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Gallery of Fantastic Fossils
Credit: artwork and composite by John Gurche, photograph by Brian Richmond
A 6 million-year- old thighbone, or femur (center), represents an upright walker of one of the earliest human ancestors (Orrorin), and resembles 2-3 million year old thighbones of australopiths (left, bottom). Thighbones of Homo (right) mark a transition toward a more modern gait about 2 million years ago.