🧬 Who carved these marks, thousands of years before the first known humans?

2024-07-27 06:00:03

Intriguing clues point to human activity in South America long before previously thought.

Cut marks were found on the caudal vertebrae of specimen CRS-10: on CV4, there was a short, deep, V-shaped mark, cup marks, a scrape mark, and elongated V-shaped cut marks; on CV5, cut marks on the neural process, Hertzian cones, and a linear mark on the body of the vertebra; on CV6, linear marks on the left transverse process, with details showing Hertzian cones and microstriations.
Credit: Del Papa et al., 2024, PLOS ONE, CC-BY 4.0

Bones of glyptodonts, gigantic armadillo-like creatures, show cut marks dating back 20,000 years, upending our knowledge of how humans first arrived on the continent. During the Pleistocene, an ice age marked by huge polar ice caps, the first humans are thought to have arrived in America via a pont land between Siberia and Alaska, well before the 13,000 years usually estimated. Archaeological sites in North America Nord and the South, recently discovered, advance this date of arrival.

A study published on July 17 in PLOS One reveals cut marks on the fossilized remains of a glyptodont, discovered in the Pampa region of Argentina. These bones of Neosclerocalyptusdated between 21,090 and 20,811 years ago, constitute one of the oldest examples of interactions between humans and megafauna in South America.

The bones found near Buenos Aires include fragments of the pelvis, tail and shell. Analysis at carbone 14 and dating of the sediments confirm the antiquity of these remains. To verify the human origin of the marks, the researchers used photographs and 3D scans, revealing V-shaped incisions, characteristic of the use of stone tools.

Illustration of a Neosclerocalyptus skeleton showing the skeletal elements marked in light blue.
Credit: Del Papa et al., 2024, PLOS ONE, CC-BY 4.0

The researchers ruled out other possible causes of the marks, such as predators or natural erosion, through careful analysis of the bones. The cutting sequences on different parts of the glyptodont’s body indicate a sophisticated butchery process, suggesting that humans of the time used meat from the pelvic and tail muscles for food.

The study suggests that the glyptodonts, weighing about 300 kilos, were prime targets for their large quantity of meat. This discovery pushes back the presence of humans and their interactions with megafauna in South America by 6,000 years compared to previously recorded sites.

Although this study provides compelling evidence, the lack of tools found at the site calls for further research. The authors stress the need to more closely link the fossil bones with cut marks and the archaeological record to confirm these findings.

Artist’s interpretation of the cutting of a glyptodont by Ice Age humans in Argentina, approximately 20,000 years ago.
Credit: Damian Voglino, A. Scasso Museum of Natural Sciences (Don Bosco School), San Nicolas de los Arroyos, Province of Buenos Aires, CC-BY 4.0

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