Transient presence of a teiid lizard in the European Eocene suggests transatlantic dispersal and rapid extinction

Several teiid specimens (frontal, vertebra, maxillae) are described from the late Eocene of Europe (MP17, Phosphorites du Quercy). The results of phylogenetic analyses confirm that these European Eocene fossils belong to teiid lizards and more specifically to the subfamily Tupinambinae. So far, the Paleogene record of teiids is limited to South America and no occurrence of crown teiids is known in Europe. This disjunct distribution of teiids during the Eocene suggests transatlantic dispersal and this possibility is discussed. The presence of teiids in the European fossil record is brief (limited to standard level MP17). The circumstances that prevented the persistence of an invading clade in Europe are examined. Ecological (e.g. biotic interactions) and/or demographic (Allee effect) processes may have been involved.Fil: Louis, Augé Marc. Muséum National d'Histoire Naturelle; FranciaFil: Brizuela, Santiago. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Les lézards fossiles de l'Oligocène et du Miocène de Mongolie Centrale

Des faunes de lézards du début de l’Oligocène, du début et de la fin du Miocène de Mongolie sont décrites. Elles comptent des membres de plusieurs groupes, Agamidae, Lacertidae and Anguidae (Glyptosaurinae). La présence de l’agamidé Pseudotinosaurus Alifanov, 1991 dans des gisements du Rupélien ancien et récent montre que ce genre était présent en Mongolie depuis l’Éocène jusqu’à l’Oligocène, ce qui vaut aussi pour les Glyptosaurinae, dont on a trouvé les ostéodermes dans le gisement de l’Oligocène inférieur de Hsanda Gol. Ceci suggère que la transition Éocène/Oligocène a eu un effet moins marqué sur les faunes de lézards de Mongolie que sur les faunes européennes. Les Lacertidae trouvés dans les gisements de Taatsiin Gol, Hsanda Gol et Tatal Gol représentent les premiers membres de la famille connus en Asie, peut-être issus d’une dispersion permise par la fermeture du détroit de Turgai qui a séparé l’Europe de l’Asie durant la première partie du Paléogène. Plusieurs fossiles apparaissent très proches de l’espèce Lacerta s.l. filholi Augé, 1988, le lacertidé le plus commun en Europe durant l’Oligocène. Si cette interprétation est correcte, elle indique une large répartition de ce lézard, de l’Asie à l’Europe durant l’Oligocène. Dans la localité de Olon Ovoony Khurem (Miocène ancien) deux taxons sont reconnus, un membre des Lacertidae et un scincoïde montrant une dentition très spécialisée. Les Lacertidae dominent largement l’assemblage de lézards du Miocène récent de Mongolie. Le matériel du gisement de Builstyn Khudag diffère des Lacertidae du Miocène inférieur, avec la première apparition des Erimiadinae en Mongolie.Lizard material from the early Oligocene and early and late Miocene of the Valley of Lakes, Central Mongolia is described. Besides the Oligocene fossorial squamate published elsewere, the material can be allocated to several major clades: Agamidae, Lacertidae and Anguidae (Glyptosaurinae). The presence of Pseudotinosaurus Alifanov, 1991 in early and late Rupelian localities shows that this taxon has a continuous history in this area from the Eocene to the Oligocene. The same is true for the clade Glyptosaurinae, represented by isolated osteoderms in the early Oligocene locality Hsanda Gol. This might suggest that the Eocene-Oligocene transition did not have such a strong or rapid impact in East Asia, in contrast to the Grande Coupure in Europe, at least among some lizard clades. The early Oligocene (early Rupelian) lacertids from Taatsiin Gol, Hsanda Gol and Tatal Gol represent one of the oldest evidences of Asiatic dispersal of this clade. It might reflect the dispersal pathways after closure of the Turgai Strait between Europe and Asia. Some of the material closely resembles the common European Oligocene taxon Lacerta s.l. filholi Augé, 1988. In the early Miocene locality Olon Ovoony Khurem, two clades can be recognized – Lacertidae and a scincoid with a specialized dentition (family indeterminate). The clade Lacertidae forms a dominant component of the late Miocene lizard fossils in Mongolia. The material from the locality Builstyn Khudag shows differences compared to the early Miocene lacertids and represents the oldest evidence of the tribe Eremiadini in this area.</p

Évolution des lézards du Paléogène en Europe

Parmi les vertébrés terrestres, les lézards ont une place à part. Leur remarquable succès évolutif est attesté par l’existence de petites espèces inoffensives, de prédateurs venimeux ou de varans géants. En dépit de ce succès évolutif et de cette diversité, peu d’études leurs avaient été consacrés jusqu’à présent. Cette lacune est en passe d’être comblée grâce à la découverte durant les dernières décennies d’un nombre considérable de fossiles nouveaux. La systématique et la biogéographie des lézards européens sont ainsi étudiées durant la première moitié de l’ère Tertiaire, notamment avec la description de formes nouvelles. Les lézards sont maintenant un des groupes dont la stratigraphie est connue à cette époque critique pour la constitution de la biodiversité actuelle. L’auteur a effectué sa thèse de doctorat dans le cadre du Laboratoire de Paléontologie de l’Université Paris VI puis au Muséum national d’Histoire naturelle. Il étudie la biodiversité des lézards fossiles.</p

Phylogenetic value of jaw elements of lacertid lizards (Squamata: Lacertoidea): a case study with Oligocene material from France

Several extinct species are known from the family Lacertidae, but due to poor preservation, many of them are based on single bones. Here, we compare phylogenetic signals of disarticulated premaxillae, maxillae and dentaries of lacertids from four French Oligocene localities (Coderet, La Colombière, Roqueprune 2, Mas de Got B). We identified five morphotypes among the premaxillae, six among the maxillae, and ten among the dentaries. These morphotypes were scored as individual taxa per locality into three separate character matrices with the same 246 characters, one matrix for each jaw element. Subsequently, the phylogenetic position of the morphotypes was tested using maximum parsimony. The consensus trees with the dentaries and the maxillae found a large polytomy including all taxa except the outgroup taxon Gekko gecko. The consensus tree with the premaxillae showed a considerably more resolved topology but found all morphotype taxa outside Lacertidae. In a second step, we compared the constitution of our three datasets and the morphotype taxa. Our results suggest that a combination of convergent characters and missing data led to the outgroup position of the premaxilla morphotype taxa. The poor resolution of the maxillae strict consensus is likely a consequence of their fragmentary preservation. For the dentaries, a high amount of missing data due to the high number of morphotype taxa most likely caused the poor tree resolution. Indeed, tests with fewer morphotypes found tree resolutions comparable to the premaxilla data. When linking the morphotypes, five possible lacertid "species" were found. Comparison with already known French Oligocene lacertid species points to a slightly higher species richness of Lacertidae at that time than known before. Reliable species classification based on phylogeny only seems possible when combining the jaw elements or in association with other cranial and postcranial material, putting some doubt on species identifications based on single bones

A complete mandible of a new amphisbaenian reptile (Squamata, Amphisbaenia) from the late middle eocene (Bartonian, Mp 16) of France

<div><p>ABSTRACT</p><p>A new genus of amphisbaenian reptile, <i>Cuvieribaena carlgansi</i>, is decribed from the late middle Eocene of France. This material from the locality of Le Bretou (Phosphorites du Quercy) is an almost completely preserved mandible. The dentary bears six teeth, with the anterior-most one the largest. The anterior teeth are blunt and enlarged (‘amblyodont’), and their size and amblyodonty decrease posteriorly. The presence of well-developed amblyodont teeth indicates a durophagous diet. Durophagy has already been recognized in some amphisbaenids, and their high skull, short jaws, and robust tooth morphology predispose them to this durophagous lifestyle. Several other amphisbaenid specimens have also been recovered from Le Bretou, mainly trunk vertebrae and two incomplete dentaries. This material and the complete mandible show unambiguous morphological features tying them to Blanidae. <i>Cuvieribaena</i> is the earliest secure record of blanid lizards in the fossil record, confirmed by phylogenetic analysis.</p><p>http://zoobank.org/urn:lsid:zoobank.org:pub:17454922-A121-447F-9D01-E4992ADB7D60</p><p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/UJVP" target="_blank">www.tandfonline.com/UJVP</a></p></div