Unraveling the interactions between the Late Pleistocene megamammals and the earliest humans of the Pampas using stable isotopes

BELLINZONI, JONATHAN E.; VALENZUELA, LUCIANO O; NEWSOME, SETH D.; ATUDOREI, VIOREL; PRADO, JOSÉ L.; BONINI, RICARDO; STEFFAN, PAMELA; GOMEZ, GUSTAVO N

Roma

Congreso; INQUA 2023; 2023

ThePampas of Argentina is one of the regions with the earliest human occupationsignals for South America. With well-dated archaeological contexts as earlieras ~ 14.5 ky cal. BP implies at least 2.500-3.000 years of coexistence andpossible interactions with the last Pleistocene mega mammals. For more than 50years, two main issues have led the archeological investigations regards themegafauna: i) the impact of the human group on their extinctions; and, ii) theimportance of these large body-sized mammals in the subsistence of the firsthuman groups of the region. Recently, it has been proposed that the arrival andexpansion of human groups would have provoked the extinction of the megafaunaat the latest Pleistocene. Indeed, the human-driving extinction of such megamammals also produced an interruption in the hunter-gatherer population growth,as well as a trophic niche shift. Nevertheless, there is a gap of about 2000years between the oldest cultural and the oldest human skeletal remains inPampas, and the evidence of anthropic exploitation of mega mammals is elusive.So, how it can be assumed a specialized niche of mega mammal hunters? It isprevailing to evaluate the paleoecology of the Pleistocene mammal community ofthe Pampas, an aspect that is hardly taken into account. In this sense, we arefocusing on reconstructing and setting the paleoecology of such mega mammalsfor the Pampas. We are building an extensive paleoisotopic database ofwell-dated samples for the last glacial-interglacial period ~ 17-8.4 ky cal. APof the Pampas, to evaluate the structure of such a community, as well as theirresponse to climatic or anthropic pressures before their extinction. Here wepresent the first systematic reconstruction of the isotopic niche of theseveral mega mammal species present in the earliest archaeological sites of thePampas, to evaluate their paleoecology and infer possible interaction levels,from scavenging to secondary exploitation or even hunting.