Early Homo sapiens arrived in South America earlier than believed, new research shows.
Sample of stone tools (scrapers, flakes and bipolar cobble) found at the Arroyo Seco 2 site. Image credit: G.G. Politis et al.
The conclusion comes from the analysis of ancient tools and bones from a variety of extinct mammal species at a rich archaeological site called Arroyo Seco 2 (AS2), located just outside the city of Tres Arroyos, in the Pampas region of Argentina.
According to a study published last week in the journal PLoS ONE, these finds suggest that early humans hunted/scavenged and butchered ancient mammals in South America at least 14,000 years ago.
That’s about 1,000 years before a prehistoric group of hunter-gathers known as the Clovis people emerged in North America.
The authors of the study, led by Dr. Gustavo Politis, a researcher at the National University of Central Buenos Aires and CONICET, used radiocarbon dating to determine the age of the mammal bones from the AS2 site and analyzed the specimens under a microscope.
The analysis revealed the presence of limb bones from extinct Pleistocene mammals, which may indicate human activities of transporting and depositing animal carcasses for consumption at a temporary camp.
The bones of some species were concentrated in a specific part of AS2, which could indicate designated areas for butchering activities.
The Arroyo Seco 2 site in Argentina: geographic location, digital elevation model of the knoll and location of the excavation units, and photograph of central excavation units and trench. Image credit: G.G. Politis et al.
“More than 100,000 faunal remains have been recovered from the AS2 excavations, approximately 6,200 have been determined at a taxonomic level. The total number of extinct Pleistocene mammal remains identified is currently 272,” the scientists said.
“A total of 12 taxonomic categories have been assigned. There are four groups of giant ground sloth (Glossotherium robustum, Megatherium americanum, Mylodon sp., Lestodontinae cf. Lestodon), two groups of extinct horse (Equus neogeus, Hippidion sp.), two South American ungulates (Toxodon platensis, Macrauchenia sp.), one camelid (Hemiauchenia), one glyptodont (Glypotodon sp.), and one giant armadillo (Eutatus seguini),” they said.
Most of the extinct fauna were dated to the end of the Pleistocene, between 14,064 and 13,068 years ago.
However, one specimen from the extinct giant armadillo (Eutatus seguini) suggests survival into the Holocene (7,400 years ago).
Microscopic examination revealed that some animal bones contained fractures most likely caused by stone tools.
According to Dr. Politis and co-authors, evidence from AS2 and other South American sites indicates that humans arrived in the continent prior to the Clovis people inhabiting the Americas, but after the onset of the Last Glacial Maximum, which took place 19,000 to 20,000 years ago.
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G.G. Politis et al. 2016. The Arrival of Homo sapiens into the Southern Cone at 14,000 Years Ago. PLoS ONE 11 (9): e0162870; doi: 10.1371/journal.pone.0162870
