October 22, 2009

Analysis Finds Ida Not ‘Missing Link’

When scientists announced in May the discovery of a fossil which showed an evolutionary "missing link" between humans and apes, experts were skeptical the fossil was even a close human relative.

A new analysis reported in Thursday's issue of the journal Nature further supports these doubts, finding instead that the fossil, dubbed Ida, is about as far removed from the monkey-ape-human ancestry as a primate could be.

Ida is the skeleton of a 47 million-year-old creature discovered in Germany, and is the subject of a book entitled "The Link: Uncovering Our Earliest Ancestor."   The fossil represents a previously unknown primate species called Darwinius.

Although the scientists who announced Ida's discovery said they didn't claim Darwinius was a direct ancestor of monkeys, apes and humans, they did maintain that it belongs in the same evolutionary grouping and that the fossil showed what an ancestor of that era might have looked like.

In the latest analysis, Erik Seiffert of Stony Brook University in New York and his colleagues compared 360 anatomical features of 117 living and extinct primate species, and then constructed a family tree.

They concluded that Darwinius does not belong in the same primate category as monkeys, apes and humans, and falls instead into the other major grouping, which includes lemurs.

Other experts agreed with Seiffert's analysis.

"This is a rigorous analysis based on many features," Yale anthropology professor Eric Sargis told the Associated Press, adding that he'd found the original argument of the Darwinius researchers unpersuasive.

Seiffert's analysis did not come as a surprise, he said.

In fact, it confirms what most scientists already believed, AP quoted David Begun, a paleoanthropologist at the University of Toronto, as saying.

Jorn Hurum of the Natural History Museum in Oslo, Norway, one of the authors of the original Ida report, said he embraced the latest analysis.

Darwinius is an example of a group of primates known as adapoids, and "we are happy to start the scientific discussion" about what Ida means regarding adapoids' position in the primate family tree, Hurum told the AP.


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