Hominin presence in Eurasia dated to almost 2 million years ago

(Press-News.org) The subject of when early hominins, closely related ancestors to humans, first left Africa to begin their slow dispersal across the globe is a matter of ongoing discussion among anthropologists. The general consensus has been that hominins were present in Eurasia at least 1.8 million years ago, but some ephemeral traces of hominins have hinted at an earlier presence. New evidence by an international team of researchers now pushes that date back to almost 2 million years ago. 

This evidence for hominins in Eurasia earlier than previously thought is based on multiple cut-marked fossil bones from the site of Grăunceanu, Romania. The site of Grăunceanu is found in the Olteţ River Valley along with a handful of other fossil localities. Most of these sites were originally excavated in the 1960s. The absence of hominin bones at the site meant anthropologists had to look for other evidence of hominin presence, such as stone tools or signs of tool use.  

More than 5,000 bones from Grăunceanu and surrounding sites were meticulously examined for evidence of cut marks from stone tools used to remove the flesh from animals. Of that total, the team identified at least 20 bones they are confident show signs of cut marks. Biostratagraphic data and high precision uranium-lead dating techniques were used to estimate the age of the bones, which put their minimum age at 1.95 million years ago. 

The findings were published in Nature Communications. The international team of more than a dozen researchers was led by Sabrina Curran, an associate professor of anthropology at Ohio University; Claire Terhune, an associate professor of anthropology at the University of Arkansas; and Alexandru Petculescu, of the “Emil Racoviţă” Institute of Speleology in Bucharest.  

Terhune noted that the team had to overcome several challenges, including the absence of hominin bones and stone tools at the site. They also had to contend with the fact that the bones were excavated more than 50 years ago, making the relationship of the bones to one another and the exact reasons for their deposition hard to determine. The fossils are currently curated in the “Emil Racoviţă” Institute of Speleology and the Museum of Oltenia. Though researchers had worked with the bones intermittently since their discovery, it was not until the last decade or so that they thought to reexamine them and conduct careful inspections of the surface of each bone. 

“We didn’t initially expect to find much,” Curran said. “But during a routine check of the collections we found several cut-marked bones. This led to further investigation in collaboration with Dr. Briana Pobiner of the Smithsonian Institution and Dr. Michael Pante of Colorado State University, and the discovery of other distinct marks across different bones, suggesting deliberate butchering activities.”

Prior to this discovery, the site of Dmanisi in the country of Georgia was thought to contain the oldest evidence of hominin activity outside of Africa, dated to roughly 1.8 million years ago. Confirming the age of the marks establishes both the presence of hominins in Eurasia 200,000 years earlier than previously thought as well as tool use by them, providing some of the earliest evidence of hominin activity in this area.  

The team combined this work with isotopic analyses led by Virgil Drăguşin from the “Emil Racoviţă” Institute of Speleology that helped to reconstruct the environment these hominins would have been living in at the time. This work suggests this region would have experienced seasonal fluctuations in temperature, much like today, but that there likely would have been higher levels of rainfall. This would likely have been different from the environments these hominins were originally adapted to in Africa. Analysis of the animal fossils from the site also shows they would have encountered a range of new fauna, including wooly rhinos, saber tooth cats, pangolins and mammoths. 

“The field of paleoanthropology can be contentious,” Terhune noted. “People get really fired up about human ancestors, and one ongoing debate has been related to the earliest evidence of tool use. Because of this we have been extremely meticulous in documenting the presence of these cut marks because we knew if we handed another paleontologist these bones, they’d say, ‘Oh, yeah these are cut marks.’ But if we told them they’re from Romania two million years ago, they’re going to say, ‘No, that can’t be right’.”

But the team is confident they got the facts right, and that the discovery is an important step forward. 

"The Grăunceanu site represents a pivotal moment in our understanding of human prehistory,” Curran added. “It demonstrates that early hominins had already begun to explore and inhabit diverse environments across Eurasia, showing an adaptability that would later play a crucial role in their survival and spread." 

“The history of human evolution is far more complex and intricate than we could have imagined,” she added, “and we are just beginning to uncover the many chapters of that story.” 

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