A teiid lizard from the european Eocene suggests trans-Atlantic dispersal

AUGÉ, M. L.; BRIZUELA, S.

Mendoza

Congreso; 4th International Palaeontological Congress; 2014

CONICET

The earliest records of teiids are from the early Paleogene of Brazil and Argentina. As far as we know, outside South America, teiid lizards have only been reported from the Neogene of North America. Here, we report the presence of teiids in the European Eocene. A frontal and several vertebrae (BFI 1877) from the late Eocene of Phosphorites du Quercy, France, are nearly identical to those of extant teiids. Several lizard remains from the Late Cretaceous have already been referred to Teiidae s.l. in Europe. None of these taxa persisted into the European Paleogene. Recent phylogenetic investigations showed that the purported Cretaceous teiids were actually distantly related to that family. The systematic position of these lizards is in a state of flux and could continue to shift with new analyses. Hence, Teiidae (sensu stricto) have no known Paleogene record in Europe. Therefore, independent evolution of the European forms is unlikely, for lack of suitablelocal ancestors. The disjunct distribution of teiids during the Eocene (South America and Europe) deserves some explanations, given the context of splendid isolation that characterizes South America in the Cenozoic. The probable origin of teiids is in the South American Late Cretaceous-Paleocene.Therefore, vicariance events explaining the distribution of teiid lizards are untenable because the opening of the South Atlantic Ocean dates back to the Early Cretaceous. Transatlantic dispersal must be favored. Two main hypotheses may be proposed: 1 - Dispersal of Teiidae to Europe mayhave occurred via a northern route (North America). 2 - Dispersal via a southern route, where Africa may have played the role of a stopover. Either hypothesis has its shortcomings: absence of fossil teiids in the Paleogene of Africa and North America. We favored the southern route as dispersal between Africa and South America as it is well documented for rodents and primates (Eocene - Oligocene). Land vertebrates with purported South American affities have also been found in the European Eocene. Admittdly, the direction of major trans-Atlantic dispersal events between Africa and South America is westwards. However, some authors have already suggestedbidirectional and even eastwards interchange during the early Tertiary