Oldest human fossil unearthed outside Africa

An 85,000-year-old fossilized human finger bone found in the Saudi Arabian desert suggests early humans migrated out of Africa along a completely different route than previously thought, according to research published on April 9 in the journal Nature Ecology & Evolution.Live ScienceThe discovery is the oldest human fossil outside Africa and the Levant, the area surrounding the eastern Mediterranean (including Israel), and the oldest human remains in Saudi Arabia.

Previously, many scientists believed that early humans left Africa around 60,000 years ago and then settled in coastal areas, living off marine resources, according to researcher Michael Petraglia, an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany. "But now, with the fossil finger bone from the Al Wusta site in Saudi Arabia, which is about 85,000-90,000 years old, we think Homo sapiens left Africa earlier," Petraglia said.

Iyad Zalmout, a co-author of the study and a paleontologist at the Saudi Arabian Geological Survey, found the 3.2-centimeter-long finger bone in the Nefud Desert in 2016. The shape of the bone suggested it belonged to Homo sapiens, according to lead researcher Huw Groucutt, an archaeologist at the University of Oxford in the UK. This is because humans have longer, more slender fingers than Neanderthals who lived at the same time. However, the team still asked colleagues to conduct a computed tomography (CT) scan to be sure.

After comparing the newly discovered fossil's CT scan with several other species with human-like fingers, including orangutans, Old World monkeys, Australopithecus afarensis, Australopithecus sediba, and Neanderthals, the team determined that the remains were human, most likely the middle segment of the middle finger. "All the studies agree that the finger is from Homo sapiens. The shape of the finger bone in Homo sapiens is quite unique compared to other species," Groucutt commented.

The finger bone belonged to an adult, but it’s unclear whether it was a man or a woman. The finger, which had been mineralized and preserved in a dry environment for thousands of years, likely didn’t contain any DNA, Groucutt said.

Al Wusta is now a desert, but about 85,000 years ago, there was a freshwater lake that attracted many animals, including hippos, Pelorovis (an extinct species of wild buffalo) and Kobus (an African antelope). The team found human-made stone tools there.

The reason African animals were in Saudi Arabia at that time may have been because the rainy season transformed the region into semi-arid grasslands interspersed with rivers and lakes, attracting animals from sub-Saharan Africa to Saudi Arabia. "And of course, hunter-gatherer communities would have followed these animals," Petraglia said.i.