April 9 (UPI) -- Archaeologists working in Saudi Arabia have unearthed the oldest Homo sapien fossil yet recovered outside of Africa and the Levant, the region consisting of present day Israel, Syria, Lebanon and Jordan.
The 87,000-year-old middle finger bone, measuring just 1.2 inches in length, suggests the earliest human migrations out of Africa and into Eurasia were more expansive than previously thought.
The fossil was found buried beneath the sands of the Nefud Desert, which today stretches across the Northern Arabia Peninsula. The site where the fossil was found was once home to a freshwater lake.
Around the time humans showed up, a climatic shift brought monsoons to the region, spawning grasslands. Animal fossils suggest antelope grazed the land and hippos swam in the ancient lake.
Researchers measured ratios of radioactive elements in the finger bone and compared the ratios to those found in animal fossils with confirmed dates. The analysis confirmed the age of the human fossil, the oldest found in Arabia.
"This discovery for the first time conclusively shows that early members of our species colonized an expansive region of southwest Asia and were not just restricted to the Levant," Huw Groucutt, a researcher with the University of Oxford and the Max Planck Institute for the Science of Human History, said in a news release. "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."
The findings, published this week in the journal Nature Ecology & Evolution, are just the latest to lend further complexity to the story of human evolution and migration.
Until recently, scientists thought modern humans left Africa in a mass exodus around 60,000 years ago, spreading out across Eurasia -- the so-called out-of-Africa migration. But over the last decade, scientists have uncovered evidence that suggests the mass exodus was preceded by earlier, smaller migrations out of Africa, some as far back as 180,000 years ago, forcing researchers to revamp the story of human evolution.
The latest research suggests some of those early migrants made it as far as the Arabian Peninsula.
"The Arabian Peninsula has long been considered to be far from the main stage of human evolution," said Michael Petraglia, a professor at the Max Planck Institute for the Science of Human History. "This discovery firmly puts Arabia on the map as a key region for understanding our origins and expansion to the rest of the world. As fieldwork carries on, we continue to make remarkable discoveries in Saudi Arabia."