Indicative Fossil from Georgia
Dmanisi in the Republic of Georgia is the well known site of the first evidence of Homo erectus outside of Africa and once more has yielded a rich find according to a paper in the journal Science this week. Known informally as Skull 5 and assigned the number D4500, this complete skull required no reconstruction. The brain cases been measured at 546 cm³ and is clearly attributable to H. erectus. Olduwan tools have been found in association with the skull.
Researchers believe Dmanisi was occupied nearly continuously from 1.85 to 1.77 million years ago (ma), or 80,000 years, based on argon/argon dating.
A team of international researchers announced finding a complete cranium and associated mandible which casts the contentious discussion of early Homo in a new light. As visitors to this website are aware, the question of which fossils comprise the earliest evidence of the genus Homo (and the related question of which may or may not be on a direct evolutionary line to later Homo) have bedeviled scientists for some time. Authors David Lordkipanidze, Marcia S. Ponce de León, Ann Margvelashvili, Yoel Rak, G. Philip Rightmire, Abesalom Vekua and Christoph P. E. Zollikofer say significant anatomical features of this skull can be found in earlier fossils assigned to the genus Homo, such as H. habilis, H ergaster and H. rudolfensis, and argue all comprise a single species within the genus Homo, with less variation among them than can be found within contemporary Homo sapiens.
The abstract of this paper reads:
The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. Here we report on a new cranium from Dmanisi (D4500) that, together with its mandible (D2600), represents the world's first completely preserved adult hominid skull from the early Pleistocene. D4500/D2600 combines a small braincase (546 cubic centimeters) with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.
Watch Donald Johanson on the PBS NEWS HOUR discussing the D4500 find.
The Guardian newspaper website has a brief but highly informative video on D4500.