The ancient remains of a group of late surviving Neanderthals from Croatia are much older than previously thought, new research has found.
Previous research suggested that the ‘Vindija Neanderthals’ living in Vindija Cave in northern Croatia lived as recently as 32,000 years ago.
This would have made them among the last known surviving Neanderthals.
It also implied that modern humans and Neanderthals must have coexisted in central Europe for at least six millennia.
The researchers dated four Neanderthal bone samples from the Vindija cave in northern Croatia, one of which was previously unidentified, by extracting the amino acid hydroxyproline (HYP) from bone collagen
But a new radiocarbon dating method has found that these remains were actually more than 8,000 years older than this initial estimate.
This means the Neanderthal group died just before the arrival of modern humans in Europe, the researchers, from the University of Oxford, claim.
‘DNA studies have demonstrated that anatomically modern humans and Neanderthals interbred,’ said Dr Thibaut Devièse from Oxford University.
‘There is no question about this. Our work has shown previously that there is an overlap in time between Neanderthals and moderns of between 2500-5000 years, although the two groups for the most part were not living side-by-side it would seem.
‘With this dating work, we continue improving our understanding of where and for how long the two species (Neanderthals and anatomically modern humans) co-existed.’
The new dating method is more accurate than previous techniques because it allows for better removal of contaminants from ancient bone samples.
‘The Vindija Neanderthals have, for decades, been considered to be a late-surviving, refugial population of humans, that overlapped with, and survived alongside, early modern human colonisers in Europe,’ said study coauthor Professor Tom Higham.
‘Our new results show that this was not correct and demonstrates, once again, the crucial importance of reliable chronology in archaeology.
‘Our previous research has shown that Neanderthals in Europe did not survive after 40,000 years ago, so the Vindija Neanderthals were not a refugial group, rather they were present just before modern humans began to penetrate Europe for the first time.’
Neanderthal remains were first found at the Vindija Cave in the 1970s.
As well as the Neanderthal bones, the cave also contained a long, rich sequence of artefacts from the Paleolithic Period dating from more than 200,000 years ago to about 10,000 years ago.
DNA has previously been isolated from some of the bone specimens, showing that the cave is one of the youngest Neanderthal sites ever found – but the new research shows it is older than first thought.
Neanderthal remains from Vindija Cave have been previously dated at approximately 32,000 years old, making them the most recent known Neanderthal remains and implying considerable temporal overlap between Neanderthals and modern humans in Central Europe
To make the discovery, the Oxford team improved a technique used to purify bones before they are radiocarbon dated.
They developed the ‘single compound method’ for radiocarbon dating of bones, which involves looking closely at single amino acids, the building blocks of proteins.
The method relies on taking just one of the amino acids from a protein known as collagen, which is present in the bone.
Specifically, the common amino acid hydroxyproline (HYP) was targeted by the team, allowing for a cleaner analysis thanks to improved contaminant removal from the specimens.
Using this new approach, the Oxford team re-dated three Neanderthal bone samples from Vindija.
The researchers analysed Neanderthal remains found in the Vindija Cave – a site where several Neanderthal fossils have been discovered
WHO WERE THE NEANDERTHALS?
An artist’s impression of a Neanderthal man, our closest human relatives that lived in Europe and Asia from around 200,000 years ago to 30,000 years ago
Neanderthals are our closest human relatives that lived in Europe and Asia from around 200,000 years ago to 30,000 years ago in the Pleistocene Epoch.
Our primitive cousins looked similar to us, but they were shorter, more heavily built and had wide noses and prominent brow ridges.
Their skeletons were discovered in the Victorian times, and it was once believed that Neanderthals were less intelligent than modern humans and more aggressive.
But recent discoveries have proved that they used tools, held elaborate burial ceremonies and could even use fire.
There is also genetic evidence that Neanderthals and the ancestors of modern humans frequently interbred and large swathes of our genome are still made up of Neanderthal DNA.
There is some debate about whether Neanderthals were truly a distinct species or a subspecies of Homo sapiens.
All of the dates were older than 40,000 years ago, much older than the dates previously obtained.
This suggests there was still a large amount of unremoved contamination in the original measurements.
A fourth Neanderthal bone fragment from the Vindija collections in Zagreb was discovered using a separate new technique from a team at the University of Manchester, who coauthored the paper.
This sample also dated to the same period, lending support to the Oxford team’s results.
Separate DNA analysis has shown that there is no modern human DNA in the Vindija Neanderthals, and supports the radiocarbon dating in suggesting that the Neanderthals at the site did not live alongside early modern humans in Europe.
Dr Thibaut Devièse, the paper’s lead author, said: ‘The research we have conducted shows the great benefits of developing improved chemical methods for dating prehistoric material that has been contaminated, either in the site after burial, or in the museum or laboratory for conservation purposes.
‘We think that all human bones from the Palaeolithic period ought to be dated using this technology due to impact of even small amounts of contamination from modern times.’