Biodiversidad, estratigrafía y sedimentología de la cuenca neógena Cacheuta, Mendoza

Abstract

New research in the petroliferous area of Tupungato, Mendoza Province, central western Argentina, has revealed a much richer fossil assemblage than previously known for this zone. First mammal remains from this area go back to the 1930s, but only three taxa were recognized since then, two notoungulates, the mesotheriid Typotheriopsis silveyrai and the hegetotheriid Hemihegetotherium achathaleptum, and the caviid rodent Cardiatherium paranense. A recent project, focused on geological and paleontological aspects of the Tupungato–Piedras Coloradas Anticlines, has allowed us to improve the geological knowledge of the area and increase its faunal diversity. This is one of the best localities for the study of the uppermost section of the Cacheuta foreland basin, and we present the first detailed section of the Río de los Pozos Formation (including part of previously considered Mogotes Formation). Concerning fossils, xenarthrans (sloths and armadillos), pachyrukhine hegetotheriids, a toxodontid, and different families of rodents (Chinchillidae, Octodontidae, Caviidae Dolichotinae, and Abrocomidae) are recognized for the first time in this locality, together with new remains of T. silveyrai, H. achathaleptum, and C. paranense. The comparison with Late Miocene–Pliocene Argentinean faunas reveals general similarities with most assemblages assigned to the Huayquerian Stage/Age, somewhat closer to those from the Cerro Azul Formation, and there are also shared taxa with Early Pliocene faunas. The biostratigraphic data presented here agree with published ages obtained for the Río de los Pozos Formation in the La Pilona Anticline.