Finger fossil unlocks mysteries of migration
The earliest Homo sapiens fossil discovered in Saudi Arabia means the first human migration out of Africa was much more geographically widespread than thought, a new study suggests.
The fossil, an adult human’s finger bone, dates to 90,000 years ago, when the region’s barren desert was green grassland.
Study lead author Huw Groucutt of the University of Oxford said the discovery shows for the first time that early humans lived in an expansive region in southwest Asia and weren’t restricted to the Levant, an area that includes modern-day Israel, Lebanon, Syria and Jordan.
“The ability of these early people to widely colonize this region casts doubt on long-held views that early dispersals out of Africa were localized and unsuccessful,” Groucutt said.
The earliest Homo sapiens fossils date to about 315,000 years ago from Africa. Previously discovered human fossils show an earlier human presence in Israel and possibly China.
The finger bone was discovered in 2016 at the site of Al Wusta, an ancient freshwater lake in the arid Nefud Desert, about 340 miles southeast of the Sinai Peninsula.
Archaeologists had believed humanity’s movement out of Africa was in a single, rapid wave about 60,000 years ago, study co-author Michael Petraglia, an archaeologist from Germany’s Max Planck Institute, said at a news briefing.
The fossil finding instead suggests modern humans moved out of Africa multiple times during many windows of opportunity in the past 100,000 years or so, he said.
The authors concluded from the early incursion into what was a green Arabia that human movement out of Africa may have been helped by natural climate change in the form of increased precipitation.
As summer rainfall fell more frequently in Arabia, it allowed migrating
“The ability of these early people to widely colonize this region casts doubt on long-held views that early dispersals out of Africa were localized and unsuccessful.”
Huw Groucutt University of Oxford
humans to occupy not only the woodlands of the Levant — which were sustained by winter rainfall — but also semi-arid grasslands in the Arabian interior such as Al Wusta. The region was “a fertile, lowland zone attractive to colonization by plants, animals and humans,” Donald Henry, an anthropologist at the University of Tulsa, said in an article that accompanied the study.
The authors suggested that adapting to the new environment would have been an early step on Homo sapiens’ path to global success.
The results were published Monday in the journal Nature Ecology and Evolution.