First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia

MÖRS, THOMAS; REGUERO, MARCELO; VASILYAN, DAVIT

Scientific Reports

Nature

Año: 2020 vol. 10

Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documentedpreviously from Antarctica, in contrast to all other continents. Here we report a fossil ilium andan ornamented skull bone that can be attributed to the Recent, South American, anuran familyCalyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica.The two bone fragments were recovered in Eocene, approximately 40 million years old, sedimentson Seymour Island, Antarctic Peninsula. The record of hyperossified calyptocephalellid frogs outsideSouth America supports Gondwanan cosmopolitanism of the anuran clade Australobatrachia. Ourresults demonstrate that Eocene freshwater ecosystems in Antarctica provided habitats favourable forectothermic vertebrates (with mean annual precipitation ≥900 mm, coldest month mean temperature≥3.75 °C, and warmest month mean temperature ≥13.79 °C), at a time when there were at leastephemeral ice sheets existing on the highlands within the interior of the continent.