Systematic status of the mid-Tertiary neobatrachian frog Calyptocephalella canqueli from Patagonia (Argentina), with comments on the evolution of the genush

Abstract

The neobatrachian genus Calyptocephalella Strand, closely allied to the Australian myobatrachoids in recent molecular analyses, is now restricted to lowland water bodies of the Austral forests of Chile but had a broader distribution according to paleontological data. New, well-preserved material from the early Miocene locality Estancia Baibián, Chubut Province, Argentina, is described herein and assigned to Calyptocephalella canqueli Schaeffer, a species erected on the basis of Deseadan (late Oligocene) specimens, but subsequently synonymized with the only living species, Calyptocephalella gayi Duméril and Bibron. Detailed comparisons suggest that Calyptocephalella canqueli is a valid taxon representing frogs that inhabited Patagonia east of the Andes in the late Oligocene-early Miocene; a revised diagnosis is provided for the species. Palynological evidence coupled with the presence of C. canqueli document that humid forests, dominated by the angiosperm Nothofagus, persisted near the Atlantic coast in the Miocene. Disappearance of suitable habitats owing to a marked drying trend that started in the middle Miocene may have been responsible for the demise of this anuran genus east of the Andes.