Lucy's Baby

UCF Spring 2007

While on an expedition to the Great Rift Valley in Ethiopia in 2000 paleoanthropologist Zeresenay Alemseged was surveying a site called Dikika with his team. While surveying, team member Tilahun Gebreselassie was the first to see the most incredible find, the remains of a juvenile Australopithecus afarensis. Over four more seasons of searching and sifting, the team has unearthed a near-complete skeleton, piece by piece. Remarkably this discovery was found only six miles from the discovery of the most famous fossil Australopithecus afarensis find by a team which was led by paleoanthropologist Donald Johnson in 1974.

That fossil find was determined to be a female in her mid twenties. It was named Lucy and it was dated 3.2 mya. Even though she was missing her skull, Lucy was the most complete fossil ever found and her bones indicated that she walked upright. Johnson and his team also found a complete knee joint, minus the knee cap, labeled AL 129-1 which conclusively proves bipedal motion in early humans as old as 3 mya. Because Lucy and the juvenile were both from the same species Australopithecus afarensis, the newly found juvenile was named Lucy's baby.

Dr. Jonathan Wynn and his colleagues at University of South Florida dated the sediments surrounding the skeletal remains of Lucy's baby and have dated it to 3.3 mya. It has been determined by the teeth that it is a female toddler which was about three years old when she perished. This determination was made by performing CT scans on the skull which enabled them to find all the unerupted teeth still in the jaw. With a full set of milk teeth still in tact that meant that she was possibly still nursing. Although she had long, curved fingers and her shoulder blades are similar to a gorilla, her leg and foot bones indicate that she, like Lucy, walked upright.

Lucy's baby is the most complete and the earliest juvenile hominid ever found. The find should give scientists a more detailed insight into how the Australopithecus afarensis looked and insight into the evolution of the brain, speech and of bipedalism. Her brain was evaluated to be about the size of a similarly aged chimpanzee. It formed 63 to 88% of the adult Australopithecus afarensis values, this is much lower than the 90% it should be if she were a chimp. Human children develop slowly and gradually which indicates