Published: Tue, April 10, 2018
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Saudi desert fossil dates back 90000 years

Saudi desert fossil dates back 90000 years

Because of this uncertainty, the Al Wusta finger bone is the oldest confirmed remnant of a modern human found outside Africa and the Levant. Now, archaeologists have evidence of humans successfully striking out into the unknown, early in our species' history. Now, they may have it.

An 85,000-year-old fossilized finger bone found in Saudi Arabia and announced by archaeologists on Monday seems to suggest humans left Africa and the Levant area much earlier than previously thought. The discovery supports the idea that early modern humans spread into Eurasia earlier and more often than many previously believed. Analysis led by Huw Groucutt from the University of Oxford, UK, identified the bone as definitively that of an anatomically modern human. For decades, the fossil evidence favored the hypothesis that anatomically modern humans stayed on the continent, with an occasional jaunt into neighboring Israel, for hundreds of thousands of years until a wave of migrants swept into Eurasia-and then throughout the world-between 50,000 and 60,000 years ago. Teeth found in Chinese caves have been dated to between 80,000 and 120,000 years, although the dates are based on the caves' stalagmites, not the teeth themselves.

Until now, many scientists thought that early humans left Africa about 60,000 years ago and then hugged the coastline, living off marine resources, said study senior researcher Michael Petraglia, an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany. Others have argued there were several migrations in and out of Africa throughout this whole period. It is also the first ancient human fossil from the Arabian Peninsula.

"These dried lake beds are being exposed by the moving sand dunes, so they're just literally lying on the surface, it's just a matter of looking around and seeing what we can find", Dr Louys said.

Fossil finger bone of Homo sapiens from the Al Wusta site, Saudi Arabia.

"These animals tell us that when humans were living there it was not a desert, that the site was a lake, a small but permanent perennial freshwater lake, in a grassland setting", said Groucutt. Dozens of sharpened stone tools buried in the sediment hinted that it might be a special place. The team estimates the bone is at least 85,000 years old.

"The Al Wusta research adds support to the notion that there were numerous, perhaps almost continuous, pulses of Homo sapiens dispersals from Africa, and that regional moist episodes may have triggered the dispersals", says Donald Henry of the University of Tulsa in Oklahoma. It is the second bone in from the fingertip, but it's not clear which finger.

The object in question is a fossilised piece of a bone, probably the middle portion of a middle finger. Professional anatomists analyzed 3D scans of the bone and concluded that it was a match for our own species, rather than another early hominins such as Neandertals or a member of Australopithecus.

Using a technique called uranium series dating, a laser was used to make microscopic holes in the fossil and measure the ratio between tiny traces of radioactive elements. Moreover, the researchers uncovered human-made stone tools there.

The single fossil finger bone of Homo sapiens - pictured from various angles - from the Al Wusta site, Saudi Arabia.

"It has major implications with respect to how our species came out of Africa and the route and the pathways that they took out of Africa".

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