New specimens of Soriacebus adrianae, with comments on pitheciin primates from the Miocene of Patagonia

Abstract

The early Miocene Pinturas Formation of southern Patagonia has yielded a diverse fauna of platyrrhine primates included in two genera, Soriacebus and Carlocebus. The smallest species, Soriacebus adrianae, is one of the more poorly known primates from Pinturas, although its morphology certainly resembles the larger species, Soriacebus ameghinorum. Here, I report two new specimens of Soriacebus adrianae, a mandibular fragment and an isolated upper canine. The mandible preserves the crown of the right canine showing an entocristid that characterize the pitheciines of the tribe Pitheciini. This is the first evidence of this trait in any Soriacebus specimen recorded until now. The isolated upper canine has a long and projecting crown and the base of the crown is not wide relative to the height, both clearly pitheciin characters. In addition to the Pinturas remains, several other pitheciins have been found in Patagonia, supporting the view of a broader radiation of this tribe in southern South America.