World's oldest child found by fossil hunters

The 3.3-million-year-old fossilized toddler was uncovered in north Ethiopia's badlands along the Great Rift Valley. …

The skeleton, belonging to the primitive human species Australopithecus afarensis, is remarkable for its age and completeness, even for a region spectacularly rich in fossils of our ancient ancestors, experts say. …

The age of death makes the find especially useful, scientists say, providing insights into the growth and development of human ancestors.

"Visually speaking, the Dikika child is definitely more complete [than Lucy]," team member Professor Fred Spoor [UCL Anatomy & Developmental Biology] said.

"It has the complete skull, the mandible, and the whole brain case. Lucy doesn't have much of a head." …

The fossil child, who died at nursing age, offers important clues to the development of early humans, says Spoor, of UCL.

"It will teach us how our early ancestors grew up," he said. "The only way you can evolve from one type of species into another is by growing up in a different way, because that's how you change."

For instance, a prolonged, dependent childhood allowed later human species to grow larger brains, which need more time to develop after birth.

"As far as we can tell, it is not yet happening [with Lucy's baby]," Spoor said. …

"For the first time we have insights that they may have grown their brains a little bit slower than your average chimp," Spoor said.

"If you take more time to form your brain, it may well be that you make more intricate connections inside," the researcher added. "Or it may not be a positive thing-perhaps you live on poorer food or are a bit behind."

Spoor favors the latter explanation in the case of these early hominins.

"They haven't progressed over great apes at all," he said. "They've just changed their locomotion for whatever reason, but they were not necessarily any more clever than chimps were." …

The skeleton's ape-like upper body includes two complete shoulder blades similar to a gorilla's that appear to have been adapted for climbing.

"This was a bit of a surprise, and controversial," Spoor said.

Some researchers will say the feature was inherited from an ancestor and reveals little about this hominin's lifestyle, Spoor adds.

"Other people will say it shows they are still using their arms for climbing quite a lot," he said.

"The question is not whether they spent all day swinging around in the trees. But it may be true there was still some climbing aspect, for instance, for building nests at night or to forage in the trees." …

James Owen, 'National Geographic News'