The new findings now point out that humankind ventured into the Arabian Peninsula instead of hugging its coasts, and did so thousands of years earlier than long thought.
Lead researcher Jeffrey Rose, a paleolithic archaeologist at University of Birmingham in the UK, who has been in Oman since 2002 and runs the Dhofar Archaeological Project (DAP) in cooperation with the Ministry of Heritage and Culture, told Muscat Daily that the new findings provide irrefutable evidence of a population expansion from northeast Africa into Arabia.
“The question remains, however, if this was a successful colonisation that led to our expansion to the rest of the world. To answer that question, we must continue exploring Dhofar, and to the north, within the Rub al Khali,” said Rose.
He added that the new discovery has led to a few surprises. “First, no one has ever considered the Nile Valley as the source of human expansion. Until now, we expected the group to have come from somewhere in East Africa.
"This was based on genetic evidence, as well as very early modern human remains found in Ethiopia. “However, with our discovery, it now seems the colonising population moved out from the Nile Valley.
"They were not fishermen, but large game hunters who were particularly well adapted to the open savannah. It is for this reason that they flourished in Dhofar, which was experiencing much wetter climatic conditions at that time.”
Second, the expansion took place tens of thousands of years earlier than predicted by geneticists, forcing Rose's team to re-evaluate the genetic dating methods.
“This early date may mean the 'great expansion' that occurred 70,000 years ago originated in Arabia, and not Africa. Third, the expanding groups moved into the interior. Not one site was found anywhere near the coast, completely overturning the prevailing coastal expansion hypothesis,” he said.
Confined to the Nejd Plateau in Dhofar, Rose's team has unearthed more than 100 sites classified as Nubian Middle Stone Age (MSA). Nubian MSA artefacts are well known throughout the Nile Valley, but this is the first time such sites have been found outside Africa.
A dating technique called 'optically stimulated luminescence,’ which measures how much radiation a mineral has absorbed over time, revealed that the tools are roughly 106,000 years old.
“This is considerably older than present biological data that indicates men left Africa between 70,000 and 40,000 years ago.”
So far the researchers have not discovered the remains of humans or any animals at the site. “The conditions are not very conducive to preservation, as all bone breaks down here.
"However, Nubian Complex artefacts are associated with modern human remains in Egypt, so it's pretty safe to assume these toolmakers are the same species that was in Arabia,” said Rose.