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.”
He sat down and closed his eyes. When he opened them, he could more clearly see the gray fossil poking out of the bleached sand and mudstone, and he realized that he had found the jawbone of a hominin—a member of the human family. He called out for the ASU expedition leader: “Kaye Reeeed!” Reed scrambled up the steep slope on her hands and knees, saw the fossil, and yelled “Woo-hoo!”
Their excitement was justified.