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Auge M.L.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Palaeobiodiversity and Palaeoenvironments | Year: 2012

In this paper, part of the amphisbaenian fossil record from the european Eocene is revised. There is no evidence for the existence of amphisbaenian lizards in Europe or on other continents during the Late Cretaceous. Crown amphisbaenians were present in Europe in the early Paleocene and throughout the Paleogene, with the notable exception of the middle Eocene. In particular, they were not found at Messel. European fossil taxa previously assigned to the amphisbaenians are briefly reviewed, and a description of some representative specimens from the Eocene fossil record is presented: dentary and vertebrae from Mutigny (early Eocene, France) are referred to the North American genus Anniealexandria; fossils from the late Eocene of the Phosphorites du Quercy (France) are attributed to Blanidae, and they are the earliest secure occurrence of Blanidae in the fossil record; and dentaries and maxillae from Grisolles (middle-late Eocene, Paris Basin, France) are referred to a new species, Louisamphisbaena ferox. Global distribution of fossil amphisbaenians in the Eocene reveals at least one episode of dispersal between North America and Europe during the early Eocene. Finally, some explanations are suggested for the absence of crown amphisbaenians at Messel and in the European middle Eocene. © Senckenberg Gesellschaft für Naturforschung and Springer 2012. Source


Rage J.-C.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Palaeobiodiversity and Palaeoenvironments | Year: 2012

The fauna of amphibians and squamates during the Eocene in western Europe resulted initially from the addition of an old, ante-Eocene fauna, and of a new fauna that arrived as a big wave of dispersals at the beginning of the Eocene (MP 7). These dispersals were likely favoured by the tropical climate. The fauna, as a whole, included taxa with Laurasian affinities, some of which indicate relationships with North America. However, some taxa showed South American affinities. The subsequent fauna (MP 8+9 and MP 10) developed from that of MP 7 and was not affected by peculiar events. The fauna of the MP 11-MP 15 interval (middle Eocene) is poorly known. The last interval (MP 16-MP 19+20, latest middle and late Eocene) is characterised by a rich and diverse fauna, despite temperatures lower than that of the early Eocene. This fauna perhaps partly originated during the preceding interval. Richness and diversity resulted from dispersals and local radiations; autochthonous forms were apparently rather frequent. This fauna still included taxa with South and North American affinities. At the end of the Eocene, there occurred a prominent extinction event, the 'Grande Coupure'. Most taxa were eliminated, at least in western Europe; they survived elsewhere, permitting subsequent repopulation. The Grande Coupure was a pivotal event. Before it, the faunas were indicative of warm climates and included American components; after the Grande Coupure, the faunas that progressively repopulated Europe were indicative of less warm climates and no longer included American forms. © Senckenberg Gesellschaft für Naturforschung and Springer 2012. Source


Janvier P.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Current Biology | Year: 2011

In contrast to lampreys and jawed vertebrates, hagfishes were thought to lack vertebrae. Now, long overlooked vertebral rudiments have been analysed in hagfish, suggesting that vertebrae existed in the last common ancestor of all vertebrates. © 2011 Elsevier Ltd. All rights reserved. Source


Tassy P.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Journal of Zoological Systematics and Evolutionary Research | Year: 2011

Phylogenetic trees published before Darwin's On the Origin of Species are scarce. Lamarck (1809) and Barbançois (1816; J Phys Chim Hist Nat Arts 82, 444) are the first and only trees devoted to illustrating the genealogical connections between organisms of different species and different higher taxa. In the late 18th and early 19th centuries, most of the trees depicted in papers dealing with natural history were classifications; classifications in the shape of trees, but classifications nonetheless. Those published by Bronn (1858) are a good example. After Darwin, phylogenetic trees incorporating the time dimension flourished. In the first half of the 20th century, the Modern Synthesis failed to renew and rejuvenate the intuitive construction of trees. It wasn't until the appearance of Hennig's phylogenetic systematics that the real nature of the connection between phylogeny and the pre-Darwinian concept of homology was made clear. © 2010 Blackwell Verlag GmbH. Source


Vincent P.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Journal of Vertebrate Paleontology | Year: 2011

The holotype and only known specimen of the pliosauroid plesiosaur Hauffiosaurus zanoni O'Keefe is a substantially complete and almost entirely articulated skeleton from the Toarcian Posidonien-Schiefer (Upper Lias, Lower Jurassic) of Holzmaden (Baden-Württemberg), Germany. The original description of this specimen was preliminary, and this paper presents a detailed re-description and revised diagnosis of the specimen, thus adding significant, new anatomical information. Characters such as the presence of a lateral palatal fenestra and the absence of a contact between the internal nares and the palatines are examples of phylogenetically relevant characters. The specimen presents a novel and unique combination of characters and body proportions, including a long ilium, short ischia, and propodials longer than any of their associated girdle bones, that separate it from all other pliosauroid taxa. Its elongate snout and long, slender teeth imply that this species most likely had a prey preference of fish. © 2011 by the Society of Vertebrate Paleontology. Source

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