During the heart of the Stone Age, from 1.7 million to 400,000 years ago, populations of our ancient ancestors in Africa, Asia, and Europe often served as brief evolutionary experiments, with most dying out before they established themselves as truly distinct species.
At least that's the implication of a peculiar fossil skull unearthed in eastern Africa last summer, according to its discoverers. The roughly 930,000-year-old cranium exhibits some features of Homo erectus as well as unique traits, say anthropologist Richard Potts of the Smithsonian Institution in Washington, D.C., and his colleagues. They describe the new find in the July 2 Science.
Stone Age specimens possessing the full anatomical signature of H. er