New Homo sapiens Fossil Found in Arabia

A new fossil finger has been unearthed as Arabia that purports to be 87 ky old.  UPI is on it.

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.

Indigenous Arabs Direct Descendents of Modern Human Wave From Africa?

PhysOrg is running a story about research coming out of Weill Cornell Medicine and Qatar.  Abigail Fagan writes:

The investigation, published online Jan. 4 in Genome Research, sequenced the genomes of 104 Arabian Peninsula natives and compared them with 1,092 genomes from worldwide populations. The researchers compared each pair of genomes in the sample, which allowed them to cluster research participants by genome similarity so that an evolutionary tree emerged. The genomes of indigenous Arabs resulted in a unique cluster separate from the initial African population, illustrating the formation of a distinct population. European and Asian clusters diverged after the Arab population.

These data reinforce the "southern route" model of early modern human origins, which argues that early modern humans left Africa initially by crossing over or ferrying over the northern tip of the Gulf of Aden, near what is currently Djibouti.

Modern Humans Out of Africa Earlier Than Thought?

The Australian is reporting on the find in Arabia of stone tools purported to be crafted to modern humans that date to around 100 000 years ago (date derived by thermoluminescence). They write:

Jeffrey Rose, an archaeologist with Britain's Birmingham University and head of the Dhofar Archaeological Project, said: "After a decade of searching in southern Arabia for some clue that might help us understand early human expansion, at long last we've found the smoking gun of their exit from Africa."

The discovery also challenges current thinking about the route the migrants took, say Dr Rose and his colleagues, including geochronologist Bert Roberts of Wollongong University.

The article shows up in PLoS¹. This is intriguing and certainly adds one more piece of the puzzle but I am not sure why it so earth-shattering. We already know that we have hominins in the Levant that pass, in most ways, for modern humans and are dated to between 90 and 110 000 B.P. We also have the Herto remains at 140-160 000, which are also mostly modern. A glance at the map shows that the gap between the Horn of Africa and the Arabian peninsula is very narrow here and it would not have been a problem to navigate the waters at this point. This just represents another migration route of many. The authors of the paper call the assemblage that was discovered a Nubian variant of the “Middle Stone Age,” which tracks as a post-Acheulean industry and is present in various forms in Africa from about 300 000 years B.P. down to around 40 000 or so. Here is the map from the article:



As you can see, there is Nubian in both Arabia and in the Nile valley. Interestingly, when you get to the Levantine peninsula, you run into “modern” humans creating Levantine Mousterian, another Middle Palaeolithic industry, which means they had contact with the Neandertals who were escaping the cold to come south during the early Würm glaciation. It is during the Early Würm/Late Würm interglacial period that the early moderns get the bright idea to head north, out of the Levant.

¹Rose JI, Usik VI, Marks AE, Hilbert YH, Galletti CS, et al. (2011) The Nubian Complex of Dhofar, Oman: An African Middle Stone Age Industry in Southern Arabia. PLoS ONE 6(11): e28239. doi:http://dx.doi.org/10.1371/journal.pone.0028239


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