After their initial assessment, some scientists were persuaded to name the Dmanisi find as a new species, Homo georgicus, which they posited as a descendant of African Homo habilis and an ancestor to Asian Homo erectus. This classification, however, was not supported, and the fossil was instead designated a divergent subgroup of Homo erectus.
The fossil skeletons present a species primitive in its skull and upper body but with relatively advanced spine and lower limbs, inferring greater mobility than the previous morphology. It is now thought not to be a separate species, but to represent a stage soon after the transition between H. habilis to H. erectus; it has been dated at 1.8 mya. The assemblage includes one of the largest Pleistocene Homo mandibles (D2600), one of the smallest Lower Pleistocene mandibles (D211), a nearly complete sub-adult (D2735), and a toothless specimen D3444/D3900.
Two of the skulls—D2700, with a brain volume of 600 cubic centimetres (37 cu in), and D4500 or Dmanisi Skull 5, with a brain volume of about 546 centimetres—present the two smallest and most primitive Hominina skulls from the Pleistocene period. The variation in these skulls were compared to variations in modern humans and within a sample group of chimpanzees. The researchers found that, despite appearances, the variations in the Dmanisi skulls were no greater than those seen among modern people and among chimpanzees. These findings suggest that previous fossil finds that were classified as different species on the basis of the large morphological variation among them—including Homo rudolfensis, Homo gautengensis, H. ergaster, and potentially even H. habilis—should perhaps be re-classified to the same lineage as Homo erectus.
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