A new old Budgett frog: An articulated skeleton of an Early Pliocene Lepidobatrachus (Anura, Ceratophryidae) from western Argentina

Abstract

The South American horned frogs or ‘escuerzos’ (Ceratophryidae) are among the best-known neobatrachians and comprise the genera Chacophrys, Ceratophrys, and Lepidobatrachus. Their relatively rich fossil record, which dates back to the Late Miocene and is largely concentrated in the Argentinean Pampas, consists mostly of variably complete cranial remains and comparatively few, mainly isolated, postcranial bones of Ceratophrys, whereas only three specimens of Lepidobatrachus are known. Here we describe two extra-Pampean ceratophryid records from the Upper Miocene–Lower Pliocene of Huayquerías del Este, Mendoza Province, Argentina, including Lepidobatrachus dibumartinez sp. nov. based on a well-preserved articulated skeleton. The new species is part of the stem of Lepidobatrachus and is diagnosed on the basis of several cranial and postcranial traits, including a large kite-shaped dorsal dermal shield. The new taxon sheds light on the evolution of a dorsal shield in the group, as well as on their paleobiogeographic history, adding support to the hypothesis of a broader ancestral distribution of Lepidobatrachus, whose diversification might have been triggered by the Late Miocene marine introgression of the Paranaense Sea. Also, it indicates that the prevalent climatic conditions during the Early Pliocene in western Argentina were much warmer and less dry than today. Finally, we discuss the potential value of the new records in calibrating the time-tree of Ceratophryidae. http://zoobank.org/urn:lsid:zoobank.org:pub:2DFB3B68-8C30-4252-A3DC-BF1F69F5AB6A.