What New Information Is Provided by the Discoveries at Dmanisi

Given the radiometric, paleomagnetic, stratigraphic, and bio-chronological evidence compiled from Dmanisi, there is no doubt that hominins were present in the Caucasus 1.8-1.7 Ma ago. This site preserves an extraordinary record of what is presently the earliest known occupation outside of Africa. However, it is unlikely that Dmanisi documents the very first human excursions from Africa into Eurasia, and most probably there were earlier dispersal events, perhaps largely unsuccessful, for which archaeological traces have not been found. In any case, it can be established that the West Asian populations were broadly coeval with both Homo habilis and Homo erectus in East Africa.

The very complete crania, entire mandibles, and teeth from Dmanisi display the suite of diagnostic characters listed in Table 5.1, and the fossils are clearly representative of Homo. Five individuals can be identified. One (D2700/ D2735) is subadult, while another (D3444/D3900), displaying severe resorption of the alveolar processes and retaining only a single (lower) tooth at death, is probably an older adult. There is considerable variation in morphology within the Dmanisi assemblage. Indeed, differences among the specimens have led some workers to claim that multiple species may be documented (Schwartz and Tattersall, 2002), or that size variation exceeds the level expected for populations belonging to genus Homo (Skinner et al., 2006). To a degree, these conclusions are driven by the appearance of the D2600 mandible. This large individual has been described as possessing a novel combination of features, not observed in Homo rudolfensis, Homo habilis, or Homo erectus (Gabunia et al., 2002). However, there are difficulties with such an argument. D2600 presents obvious signs of periodontal disease, and this has affected the original morphology. Also, it has not been demonstrated that corpus size precludes placing D2600 with the other lower jaws (Rightmire et al., 2008).

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