Nuevo registro de Sphenotherus (Xenarthra, Mylodontidae) en el Terciario superior del valle de El Cajón (provincia de Catamarca, Argentina). Revisión sistemática del género

Abstract

The new material of Sphenoiherus is from Huayquerian levels (late Miocene) in the northem part of El Cajón valley, Catamarca province (NW Argentina). This record extends the geographic distribution of the genus, and helps to define the diagnostic characters. The revised diagnosis includes the following features: lower tooth rows laterally concave, lower caniniform lying on the lingual side, and last lower molariform with a singular combination of characters. The two species included in this genus are: Sphenotherus zaoaleiianus Ameghino and Sphenotherus paranensis Ameghino. The latter has been characterized by having the posterior lower molariforms smaller than those of the former. However, this feature is considered not valid and thus S. paranensis is synonymized to S. zavaletianus.