Human ancestor gets digital facelift

By Ker Than

Staff Writer

updated 2:05 p.m. ET March 30, 2007

An ancient member of the human family has gotten a digital facelift, and the new mug looks more ape-like than scientists previously thought.

The new reconstruction suggests the large brains and flatter faces characteristic of modern humans did not appear in our lineage until much later in our history.

“For how many years now, people have been using this [skull] and the numbers may not be very meaningful,” said Timothy Bromage, an anthropologist at New York University who led the new reconstruction effort.

The skull in question, KNM-ER 1470, is arguably the most controversial fossil in the history of anthropology. When it was first discovered in northern Kenya in 1972, it was initially dated to nearly 3 million years old. Yet the skull — which scientists painstakingly pieced together from hundreds of bone fragments — had a large brain and a flat face, features reminiscent of modern humans but completely unlike any hominid known to exist at the time.

So troublesome was the skull that famed paleo-anthropologist Richard Leakey, the leader of the team that discovered it, once told reporters: "Either we toss out this skull or we toss out our theories of early man. It simply fits no models of human beginnings."

Leakey later revised the age of KNM-ER 1470 to 1.9 million years, but even then, some scientists have argued that the skull’s features are much more humanlike than its contemporary, Homo habilis.

Other scientists claim Homo rudolfensis, the name that some anthropologists have assigned to the skull, should be identified as a H. habilis and not a separate species at all. Whether either of these hominids was a direct ancestor of humans is still an open question.

Impossible face
For the new reconstruction, the researchers used a combination of a deformable cast and computer-generated models to create replicas of KNM-ER 1470’s skull that could be shaped.

Bromage said the original reconstruction relied on preconceptions about how early humans looked that are now known to be incorrect. The result, he said, was a skull that shared several features in common with modern humans, including a relatively flat face and a large brain case.

“It’s always been an outlier in every study ever performed on [hominid] brain sizes” from that period, Bromage said.

Bromage said his team’s reconstruction includes biological principles not known at the time of the skull’s discovery, which state that a mammal’s eyes, ears and mouth must be in precise relationships relative to one another.

“It doesn’t matter if you’re a rat, a kangaroo, an elephant, a human or a dog—their [facial features] are all organized to a very specific architectural plan,” Bromage said.

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