New records of frogs (Anura, Lissamphibia) from the Late Cretaceous Bauru Group of Brazil and its paleobiogeographic implications

Abstract

South America hosts one of the largest diversities of living frogs in the world, but our knowledge of the group during the Mesozoic Era is still limited. The Upper Cretaceous Bauru Group, in the south-central region of Brazil, has yielded a variety of vertebrate groups. Frog records are rare and restricted to a few well-preserved skeletons and fragmentary material. Nevertheless, they have offered important clues about the early diversification and distribution of frogs, especially among the speciose clade Neobatrachia. Here, we report new records of frogs from the Adamantina and Serra da Galga formations. The described specimens expand the geographical range of frogs in the Bauru Group and corroborate the hypothesis of a widespread distribution of neobatrachians in Gondwana landmasses by the Late Cretaceous. The discovery of the first putative Calyptocephalella-like form from a northern region in South America sheds light on the proposed biogeographic provincialism of frog faunas in South America by the Late Cretaceous.