A new helmeted frog (Anura: Calyptocephalellidae) from an Eocene subtropical lake in northwestern Patagonia, Argentina

ABSTRACT

Eocene caldera-lake deposits from Río Pichileufú have yielded anuran remains in association with a taxonomically diverse flora. The floral evidence suggests that these anurans lived under climatic conditions similar to those of extant subtropical rainforests. One of the anurans is a helmeted neobatrachian, which is represented by articulated remains and represents a new species that can be assigned to the extant genus Calyptocephalella on the basis of both cranial and postcranial traits. Calyptocephalella pichileufensis, gen. et sp. nov., indicates that, despite the relatively conservative skeletal anatomy of the genus, Calyptocephalella has not always been associated with the temperate austral forests that it inhabits today. The new species also provides evidence of a biotic link with Australia, which has been proposed on the basis of other faunal and floral records, as well as on the paleogeographic history of Patagonia during the mid-Cretaceous–Eocene interval. We also discuss the significance of neobatrachian cranial features that might reflect hyperossification.

ACKNOWLEDGMENTS

We thank the members of the ‘Asociación Paleontológica Bariloche’ for their unending enthusiastic fieldwork, which led to the discovery of the material studied herein, and Alejandro Kramarz (MACN) and Eduardo Ruigómez (MPEF) for access to collections under their care. We also acknowledge the contribution of Santiago Reuil, who skillfully prepared the latex molds. This work has been supported by grant PICT 223/2006 to AMB from the ‘Agencia Nacional para la Investigación Científica de Argentina.’

Handling editor: Sean Modesto