No cause has been determined for Lucy’s death. Lucy clearly fits into the smaller group. At Hadar, the size difference is very clear, with larger males and smaller females being fairly easy to distinguish. The vertebrae show evidence of the spinal curvatures necessitated by a permanent upright stance.īack to top How do we know she was female?Įvidence now strongly suggests that the Hadar material, as well as fossils from elsewhere in East Africa from the same time period, belong to a single, sexually dimorphic species known as Australopithecus afarensis. The talus, in her ankle, shows evidence for a convergent big toe, sacrificing manipulative abilities for efficiency in bipedal locomotion. The entire structure has been remodeled to accommodate an upright stance and the need to balance the trunk on only one limb with each stride. The pelvis exhibits a number of adaptations to bipedality. Her condyles are large and are thus adapted to handling the added weight that results from shifting from four limbs to two. There is a prominent patellar lip to keep the patella (knee cap) from dislocating due to this angle. The shaft is angled relative to the condyles (knee joint surfaces), which allows bipeds to balance on one leg at a time during locomotion. Her distal femur shows several traits unique to bipedality. The most conspicuous of these traits is bipedal locomotion, or walking upright.īack to top How do we know Lucy walked upright?Īs in a modern human’s skeleton, Lucy's bones are rife with evidence clearly pointing to bipedality. While these species differ in many ways, hominids share a suite of characteristics that define them as a group. Hominidae encompasses all species originating after the human/African ape ancestral split, leading to and including all species of Australopithecus and Homo. The term hominid refers to a member of the zoological family Hominidae. At some point during that night, no one remembers when or by whom, the skeleton was given the name “Lucy.” The name has stuck.īack to top How do we know she was a hominid? There was drinking, dancing, and singing the Beatles’ song “Lucy in the Sky With Diamonds” was playing over and over. Later in the night of November 24, there was much celebration and excitement over the discovery of what looked like a fairly complete hominid skeleton. Two weeks later, after many hours of excavation, screening, and sorting, several hundred fragments of bone had been recovered, representing 40 percent of a single hominid skeleton. Shortly thereafter, he saw an occipital (skull) bone, then a femur, some ribs, a pelvis, and the lower jaw. Within moments, he spotted a right proximal ulna (forearm bone) and quickly identified it as a hominid. Johanson suggested taking an alternate route back to the Land Rover, through a nearby gully. After a long, hot morning of mapping and surveying for fossils, they decided to head back to the vehicle. They had taken a Land Rover out that day to map in another locality. Lucy was found by Donald Johanson and Tom Gray on November 24, 1974, at the site of Hadar in Ethiopia. How do we know that her skeleton is a single individual?.
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