Hugh Pickens DOT Com writes: The idea that there were several different human species walking the Earth two million years ago has been dealt a blow as Melissa Hogenboom writes at BBC that palaeoanthropologists say that discoveries in Georgia support the idea that that Homo habilis, Homo rudolfensis and Homo erectus are all part of a single evolving lineage that led to modern humans, not three distinct species. A team looked at the most complete hominid skull ever found which was uncovered in Dmanisi, Georgia. It had a small braincase, large teeth and a long face, characteristics it shares with H.habilis but many features from the braincase were also unique to H.erectus. The fossil remains show a lot of variation which had previously puzzled archaeologists, but that it is clear that these features were all from one population. "When we looked at this variability and compared it with modern humans, you can see this is a normal range of variation," says Prof Lordkipanidze. The skull was uncovered eight years ago and since then the team has compared it to other Homo fossils found in Africa from as early as 2.4 million years ago. "We see a similar pattern and range of variation in the African fossil record, it is sensible to assume that there was a single Homo species at that time in Africa," says Prof Zollikofer. "And since the Dmanisi hominids are so similar to the African ones, we further assume that they both represent the same species." Other palaeoanthropologists believe that at least three distinct species of humans co-existed in Africa. Chris Stringer at the Natural History Museum in London says he is doubtful that all of the early Homo fossils can be lumped into an evolving H.erectus lineage. "Only H.Erectus survives and becomes successful but at the origin nature was experimenting with how to evolve humans in terms of increasing brain size," says Stringer. "Creatures were starting to use tools and eat meat, and this drove evolution, but I think it also drove diversity. The Dmanisi group is an example of the successful species that came out of that and then carried on to spread around the old world."