WASHINGTON — The world wide spread of ancient humans has long been depicted as flowing out of Africa, but tantalizing new evidence suggests it may have been a two-way street.
A long-studied archaeological site in a mountainous region between Europe and Asia was occupied by early humans as long as 1.85 million years ago, much earlier than the previous estimate of 1.7 million years ago, researchers report in today’s edition of Proceedings of the National Academy of Sciences.
Early human Homo erectus is known to have occupied the site at Dmanisi later. Dmanisi is located in the Republic of Georgia.
Discovering stone tools and materials from a much earlier date raises the possibility that Homo erectus evolved in Eurasia and might have migrated back to Africa, the researchers said — though much study is needed to confirm that idea.
“The accumulating evidence from Eurasia is demonstrating increasingly old and primitive populations,” said Reid Ferring of the University of North Texas.
“The recently discovered data show that Dmanisi was occupied at the same time as, if not before, the first appearance of Homo erectus in east Africa,” said the team led by Ferring and David Lordkipanidze of the Georgia National Museum. They uncovered more than 100 stone artifacts in deep layers at the site. Previously, fossil bones from a later period had been found at the site.
The new discovery shows that the Caucasus region was inhabited by a sustained population, not just transitory colonists.
“We do not know as yet what the first occupants looked like, but the implication is that they were similar to, or possibly even more primitive than those represented by Dmanisi’s fossils,” Ferring explained.
The occupants of Dmanisi “are the first representatives of our own genus outside Africa, and they represent the most primitive population of the species Homo erectus known to date,” added Lordkipanidze.
The geographic origins of Homo erectus are still unknown.
The early humans at Dmanisi “might be ancestral to all later Homo erectus populations, which would suggest a Eurasian origin of Homo erectus,” said Lordkipanidze. However, there’s another theory as well: Homo erectus originated in Africa, and the Dmanisi group might represent its first migration out of Africa.
