'Hobbit' research stretches imagination

But this little hominid, popularly dubbed “the hobbit” for its diminutive size and big feet, was an anomaly. Dated around 18,000 years old, its time period paralleled that of Homo sapiens, but its skeletal structure was markedly different.

Could there have been a miniature human species evolving in an isolated corner of the world, a line that later died out?

As it turns out, Larson and her colleague William Jungers (pictured above left), both human anatomists at the State University of New York at Stony Brook and members of the United University Professions/AFT, got to examine this question firsthand. Larson was called to Indonesia by the research team for her renowned expertise on the anatomy of the shoulder, and Jungers, whose special interest is the relationship between biology and body size, followed.

The “hobbit” was unearthed in 2003 on Flores Island and is formally classified as Homo floresiensis. The skeleton is called LB1, as the first specimen from a cave called Liang Bua. Larson presented research this spring showing that LB1 and several other tiny individuals may have evolved from an isolated Homo erectus population. “It reminds me of a science fiction novel called ‘The Lost World,’ where dinosaurs still live,” says Larson. The findings indicate a human-like individual just over one meter tall, with a tiny skull and oddly shaped upper arm bone, or humerus, quite different from that of modern humans.

On a modern human, the humerus is twisted so that when a person stands, the insides of the elbows face forward and the arms flex in front of the body, allowing work with the hands. The hobbit’s inner elbows actually face outward, seemingly precluding such dexterity—but evidence at the site shows Homo floresiensis to be a toolmaker, an important distinction in the study of human evolution. Larson’s research reveals that LB1’s shoulders made the difference. The shoulder blades are hunched forward to change the angle of the humerus and allow work in front of the body.

Jungers also found that the foot on LB1 is unusually large. “There is no known modern human, whether they’re pygmies or basketball players, who have feet as large proportionally,” he says. But the big toe is straight, like a modern human toe: “It’s a modern foot, just a big one.”

An entire team of researchers has been on the case of Homo floresiensis, so perhaps it’s no surprise that there’s been some disagreement. One group is seriously considering that the LB1 specimen is simply a human with a disease, microcephaly, which causes the brain and skull to be abnormally small. But both Jungers and Larson point to the many specimens found in the cave—bones from nine individuals. Could they all have been sick?

Jungers chalks up the microcephaly theory to skepticism over a separate species. He himself thought the initial report, on the cover of Nature magazine, might have been an April Fool’s joke. “Part of the controversy is that people just couldn’t imagine that there would be something evolving in isolation,” he says.

In addition, the find challenges the correlation between brain size and ability. It turns out that early tool technology may have been attainable with a smaller brain than originally thought. “The appearance of these fossils has made us rethink a lot of what we thought we understood,” says Jungers.