Fossil Frogs of the Late Clarendonian (Late Miocene) Pratt Slide Local Fauna of Nebraska, with the Description of a New Genus

Abstract

Abstract The Pratt Slide fossil site of Brown County, Nebraska has yielded a diverse frog fauna from the late Clarendonian North American Land Mammal Age (late Miocene; ca. 10.5–9.5 Ma). The fauna includes the extant genera Spea, Rana, Bufo, Hyla, and cf. Acris, the second record of the late Clarendonian genus Tregobatrachus, and a new, unique genus of frog. The fauna was dominated by Rana (at least 39 individuals). Overall, the taxonomic composition of the Pratt Slide frog fauna supports suggestions by others that the frog fauna of the Great Plains was predominantly modern at the generic level by ca. 10 Ma. Fossil evidence also suggests that the extinct toad Bufo pliocompactilis was common in the Great Plains during the late Miocene, and the extant genus Hyla occupied a larger Great Plains distribution during the late Miocene than today.