The taxonomic placement of the Miocene Patagonian frog Wawelia gerholdi (Amphibia: Anura)

Abstract

The Miocene frog Wawelia gerholdi, from northern Patagonia, has previously been attributed to Ceratophryidae, the clade of the extant South American horned frogs, making it one of the older records known for this group. However, the only known specimen has juvenile attributes and a strong similarity with the australobatrachian Calyptocephalella. We re-examine the morphology of Wawelia gerholdi and provide additional anatomical information and comparisons with juvenile individuals of Ceratophryidae and Calyptocephalella gayi, the only extant species of the genus Calyptocephalella. We subsequently reject a close relationship between Wawelia gerholdi and Ceratophryidae. Furthermore, the holotype is indistinguishable from juveniles of C. gayi and manifests a similar character state combination that seems unique among anurans. We therefore consider Wawelia to be a junior synonym of Calyptocephalella. The problematic taxonomy of Calyptocephalella fossils, together with its untested monophyly, also prompts us to provisionally preserve the extinct species pending a comprehensive revision of all available remains.