Taxonomic reinterpretation of a Notoungulata Typotheria from the early Oligocene of Cañadón Blanco (Chubut, Argentina)

CERDEÑO, E.; REGUERO, M.A.; VERA, B.

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2010 p. 401 - 405

0002-7014

The Cañadón Blanco locality, in Chubut Province (figure 1), is a classical Paleogene site in Patagonia with mammals mostly collected by Dr. S. Roth. As for other classical collections, precise geographic and geologic data were never recorded, and consequently some problems arise. Reguero (1999), studying the Deseadan notoungulates, made a full revision of many of these materials and synthesized the problems with different localities. Concerning Cañadón Blanco, he explained that Roth provided scarce data on the localities where he recovered fossils. Following the inventory of the Museo de La Plata, Roth collected between 1896 and 1898 at several Patagonian localities, including a trip across the Genoa valley to the Paso de Indios, collecting at different sites, Cañadón Blanco among others. Reguero (1999: 43) deduced that Cañadón Blanco corresponds to any basin NW of Laguna Palacios in the Paso de los Indios Department. Roth (1904) described several taxa from the Lower Tertiary deposits of Cañadón Blanco, without any further reference to the fossiliferous beds. Concerning age, Cañadón Blanco seems to correspond to the “Astraponotéen plus supérieur” of Ameghino from Gran Barranca, which is currently correlated to the Tinguirirican age (Reguero, 1999; Reguero et al., 2003). The specimen presented in this work is a very interesting incomplete mandible of a notoungulate presenting a set of characters that a priori could indicate different families of Typotheria, which is why it deserves a particular study.