Scientists find child fossil from 3.3 million years ago

WASHINGTON — Fossil hunters have unearthed the skeleton of a child who died 3.3 million years ago, marking the first time scientists have discovered the nearly complete remains of a child of an ancient human ancestor.

The girl, who was about 3 years old when she died in what may have been a flash flood, provides an unprecedented window into human evolution, in part because she belongs to the same species as "Lucy," one of the most famous hominid specimens in paleontology, experts said.

That prompted some scientists to refer to the new skeleton as "Lucy's baby," even though they estimate she lived about 150,000 years earlier. The researchers who discovered her in an Ethiopian desert named her Selam, which means "peace."

Although scientists have found individual bones and bone fragments of children from this and other species of human predecessors, and a few skeletons, the discovery represents one of the most complete individuals ever recovered, and by far the oldest. Bones of children are so small and soft that few survive.

"I'm very excited," said Zeresenay Alemseged of the Max Planck Institute in Leipzig, Germany, who led the international team reporting the find in today's issue of the journal Nature. "This is a unique discovery in the history of paleoanthropology."

Although scientists are still extracting the fossilized bones from stone, they have already begun making striking discoveries, including a tiny throat structure that suggests that if the 1-½-foot-tall child cried out for her mother, her wails probably sounded more like a chimp than a human child.

"If you imagine how this child would have sounded if it was crying out for its mother, its cry would appeal more to chimp ears than to human ears," said Fred Spoor of University College in London, who is helping to study the remains. "Even though it's a very early human ancestor, she would sound more apelike than humanlike."

The remains also confirm how much of a hybrid between humans and apes these creatures were. While they had legs like humans that enabled them to walk upright on two feet, they had shoulders like gorillas that may have also enabled them to climb trees. While their teeth seem to have grown quickly, like chimps' teeth, their brains may have matured more slowly, like humans.

"This confirms the idea that human evolution was not some straight line going from ape to human," said Rick Potts of the Smithsonian Institution. "The more we discover, the more we realize that different parts evolve at different times, and some of these experiments of early evolution had a combination of humanlike and apelike features."

The child's species, Australopithecus afarensis, lived between about 3.8 million and 3 million years ago and is among the earliest known direct ancestors of modern humans. It has long played an important role for scientists studying evolution, in part because of the well-preserved remains of Lucy, an adult discovered nearby in 1974.

The child's fossilized remains were found in northeastern Ethiopia in 2000 when an expedition member spotted the skull poking out from a steep, dusty hillside. The surroundings indicate the child might have drowned in a flash flood, which then immediately buried the intact remains in sand that hardened to encase the bones, the researchers said.

During the next four years, researchers slowly recovered most of the rest of the child's skeleton, including the entire skull, with a sandstone impression of the brain, jaws with teeth, most of the torso and upper limbs, shoulder blades, collarbones, ribs, the spinal column, right arm, fingers, legs and almost a complete left foot.

National Geographic magazine provided some of the funding for the project and will publish a story in the November issue.

The skeleton offers scientists the first opportunity to examine various parts of the body in a single specimen rather than looking at individual bones from different representatives.