"Lucy" (AL-288-1), Australopithecus afarensis
Discovered by Donald Johanson and Tom Gray in 1974 at Hadar in Ethiopia, and named after the Beatles' song "Lucy in the Sky with Diamonds". Its age is about 3.2 million years. Lucy was an adult female of about 25 years. About 40% of her skeleton was found, and her pelvis, femur (the upper leg bone) and tibia show her to have been bipedal. She was about 107 cm (3'6") tall (small for her species) and about 28 kg (62 lbs) in weight.
Credit: photo and (edited) text courtesy of Talk Origins.