21,000 years ago, the Pampas plain was an inhospitable place. The territory that today occupies central Argentina, during the late Pleistocene, was cold, arid and populated by large mammals that are now extinct, such as megatheriums, sabre-toothed tigers and glyptodonts, among others. However, the cuts detected in the posterior bones of one of these animals show that there were already humans in the region, and are the oldest evidence of human occupation in the area to date. The discovery, published this week in the magazine Plos Oneprovides new data on the early population of South America.
The fossil studied is a Neosclerocalyptusbelonging to the group of armoured mammals called glyptodonts, gigantic relatives of the modern armadillo that lived in these lands until about 10,000 years ago. It was found in 2015 in an excellent state of preservation on the banks of the Reconquista River, near the town of Merlo, in the province of Buenos Aires. The bone marks on the animal caught the attention of its discoverer, the paleontologist Guillermo Jofré, because they did not seem to have been caused by animals.
This intuition was confirmed by subsequent analyses carried out under the supervision of the team of archaeologists and paleontologists from the La Plata Museum. They counted 32 marks, which were not made randomly, but distributed in places where tendons connect and muscles are attached, a characteristic pattern in bones consumed by prehistoric hunter-gatherers. “This pattern allowed us to establish that it was humans who used it as part of their diet,” says archaeologist Mariano del Papa.
Researchers do not know whether humans hunted the animal or found it trapped near the river, but they do know from the cuts that they removed all the meat they could to feed themselves. The glyptodont found “weighed about 300 kilos and measured 1.40 meters long by about 85 centimeters high,” describes paleontologist Martín de los Reyes, another of the authors of the work. The animal was covered “unexpectedly, possibly by a dust storm,” he adds, which facilitated its preservation and subsequent discovery.
Researchers suspect that humans used sharp stone tools to butcher the body and that they may also have had an axe-like artifact, given some of the marks studied. These are assumptions that they hope to see supported by new findings when they carry out a systematic excavation of the site, which has not been possible so far due to lack of funds. The scarce financial resources also slowed down the entire investigation, laments De los Reyes.
“When we went to see it, we were surprised and astonished because it was a barbaric find,” says Del Papa. Until then, there was evidence of human presence in the area around the Reconquista River 8,000 years ago, but glyptodonts had become extinct 2,000 years earlier. “The issue arose when we sent the laboratory in France to date it and it gave an age of 21,000 years,” says this paleontologist about the carbon 14 dating. “That was when things changed because it represented the earliest date of human occupation for the southernmost part of South America,” he says.
The discovery brings new data to the scientific discussion about how the human population of America came about. The most widely held theory is that the first inhabitants came from Asia and crossed to North America through the Bering Strait in Siberia during the last Ice Age. From there, they spread across the continent, but there are two major currents of thought that try to explain how they did it. The late population theory estimates that migration to the south began about 16,000 years ago, coinciding with the end of the last Ice Age. On the other hand, the early population theory believes that it happened much earlier. The latter has more and more records, dating back as far as 33,000 years, according to the dating of artifacts found in a cave in Mexico. Until now, the earliest evidence of human presence in Argentina was about 16,000 years old, also in the province of Buenos Aires, the largest in Argentina.
A few thousand years ago, when the last ice age had not yet ended, the area was cold, dry, with very little vegetation and populated by megafauna that is now extinct. “These people we are talking about must have been the first settlers, small groups of explorers. We imagine a few individuals travelling over very wide spaces, which is why the discovery is very significant,” says Del Papa.
The research was carried out with contributions from specialists from the La Plata Museum, the Geological Research Centre (CIG-UNLP-CONICET), the Pasteur Institute in Paris, the Municipality of Merlo and the Azara Foundation. The researchers are confident that future excavations at this archaeological site will reveal new information about the first inhabitants of the southern tip of the American continent.
You can follow SUBJECT in Facebook, X and Instagramor sign up here to receive our weekly newsletter.
#Tool #marks #giant #armadillo #show #human #presence #Argentina #years