Paleoanthropologist Yohannes Haile-Selassie, co-editor of Ardipithecus kadabba and member of the team that discovered the hominid “Ardi“, is the leader of a team that has just announced another major discovery in human evolution.
Working in Ethiopia’s Afar region, Haile-Selassie’s team uncovered the 3.6 million-year-old partial skeleton of a male Australopithecus afarensis—the same species as the famous “Lucy”, but 400,000 years older and almost 2 feet taller. The skeleton, named “Kadanuumuu”, reveals surprising details about this human ancestor and sheds new light on human origins.
Until now, Lucy was the only partial Australopithecus afarensis skeleton known to science. Her short legs and small size led researchers to conclude that her species did not walk upright, but Kadanuumuu reveals otherwise. His bones suggest he walked upright much like we do, said the team.
The findings indicate that upright walking emerged much earlier in human evolution than was previously thought, said Haile-Selassie: “As a result of this discovery, we can now confidently say that ‘Lucy’ and her relatives were as proficient as ourselves walking on two legs. Human-like bipedality has deeper roots.”
Kadanuumuu’s shoulder bone was also remarkably similar to a human shoulder, showing that this feature has hardly changed in 3.6 million years or more, and suggesting, as Ardi’s skeleton did, that our earliest ancestors did not look like chimpanzees.
Yohannes Haile-Selassie discusses Kadanuumuu’s significance in this video from the Cleveland Museum of Natural History. The team’s findings were published online in Proceedings of the National Academy of Sciences (PNAS) the week of June 21, 2010, and also announced by the Cleveland Museum of Natural History.