Paleoanthropologist Donald C. Johanson is shown here with a selection of Lucy's bones. Although she represented the oldest and most complete skeleton of an early human ever found at the time, she lacked the most revealing of all anatomical cluesa skull.

It was not until 1992 that Johanson and his team unearthed an adequately intact A. afarensis skull. Their resulting research suggested that the species endured nearly unchanged for 900,000 years.

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