Oldest human fossil unearthed outside Africa

An 85,000-year-old fossilized human finger bone found in the Saudi Arabian desert suggests that 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 region 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 fossilized finger bone from the Al Wusta site in Saudi Arabia, which dates back to around 85,000-90,000 years ago, we think Homo sapiens left Africa much 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 author Huw Groucutt, an archaeologist at the University of Oxford in the UK. That’s because humans have longer, more slender fingers than Neanderthals who lived around 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 said.

The finger bone belonged to an adult, but it’s unclear whether it was a man or a woman. The finger became fossilized through mineralization and was preserved in a dry environment for thousands of years, with no trace of DNA remaining, 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 (a species of 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 the sub-Saharan region to Saudi Arabia. "And of course, the hunter-gatherer community would have followed these animals," Petraglia said.i.

Phuong Hoa