Neanderthal fossils from a cave in Belgium believed to belong to the last survivors of their species never discovered in Europe are thousands of years older than previously thought, according to a new study.
Previous radiocarbon dating of the remains of Spy Cave produced ages as recent as about 24,000 years ago, but new evidence puts the clock back to 44,200 to 40,600 years ago.
The investigation appeared in the Proceedings of the National Academy of Sciences and was carried out by a team from Belgium, Britain and Germany.
Lead co-author Thibaut Deviese of 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 was able to better exclude pollutants.
Having a firm idea of when our closest human relatives disappeared is considered a key first step in understanding more about their nature and abilities, 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 perfects the way specimens are collected.
All living things absorb carbon from the atmosphere and its food, including the radioactive form carbon-14, which decays over time.
Because plants and animals stop absorbing carbon-14 when they die, the amount left when they date tells us how long they lived.
When it comes to bones, scientists extract the part made up of collagen because it is organic.
“What we’ve done is go a step further,” Deviese said, as contamination of the funeral environment or through glues used for museum work can ruin the sample.
Instead, the team looked for the basic blocks of collagen, molecules called amino acids, and in particular some selected specific amino acids that they could be sure were part of collagen.
“Reliable framework”
The authors also dated Neanderthal specimens from two additional Belgian sites, the Fonds-de-Foret and the Engis, which found comparable ages.
“Going out with all these Belgian specimens was very exciting, as they played an important role in understanding and defining Neanderthals,” said co-author Gregory Abrams of the Scladina Cave Archaeological Center in Belgium.
“Nearly two centuries after the discovery of Engis’ Neanderthal child, we were able to provide a reliable age.”
Meanwhile, genetic sequencing showed that a Neanderthal shoulder bone previously dated 28,000 years ago was heavily contaminated with bovine DNA, suggesting that the bone had been preserved with a glue made of cattle bones.
“The quote is crucial in archeology. Without a reliable chronological framework, we cannot be sure we understand the relationship between Neanderthals and homo sapiens“added co-author Tom Higham of Oxford University.
Deviese claimed that some use of stone tools has been attributed to Neanderthals and has been interpreted as a sign of their cognitive evolution.
But if the chronology of the existence of Neanderthals is receding, Deviese added, then Paleolithic industries should be re-examined to determine if they were really the work of extinct hominid species.
© France-Presse Agency