The bizarre "hobbit" bones unearthed a few years ago in Liang Bua cave on the Indonesian island of Flores were billed as a rare find--a new species of human, Homo floresiensis (ScienceNOW, 11 October 2005). But a few critics weren't buying. Now in a report released today in the Proceedings of the National Academy of Sciences (PNAS), the skeptics lay out a detailed case arguing that the leading hobbit specimen, a one-meter-tall, 18,000-year-old skeleton with a brain the size of a grapefruit, was merely a diseased Homo sapiens.
"This is not a new species," says co-author Robert Eckhardt of Pennsylvania State University in State College. "This is a developmentally abnormal individual."
The team uses several lines of evidence to challenge the hobbit's novelty. For example, they point out that elephants apparently colonized the island twice. Because even early hominids presumably had better travel skills than elephants, humans probably also arrived on the island more than once; lack of isolation would have prevented the evolution of a new dwarf species, they say.
The team further argues that the sole skull from the cave, part of a specimen labeled LB1, is deformed. Mirror imaging the left side of LB1's skull and putting those halves together creates a distinctly different face than two right halves put together in the same way (see picture). Such asymmetry suggests developmental abnormalities, the researchers report.
The researchers, including Teuku Jacob and Etty Indriati of Gadjah Mada University in Yogyakarta, also studied 76 Rampasasa pygmies who now live only a few kilometers from Liang Bua cave; they report that the Rampasasa lack chins and sometimes have oddly shaped premolar teeth, features identified as distinctive in H. floresiensis. The original work on the skeleton and other bones dug up from the cave tended to emphasize that the Flores bones were "different from anything that has been seen before," says Indriati. "That simply isn't true."
But others are fiercely critical of the PNAS paper and ready to rebut each point. The skull distortion happened after death, as the bones were buried 9 meters down in the cave, says Peter Brown of the University of New England, Armidale, who originally studied the bones; he calls the new paper "complete nonsense." And many researchers insist that all modern humans, including the Rampasasa pygmies, have a chin, making that an unusual feature of the tiny Flores bones. As the battle of the hobbit rages on, "We have a ways to go before the controversy is resolved," says Indriati.
For more detailed coverage of the study, stay tuned for the 25 August issue of Science.