First Record of the Anuran Family Rhinophrynidae from the Oligocene of Eastern North America

The anuran family Rhinophrynidae today comprises a single species restricted to southernmost Texas and Central America. Three extinct genera allied to this family are known from the Jurassic (Rhadinosteus) and Eocene (Chelomophrynus, Eorhinophrynus), whereas the sole extant genus Rhinophrynus is known from the latest Eocene (Chadronian) of Saskatchewan and the Pleistocene of Mexico. We provide the first records of the Rhinophrynidae from the Oligocene of eastern North America. From two of the oldest terrestrial vertebrate sites on the Florida peninsula (I-75, early Oligocene; Brooksville 2, late Oligocene), we have identified one nearly complete and several partial humeri, two radioulnae, two partial presacral vertebrae, three partial ilia, and one femur that are all referable to the Rhinophrynidae. These specimens are similar in size to the Eocene Rhinophrynus canadensis, smaller than the extant R. dorsalis, and might be distinguishable from both by features of the ilium and humerus. The presence of rhinophrynids during the Oligocene provides the first indication of change in the anuran fauna on the Florida peninsula during the Cenozoic.