On a hot January morning 2 years ago, Chalachew Seyoum was searching for fossils at a desolate site in Ethiopia called Ledi-Geraru, where no human ancestor had turned up in a decade of searching. But Seyoum, an Ethiopian graduate student at Arizona State University (ASU), Tempe, was upbeat after a week off. "I had a lot of energy and fresh eyes," he says. "I was running here and there. I went up a little plateau and over the top when I spotted this specimen popping right out."
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