Oldest human fossil from Saudi Arabia changes timeline for migration out of Africa

Doyle Rice | USA TODAY

Show Caption Hide Caption Oldest human fossil found outside of Africa The oldest known human fossil found outside of Africa has been uncovered, and it disrupts the timeline for when modern humans left the continent.

The oldest homo sapiens fossil ever discovered in Saudi Arabia means the first human migration out of Africa was much more geographically widespread than originally thought, a new study suggests.

The fossil, an adult human's finger bone, dates back 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 for the first time conclusively shows that early humans lived in an expansive region in southwest Asia and weren't just 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 around 315,000 years ago from Africa. Previously discovered human fossils show an earlier human presence in Israel and possibly China.

More: Scientists discover oldest human fossil outside of Africa

The finger bone was discovered in 2016 at the site of Al Wusta, an ancient freshwater lake located in what is now the extremely arid Nefud Desert, about 340 miles southeast of the Sinai Peninsula.

Archaeologists previously thought humanity's movement out of Africa was in a single, rapid wave some 60,000 years ago, study co-author Michael Petraglia, an archaeologist from Germany's Max Planck Institute, said at a news briefing.

The finding instead suggests modern humans moved out of Africa multiple times during many windows of opportunity during the last 100,000 years or so, he said.

"This discovery of a fossil finger bone for me is like a dream come true because it supports arguments that our teams have been making for more than 10 years,” Petraglia said.

The authors conclude from this early incursion into what was then 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 began to fall more frequently in Arabia, it allowed migrating humans to occupy not only the woodlands of the Levant — which were sustained by winter rainfall — but also such semi-arid grasslands in the Arabian interior as Al Wusta.

At that time, the region was "a fertile, lowland zone attractive to colonization by plants, animals and humans," noted Donald Henry, an anthropologist at the University of Tulsa, in an article that accompanied the study.

The authors suggest that adapting to this new environment would have been an early step on homo sapiens‘ path to global success.

The results were published Monday in Nature Ecology and Evolution, a peer-reviewed British journal.

Contributing: The Associated Press



