31 August 2008
Prehistoric Pacific islanders grow in stature and controversy
People who inhabited Palau in western Micronesia nearly 3,000 years ago have achieved new and disputed heights. Contrary to an earlier report that these ancient islanders had unusually small bodies, human remains recently excavated in a Palau cave come from individuals who physically measured up to people today, according to a new report.
This is no arcane archaeological dispute. An earlier study of human remains on Palau found them to be remarkably small and posited that if human seafarers quickly took on tiny statures after settling Palau due to isolation and a lack of varied resources, then the same could have happened on other islands. That would cast doubt on reports that a prehistoric skeleton from the Indonesian island of Flores represents a tiny humanlike species called Homo floresiensis, or hobbits for short, rather than a person with a disorder that stunted brain growth.
"Detailed studies of human remains from Palau suggest that, over the past 3,000 years, these individuals were all normal-sized and what you would expect to see in a Micronesian population," says Scott Fitzpatrick, lead author of the new study. Fitzpatrick, an anthropologist at North Carolina State University in Raleigh, and his colleagues analyzed human remains that they have excavated since 2000 at an ancient cemetery known as Chelechol ra Orrak. The coastal cave site lies on a small island near Palau's main island. Finds come from about 25 individuals of both sexes and a range of ages. The new investigation focuses on a nearly complete skeleton, a handful of largely intact skulls and numerous limb bones.
The scientists reject an earlier claim by anthropologist Lee Berger of the University of the Witwatersrand in Johannesburg, South Africa, that nearly 3,000-year-old fossils from another Palau cave came from people who were roughly a meter tall and may have adapted to island life by evolving small bodies. At Orrak, adult females stood between 1.52 and 1.57 meters tall, or roughly five feet, Fitzpatrick says. Males were slightly taller than that. Berger underestimated the height of his fossils by assuming that a relatively small socket connecting the upper leg bone to the hip signified dwarflike height, Fitzpatrick asserts. Orrak individuals possessed heads as large as those of later human populations throughout the region, the researchers find. Ancient Palauans displayed large teeth typical of hunter-gatherers, according to Fitzpatrick and his colleagues. Berger said that his finds included teeth so large that they resembled those of small-bodied human ancestors from more than 3 million years ago.
It's unlikely that small-bodied and typical-sized groups lived simultaneously on prehistoric Palau, Fitzpatrick adds. Archaeological, linguistic and historic evidence indicates that a single cultural group occupied Palau over the past 3,000 years. Berger says that the new investigation misses the point of his earlier paper. "As both we and Fitzpatrick point out, islands in the Pacific have commonly produced very small-bodied populations, by global population standards," Berger says. The body size and height of the Flores find, which remain subject to dispute, resemble corresponding dimensions of island people throughout the region today, he asserts.
Skeptics of H. floresiensis, such as Robert Eckhardt of Pennsylvania State University in University Park, don't think that people evolved dwarfed bodies once they reached Flores. So Fitzpatrick's findings have no bearing on the debate, in Eckhardt's view. He and his coworkers argue that, aside from a tiny brain apparently caused by a developmental disorder, the hobbit skeleton looks much like small-statured individuals now living on Flores and on other islands in the region.
Sources: ScienceNews, Plos One (26 August 2008)