Modern humans may have arrived in the Middle East and Europe at roughly the same time, according to a new study conducted by an international team of researchers.
Published in the journal PLOS ONE, the paper offers an intriguing twist to the story of how humanity's ancestors left Africa.
Included in the study are the radiocarbon dates of marine shell beads uncovered at a site in Lebanon known as Ksar Akil. The beads, the researchers deduced, are between 42,400 and 41,700 years old -- information that allowed them to date the oldest human fossil from the same sequence of archaeological layers back to the same period.
The shells are perforated, suggesting they were used for decoration either on clothing or the body -- a trend unique to modern humans. Based on this evidence, the researchers argue against the possibility that the artifacts date back to the time of the Neanderthals who occupied the region prior to the modern human population.
Furthermore, the scientists were able to confirm that the shell beads are only linked to those parts of the archaeological sequences assigned to modern humans, leaving no room for doubt regarding their origins.
Current theories hold that early modern humans arrived in Europe 45,000 years ago after traveling out of Africa through the Middle East. The new dating evidence suggests modern humans arrived at the two places more or less simultaneously, however, pointing to the possibility that different routes were taken during this time of expansion.
"It is possible that instead of the Near East being the single point of origin for modern humans heading for Europe, they may also have used other routes too," lead author Katerina Douka, a professor of archaeology at the University of Oxford, said in a statement. "A maritime route across Mediterranean has been proposed although evidence is scarce. A wealth of archaeological data now pinpoints the plains of Central Asia as a particularly important but relatively unknown region which requires further investigation."