Bufonid toads from the late Oligocene beds of Salla, Bolivia

ABSTRACT

Isolated fragmentary anuran remains from several fossil-bearing levels of the continental succession exposed in the Salla-Luribay basin, Eastern Cordillera, are described herein. The anuran material consists of poorly preserved postcranial bones that are referable to toads of the nearly cosmopolitan genus Bufo, now widely distributed in South America. Moreover, these remains strikingly resemble skeletal elements of extant South American species of the B. marinus group, most of which inhabit humid to semiarid lowlands. Based on the ilial morphology, two species appear to be represented in the Salla Beds: one close to B. arenarum and another, possibly new, that attained large size. This study does not confirm an earlier suggestion that a taxon closely related to the living South American aquatic leptodactylid Caudiverbera is represented in the Salla succession. This record supports an Early Tertiary, or even older, major diversification of bufonids.