Scientists say bones proof of earliest walking human

ADDIS ABABA, Ethiopia — A team of U.S. and Ethiopian scientists has discovered the fossilized remains of what they think is humankind's first upright-walking ancestor, a hominid that lived in the wooded grasslands of the Horn of Africa nearly 4 million years ago.

The bones were discovered last month at a new site called Mille, in the northeastern Afar region of Ethiopia, said Bruce Latimer, director of the Cleveland Museum of Natural History in Ohio. They are estimated to be 3.8 million to 4 million years old.

The fossils include a complete tibia from the lower part of the leg, parts of a thighbone, ribs, vertebrae, a collarbone, pelvis and a complete shoulder blade, or scapula. There also is an ankle bone which, with the tibia, proves the creature walked upright, said Latimer, co-leader of the team that discovered the fossils.

"Right now we can say this is the world's oldest bipedal (an animal walking on two feet) and what makes this significant is because what makes us human is walking upright," Latimer said. "This new discovery will give us a picture of how walking upright occurred."

The findings have not been reviewed by outside scientists or published in a scientific journal.

Leslie Aiello, an anthropologist and head of the Graduate School at University College in London said, however, that the new finds could be significant.

"It sounds like a significant find, ... particularly if they have a partial skeleton because it allows you to speculate on biomechanics," said Aiello, who was not part of the discovery team.

Paleontologists previously discovered in Ethiopia the remains of Ardipithecus ramidus, a transitional creature with significant ape characteristics dating as far back as 4.5 million years. There is some dispute over whether it walked upright, Latimer and Aiello said.

Scientists know little about A. ramidus. A few skeletal fragments suggest it was even smaller than Australopithecus afarensis, the 3.2-million-year-old species widely known by the nearly complete "Lucy" fossil, which measures about 4 feet tall.

The specimen is only the fourth partial skeleton ever to be discovered that is older than 3 million years. It was found after two months of excavation at Mille. "It is a once-in-a-lifetime find," Latimer said.