Neanderthal fossils from a cave in Belgium believed to be among the last survivors of their species ever discovered in Europe are thousands of years older than ever thought, a new study said Monday.
Earlier radiocarbon dating of the Spy Cave’s remains gave ages from about 24,000 years ago, but the new test pushes the clock back to between 44,200 and 40,600 years ago.
The research appeared in the Proceedings of the National Academy of Sciences and was performed by a team from Belgium, Great Britain and Germany.
Co-lead author Thibaut Deviese of the University of Oxford and Aix-Marseille University told AFP that he and his colleagues had developed a more robust method of preparing samples that was better able to exclude contaminants.
Having a good idea of when our closest human relatives disappeared is considered an important first step in learning about their nature and abilities, as well as why they eventually died out while our own ancestors thrived.
The new method is still based on radiocarbon dating, long considered the gold standard for archaeological dating, but refines the way specimens are collected.
All living things absorb carbon from the atmosphere and their 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 over when they are dated tells how long ago they lived.
When it comes to bones, scientists extract the part that is collagen because it is organic.
“What we’ve done is take it a step further,” said Deviese, as contamination from the burial environment or from adhesives used for museum work can spoil the sample.
Instead, the team looked for the building blocks of collagen, molecules called amino acids, and in particular selected specific individual amino acids that they could be sure were part of the collagen.
‘Reliable framework’
The authors also dated Neanderthal specimens from two other Belgian sites, Fonds-de-Foret and Engis, and found similar ages.
“Dating all these Belgian specimens was very exciting because they played an important role in understanding and defining Neanderthals,” said co-lead author Gregory Abrams of the Scladina Cave Archaeological Center in Belgium.
“Almost two centuries after the discovery of the Neanderthal child of Engis, we were able to provide a reliable age.”
Genetic sequencing, meanwhile, was able to show that a Neanderthal shoulder bone previously dated 28,000 years ago was heavily contaminated with bovine DNA, suggesting the bone was preserved with a glue made from bovine bones.
“Dating is crucial in archeology. Without a reliable chronological framework, we cannot really be sure that we can trace 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 interpreted as a sign of their cognitive evolution, Deviese said.
But if the timeline for Neanderthals’ existence is pushed back, Deviese added, then Paleolithic industries would need to be re-examined to determine if they were really the work of the extinct hominin species.
© Agence France-Presse