New Details on our Oldest Ancestors

Ardipithecus kadabbaPaleoanthropologist 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.

Tim White in Time 100

Paleoanthropologist Tim White is one of the 2010 Time 100, Time Magazine’s annual list of the most influential people in the world.

As one of the leaders of the Middle Awash Project and editor of the UC Press Middle Awash series, White and his team work in Ethiopia’s Afar region, sifting through layers of earth to find traces of human origins. Their work has yielded many fossil treasures that offer a glimpse of the world millions of years ago, and reveal the faces of some of the earliest hominids.

Last October, the 47-member team, which also includes UC Press editors Giday WoldeGabriel, Berhane Asfaw, and Yohannes Haile-Selassie, published their revolutionary discovery of Ardipithecus ramidus (“Ardi”), a 4.4 million year old fossil hominid. Ardi’s skeleton is the most complete fossil evidence older than “Lucy”, and her bones reveal new details about human evolution. The discovery of Ardipithecus ramidus was Science Magazine’s Breakthrough of 2009.