Blow to multiple human species idea
18 October 2013 Last updated at 13:37 BST
Scientists believe a skull, discovered in Georgia, disproves a theory that there were several different human species walking the Earth two million years ago.
Instead, experts have said early human fossils found in Africa and Eurasia may have been part of the same species.
Writing in the journal Science, the team said that Homo habilis, Homo rudolfensis and Homo erectus were all part of a single evolving lineage that led to modern humans.
David Lordkipanidze from the Georgian National Museum in Tblisi, led the team that made the discovery.