YEMEN SITE YIELDS TOOLS FROM 63,000 YEARS AGO -- TOOL MAKERS VERY FAR INLAND A SURPRISE!

Stone Age tools uncovered in Yemen point to humans leaving Africa and inhabiting Arabia perhaps as far back as 63,000 years ago, archaeologists report from the site of Shi'bat Dihya located in a wadi, or gully, that connects Yemen's highlands to the coastal plains of the Red Sea.

The age of the site puts it squarely at a time when early modern humans were thought to be first emigrating from Eastern Africa to the rest of the world. "The Arabian Peninsula is routinely considered as the corridor where migrating East African populations would have passed during a single or multiple dispersal events," says the study.

"It has also been suggested that the groups who colonized South Asia rapidly expanded from South and East Africa along the Arabian coastlines, bringing with them a modern behavioral package including microlithic (stone) backed tools, ostrich-eggshell beads or engraved fragments.

One new site is the study's subject, Shi'bat Dihya, located along the Wadi Sudud. Excavating down to a level dating to perhaps 63,000 years ago, when the region was quite arid, the team found some "5,488 artifacts" -- Stone Age blades, pointed blades and pointed flakes, nearly an inch long or longer, as well as the bones of 97 animals, mostly cows, horses, pigs and porcupines.

Finding tool-makers so far inland, nearly 75 miles from the coast, surprised the study team, as most models of human expansion picture our ancestors migrating along the coasts on their way to Europe and Asia. "The adaptation of the occupants of Wadi Sudud to an arid environment significantly nuances the environmental determinism inherent in nearly all models concerning the peopling of southern Arabia," says the study.

Most intriguing, the stone tools found at the site fall into the tradition of older Stone Age tools, rather than ones associated with the early modern humans thought to have left Africa roughly 60,000 years ago. They might have belonged to descendants of earlier modern human migrants from Africa who established themselves in Arabia despite its desert conditions. Or maybe they belonged to a sister human species, our Neanderthal cousins, suggest the researchers:

"Our fieldwork at the Wadi Surdud in Yemen demonstrates that during the period of the supposed expansion of modern humans out of Africa (60,000 to 50,000 years ago), and their rapid dispersal toward south-eastern Asia along the western and southern Arabian coastlines, the interior of this region was, in fact, occupied by well-adapted human groups who developed their own local technological tradition, deeply rooted in the Middle Paleolithic. Future research will likely reveal whether the archaeological assemblages recovered from the Wadi Surdud can be associated with the descendents of anatomically modern human groups who occupied the Arabian Peninsula during (this era) or the southernmost expansion of the Neanderthals."