Did a tiny Indonesian hominid purported to be 18,000 years old have a tooth filled by a dentist? That's the bizarre question raised by paleopathologist Maciej Henneberg of the University of Adelaide in Australia about the Indonesian "hobbit," a 1-meter-tall hominid with a grapefruit-sized brain that has confounded anthropologists since being announced in 2004. If the claim is true, the hobbit cannot be a new species of human, as its discoverers maintain. But many experts remain unconvinced.
Thus far, most of the distinctive hobbit anatomy described has belonged to one hobbit specimen, a skull and skeleton dubbed LB1. Its bones look quite different from those of modern humans, and the discovery team classifies it as a new species, Homo floresiensis (named after Flores, the island on which the bones were found). That designation would force anthropologists to accept that such tiny-brained hominids could make tools, and that humans moved out of Africa much earlier than thought. Others have argued that the hobbit was merely a modern human suffering from microcephaly or some other growth syndrome (ScienceNOW, 5 March).
Henneberg and a small group of other longtime H. floresiensis skeptics got a look at the LB1 skull in 2005 when the bones were borrowed by the late Teuku Jacob of Gadjah Mada University in Yogyakarta, Indonesia. The researchers had relatively little time, Henneberg says, so they photographed the jaws and noted uneven tooth wear but did not examine the teeth in detail. Later, studying the photos, Henneberg was struck by the odd appearance of the lower first molar, which has a high ridge of enamel next to a scooped-out white area. Dentists began working in this region of Flores in the 1930s, says Henneberg, and they might have used a temporary filing of a whitish cement rather than the permanent metal amalgams used in Western countries today.
If Henneberg is right, the hobbit cannot be 18,000 years old, because only modern cultures do this kind of dental work. He wanted to see the bones again to test his idea, but his group has been denied access to the specimen by the Indonesians now in charge of it, because the discovery team is still analyzing it. "Access to the [original] specimens could have settled the tooth question ... in minutes," Henneberg says. So he made his claim not in a meeting or paper but in a book published last week and in hallway chat at the American Association of Physical Anthropologists meeting in Columbus, Ohio, earlier this month.
The idea spread around the blogosphere this week and sparked a furious response from, among others, Peter Brown of the University of Adelaide, who was part of the team that originally reported the hobbit. Brown calls the claim "nonsense" and says, "I cleaned the teeth of LB1 using brushes and soft probes. There was no filling."
At least one independent expert who has seen the specimen agrees. Dental anthropologist Shara Bailey, now of New York University, has not taken sides in the hobbit wars but had the chance to examine the specimen in detail while it was in Jacob's lab. "I was surprised by the hypothesis," she says. The first molar had odd dental wear and coloration, she admits--"I was struck by the opacity and whiteness of the dentine"--but it didn't look like a filling. She points out that "the canine and incisor have the same overall look. ... If someone filled that [molar] tooth, they filled the [tops] of the canine and incisor too, which would be unusual."
Brown, who has a detailed paper on the teeth in the works, says that the chalky limestone in which the hobbit lay caused exposed dentine to appear white rather than the more common yellow. He has posted on his Web site computed tomography scans that he says show a normal-looking pulp cavity for the tooth.
Hobbit watcher John Hawks of the University of Wisconsin, Madison, says he was initially intrigued by Henneberg's claim. "[The] hypothesis was reasonable based on the photos," he says. With Brown's rebuttal, however, Hawks now considers the question "totally settled." Henneberg is undeterred, however, continuing to call for independent scientists to be able to take a fresh look at the bones.