Australopithecus afarensis skeleton ("Lucy")

AL 288-1
Site: Hadar, Ethiopia
Year of Discovery: 1974
Discovered by: Donald Johanson and Maurice Taieb
Age: About 3.2 million years old
Species: Australopithecus afarensis

At home in two worlds
Lucy is arguably the most famous of all early human individuals due to her age and relative completeness. Partial skeletons like hers allow us to learn much more about early human body size, shape, and locomotion than more fragmentary and sparse remains. 
                         
Her long arm bones and the crest created by muscles that attach to her humerus (upper arm bone) are evidence of a powerful chest and strong upper arm muscles necessary for tree climbing. Her short, broad pelvis also held her body upright while angled-in thigh bones kept her body weight directly above her knees while in stride, both requirements for walking efficiently on two legs. Lucy’s compact feet were capable of supporting her full body weight as she walked upright, but her long, curved toe bones resemble that of a tree-climbing ape. Because Lucy could walk upright on the ground and climb trees, she and other members of her species were able to use resources from woodlands, grasslands, and other diverse environments.

Lucy was nicknamed the night she was discovered while Johanson’s team celebrated to the Beatles’ hit “Lucy in the Sky with Diamonds.”  Her Ethiopian name ‘Dinknesh’ is the Amharic term for ‘You are marvelous.’