Circum-Mediterranean biological connections and the pattern of late Pleistocene human evolution

The isolation of human populations in Europe and in Africa is critical for models of modern human origins based on speciation events and total replacement of Neandertals and other archaic human groups by modern humans. Pleistocene human samples from Africa, west Asia and Europe are investigated to assess the morphological evidence for both isolation and regional interconnections. Four types of data are utilized : (1) results of a multivariate analysis of frontal bone shape, (2) distribution of patterns of supraorbital torus/brow ridge shape, (3) incidence of "cladistic" markers for Neandertals, and (4) occurrence of occipital buns. Environmental factors possibly influencing middle and late Pleistocene human evolution are also discussed. It is concluded that enough evidence exists for biological interconnections around the Mediterranean during this period to rule out regional isolation extensive enough to foster speciation. Thus, Homo sapiens has been a single, polytypic species since the Middle Pleistocene.