"The Dmanisi fossils give us a new yardstick, and when you apply that yardstick to the African fossils, a lot of that extra wood in the tree is dead wood. "Some palaeontologists see minor differences in fossils and give them labels, and that has resulted in the family tree accumulating a lot of branches," said White. The fossil is described in the latest issue of Science. If the scientists are right, it would trim the base of the human evolutionary tree and spell the end for names such as H rudolfensis, H gautengensis, H ergaster and possibly H habilis. We are using five or six names, but they could all be from one lineage." But one population can have all this variation. Illustration: J H Matternesĭavid Lordkipanidze at the Georgian National Museum, who leads the Dmanisi excavations, said: "If you found the Dmanisi skulls at isolated sites in Africa, some people would give them different species names. Reconstruction of the early human ancestor Homo erectus from the latest skull found at Dmanisi in Georgia. Part of the community will like it, but for another part it will be shocking news." "We are not saying that palaeoanthropologists did things wrong in Africa, but they didn't have the reference we have. "Everything that lived at the time of the Dmanisi was probably just Homo erectus," said Prof Zollikofer. Rather than being separate species, the human ancestors found in Africa from the same period may simply be normal variants of H erectus. They concluded that the variation among them was no greater than that seen at Dmanisi. The scientists went on to compare the Dmanisi remains with those of supposedly different species of human ancestor that lived in Africa at the time. They found that while the Dmanisi skulls looked different to one another, the variations were no greater than those seen among modern people and among chimps. The odd dimensions of the fossil prompted the team to look at normal skull variation, both in modern humans and chimps, to see how they compared. The dimensions were so strange that one scientist at the site joked that they should leave it in the ground. But at just under 550 cubic centimetres, it also had the smallest braincase of all the individuals found at the site. It had a long face and big, chunky teeth. The latest skull discovered in Dmanisi belonged to an adult male and was the largest of the haul. The Dmanisi fossils show that H erectus migrated as far as Asia soon after arising in Africa. The species arose in Africa around 1.8m years ago and may have been the first to harness fire and cook food. The remains at Dmanisi are thought to be early forms of Homo erectus, the first of our relatives to have body proportions like a modern human. The most recently unearthed individual had a long face and big teeth, but the smallest braincase of all five H erectus skulls found at the site. Over decades excavating sites in Africa, researchers have named half a dozen different species of early human ancestor, but most, if not all, are now on shaky ground. This is going to be one of the real classics in paleoanthropology," said Tim White, an expert on human evolution at the University of California, Berkeley.īut while the skull itself is spectacular, it is the implications of the discovery that have caused scientists in the field to draw breath. "The significance is difficult to overstate. Other researchers said the fossil was an extraordinary discovery. Homo is the genus of great apes that emerged around 2.4m years ago and includes modern humans. They simply did not exist before," he said. "This is the first complete skull of an adult early Homo. "Nobody has ever seen such a well-preserved skull from this period," said Christoph Zollikofer, a professor at Zurich University's Anthropological Institute, who worked on the remains. They are thought to have died within a few hundred years of one another. The remains of the individuals were found in collapsed dens where carnivores had apparently dragged the carcasses to eat. The site was a busy watering hole that human ancestors shared with giant extinct cheetahs, sabre-toothed cats and other beasts. Photograph: Ponce de León, Zollikofe/University of Zurich The five H erectus skulls found in Dmanisi, Georgia.
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