In September 1909, Walcott discovered many more petrified creatures from the Burgess Shale, where today the Yoho National Park is located. Until 1924, he went back to the "crime scene" every year and collected about 65,000 fossils, which he tried to classify according to the taxonomy of modern animal species. During his work, he made many mistakes, which sometimes seem rather amusing today. Even a Charles Walcott was not infallible and he was, after all, a child of his time. For the time being, the fossils were put aside, as they were regarded as mere "curiosities"... Names like Simonetta (1962) and Wittington (1966) stand for the revision of these fossils, for new excavations in the "Walcott Quarry" and its surroundings as well as for the realization that these fossils were something really special. This biota had been considerably more diverse and more unusual than its discoverer Walcott had ever thought. "Parks Canada" and the UNESCO recognized the importance of the Burgess Shale in 1970, and the book "Wonderful Life - the Burgess Shale and the Nature of History" by Stephen Jay Gould (1989) eventually made the "wonderful life" of the Middle Cambrian famous. Fossil names like Hallucigenia or Anomalocaris imply what kind of impression the signs of life in the clay

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Claus Friis found these traces near Djupvik at the west coast of northern Öland (finding place to the right). The crossing and branching traces on the surface were produced by Palaeophycus tabularis on a Mid-Cambrian Eophyton sandstone (Paradoxides siltstone). Size: 17x11x2 cm, photos: C. Friis, Troppenz collection.

At the beginning of the "Cambrian Explosion", there were organisms like this undefined „worm", which burrowed the sea floor thoroughly. Hardeberga sandstone from the Lower Cambrian, finding place: Endeholz, Südheide Nature Park/Germany, Troppenz collection.

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shale must have made on the amazed palaeontologists. With growing amazement, they were recovering fossilized creatures that saw the light of day for the second time after more than 500 million years. Everything was preserved: Eyes, fins, legs, antennae, digestive tracts, and so on. Opabinia even had five eyes for a good view around. A real treasure chest for research! The composition of the Burgess deposits in the Stephen Formation is very interesting. For the first time, the concept of feeding and being fed appears to have played a greater role in the history of life - but apparently, it hadn't been that bad after all! What scientists found out (of course always under reserve): only about 10% of the animals were carnivores or scavengers. All other animals fed on organic substances on the sea floor or in the ground and on small particles they filtered from the water. The proportion of animals with skeletons or shells amounted to a mere 14%. The mobile biota on the sea floor made up roughly 40% of the entire biota and was dominated by arthropods (such as crustaceans or trilobites). Only 10% of all animals seemed to live above the sea floor. However, the floating animals may have been better at escaping the mud currents, which buried the Burgess biota and are thus under-represented among the finds. At the time, the superior "predator" of the animal world had been Anomalocaris. It was about 1 m big, had lobe-like extensions which enabled it to swim, had extremely nimble tentacles, keen telescope eyes and a disk-like mouth with horn plates. Obviously, it was very successful, as its relatives lasted until as much as 100 million years later! A single find from the German Hunsrück Shale with the witty name Schinderhannes bartelsi proved that the Anomalocaridids lived and hunted even in the Late Devonian. Who knows what else may hide inside the rocks that will eventually turn our ideas about the development of life upside down once again... The media quickly started calling the news "sensational" - but this time, it really was. In the summer of 2012, Professor Jean-Bernard Caron at the Royal Ontario Museum (ROM) and his team discovered another large soft fossil finding place in the Burgess Shale! This time in the nearby Kootenay National Park. Caron, expert on the early Cambrian, also represented the University of Toronto. Moreover, scientists of the

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Two typical Burgess fossils with reconstructions: Hallucigenia (above) and Marrella (below, both approx. 2 cm). In the background: the Walcott Quarry. Images: Wikimedia Commons.

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Canadian University of Saskatchewan and the Swedish University of Uppsala were involved. The yield was incredible already after the first 15 days: 3,000 fossils were found, among them more than 50 new species, hitherto unknown to the scientific world. The finding place was kept secret at first. The information "Marble Canyon" was deliberately misleading, because the fossils from the bottom of a tropical ocean were not found in the valley, but 2,000 m above today's sea level, only accessible by helicopter. Everything else would have been far too troublesome for the excavation works and the removal of the fossils from the site. When telling about the first venture, it became apparent that Dr Caron did not want to be just a technocratic scientist, but that he was involved with ardour and passion. In his blog on the ROM's website, he wrote: "The story of the discovery of the new Kootenay site is first and foremost a human story of a group of researchers, students and volunteers working together to unlock a critical chapter in life history using fossils as the main source of evidence." The first fossil to be picked up sat on a loose boulder that had come off a more elevated piece of rock. The next fossils were found quickly after that. Caron remembers his colleagues' frequent exclamations of surprise and admiration. "It was unbelievable!" He realized that they had "stumbled upon" something really special. Caron described very vividly the ordeal and hard work the team had to go through: "Hammer in hand, chisel in pocket, ready for action, we have to be prepared for frigid temperatures, scorching sun and roaring rain - basically all four seasons even in the middle of summer!" He called the fossils they subsequently found "time capsules of life on our planet". They were the reward for all the hard work. "Once collected," Caron continued, "a fossil will have a life of its own again, after being frozen in obscurity for millions of years." In February 2014, Jean-Bernard Caron commented in the "Media Room" of the University of Toronto: "there is no doubt in my mind that this new material will significantly increase our understanding of early animal evolution." The neighbouring country, the USA, were impressed, too. The "second Burgess Shale Formation site nearby which is as rich, if not richer, than the 1909 original", the "Scientific American", a popular scientific magazine, enthused two days later. The first publication in 2010 made the finds famous. "A new Burgess

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Shale-type assemblage from the ,thin' Stephen Formation of the southern Canadian Rockies" is the headline of an article in "Geology", the publication of the Geological Society of America (GSA). A detailed report followed in early 2014 in "Nature Communications". In Germany, the popularscientific magazine "Geo" spread the good news in its December 2014 issue with a comprehensive and impressively illustrated text. The digging went on. And here they were again: Opabinia, Hallucigenia, Marrella, Isoxys, Leanchoilia, Canadaspis, Sidneyia, Wiwaxia, the vertebrate progenitor Metaspriggina and all the others. The finds of Primicaris fossils are of special importance, as this arthropod has been excavated solely in the Lower-Cambrian Chengjiang/China so far. In this way, the time period and the prevalence of these animals can be gauged. In the course of the summer of 2014, an estimated 10,000 fossils were excavated, and once more, there were numerous hitherto unknown species among them. In total, the percentage of new types of fossils amounted to 22% - really a substantial proportion! Has there ever been a fantastic place like this - a real heaven for palaeontologists? Yes, there has: the claystones of Chengjiang. Chengjiang: clearance sale of predators No specific number is known - but there must have been hundreds of thousands of the most bizarre soft fossils from the Lower-Cambrian Lagerstätte around the Chinese city of Chengjiang. They were excavated in the course of the years not only by scientists, but also by "grave robbers" or profiteers. Many of these fossils match the Burgess organisms, which are actually 20 million years younger. I know a Japanese collector, who himself owns several thousand Chengjiang fossils. There were numerous Chinese dealers, who at times sold masses of these 525-million-year-old living beings from Hong Kong via the Internet to collectors all over the world. In many cases, the fossils were sold for only 1 Dollar, when the auctions on eBay did not go that well... Today, this is over. There had been attempts by the government to protect this unique finding place, but the final measure was taken when the UNESCO declared the finding place a World Heritage Site in 2012. Ever since that date, the thumbscrews have been put on and the dealers have been withdrawn from this business, in order to prevent a further clear-

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ance sale of these treasures. As far as I am concerned, I have lent my specimens mostly to interested scientists and have passed on contacts with collectors, so that possibly important information will not get lost. The biota association in the Maotianshan Shales (symbol: Maotianshania worm) of the Yunnan Province in the People's Republic of China is part of the Heilinpu Formation. It is a claystone deposit with a thickness of about 50 m, extending over tens of thousands of square kilometres and offering abundant scattered outcrops. The claystone fossils' state of preservation is superior to that of the Burgess Shale fossils, which can be compressed. Thus, they are easier to investigate, showing delicate details that allow conclusive interpretations. Actually, the Chinese deposits have been known for more than 100 years. The Frenchman Mansuy, for example, made excavations in the years 1909 and 1910 and described as early as 1912 Kunmingella douvillei from Yunnan. In the 1930s and 1940s, Chinese researchers like Chen, Wang, Chiang and Lu worked hard in this area. About half a century ago, in 1965, Huo described among others Kunyangella cheni, a bivalved arthropod. The actual thunderbolt, however, did not occur until 1984. Xiguang Zhang and Xianguang Hou, both at the Yunnan University in Kunming, conducted palaeontological investigations at the Maotian Mountain and were closely examining the delicate claystones, which had originally been grey, and were now yellow from weathering. They were working assiduously for ten weeks, from June until August. Their third find already was the key for their success and this outcrop's fame: When splitting a claystone, they uncovered a complete animal with a size of approximately 5 cm. "The animal almost appeared alive on the wet surface", Hou and Bergström wrote in 1997 in "Fossils and Strata". The find was Naraoia longicaudata; since 1997 it has been called Misszhouia longicaudata in honour of a brilliant preparator: Miss Zhou. Since then, a tropical underwater world that had existed close to the Proterozoic-Phanerozoic turning point has gradually come to light. The incredibly diverse metazoa biota can serve as a database, as it were, for our understanding of the "Cambrian Explosion". In 1992, Prof Chen Junyuan (Nanjing University), Dr Berndt-Dietrich Erdmann (Technical Uni-

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Lower Cambrian of Chengjiang: The superior predator, Anomalocaris (in the background) reaches for its prey (from above): Waptia (1.5 cm) with preserved soft parts, Leanchoilia (2 cm) with legs and Fuxianhuia (section 3 cm) with "telescope eyes". Troppenz collection. 105

versity Berlin) and Dr Michael Steiner (Freie Universität Berlin) expressed it very vividly in the journal "Fossilien": "With the Chengjiang fossils, it was probably a combination of several favourable circumstances that enabled us to observe the anatomy of these early stages of animal life as if we were looking through a crystal-clear window. With all other fossils, we are at best allowed a look through the frosted glass of shell preservation." The Chengjiang biota is incomparable: Apart from the trilobitomorphs Naraoia and Misszhouia and the genuine trilobites Eoredlichia, Paleolenus or Yunnanocephalus, there were floating animals like the indefinable Vetulicola or the largest "predator" of the time, Anomalocaris with its dangerous tentacles; also jellyfish were floating through the water. On the sea floor, other animals were running around or digging into the ground. They included the lobopodian Microdictyon with its stubby feet and shell, Hallucigenia with its spikes on its back, the crablike creatures Leanchoilia or Chengjiangocaris, or Alalcomenaeus with its five eyes. Furthermore, there were a great number of bivalved arthropods like Waptia or Isoxys. Worms were digging into the sediment: Cricocosmia, Palaeoscolex or Maotianshania. Sessile beings like sponges, hyoliths, algae or brachiopods (e.g. Lingulella with pedicle) were also around. The most exciting thing, however, was probably the fact that Chengjiang contained the earliest Chordata - even eight different species! Among them was the fish-like Haikouella lanceolata. In 1999, Jun-Yuan Chen at Nanjing University and other authors recounted in "Nature" of 305 finds with sizes up to 4 cm, which they found approximately 35 km south-east of Haikou. The fossils showed exciting details like hearts, blood vessels, gills, hints at a cranium, a neural tube and a relatively "large" brain, toothlike structures... "These findings", wrote the authors, "will add to the debate on the evolutionary transition from invertebrate to vertebrate" - and thus up to us, the human vertebrates, as well! Conclusion: The Cambrian soft fossil biota of Burgess, Chengjiang and Sirius Passet primarily demonstrated that incidental discoveries often draw a completely new picture of the history of life. This is also exactly what we experienced with the fossils of Franceville/Gabon, which had not been expected there at all. Our ideas about the "Cambrian Explosion" were inadequate, as long as it was related merely to the "invention" of defensive hart parts and biological offensive weapons. This alone does not account for an explosion - because the enormous biodiversity does

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The first Chordata (vertebrates) can be found not only in the Burgess Shale, but as early as in Lower-Cambrian Chengjiang like this fish-like specimen of Haikouella (to the left, 1.5 cm). Troppenz collection.

To the right, the most extraordinary being Vetulicola, that nobody can really classify (with "tail", 4.5 cm, see also background); below the 3-cm-wide trilobite Eoredlichia with delicate antenna (visible in the image above to the right). Troppenz collection.

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not become apparent until we marvel at the densely populated underwater world with its numerous, often seemingly bizarre (because unusual) soft fossils, all the more because they are so scarce in all other places. The time period these biotas comprise according to the latest fossil record - i.e. from 525 to 505 million years - is, in turn, just a section of the whole picture, a jackpot in the palaeontological game of chance. A door was opened into hitherto unknown worlds, just because a horse (allegedly) tripped over a fossiliferous shale or just because a telling outcrop from a snow-capped summit happened to roll in the way of a curious and eager researcher. The living beings seem to have emerged right from the depths of the Precambrian and seem to have prevailed until at least 100 million years later - at any rate this has been proven in some cases. This means that the last word about the Earth's history and its biological contents is far from being spoken. Of course it is. It remains to be seen when chance itself is planning its next sensation, putting together a completely new primeval mosaic. Astonishing structures in the Västervik basin The recent discovery by Professor Roland Vinx, Hamburg, in the Swedish Västervik Formation was perhaps one of these coincidental sensations. Structures with an estimated age of 1.9 billion years were now described. With that age, they were ironically precisely from a time with minimum oxygen levels. Should these structures prove biogenic, the primeval mosaic would indeed have to be put together in a different way once again. A rock exposure in the nearly 1.9-billion-year-old Swedish-Finnish metasediments of the Västervik basin (north-eastern Småland) exhibits remarkable structures that cannot be explained as diagenetic or metamorphic features. They were obviously created with sedimentation and might have biological causes. The protolithic sediments of the finding place were deposited in a shallow sea comparable with an intertidal mudflat. In spite of amphibolite facies metamorphism, the primary sediment structures are perfectly preserved. These unusual Paleoproterozoic rocks of the Swedish basement are de-

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Wave-formed ripples (to the right) as well as spherical and oblong annulated structures that are difficult to explain in petrographic terms. Photos: R. Vinx

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scribed in the article: "Remarkable sedimentary structures in the 1.881.85-billion-year-old Västervik Formation, Sweden" (TROPPENZ, VINX & SCHMÄLZLE 2016). With regards to the 2.1-billion-year-old Franceville biota that was discovered by Prof El Albani and has been supported by an international and interdisciplinary group of about 30 scientists, we cannot exclude a biogenic interpretation of the Swedish problematica, either. In most cases, metamorphism destroys pre-metamorphic structures. The causes are tectonic deformations and/or crystal growth during the transformation. Neither of these is significant at this locality, which means that the structures could be preserved. The presence of well-preserved ripple marks shows that occurrences of other sedimentary structures of a similar scale are not a problem; they may even include biogenic structures. However, it does seem a problem that the Västervik structures were produced in a time with minimum levels of oxygen in the atmosphere and hydrosphere. On the other hand, this does by no means contradict the existence of complex living beings. Grypania spiralis, for example, who has been interpreted as multicellular alga, also survived this time with its hostile conditions of life: It was found in 2.1-billion-year-old strata (Michigan/USA), but also in 1.3-billion-year-old rock (Gaoyuzhuang/China). The well-known "hairpin traces" from the quartzite Stirling Range Formation in Western Australia are also from the "Västervik Era" with their age of 2.0 to 1.8 billion years. Bengtson, Rasmussen & Krapez (2007) described them as part of a "megascopic fossil biota", that was influenced by longshore currents and tides. Let's summarize: If there is a possibility of complex living beings in an interval of extremely low oxygen levels (comparable to those before the "Great Oxydation Event"), then another conclusion is possible: Even b e f o r e the GOE and b e f o r e the "Gabonionta", comparable organisms are conceivable, because the low oxygen level corresponds approximately to that from the "Västervik Era". Prokaryotes could definitely be responsible for complex life before the Gabonionta. "First signs of aerobic photosynthesis" 2.7 billion years ago,

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ascertained Joachim Reitner in 2009. There is verifiable evidence of multicellular differentiated cyanobacteria about 2.3 billion years ago (SCHIRRMEISTER et al. 2012). Plus, Diskagma buttonii is dated at an age of 2.2 billion years (RETALLAK 2013)... The almost exact dating of the end of the world We know these assertions from some sects (like the "creationists") that want to hear nothing about the relativity of time in religious texts. In geology or palaeontology, too, we use a concept of relativity: Considering that the history of the Earth is about 4.5 billion years old, we tend to say that 50 million years, for example, are a "short" period of time. If we project a "short" period of time like this into the future, we are not talking about next week, so there is no need to pack our bags now. No, we are talking about scientific apocalypse scenarios here. Dr Joachim Scholz, laureate of the Alexander von Humboldt memorial prize of the German Senckenberg Nature Research Society, wrote to me in November 2014 about cyanobacteria and commented about multicellular organisms merely as an aside: "Within the life cycle of a planet, metazoa form just a short episode between the first and the second microbial mat age. Translated to the Earth, this amounts to 3 billion years, then 800 million years for the metazoa (it is already drawing to a close) and maybe another 2 billion years for a second microbial mat age (the latter is called 'Swansong Biosphere')." Swansong? The expression goes back to an ancient Greek myth, according to which swans sing a last sad, but beautiful song before they die. So what does it mean that the era of multicellular organisms (which is in fact our era) "is already drawing to a close"? Do we have to pack our bags now? Joachim Scholz responds: "We can argue about the time. Today we assume that this biosphere, which looks to be dominated by metazoa and plants, has another 150 to 400 million years to go, at best. In geological terms, this is nothing. The reason being, that the atmosphere will no longer be able to considerably increase its cooling effect. After that, there will be a great era of microbes again - a fairly long swansong." On 19 December 2012, astronomy professor Dietrich Lemke from Heidelberg gave an interview with the Germany radio station "Deutschlandradio

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Kultur" about "the end of the world from an astronomical perspective". He marked the demise of our planet at about 7 billion years. In each second, the sun burns about 560 million tons of hydrogen, forming helium, according to Lemke. We could calculate that the core fuel therefore lasted about 7 billion years. But already within 6 billion years, the sun would have doubled its diameter, thus emitting a correspondingly higher amount of radiation, light and heat towards the planets - while the temperature on the sun's surface amounted to approximately 6,000 degrees. "We have to pay attention to a moment shortly before", said Lemke. Because already within 1 billion years, the sun's luminosity would have increased by as much as 10 per cent, leading to a temperature increase on Earth by 30 degrees - "a value that the people today were unlikely to survive". Unfortunately, the assumed apocalypse date (1 billion years) will probably have to be rescheduled in our direction... The "Swansong Biosphere" is part of the Rare Earth hypothesis, which claims that the formation of complex multicellular life on Earth (including intelligent beings) results from an improbable combination of special astrophysical and geological circumstances and events. Complex extraterrestrial life is therefore a highly unlikely and at best extremely seldom phenomenon. "You could almost think that the universe really wanted us", was a comment by Prof Harald Lesch, a German astrophysicist and natural philosopher in the TV broadcast "Terra X - Faszination Universum" (28 September 2014, channel: ZDF). In 2000, the professors Peter D. Ward and Donald E. Brownlee, both at the University of Washington, proclaimed their theses in their book "Rare Earth: Why Complex Life Is Uncommon in the Universe". This scientific duo is a good example of interdisciplinary cooperation: Ward is a palaeontologist and teaches biology as well as earth and space sciences. His colleague Brownlee teaches astronomy at the same university and is a principal investigator at NASA with the special field of astrobiology. The term "cosmopalaeontology" could be used to underline the importance of cosmology/astronomy for the development of our planet and of life. Here, they live exactly this vision. In its way, the approach to search for animated extraterrestrial worlds has been as wrong as the approach to search for Precambrian multicellular

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"Brave new world": Is this what the second biomat Earth will look like? Like these "redcapped domes" in Western Australia? Photo: Wikimedia Commons

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life forms. "There cannot be fossils before Ediacara, because no such fossils have been found in the respective strata, and this is why all these finds must be of inorganic material, i.e. pseudo-fossils." By now, this pessimistic circular argument has been refuted, but it resembles the optimistic false conclusion of those who support the hypothesis that "We are not alone" in the universe. Their stance has been that the seemingly unlimited universe contained billions of terrestrial planets and thus planets with (possibly intelligent) life - and so they began searching for them. If there was complex, intelligent life on Earth, they reasoned, something similar must exist also elsewhere in the vast expanses of space. No, say Ward and Brownlee, we can forget about that. Let's assume there really were a projected 11 billion planets - as reported in November 2013 by the Kepler mission - that orbited sun-like stars and some of them even in "habitable zones", it is still highly unlikely that the special situation of our solar system can be encountered in much the same way somewhere else. "Earth-like planets found" was the headline of the newspapers on 6 January 2015. The German newspaper "Süddeutsche Zeitung", for example, reported that, using the Kepler space telescope, US astronomers found two planets ("Kepler-438b" and "Kepler- 442b"), which "showed the Kepler space telescope, which "showed the most similar characteristics compared to Earth that have ever been found". "With a likelihood of 70 percent", no. 438b was a rocky planet and was moving - likewise "with a likelihood of 70 percent" - in the habitable zone of its sun - albeit a "red dwarf" with low luminosity. No. 442b, too, was orbiting a "red dwarf". It is 1,100 light years away from us - that is more than 10 quadrillion kilometres, which actually prevents closer investigation for the near future... These spatial distances are even harder to grasp than the temporal distances in the history of the Earth, which keep presenting us with ever new mysteries. Anyway, even if we assume that comparable conditions happen to produce similar developments - the suns and planets do not have the same age. If they were older, for example, they could already find themselves in the second biomat era, which still lies ahead of us... And here the hypothesis of the Swansong Biosphere comes into play. It

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surmises different developments, leaves the anthropocentric view behind and regards the search for unicellular life in the early or late stages of exoplanets as more realistic than to hope for worlds that matched our own, even if only to a small extent. Hence, is was not "pessimistic", but "reasonable to assume that microbial life will be the most abundant form of life (if it is found) in habitable extra-terrestrial environments", said the Scottish astrobiologist Jack T. O'Malley-James and his co-authors in their first swansong paper in 2012. In "Swansong biospheres II" (late 2013) they underlined this thesis. When searching for extraterrestrial life, we have only one example of a biosphere - our own. In most cases, today's focus is to find planets that resemble modern Earth. However, the history of life stretches over billions of years with completely different kinds of biospheres. Other planets did not come into being at the same time as the Earth, some are younger, some are older. We should not only compare the "young Earth" with the current situation, but also imagine the terrestrial biosphere of the future. In cooperation with astronomers, astrobiologists, biologists and palaeontologists, the pursuit of life forms on distant planets has developed into a somewhat eerie view into the future of life on our hitherto blue planet - a future that looks like the past. Although the total congruence of microbe era I and microbe era II is rather questionable, and unfortunately, no scientist will be able to verify it... In about 1 billion years, claim the authors, there will be so little carbon dioxide left in the atmosphere that plants will not be capable of maintaining the process of photosynthesis any more, which is essential for them to survive. Next come the animals, which depend on the plants. The first organisms affected will be the large mammals and the birds, then the small mammals, the fishes, the amphibians and reptiles, eventually there will be only the invertebrates left - but approximately 100 million years after the great perishing of the plants, this will be over as well. The final inhabitants of the Earth will be yet again the microbes, just as they had been during primeval times on Earth. In 1.85 billion years, the entire surface of the Earth will be uninhabitable for any kind of life form due to the ever-increasing heat radiated by the inflating sun. And finally, in 2.8 billion years, not even the hyperthermophilic archaea (especially resilient unicellular organisms) will be able to survive in their underground

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reservoirs, even if they were located several kilometres underneath the ground... There are different time determinations resulting from different earth system models - such as the "Gaia hypothesis" that states that the geosphere and the biosphere interact with each other, forming a selfregulating "superorganism", as it were. With all theories, however, the question will always remain whether there is not a whole range of unknown variables inherent to all projections of the future. Will volcanism continue to take place, even if the interior of the Earth continues to cool down? How will plate tectonics evolve - with ever less water in the oceans? Will future generations of organisms be capable of adapting to the different environment, thus existing longer than assumed? There have been numerous examples both in the past and in the present. The apocalypse has a father and a mother: the decreasing carbon dioxide level in the Earth's atmosphere and the dying sun with its deadly radiation and heat (image p. 111: Wikimedia Commons). What this means explained Dr Joachim Scholz in a note of 28 January 2015: "We must not only pay attention to temperature. We are in a CO2 crisis - but in a slightly different way than described in everyday political discussions. In the short run, there is too much CO2, but what does that mean? In geophysiological periods of time, we have far too little CO2 to fuel a photoautotrophic metabolism that generates oxygen." In 1982, the British scientists James E. Lovelock and Mike Whitfield were the first to calculate the lifetime our current biosphere. They knew that the carbon dioxide levels in the Earth's atmosphere would have to decrease in order to counteract the sun's increasing luminosity. The lowest limit for photosynthesis was "nearly" reached according to their climate model they granted the plant life merely 100 million years and, connected with that, the animal life hardly any longer. All the while, there are different types of plants: C3 plants and C4 plants, as they are called. C4 plants can endure longer than C3 plants, because they are capable of enriching CO2 in their tissue, thus enabling them to survive longer in case of shortness of water, high levels of light irradiation and extreme temperatures. Using these plants (e.g. maize, millet and sugar cane), the US researchers Ken Caldeira and James F Kasting started from a different climate model in 1992. Assuming different conditions than Lovelock and Whitfield, they calculated at least a total of 900 million years.

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A group of German scientists at the Potsdam Institute for Climate Impact Research started their own investigations in this subject in 2000 and published the results in 2004. Prof Siegfried Franck, Dr Werner von Bloh and Christine Bounama approached the subject in a different way and considered especially geodynamic processes and their effects on weathering, tectonics, volcanism and CO2 production, among others, as well as a more detailed analysis of the global carbon cycle and the carbon reservoirs. All things considered, their calculations predicted the end of the entire biota on the Earth's surface between 800 and 900 million years. In their premise, the end of photosynthesis is not expected before 1.6 billion years, but they calculated a considerably higher surface temperature, making heat strike earlier than the lack of CO2. The researchers from Potsdam grant the eukaryotes 1.3 billion years, the prokaryotes about 300 million years more. What about Earth itself? "In the course of its transformation into a red giant, the sun will grow to such an extent that its radius will reach the value of the current terrestrial orbit in about 7.8 billion years." There is probably no verified "truth". The explanation the astrophysicist Professor Arnold Benz gave in his book "Die Zukunft des Universums" ("The future of the Universe", 3rd edition 2010) is the following: "Natural sciences grasp reality by making measurements and observations. Observations alone, however, cannot explain reality alone, as the facts often allow for several explanations." At any rate: The dating - whichever you may prefer - is almost exact. After all, a couple of hundreds of million years hardly matter in the context of the history of the Earth. Dr Joachim Scholz at the Senckenberg Research Institute is unperturbed about the time of microbes ahead before the definite end of the world. He said, Earth "does not need humans, animals or plants. Bacteria, archaea and viruses as "predators" are perfectly sufficient to keep the planetary metabolism going for a little longer". Maybe we will not even get that far. Maybe the Earth will be destroyed before that. One day, a comet might reach us with more precision than that of 1989. "Three days before Easter in the year of 1989, the world almost ended. Nobody noticed. On Maundy Thursday, the unsuspecting Germans complained about growing petrol prices... On that 23 March, nobody saw the mountain-sized chunk of rock that raced towards the

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Earth in a nosedive. Only a few tens of thousands of kilometres beyond the moon's orbit, so to speak in the Earth's front garden, the 800-meterlong lumpy colossus barely missed. Had this celestial body with its speed of 70,000 km/h been just a couple of hours later, it would have collided with the terrestrial globe... 'It would have eradicated everything', said Don Yeomans, an American expert on comets." (From the German magazine "Der Spiegel" 28/1994). Or maybe we will manage to destroy it all by ourselves. Walter Hähnel, a merited preparator from Hamburg, who is the namesake for a medal of honour of the Association of German Preparators, finds radical words in his booklet "Erdgeschichten" ("Earth stories", 2014): "Man's behaviour towards nature is reckless... There is no prospect that this behaviour will change... You get the impression that man is an aberration of evolution... Regrettably, they will finally eradicate themselves." At any rate, we are not even needed, see above. At best, we are useful to take the time between two biomat eras to write some papers on the presumable past and the possible future of life on Earth. After all, this is really something, microbes cannot.

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Acknowledgements Many thanks to Prof Abderrazak El Albani, University of Poitiers, France. His discovery in Gabun was the reason for this book and my new reflections on the Precambrian. Abderrazak allowed me to use his pictures of the Gabonionta and we had a very intensive and amicable correspondence, which had influenced the text of my book in a very essential way. Furthermore, I would like to give sincere thanks to Prof Gero Hillmer, University of Hamburg/Germany, who has supported this project ab initio. Without his help this book would not exist. And without Prof Roland Vinx, Elmshorn/Germany, I would have never heard anything about Västervik’s very interesting rocks containing probably biogenic structures. He gave me the one item he had picked up in Sweden and sent me many pictures from Västervik and Mångsboderna. Good discussions and some scientists’ interesting statements are the reason of the book’s highly topical content. I would like to mention: Prof Stefan Bengtson, v Stockholm/Sweden, Dr Zdenek Gába, Šumperk/Czech Republic, Dr Gisela Gerdes, Wilhelmshaven/Germany, Dr Sören Jensen, Badajoz/Spain, Dr Joachim Scholz, Frankfurt am Main/Germany, Dr Wolfgang Zessin, Jasnitz/Germany, and Prof Maoyan Zhu, Nanjing/China. I am thankful for the good cooperation with Claus Friis, Kottenheim/Germany, Tom Kapitany, Victoria/Australia, Heiko Koch, Hemse/Sweden, Dr Stefan Meng, Greifswald/Germany, my friend David Schmälzle, Berlin/Germany, Dr Gianpaolo Di Silvestro, Trieste/Italy, and my son Frank Troppenz, computer expert in Hamburg/Germany. Also: Space Telescope Science Institute (STScI) at Baltimore/Maryland, USA, De Nationale Geologiske Undersøgelser for Danmark og Grønland (GEUS) at Københavns Universitet, Institut für Chemie und Biologie des Meeres, Universität Oldenburg, and Berliner Museum für Naturkunde/Leibniz-Institut für Evolutions- und Biodiversitätsforschung.

In particular, I would like to say „thank you“ with all my heart to my wife Regina Troppenz (1951-2015), who supported me in any possible way: drawing fossils, constructing tables, taking photographs, assisting me with organizational and technical solutions and - having a lot of patience with me. We were an excellent team!

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Some feedback from scientists: Prof Maoyan Zhu, Chinese Academy of Sciences, Nanjing Institute of Geology and Palaeontology: "Interesting book! Nice story about the fossils from Gabon with additional information. In the community, very few believe these structures are individual organisms. In contrast, our Gaoyuzhuang fossils preserved as carbonaceous imprints exhibit regular morphology as shown by morphometric data. Anyway, the book will stimulate new thinking of evolution in Precambrian from both science and public society. I would say the 'boring billion' is not that boring, more new discoveries and information are waiting for us. It is necessary to rewrite the textbook about early evolution of eukaryotes." Henrik Hójmark Thomsen, Geological Survey of Denmark and Greenland (GEUS), Kóbenhavn/Danmark: "Thank you very much for your book. Impressive work. Congratulations!" Prof Subir Sarkar, Jadavpur University, Department of Geological Sciences, Calcutta/India: "I had a chance to see your book at a glance. I love it. However I shall go through once again and send my comment after return from my fieldwork." Prof Roland Vinx, geologist, University of Hamburg, Germany (German edition): “I like your unconventional and ‘irreverent’ approach. I am also impressed by your profound background knowledge... The book broadens our horizon with really new content. For me it partly belongs to the same category as the discovery of plate tectonics and Wegener’s continental drift. Something like this is generally more valu-able than the umpteenth repetition of well-known information, even if some statements might not prove tenable in the end.” (English edition:) "Thank you so much for 'The New Precambrian'. When flicking through the pages for the first time, I was already thrilled. The book apparently causes heavy motion in the history of the Earth, and that in a very clear and perfect form.” Dr Denis Leypold, curator, Mineralogical Museum/School and Observatory of Earth Sciences (EOST) at the University of Strasbourg, France: “Mr. Masson, director of EOST, kindly made me aware of your work about the Precambrian. You are presenting an inspiring analysis about the early stages of life on Earth, especially about Gabon.”

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Prof Gero Hillmer, palaeontologist, University of Hamburg, Germany (German edition): “I would like to congratulate you to accomplishing your work with such great enthusiasm. After all, you are shaking the ‘fundamental’ findings regarding the history of life. I can strongly recommend this book to all earth scientists and biologists.” (English edition): “I was very happy about your book present ‘The New Precambrian’. When somebody works at a fundamental topic with your enthusiasm and determination, they will succeed in presenting such a book, a work that will be - or is already - acknowledged nationally and internationally. I sincerely congratulate you!” Dr Gianpaolo Di Silvestro, palaeontologist, Trieste/Italy: "I am reading your book...it's fantastic!" Dr Gisela Gerdes, microbiologist, Wilhelmshaven, Germany (formerly Senckenberg Institute): “Congratulations to your book. I am convinced that it will contribute interestingly and variedly and give a new impetus to the concept of the Precambrian and the discussions on the biological and ecological possibilities of that time.” v

Dr Zdenek Gába, geologist, Šumperk, Czech Republic: “The text provides relatively solid information on many new discoveries about life in the Precambrian - both for the broad public and for experts from geological and biological scientific fields.” Emma Hammarlund, Syddansk Universitet, Nordic Center for Earth Evolution (NordCEE), Departmen of Biology: "Congratulations! Lots of work, indeed." Prof K.-D. Meyer, geologist, Technical University of Braunschweig: “I would like to say thank you very much for your interesting new book. I hope it will spread very well - it was a really inspiring read!” Prof Ulrich Heimhofer, geologist, University of Hanover: “Congratulations to the publication of your book. I think it contains many new and hitherto little noticed facts for the Precambrian community. I find your great commitment for this topic with all its questions highly remarkable.”

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Book review by Dr Gisela Gerdes, microbiologist, Wilhelmshaven, Germany (formerly Senckenberg Institute) The first (German) book by Uwe-M. Troppenz concentrates on fossil records mainly from the Montana biota, whose producers lived in Precambrian marine sediments between 1,800 and 800 million years ago, that is long before the Ediacaran (635 to 542 million years ago). This book now (German and Englisch edition) expands the timeline of multicellular biota into the Paleoproterozoic, adding the Franceville biota discovered in the Franceville rock group in Gabon by Abderrazak El Albani, the palaeontologist who also described these fossils. In the fossil-rich clay shale, the scientists found evidence of lively multicellular organisms that existed as early as 2.1 billion years ago, thus being much older than Montana and Ediacara. In the Franceville deposits, macrofossils with sizes between 2 and 12 cm are spectacular finds. They were named Gabonionta. Imaging techniques using three-dimensional reconstruction point towards internal organisation, which could have been connected with coordinated growth. The structures suggest a biota in the Paleoproterozoic that was no less spectacular than that of the “Cambrian revolution”, albeit with other life forms. This idea has contradicted traditional viewpoints and raised controversy, which is described in the present book. The author’s courage to use these new discoveries and contribute to drawing a new picture of the Precambrian, is thus all the more impressive. The notion that faunistic life was prospering in the more than 2-billionyear-old Franceville rock renders certain postulates not conclusive any more. The “boring billion” is one of these postulates mentioned in the book. It is a period that lasted up to about 1.4 billion years ago, and was named after a hitherto observed lack of animal traces and a predominance of the so-called “biomats” in marine sediments. The author is right in pointing out that merely the discovery of the Franceville structures provides plenty of reason to warn against these hasty evaluations. After all, similar surprises may await in other Precambrian rock, too. Another important point of the book is the notion that the interval-like changes of geospheres did not take place continuously and progressively, but rather in episodes and were triggered by impacts, as more recent findings suggest. The author mentions major asteroid impacts, which early animate worlds were repeatedly subjected to, as well as their con-

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sequences, for example the reduced availability of free oxygen (see for example the “Great Oxygen Event” about 2.5 to 2.3 billion years ago, that is somewhat older than the Franceville biota!). In this context, another interesting point is the timely position of the Sudbury impact at the border between the Franceville biota and the Montana biota (see chronology table on page 73). Here again, the reduction of free oxygen is pointed to. These environmental changes, together with changes caused by glaciations, make us think of “catastrophism”. The author, however, distances himself from this concept by using the metaphor “creative catastrophes”. In between the cyclicality of the three discovered biotas - Franceville as the oldest known so far, - Montana in the middle of the chronological order and Ediacara as the youngest in the Precambrian so far - the author suspects transitions, in which the animate world did not become extinct in its entirety, but in which new environments with new ecological niches could develop, which in turn gave a boost to new populations. After all, similar transitions are suspected when we look at the more recent history of the Earth, for example at the borders between the Permian and the Triassic or between the Cretaceous and the Tertiary. Much fossil evidence will still be needed to underpin the dialectical sequence of catastrophes and developments of new symbiotic communities, graphically described in the present book using the metaphor “creative catastrophes”. But still, the fact that this evidence is often missing today, does not automatically mean that it has never been there. In the third chapter “From the war between the creatures to the apocalypse”, a view into the Phanerozoic is given. Here, topics of discussion are the overlap between the Ediacara biota and the hard-shelled biota at the border to the Cambrian, as well as the substantial changes in the animal world visible in the Cambrian fossil record, whose functional patterns reminded us already 550 to 540 million years ago of marine species living today. The spectacular finds of the Burgess Shale are among the examples mentioned. In connection with the discovery of the Cambrian softfossil biota in Chengjiang, China, the author emphasises once more, how incidental finds can often draw a surprising new picture of the history of life. In closing, almost precise dating of the “end of the world” is referred to, which fits our colleague Joachim Scholz’s train of thoughts with respect to the “Swansong Biosphere”. To conclude, I would like to make a comment on my own account: For me, the book is a real treasure trove, and it helps to remain open for new thoughts and interpretations about the history of life on our planet in its childhood days. It permits new ideas and does not restrict them to dog-

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matic views. The Franceville biota, the Montana biota, and finally the Ediacara biota possibly present on different timelines similar intervals, in which lively biological activity of benthic (or maybe also planktic??) biocoenoses in a flat marine and ecologically moderate environment took place („bustling billions”). They do not convey the image of a bleak landscape, void of any biota and dominated by mat-forming prokaryotes („boring billions”). I have deliberately widely ignored comments on the palaeozoology of the invertebrates mentioned in the book, as this is not my métier. My focus lies on the biosedimentology and biogeology of microbial mats and stromatolites, a topic that resonates in different facets in this book. The question when and how invertebrate fauna hit on microbial mats for the first time is conventionally answered with a timeline of about 1,000 million years before our time, that means close to the Ediacaran. With the further development and spreading of multicellular animals close to the Precambrian/Cambrian border, the mats are said to have been forced out more and more from ecologically moderate habitats. Up to today, they are said to have succeeded in finding refuge under ecologically more extreme circumstances and been able to form laminated growth structures without being destroyed by the digging or grazing activities of marine animals. I find this thesis to apodictic, all the more because there is a large number of fossil and recent examples that microbial mats and benthic biota can indeed coexist under certain circumstances and have done so (the one does not generally exclude the other). The constructive properties of biofilms and biomats interacting with benthic biotas is by contrast a rather interesting point, because by coating bedding planes, they increase the potential of preserving the traces contained within. Even the “Wellenwurm”, a structure found on a wave ridge and discussed in the present book, may have originated in or close to a surface that had been stabilised by biofilm mats. The most important thing is unambiguous evidence in the fossil record, which can help develop an image of the evolving Earth during the billions of years it has existed as an animate body. The fossil record in the Precambrian sediment of Franceville provides facts that make it quite difficult to return to the notion of a linear succession from the emptiness of the Paleoproterozoic („boring billion”).

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Chengjiang, China - The Flowering of Early Animal Life“ - 233 pp., many pictures and tables, Malden. ZHU, S., ZHU, M., KNOLL, A. H., YIN, Z., ZHAO, F., SUN, S., QU, Y., SHI, M. & LIU, H., 2016: „Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China“ - Nature Commun. 7:11500 doi: 10.1038/ncomms11500, 7 figs., London. ZWENGER, W., 2010: „Der Trebuser Sandstein - ein Massenvorkommen jotnischer Sandsteingeschiebe“ - Brandenburgische Geowissenschaftliche Beiträge 17 (1/2): 77-90, 10 figs., 1 table, Cottbus.

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224 pp., many b/w-figs. in the text, 8 coloured tables, Paris. The title gives an idea of the Franceville biota.

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TROPPENZ, U.-M., 2014: „Wohin die Spuren führen“ (vol. 1) 172 pp., 136 figs. and 1 timetable, Parchim.

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TROPPENZ, U.-M. & SCHMAELZLE, D., 2015: „Wohin die Spuren führen“ (vol. 2) 192 pp., 162 figs. and 2 timetables, Parchim.

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Crystal World has a focus on deep time geology with a large range of stromatolites, microbialites, acastian gneiss and zircon. Crystal World is the largest retail and wholesale supplier of crystals, fossils, meteorites, lapidary, gems, minerals and metaphysical supplies in Australia. Tom Kapitany, B.Sc. Geology/Botany Managing Director 13 Olive Rd. Devon Meadows 3977 Victoria Australia Crystal World & Prehistoric Journeys Australian Mineral Mines Pty. Ltd. National Dinosaur Museum Canberra Collectors Corner, Garden World www.Crystal-World.com www.CollectorsCorner.com.au www.NationalDinosaurMuseum.com.au

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