South Swartkrans

AFRICA A. robustus

TAUNG Australopithecus africanus

STERKFONTEIN A. africanus

KONSO A. boisei

It is the visage of the lost relative he has sought for 26 years. "He is the oldest one" the veteran fossil hunter murmurs, "the oldest hominid

same time, Tim D. White of the University of California at Berkeley and his colleagues described a collection of 4.4-mil-lion-year-old fossils recovered in Ethiopia that represent an even more primitive hominid, now known as Ardipithecus ramidus ramidus. Those findings gave scholars a tantalizing glimpse into Lucy's past. But estimates from some molecular biologists of when the split between chimps and humans occurred suggested that even older hominids lay waiting somewhere to be discovered.

Those intriguing predictions have recently been borne out. Over the past few years, researchers have made a string of stun ning discoveries—Brunet's among them—that may go a long way toward bridging the remaining gap between humans and their African ape ancestors. These fossils, which range from roughly five million to seven million years old, are upending long-held ideas about when and where our lineage arose and what the last common ancestor of humans and chimpanzees looked like.

Not surprisingly, they have also sparked vigorous debate. Indeed, experts are deeply divided over where on the family tree the new species belong and even what constitutes a hom-inid in the first place.

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