This was a big week for Middle-Late Pleistocene fossil humans. Chun-Hsiang Chang and colleagues describe a mandible dredged up off the western coast of Taiwan, which they note in the title as, “The first archaic Homo” fossil known from the region. The geological context makes it difficult to date the specimen precisely, but authors argue it is probably younger than 190 thousand years old.
In life, this individual was fully grown but appears never to have developed third molars (the “wisdom teeth”). Such “third molar agenesis” is relatively rare before modern times, but is also seen in the D2735 Homo erectus mandible from Dmanisi. I wouldn’t make much of this coincidence, but it does raise the question of whether the cause of agenesis, not uncommon today, was the same then as now.
Shortly after the announcement of the Penghu mandible, Israel Hershkovitz and colleagues presented a 55,000 year old brain case from Manot Cave in the Levant. The calvaria (fancy word for brain case) looks very similar to the skulls of the slightly younger “anatomically modern” humans of the Upper Paleolithic in Europe, albeit with a few Neandertal-like traits here and there (hey, just like many of the Upper Paleolithic humans).
John Hawks has good posts dedicated to both Penghu and Manot. The upshot of these discoveries is that Middle and Late Pleistocene human population diversity, and the interactions between these populations, are probably much more complicated and interesting than the old model of ‘modern’ humans arising singly in Africa and replacing ‘archaic’ humans in different parts of the globe. With the technological advances and fossil discoveries of the past decade, the rather simple Replacement model has given way to a better appreciation of true complexity of human evolution toward the end of the Ice Age. Both of these new papers reflect this new perspective.
Along these lines, accompanying the Manot paper in Nature is an editorial, “Human history defies easy stories.” What caught my attention reading this (anonymous?) commentary is that it puts scientific interpretations of the past into a social and historical context. The author notes that the traditional story of modern humans arising, spreading and eradicating other groups of human has “imperialist framing, in which evolution and replacement can be justified after the fact as a kind of manifest destiny.” Science doesn’t occur in a vacuum, it’s done by people whose minds and creativities are molded in specific historical, economic and cultural contexts. This editorial comment makes one wonder how the human fossil record would have been interpreted, had most of it not discovered against the social backdrop of ruthless capitalism.