Neanderthal fossils from a cave in Belgium that are believed to be among the last survivors of their species ever discovered in Europe are thousands of years older than once thought, a new study said Monday.
Previous radiocarbon dates of the remains from the Spy Cave have yielded ages as recent as about 24,000 years ago, but the new test pushes the clock back to between 44,200 and 40,600 years ago.
The research appears in the Proceedings of the National Academy of Sciences and was performed by a team from Belgium, Britain and Germany.
Co-lead author Thibaut Deviese of the University of Oxford and Aix-Marseille University told AFP he and colleagues had developed a more robust method of preparing samples, which is better able to rule out pollution.
Having a firm idea of when our closest human relatives disappeared is considered an important first step in understanding more about their nature and abilities, as well as why they eventually became extinct while our own ancestors prospered.
The new method still relies on radiocarbon dating, which has long been considered the gold standard of archaeological dating, but refines the way samples are collected.
All living things absorb carbon from the atmosphere and their food, including the radioactive form carbon-14, which decays over time.
As plants and animals stop absorbing carbon-14 when they die, the amount left over when they date tells how long ago they lived.
When it comes to bones, scientists take the part that consists of collagen, because it is organic.
“What we have done is to go a step further,” Deviese said, as pollution from the funeral environment or from glue used for museum work can spoil the monster.
Instead, the team looked at the building blocks of collagen, molecules called amino acids, and especially selected specific single amino acids that they could be sure were part of the collagen.
‘Reliable framework’
The authors also date Neanderthal samples from two other Belgian sites, Fonds-de-Foret and Engis, and find similar ages.
“Dating all these Belgian specimens was very exciting because it played an important role in the understanding and definition of Neanderthals,” said co-author Gregory Abrams, of the Archaeological Center of the Cave Scladina in Belgium.
“Nearly two centuries after the discovery of Engis’ Neanderthal child, we were able to provide a reliable age.”
Genetic sequencing, meanwhile, could indicate that a Neanderthal shoulder bone dated earlier, 28,000 years ago, was heavily contaminated with bovine DNA, suggesting that the bone was preserved with an adhesive of bovine bones.
“Dating is crucial in archeology. Without a reliable framework of chronology, we can not really have confidence in understanding the relationships between Neanderthals and Homo sapiens, ”Adds co-author Tom Higham of Oxford University.
Certain uses of stone tools are attributed to Neanderthal people and were interpreted as a sign of their cognitive evolution, Deviese said.
But if the timeline for the existence of Neanderthals is pushed back, Deviese added, the Paleolithic industries need to be re-examined to determine if it really is the work of the extinct hominid species.
© Agence France-Press