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.How do we know it was from Homo sapiens?
Among these finds was a well preserved and small fossil, just 3.2 cm long, which was immediately recognized as a human finger bone. The bone was scanned in three dimensions and its shape compared to various other finger bones, both of recent Homo sapiens individuals and bones from other species of primates and other forms of early humans, such as Neanderthals. The results conclusively showed that the finger bone, the first ancient human fossil found in Arabia, belonged to our own species.I do not have access to this article as neither the lab nor UT has a subscription to Nature: Ecology & Evolution. Aside: Given our focus on materials science and computing, I kind of get why ORNL does not have a subscription. UT, not so much. This journal should be in their wheelhouse. According to the abstract, the find is securely dated and:
The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna.Maddenly, there is no information in the abstract about the morphology of the find, especially given that Neandertal and early anatomically modern phalanges are remarkably similar. I am sure they were able to differentiate it, but I would sure like to know how.