Updated
Scientists say they have discovered a fossilised human finger bone in the Saudi Arabian desert estimated to be about 85,000 years old.
If confirmed, the Arabian finger bone would be the first and earliest homo sapiens fossil found on the Arabian Peninsula, as well as the oldest specimen of the human species to be discovered outside of Africa and its doorstep, the Levant.
Palaeontologist Julien Louys from Griffith University said the discovery showed that modern humans were out of Africa and the nearby Levant region by about 85,000 or 90,000 years ago.
"It really challenges that idea that humans only left 60,000 years ago," he said.
The Nefud Desert is not what it once was
Saudi Arabia's Nefud Desert is vast and dry, and filled with huge shifting sand dunes.
An international research team, including Oxford University scientists and the Saudi Commission for Tourism and National Heritage, has been scouring the region's ancient lake beds for signs of what life was like tens of thousands of years ago.
It was a very different landscape then, with grasslands and lakes hosting animals and humans.
A few dates:
- Human fossils found in north Africa have been dated back to 310,000 years
- A fossilised human jaw bone with teeth found in a cave in northern Israel dates back 180,000 years
- Humans didn't move into Saudi Arabia until tens of thousands of years later
Researchers zeroed in on the site using satellite images, and then looked around.
"These dried lake beds are being exposed by the moving sand dunes, so they're just literally lying on the surface, it's just a matter of looking around and seeing what we can find," Dr Louys said.
What they found was a fossilised human finger — the middle bone of the middle finger to be exact.
Using a technique called uranium series dating, the fossil was found to be up to 90,000 years old.
Dr Louys said stone tools and fossils of animals, like oryx and hippopotamus, are relatively common.
"But this is the first time that we've actually found a human fossil in amongst those deposits," he said.
Further tests on the small, well-preserved bone showed it could only belong to a modern human, and CT scans showed the bone was quite "robust".
"We think this robustness basically means they were using their hands a lot," Dr Louys said.
"And that makes sense when you think these guys are making [and using] stone tools so they're really using their hands to do a lot of hard, manual labour."
We moved because of climate change
The human trip from Africa to Australia
- Head through north-east Africa, into the Levant
- Travel down the Arabian peninsula
- Move into south Asia, India
- Then through south-east Asia (humans remains have been found in Sumatra from around 62,000 to 72,000 years ago)
- Transfer to a boat
- Arrive in Australia 65,000 years ago
The finding indicates modern humans travelled to follow kinder climates, but they did not stay indefinitely.
It also suggests that as the climate changed and the region dried up and became desert, humans moved on, along with other animals, to places where the climate was good.
"It really speaks to the flexibility of our species," Dr Louys said.
Other remains found at the site, like animal bones with cut marks on them and stone tools, are signs the humans relied on the animals for food.
"What we think is actually happening is these areas, although they were much better than they are today in terms of environmental conditions, they still would have been relatively dry, so these lakes and waterholes would have attracted all sorts of animals," Dr Louys explained.
"We find things like extinct panthers or hyenas, those sorts of animals … as well as humans.
"Basically, humans followed these better environments all the way till eventually getting to Australia."
Many more lakes to be surveyed
Dr Louys thinks the findings can reveal a lot about humans as a species and how we deal with new situations.
"They're coming up against animals that they've never seen before; environments they've never seen before," he said.
"For me, [it's about] ... what sort of impact humans are having in those new environments."
The research team has only explored a couple of hundred lakes out of 10,000 in the region.
Dr Louys is hoping to return early next year.
The paper was published in the journal Nature: Ecology and Evolution.
Topics: archaeology, science-and-technology, history, saudi-arabia
First posted