Small Bones, Big Controversy

In two rocky caves on the Micronesian nation of Palau, a team of scientists including Duke paleontologist Steven Churchill has discovered fossil bones from some two dozen tiny humans who inhabited the island between roughly 900 and 2,900 years ago.

Writing in the online journal PloS ONE, the team said the bones were from modern humans (Homo sapiens), with the earliest fossils belonging to individuals who were three to four feet tall and weighed 70 to 90 pounds. Though modern, the individuals to whom the bones once belonged had several traits considered primitive, or archaic, for the human lineage.

(In the top photo, a lower jaw dated at 2,900 years old and one from an average-size modern female show the size difference between the early Palauans and people today. In the bottom photo, a team member explores a cave.)

The team says the findings expand the known range of variation in modern humans in Southeast Asia.

But what has led the New York Times and numerous other popular media outlets to run with the story is that the findings add fuel to debate raging -- at least in paleontological circles -- around the 2003 discovery by other scientists of some older and even smaller human fossil bones than those found on Palau. Check this report from the National Geographic Society, which funded the search in Palau.

At issue is whether the smaller specimens, found on the Indonesian island of Flores and immediately dubbed “hobbits,” represent modern humans reduced in stature by disease, genetics or some other biological process -- or, as their discoverers claim, represent a separate species, termed Homo floresiensis.

Previous Duke-affiliated research and work elsewhere favor the former argument. But backers of Homo floresiensis as its own species are vocally defending their claims.

The Palau findings likely won’t settle this hash. But Churchill (photo), an associate professor of biological anthropology & anatomy, says they add context in which to interpret the hobbit fossils.

His team also told the Times that its fossils support “at least the possibility that the Flores hominids are simply an island-adapted population of Homo sapiens, perhaps with some individuals expressing congenital abnormalities.” Humans and other animals living on isolated islands often are of smaller stature than their mainland cousins -- a phenomenon known as island dwarfism.

Stay tuned to your local paleontologist.