Neanderthal fossils from a cave in Belgium believed to belong to the last survivors of their species ever discovered in Europe are thousands of years older than previously thought, a new study said on Monday.
Earlier radiocarbon dating of the remains of Spy Cave gave ages as recent as about 24,000 years ago, but new tests push the clock back between 44,200 and 40,600 years ago.
The research appeared in The works of the National Academy of Sciences and was performed by a team from Belgium, the United Kingdom 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 of sample preparation that was better able to rule out contaminants.
With a firm idea of when the closest human relatives disappeared, it is considered a key first step toward a greater understanding of their nature and capabilities, as well as why they eventually disappeared while our ancestors prospered.
The new method is still based on radiocarbon dating, long considered the gold standard of 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 degrades over time.
Because plants and animals cease to absorb carbon 14 when they die, the amount that remains when dated tells us how long they lived.
When it comes to bones, scientists extract the collagen part because it is organic.
“What we have done is take it a step further,” Deviese said, as contamination from the funeral environment or glue used for museum work can ruin the test.
Instead, the team looked for the basics of collagen, molecules called amino acids, and in particular, selected specific individual amino acids that could be sure to be part of collagen.
“Trust framework”
The authors also dated Neanderthal specimens from two additional Belgian sites, Fonds-de-Foret and Engis, finding comparable ages.
“The meeting with all these Belgian specimens was very interesting because they played a major role in understanding and defining Neanderthals,” said co-author Gregory Abrams of the Scladina Cave Archaeological Center in Belgium.
“Almost two centuries after the discovery of Engis’s Neanderthal child, we have managed to offer a reliable age.”
Genetic sequencing has since been able to show that a Neanderthal shoulder bone previously dated 28,000 years ago was heavily contaminated with bovine DNA, suggesting that the bone was preserved with a bovine bone adhesive.
“Meetings are crucial in archeology. Without a reliable timeline, we cannot be truly confident in understanding the relationship between Neanderthals and homo sapiens“added co-author Tom Higham of Oxford University.
Certain uses of the stone tools have been attributed to Neanderthals and have been interpreted as a sign of their cognitive evolution, Deviese said.
But if the timeline for the existence of Neanderthals is pushed back, Deviese added, then Paleolithic industries should be re-examined to determine if they were indeed the work of extinct hominid species.
© Agence France-Presse