A fossil finger bone has lent further evidence to the increasingly firm theory that Homo sapiens migrated out of Africa much earlier than previously thought.
A paper in the journal Nature Ecology and Evolution details the analysis of a small human finger bone uncovered at a Saudi Arabian archaeological site known as Al Wusta, an ancient freshwater lake located in what is now the Nefud Desert.
Excavations at the site produced an abundance of animal bones, including those from hippos, as well as many fossilised freshwater snails. Stone tools were also recovered.
Among the finds was a single small hominin bone. Analysis led by Huw Groucutt from the University of Oxford, UK, identified the bone as definitively that of an anatomically modern human.
Uranium-thorium dating – in which the age of an object is deduced by measuring the relative presence of the radioactive isotopes thorium-230 and uranium-234 – established that the fossil was 90,000 years old – making it one of the most ancient human remnants discovered outside Africa.
The find represents another challenge to the long-held theory that human migration from Africa began about 60,000 years ago.
While the picture is still unclear, discoveries from around the world are revealing that the spread of our species began much earlier than initially assumed.
A paper published in February this year reported that a human jaw bone unearthed at a site in Israel known as the Misilya Cave dated to between 177,000 and 194,000 years before present. And a celebrated find in northern Australia, announced in 2015, found evidence of human settlement at a site called Madjedbebe dating to at least 60,000 years ago – an impossible feat if Homo sapiens was only just exiting Egypt at the time.