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Fossils hint at distant cousins to our ancestors

WASHINGTON — Our family tree may have sprouted some long-lost branches nearly 2 million years ago. A famous paleontology family has found fossils they think confirm their theory that there were two pre-human species besides the one that eventually led to modern humans.

A team led by Meave Leakey, daughter-in-law of famed scientist Louis Leakey, found facial bones from one creature and jawbones from two others in Kenya. That led the researchers to conclude that man's early ancestor had plenty of human-like company from other species.

These wouldn't be Homo erectus, believed to be our direct ancestor. They would be more like distant cousins, who, when you go back even longer in time, shared an ancient common ancestor, one scientist said.

In their new findings, the Leakey team says none of their newest fossil discoveries match erectus, so they had to be from another flat-faced, relatively large species with big teeth.

The new specimens have "a really distinct profile" and thus they are "something very different," said Meave Leakey, describing the study published online Wednesday in Nature.

What these new bones did match was an old fossil that Meave and her husband, Richard, helped find in 1972. That skull, called 1470, just didn't fit with Homo erectus, the Leakeys contended. They said it was too flat-faced with a non-jutting jaw.

For the past 40 years, the scientific question has been whether 1470 was a freak mutation of erectus or something new. For many years, the Leakeys have maintained that the male skull known as 1470 showed there was more than one species of ancient hominids, but other scientists said it wasn't enough proof.

The Leakeys' new discoveries are more evidence that this earlier "enigmatic face" was a separate species, said study co-author Fred Spoor of the Max Planck Institute in Germany. The new bones were found between 2007 and 2009 about 6 miles from the old site near the fossil-rich Lake Turkana region, Leakey said.

So that would make two species — erectus and the one represented by 1470.

But the Leakey scientific team contends that other fossils of old hominids — not those cited in their new study — don't seem to match either erectus or 1470. So the Leakeys believe three Homo species were living between 1.8 million and 2 million years ago — Homo erectus, the 1470 species and a third branch.

"Anyway you cut it there are three species," said study co-author Susan Anton, an anthropologist at New York University.

Both of the species Meave Leakey said existed back then went extinct more than a million years ago in evolutionary dead-ends.

"Human evolution is clearly not the straight line that it once was," Spoor said.

Fossils hint at distant cousins to our ancestors 08/08/12 [Last modified: Wednesday, August 8, 2012 10:21pm]
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