Lucy Wasn't the First to Walk Upright
In 1974, Cleveland scientists found the remains of a small female hominid—Lucy—who proved that humans started walking about 3.2 million years ago.
This summer, the world learned Lucy was not the first to walk upright. The discovery of Lucy's great-great-great-etc.-grandfather shows that advanced upright walking began at least 400,000 years before she was born.
Three Case Western Reserve University researchers: Yohannes Haile-Selassie, PhD, Bruce Latimer, PhD, and Beverly Saylor, PhD, were among an international team of scientists who reported the newest addition to the Australopithecus afarensis family tree in Proceedings of the National Academy of Sciences.
"This finding shows that nearly 1 million years before humans' ancestors started making stone tools, they already had long legs similar to modern humans," says Haile-Selassie, a paleoanthropologist and the study's lead author. "This overturns the theory that man developed long legs later in its evolution to walk miles during persistent hunting."
Standing at nearly 5 feet 5 inches tall, the hominid towered over Lucy—a mere 3 feet 4 inches—giving it the nickname Kadanuumuu, which means "big man" in the Afar language of the Ethiopian Afar region, where the fossil was found.
"We now know Lucy and her relatives better than ever," Haile-Selassie says. "We can now confidently say that Lucy and her relatives were almost as proficient as we are walking on two legs."
A partial skeleton, Kadanuumuu generates new information not only about locomotion but also about shoulder morphology and shape of the rib cage in the species.
"Partial skeletons are rare, which is why they are so valuable," says Latimer, an expert in evolution and anatomy. "This particular skeleton preserves portions of the shoulder and thoracic cage—elements not previously found together in an associated individual."
He says the hominid's shoulder complex was more like humans' than chimpanzees', effectively debunking the idea that humans went through a knuckle-walking phase.
Other researchers involved in the discovery are from the Cleveland Museum of Natural History, Kent State University, Addis Ababa University, Berkeley Geochronology Center and Stanford University.