Miguel Eduardo Delgado and others.
Martin De Los Reyes (left) and Guillermo Joffre, two of the researchers involved in the study, discovered fossils of an extinct Ice Age armadillo relative known as Neosclerocalyptus.
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More than 20,000 years ago in what is now Argentina, some of the earliest humans in the Americas encountered and butchered a giant armadillo-like creature with stone tools, according to a new study.
The discovery, based on cut marks on the fossilized remains of an Ice Age creature, is significant because it adds to a wave of recent finds that suggest the Americas were settled much earlier than archaeologists first thought — perhaps earlier more than 25,000 years.
“These animals are closely related to the armadillos that are still alive,” said study co-author Miguel Delgado, a researcher at the National University of La Plata in Buenos Aires. The animals are known for their armored scales and their ability to curl up into a ball when threatened.
“The specimen we found belongs to one of the smallest species (of an extinct armadillo species called Neosclerocalyptus),” said Delgado, noting that it weighed about 300 kilograms (660 pounds) and was 180 centimeters (almost 6 feet ), including the tail.
A bulldozer uncovered the animal’s fossilized vertebrae and pelvis found on the banks of the Reconquista River near the town of Merlo in the Buenos Aires metropolitan area.
Radiocarbon dates from bones and bivalve shells found in the same layer of sediment reveal that the armadillo remains are between 20,811 and 21,090 years old, according to the study, published Wednesday in the journal PLOS One.
The incisions were not immediately apparent, but cleaning the fossil revealed 32 linear scars. After careful analysis, the team ruled out that the marks were made by rodents, carnivores that may have preyed on the animals, or other factors such as trampling, Delgado said.
Miguel Eduardo Delgado and others.
In this illustration, the highlighted areas (in blue) identify the fossilized bones of the Neosclerocalyptus specimen discovered during excavations near the city of Merlo in Argentina.
Instead, the team found that the shape of the cut marks was consistent with those made by stone tools. The placement of the scars suggests the animals were butchered for their meat with a deliberate sequence of cuts that focused on dense areas of the armadillo’s flesh, according to Delgado.
“The cuts are not randomly distributed, but focused on those skeletal elements that contain large muscle bundles such as the pelvis and tail,” he said.
The authors provide “compelling evidence” that humans butchered this extinct armadillo 21,000 years ago, said paleoanthropologist Briana Pobiner, a researcher in the Human Origins Program at the Smithsonian National Museum of Natural History in Washington, DC.
“The authors have done a solid job of demonstrating through qualitative and quantitative analyzes that the cuts on the armadillo fossils were most likely made by humans,” Pobiner, who was not involved in the study, said via email.
When and how early humans first migrated to the Americas, the last places to be inhabited as humans left Africa and spread around the world, has long been debated by experts and remains poorly understood.
Current estimates of the first inhabitants range from 13,000 years ago to more than 20,000 years ago, but the earliest archaeological evidence for the settlement of the region is scarce and often contradictory.
The discovery of 21,000- to 23,000-year-old fossilized footprints pressed into mud in New Mexico, described in a September 2021 study, is the most definitive of a string of recent evidence suggesting that the arrival of the first inhabitants was much earlier. earlier than many scientists had thought.
Miguel Eduardo Delgado and others.
Detailed examination of cut marks on the fossils revealed that they were made by stone tools in a deliberate sequence.
During this time, the planet was in the grip of the Last Glacial Maximum, a period 19,000 to 26,000 years ago when two massive ice sheets covered the northern third of North America, reaching as far south as what is now New York, Cincinnati, and Des Moines. Iowa.
The ice sheets and cold temperatures caused by the glaciers would have made travel between Asia and Alaska—the most likely route—impossible during that time, meaning the people who made the footprints likely arrived much earlier.
Along with three perforated giant sloth bones found in Brazil that archaeologists believe were used as pendants by humans 25,000 to 27,000 years ago, the butchered armadillo bones suggest humans were in South America a surprisingly long time ago .
When humans first settled in the Americas, then home to many now-extinct Ice Age creatures, is a “hotly debated topic,” Delgado said.
“Until recently, the traditional model suggested that humans entered the continent 16,000 calendar years ago,” he said.
“Our results, together with other evidence, suggest a different scenario for the first human settlement of the American continent, that is, the most likely date for the first human entry is between 21,000 and 25,000 years ago, or even earlier.”
