Quaternary megamammals in north Patagonia and first human occupation

FORASIEPI, A.M.; GIL, A.; NEME, G.; FILIPPI, L.; AGUIRREZABALA, G.

San Rafael

Conferencia; 12th International Conference of Archaeozoology; 2014

Museo de Historia Natural de San Rafael

Patagonia has contributed very few Quaternary megamammal remains and those currently are taxonomically poorer compared to other South American regions. Here we analyze the fossil record of northern Patagonia (south Mendoza and Neuquén, between 35ºS and 41ºS) while considering environment and early human occupation. Fossil megamammals were found in 14 paleontological localities (Manqui-Malal, Volcán El Hoyo, and Agua de Pérez in south Mendoza; near Rincón de los Sauces, near Chos Malal, Hualcupén, Cajón de Almaza, Campana Mahuida, near Las Lajas, Cuchillo Curá, Covunco Abajo, Sierra del Portezuelo, near Neuquén city, and Arroyito in Neuquén) and 7 archaeological sites (Cueva El Chacay, Gruta El Manzano in south Mendoza; Cueva Huenul I, Leuto Caballo, Cueva Epullán Grande, Cueva Traful I, and Cueva el Manzano in Neuquén). Ground sloths (Megatherium and sloths coprolites) are the most abundant remains followed by native horses (Hippidion and Equus (Amerhippus)). There are very few native ungulates (Macrauchenia), mastodonts (Stegomastodon?), and deer (Antifer) in the association. The last two in Arroyito represents the south and westernmost extreme distribution for these taxa. Radiocarbon dates of north Patagonian material provides ages between 20.400 and 10.200 BP, while in Pampa, and in central west Argentina megamammals are recorded until ca. 8000 BP. Stable isotope data (13C, 15N, and 18O) were performed on bone collagen and bone apatite in fossil megamammals. Around 12.000 BP, isotopic data suggests that sloths changed their diet to match floral change in the area. In around 11.000 BP initial human habitation occurred in northern Patagonia, with consequent cohabitation with megamammals. North Patagonian marginal environments would produce a reduced biomass than comparable latitudinal areas of Pampa. A variety of factors (environmental changes, ecological interaction) could have together contributed to megamammal extinction.