Study of bones challenges `little people' as new species

August 22, 2006|By NEW YORK TIMES NEWS SERVICE

After the 18,000-year-old bones of diminutive people were found on the Indonesian island of Flores, the discoverers announced two years ago that these were remains of a previously unknown species of the ancestral human family. They gave it the name Homo floresiensis.

Doubts were raised almost immediately. But only now have opposing scientists from Indonesia, Australia and the United States weighed in with a comprehensive analysis based on their first-hand examination of the bones and a single mostly complete skull.

The evidence, they reported yesterday, strongly supports their doubts. The discoverers, however, hastened to defend their initial new-species interpretation.

The critics concluded in an article in the current Proceedings of the National Academy of Sciences that the "little people of Flores," as they are often called, were not a newfound extinct species.

They were, instead, modern Homo sapiens who resemble pygmies now living in the region and, as suggested in particular by the skull, appear to have been afflicted with the developmental disorder microcephaly, which causes the head and brain to be much smaller than average.

The international team of paleontologists, anatomists and other researchers who conducted the study was headed by Teuku Jacob of Gadjah Mada University, who is one of Indonesia's senior paleontologists.

In the report, Jacob and his colleagues cited 140 features of the skull that they said placed it "within modern human ranges of variation." They also noted features of two jaws and some teeth that "either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave," where the discovery was made.

"We have eliminated the idea of a new species," Robert B. Eckhardt, a professor of developmental genetics at Penn State who was a team member, said in a telephone interview. "After a time, this will be admitted."

That time has not yet come.

Peter Brown, a paleontologist at the University of New England in Armidale, Australia, who was a leader of the team that discovered the "little people" bones, took issue with the new report.

In an e-mail message, Brown said, "The authors provide absolutely no evidence that the unique combination of features found in Homo floresiensis are found in any modern humans."

The features he referred to include body size, body proportions, brain size, receding chin, shape of premolar teeth and their roots, and the shape and projection of the brow ridge. But the critics asserted that many of the features in the specimen with the cranium, said to be diagnostic of a new species, are present in the Rampasasa pygmies.

Brown said the critics' claim of "the asymmetry of the skull being the result of abnormal growth is fiction." The skeleton was buried deep in sediment, he said, and this brought on "some slight distortion."

In response, Eckhardt said, "Our paper accounts neatly for everything we see in the asymmetry" of the face and other parts of the skeletons.

Brown said an independent study led by Debbie Argue, an anthropologist at the Australian National University in Canberra, discounted microcephaly as an explanation. He said the report, accepted for publication in The Journal of Human Evolution, "completely supports my arguments for a new species."

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