Scientists have unearthed a complete skull from Dmanisi, Republic of Georgia, which combines traits found in early Homo skulls from Africa. The 1.78-million-year-old find has a large brow typical of Homo erectus, the small brain of Homo habilis, and large teeth similar to Homo rudolfensis – all recognized as separate species in East Africa. Analysis of the new skull suggests that these early forms of the genus Homo evolved as a single, highly variable lineage, assigned to the species Homo erectus.
This controversial conclusion arises from how species originate: populations can diverge and become independent species or may reunite with distinctive variations of a single species. Five skulls already discovered at Dmanisi are the oldest known fossils of the genus Homo outside of Africa. Experts familiar with fossil Homo celebrate the new discovery, but many think the African fossils still reflect three species of early Homo between 1.5 and 2.0 million years ago.
The Dmanisi skull study was led by David Lordkipanidze, and was published in the journal Science, October 18, 2013.
Newly reported Dmanisi cranium (center) is compared with scanned replicas of East African Homo erectus (2 crania at top), Homo rudolfensis (bottom left), and Homo habilis (bottom right). 5 centimeter scale. Credit: Georgian National Museum and Fred Spoor