The Guardian reports: The spectacular fossilised skull of an ancient human ancestor that died nearly two million years ago in central Asia has forced scientists to rethink the story of early human evolution.

Anthropologists unearthed the skull at a site in Dmanisi, a small town in southern Georgia, where other remains of human ancestors, simple stone tools and long-extinct animals have been dated to 1.8m years old.

Experts believe the skull is one of the most important fossil finds to date, but it has proved as controversial as it is stunning. Analysis of the skull and other remains at Dmanisi suggests that scientists have been too ready to name separate species of human ancestors in Africa. Many of those species may now have to be wiped from the textbooks.

The latest fossil is the only intact skull ever found of a human ancestor that lived in the early Pleistocene, when our predecessors first walked out of Africa. The skull adds to a haul of bones recovered from Dmanisi that belong to five individuals, most likely an elderly male, two other adult males, a young female and a juvenile of unknown sex.

The site was a busy watering hole that human ancestors shared with giant extinct cheetahs, sabre-toothed cats and other beasts. The remains of the individuals were found in collapsed dens where carnivores had apparently dragged the carcasses to eat. They are thought to have died within a few hundred years of one another.

“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. “This is the first complete skull of an adult early Homo. They simply did not exist before,” he said. Homo is the genus of great apes that emerged around 2.4m years ago and includes modern humans.

Other researchers said the fossil was an extraordinary discovery. “The significance is difficult to overstate. It is stunning in its completeness. 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. [Continue reading…]