New evidence has emerged that shows human ancestor Homo erectus may have evolved in Asia and then gone to Africa, not vice versa as many scientists have assumed.
The findings showed the species occupied a West Asian site called Dmanisi from 1.85 million to 1.77 million years ago, at the same time or slightly before the earliest evidence of this humanlike species in Africa.
Geologist Reid Ferring of the University of North Texas in Denton and his colleagues said the new Dmanisi discoveries point to an Asian homeland for H erectus.
"Dmanisi was occupied repeatedly for roughly 80,000 years and supported a population that was well established and probably quite mobile," Science News magazine quoted Ferring as saying.
Ferring's team suspects that an as-yet-unidentified African hominid reached Asia before 1.85 million years ago and evolved into H erectus.
"With the new Dmanisi dates, it certainly looks as though the African origin of H erectus must be reconsidered," Harvard University anthropologist Philip Rightmire said.
The new Dmanisi discoveries come from just beneath soil that previously yielded 1.77-million-year-old H erectus fossils, including skulls with surprisingly small brain cases suggestive of an early form of the species.
Excavations produced 73 stone tools for cutting and chopping, as well as 34 bone fragments from unidentified creatures.
The artefacts came from a series of H erectus camps at Dmanisi between 1.85 and 1.78 million years ago, the scientists said.
Measurements of reversals in Earth's magnetic field and of the rate of decay of the element argon in a series of volcanic ash layers provided age estimates for the new finds.
The findings have been published online June 6 in the Proceedings of the National Academy of Sciences.