The BBC reports that a million-year-old human skull found in China suggests that the human species "began to emerge at least half a million years earlier than we thought, researchers are claiming in a new study."It also shows that we co-existed with other sister species, including Neanderthals, for much longer than we've come to believe, they say. The scientists claim their analysis "totally changes" our understanding of human evolution and, if correct, it would certainly rewrite a key early chapter in our history. But other experts in a field where disagreement over our emergence on the planet is rife, say that the new study's conclusions are plausible but far from certain. The discovery, published in the leading scientific journal Science, shocked the research team, which included scientists from a university in China and the UK's Natural History Museum. "From the very beginning, when we got the result, we thought it was unbelievable. How could that be so deep into the past?" said Prof Xijun Ni of Fudan University, who co-led the analysis. "But we tested it again and again to test all the models, use all the methods, and we are now confident about the result, and we're actually very excited." Thanks to long-time Slashdot reader sinij for sharing the article.Read more of this story at Slashdot.