I thought it was very cool that scientists from UC Berkeley, just announced the discovery of a Homind older than Lucy. They call it Ardipithecus ramidus. At an age of 4.4 million years, it lived well before and was much more primitive than the famous 3.2-million-year-old Lucy, of the species Australopithecus afarensis.
The adult female specimen, probably stood four feet tall and weighed about 120 pounds, almost a foot taller and twice the weight of Lucy. Its brain was no larger than a modern chimp’s. It retained an agility for tree-climbing but already walked upright on two legs, a transforming innovation in hominids, though not as efficiently as Lucy’s kin.
Ardi’s feet had yet to develop the arch-like structure that came later with Lucy and on to humans. The hands were more like those of extinct apes. And its very long arms and short legs resembled the proportions of extinct apes, or even monkeys.
Tim D. White of the University of California, Berkeley, a leader of the team, said in an interview this week that the genus Ardipithecus appeared to resolve many uncertainties about “the initial stage of evolutionary adaptation” after the hominid lineage split from that of the chimpanzees. No fossil trace of the last common ancestor, which lived some time before six million years ago, according to genetic studies, has yet come to light.
The other two significant stages occurred with the rise of Australopithecus, which lived from about four million to one million years ago, and then the emergence of Homo, our own genus, before two million years ago. The ancestral relationship of Ardipithecus to Australopithecus has not been determined, but Lucy’s australopithecine kin are generally recognized as the ancestral group from which Homo evolved.
Scientists not involved in the new research hailed its importance, placing the Ardi skeleton on a pedestal alongside notable figures of hominid evolution like Lucy and the 1.6-million-year-old Turkana Boy from Kenya, an almost complete specimen of Homo erectus with anatomy remarkably similar to modern Homo sapiens.
Importantly, Giday WoldeGabriel, a geologist at Los Alamos National Laboratory, said the discovery countered the hypothesis that upright walking had evolved as an adaptation to life on grassy savanna.
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