Neanderthal fossils from a cave in Belgium believed to belong to the last survivors of their species discovered in Europe are thousands of years older than previously thought, according to a new study.
Earlier radiocarbon dating of the spy cave remains yielded ages as recent as about 24,000 years ago, but new evidence sets the clock back to between 44,200 and 40,600 years ago.
The investigation appeared in the procedures of the National Academy of Sciences and it was performed by a team from Belgium, Great Britain and Germany.
Co-lead author Thibaut Deviese, from the University of Oxford and the University of Aix-Marseille, told AFP that he and his colleagues had developed a more robust method for preparing samples, which could better exclude contaminants.
Having a firm idea of when our closest human relatives disappeared is considered a key first step in understanding more about their nature and capabilities, as well as why they eventually became extinct while our own ancestors thrived.
The new method is still based on radiocarbon dating, long considered the gold standard of archaeological dating, but it refines how specimens are collected.
All living things absorb carbon from the atmosphere and their food, including the radioactive form carbon-14, which disintegrates over time.
Since plants and animals stop absorbing carbon-14 when they die, the amount left over when they are dated tells us how long they have lived.
When it comes to bones, scientists extract the part made up of collagen because it is organic.
“What we have done is go one step further,” Deviese said, as contamination from the burial environment or from the glues used for museum work can spoil the display.
Instead, the team looked for the building blocks of collagen, molecules called amino acids and, in particular, specific amino acids that they could be sure were part of collagen.
The authors also dated Neanderthal specimens from two additional Belgian sites, Fonds-de-Foret and Engis, finding comparable ages.
“Dating all of these Belgian specimens was very exciting as they played an important role in understanding and defining Neanderthals,” said co-lead author Gregory Abrams of the Scladina Cave Archaeological Center in Belgium.
“Nearly two centuries after the discovery of Engis’ Neanderthal boy, we were able to provide a reliable age.”
Meanwhile, genetic sequencing was able to show that a Neanderthal shoulder bone dated earlier to 28,000 years ago was heavily contaminated with bovine DNA, suggesting that the bone had been preserved with a glue made from cattle bones.
“Dating is crucial in archeology. Without a reliable chronological framework, we can’t really be sure of understanding the relationships between Neanderthals and Homo sapiens“added co-author Tom Higham of the University of Oxford.
Certain use of stone tools has been attributed to Neanderthals and has been interpreted as a sign of their cognitive evolution, Deviese said.
But if the timeline for Neanderthals is lagging behind, Deviese added, then Paleolithic industries should be re-examined to determine if they were really the work of the extinct hominin species.
© Agence France-Presse