Fossil find may result in evolution revolution
By Thomas H. Maugh II
Los Angeles Times
Updated: 10/02/2009 02:20:51 AM MDT
A treasure trove of 4.4-million- year- old fossils from the Ethiopian desert is dramatically overturning widely held ideas about the early evolution of humans and how they came to walk upright, even as it paints a remarkably detailed picture of early life in Africa, researchers reported Thursday.
The centerpiece of the diverse collection of primate, animal and plant fossils is the near-complete skeleton of a human ancestor that demonstrates our earliest forebears looked nothing like a chimpanzee or other large primate, as is now commonly believed. Instead, the findings suggest that the last common ancestor of humans and primates, which existed nearly 2 million years earlier, was a primitive creature that shared few traits with modern- day members of either group.
The findings, analyzed in a large group of studies published Thursday in the journal Science, also indicate that our ancestors began walking upright in woodlands, not on grassy savannas as previous generations of researchers had speculated.The discovery of the specimen, called Ardipithecus ramidus, "is one of the most important discoveries for the study of human evolution," said paleoanthropologist David Pilbeam of Harvard University, who was not involved in the research.
The fossils were found 15 years ago in the Afar Triangle of Ethiopia by a team led by paleoanthropologist Tim White of the University of California, Berkeley. But White and his team have been relatively quiet about the fossils, and other researchers — some of whom have accused him of hoarding the fossils for his own use — have been eagerly awaiting more information.
Thursday, they are getting a surfeit: 11 papers by 47 authors and a similar number of short summaries prepared by each paper's authors.
The fossils were found in a layer of sediment sandwiched between two layers of volcanic ash, each dating from 4.4 million years ago — indicating that the fossils are also of that age.
In addition to the nearly complete fossil specimen of the female primate, which investigators have dubbed Ardi, the team found more than 100 fossils from 36 other members of the same species.
"These fossils are much more important than Lucy," the 3.2-million-year-old specimen of Australopithecus afarensis that was found in the Afar desert in the 1970s, said paleoanthropologist Alan Walker of Penn State University, who was not involved in the research. "These fossils are of a completely unknown creature, and are much stranger and more primitive than Australopithecus."
This whole collection of data "gives us information we have never had before about human evolution," said paleoanthropologist C. Owen Lovejoy of Kent State University, one of the primary authors of the papers.
"The whole savanna theory goes out the window in terms of it being the explanation for upright walking. . . . And the idea that we evolved from something like a chimpanzee also goes out the window." Linkback:
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