Dental macro- and micromorphology of a new pitheciid primate from the Miocene of Patagonia

TEJEDOR, M.F.; NOVO, N. M.; HOGG, R.T.; ROSENBERGER, A.L.

Portland, Oregon

Congreso; 81St Annual Meeting of the American Association of Physical Anthropologists; 2012

American Association of Physical Anthropologists

We report a new primate from Cerro de los Monos, of the early Miocene Pinturas Formation in central-western Patagonia, Santa Cruz Province. Pinturas primates deserve attention because they are the most diverse assemblage known from Patagonia. Prior to this report, four species from Pinturas have been named: Soriacebus ameghinorum, S. adrianae, Carlocebus carmenensis, and C. intermedius. The most complete specimen of the new primate is a palate containing the left I2, P4-M1, M3, roots of the left M2, and of the right P4-M3. More than a dozen referred dental specimens exist. Molars and premolars are bunodont, with low occlusal relief. Upper molars are transversely broad and rectangular with large, rounded hypocones. Lower molars are buccolingually broad, with trigonids that are broad and taller than the talonids. The cristid obliquid is relatively short in the lower molars. Cusps, crests and crown sidewalls are smooth and rounded, with shallow basins. The mandible is robust at the symphysis, and near the alveolar surface. SEM analysis of enamel microstructure reveals a radial pattern as in Callicebus, contrasting the highly decussating enamel of pitheciines. This suggests that molars in the new taxon were not used to process mechanically demanding foodstuffs. This morphology is similar to Carlocebus and Homunculus, supporting a link to Homunculinae. However, the new taxon is somewhat larger and more bunodont. Since there are at least three Miocene homunculine genera in Santa Cruz, this reinforces the idea of an unexpectedly high diversity of the pitheciid radiation in extra-Amazonian, Neogene South America.