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.

Around the world in 10 million years: biogeography of the nearly cosmopolitan true toads (Anura: Bufonidae)

“…3a). Notably, the oldest fossil attributable to the genus formerly known as ‘ Bufo ’ dates from the Late Palaeocene of Itaborai, Brazil ( c. 55 Ma; Báez & Nicoli, 2004), with the oldest bufonid being only slightly older ( c. 57 Ma; Báez & Gasparini, 1979). The specimen attributed to ‘ Bufo ’ reportedly is of a species aligned with the Rhinella marinus group (Báez & Nicoli, 2004).…”

“…Notably, the oldest fossil attributable to the genus formerly known as ‘ Bufo ’ dates from the Late Palaeocene of Itaborai, Brazil ( c. 55 Ma; Báez & Nicoli, 2004), with the oldest bufonid being only slightly older ( c. 57 Ma; Báez & Gasparini, 1979). The specimen attributed to ‘ Bufo ’ reportedly is of a species aligned with the Rhinella marinus group (Báez & Nicoli, 2004). Because this fossil was described on ‘an incomplete basal portion of the left ilium’ (Báez & Nicoli, 2004), it may be reasonable to assume it can only be assigned with confidence to the South American Rhinella clade.…”

Frogs (Amphibia, Anura) from the Eocene and Oligocene of the Phosphorites du Quercy (France). An overview

“…Therefore, Eocene bufonids are perhaps known in South America. Oligocene bufonids are reliably known only from Bolivia (Báez and Nicoli 2004). Oligocene bufonids were also reported from Asia (Kazakhstan), but they were only listed and not described (Chkhikvadze 1985); this Asian report needs confirmation.…”

New Fossil Record of Bufonidae (Amphibia, Anura) in the Late Pleistocene-Early Holocene of Northeastern Brazil and Its Paleoenvironmental Significance

“…According to Frost (2013), about 53 genera and 576 species are included in Bufonidae and, according to Segalla et al (2012), around 70 of them occur in Brazil. In Brazil, fossils of Bufonidae were mentioned by Estes (1970) and Báez and Nicoli (2004) to the Itaboraí Basin (late Paleocene), though those specimens were not formally described or figured. Recently, Araújo-Júnior and Moura 2014 Rhinella jimi is one of the largest species of neotropical anurans (Stevaux, 2002), a condition that may facilitates its preservation in comparison to other anuran species.…”