Juvenile skeleton enlightens human evolution

A team of paleontologists has unearthed the most complete skeleton of a prehistoric ape-man species thought to be a forerunner of humans. A 3.3-million-year-old skeleton of a presumed 3-year-old female hominid has shown incredible features of walking upright and more identities of apes, an international research team, which included scientists from Ethiopia, France, Britain and the United States, reported on Wednesday.

The skeleton classified as Australopithecus afarensis (A. afarensis) or more commonly known as "Lucy," is the oldest and most complete juvenile of a human relative ever found. The first specimen of this group, Lucy, a 3.2-million-year-old adult female was discovered nearby in 1974. The recently found baby skeleton is about 150,000 years older than Lucy. That made some scientists name the new skeleton as "Lucy's baby."

Scientists, who unearthed the skeleton at Dikika of eastern Ethiopia in year 2000 and named her "Selam," which means "peace" in Ethiopia's official Amharic language, assert that the discovery will surely fill an essential gap in understanding this particular species and potentially its place in human evolution.

Zeresenay Alemseged of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, headed the expedition that found the “Salem” remains in 2000. His team found the skull protruding from sandstone about six miles (10 kilometers) from where the first A. afarensis specimen, Lucy, was unearthed in 1974.

Unlike “Lucy”, who has most of the parts but lacks the most important, skull, the toddler is far more complete, with fingers, a foot, and a torso in addition to a skull. "But the most impressive difference between them," says Zeresenay "is that this baby has a face." He contends no earlier fossil of a toddler pre-human has consisted of more than a partial skull, jawbone, or some teeth. And, as this one is in such good shape, Zeresenay says it could unveil what this human ancestor really looked like.

It has traits that stand as astonishing examples of part-way evolution between primitive apes and modern humans, the researchers said. Although the elongated face is more chimp-like than human, its leg and foot bones show the child would have walked upright.

The skeleton provides some new guiding information about how the afarensis species blears the line between ape and human. Though, the angle of the thigh bone from knee to hip is very human, implying she walked on two legs, but her torso is ape-like, as observed by another co-author of the research, Fred Spoor of University College London.

The juvenile remains will be compared to Lucy. "We know a lot about Lucy and other adult ancestors," Zeresenay says, "but this fossil is rare evidence of what babies were like."

The study was published in the Sept. 20 issue of the journal Nature.