From Milwaukee, at a joint meeting of the Paleoanthropology Society and American Association of Physical Anthropologists
Human ancestors that lived in Africa around 3 million years ago possessed backbones like those of people today and thus walked much as we now do, says Carol V. Ward of the University of Missouri-Columbia.
Ward and Bruce Latimer of the Cleveland Museum of Natural History analyzed the anatomy of spinal columns from the 3.2-million-year-old Australopithecus afarensis skeleton known as Lucy and a pair of roughly 2.5-million-year-old Australopithecus africanus specimens.
As in modern people, the spines of the three australopithecines bend inward at the middle of the back and curve outward at the lower back. A bony column angled in this fashion positions the torso directly over the hip joints, fostering erect posture and a two-legged gait, Ward says. The shapes of australopithecine vertebrae also correspond closely to those