YOUNGEST RECORD OF THE BOID SNAKE CHUBUTOPHIS IN THE MIOCENE OF SOUTHWESTERN AMAZONIA

YOUNGEST RECORD OF THE BOID SNAKE CHUBUTOPHIS IN THE MIOCENE OF SOUTHWESTERN...

Annie S. HSIOU1 and Adriana M. ALBINO

1 Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, SP,

Brazil; 2 Departamento de Biología, Universidad Nacional de Mar del Plata, Mar del

Plata, Argentina.

One of the most relevant South American Neogene vertebrate assemblages is known from the Solimões Formation of Acre and Amazonas states in southwestern Brazilian Amazonia. Its squamate association from the Late Miocene demonstrates extensive affinities with other Miocene faunas of northern South America (e.g., La Venta in Colombia, Urumaco in Venezuela). Here we report a new vertebra of the boid snake Chubutophis Albino 1993, which is a genus previously known only for the Middle-Late Eocene of Patagonia (Argentina). The new specimen was collected at the border between Peruvian and Brazilian Amazonia, in the “False Acre VI” locality, Acre River. It is assigned to Chubutophis based mainly on the following combination of vertebral characters: large size; neural arch high and wide; neural spine anteroposteriorly oriented; zygosphene thick, rather narrower than cotyle; prezygapophyseal articular facets dorsally inclined; prezygapophyseal process strongly reduced; paradiapophyses large, robust and elevated; centrum very short; shallow subcentral grooves; hipapophyses or haemal keel anteriorly indistinct, only prominent posteriorly; and presence of paracotylar foramen. This record implies the survival of this Eocene genus until at least the Late Miocene of northern South America. The tropical climate in this area would have been favorable for the living of large boid snakes such as Chubutophis and Eunectes (Hsiou and Albino, 2009), due to the development of a large fluvial megafan complex characterized by open areas and forest galleries along rivers, swamps, and shallow lakes, similar to that seen currently in the Pantanal wetland (Latrubesse et al., 2010).

Albino, A.M. 1993. Snakes from the Paleocene and Early Eocene of Patagonia, Argentina: paleoecology and coevolution with mammals. Historical Biology 7:51–69. Hsiou, A.S. and Albino, A.M. 2009. Presence of the genus Eunectes (Serpentes, Boidae) in the Neogene of Southwestern Amazonia, Brazil. Journal of Herpetology 43 (4), 612–619.

Comentários