January 31, 2007

"Hobbit" wars continue

From the Toronto Star:
In the ongoing battle between the two camps, the latest evidence is in.

The hobbit is definitely a new species of human, related to but separate from Homo sapiens, concludes a study by a Florida State University team published yesterday in the Proceedings of the National Academy of Sciences. Neuro-paleontologist Dean Falk, the head researcher, says she is "absolutely convinced" the brain of LB1, as the hobbit is officially known, is not abnormal.

"It isn't microcephalic in any way," she told the Star. "Furthermore, its features are the antithesis of that condition."

Because the brain leaves an image imprinted on the skull, its shape can be reconstructed into a three-dimensional, computer-generated model called an endocast. Falk's team compared the endocasts of 21 skulls; 10 of normal humans, nine of people with microcephaly, one a dwarf and LB1. Using statistical techniques, they classified them into normal and microcephalic.

The hobbit's brain – one-third the size of a modern human's – fell clearly within the normal range, says Falk. Furthermore, its brain has four unusual features, including large frontal and temporal lobes, which distinguishes it from Homo sapiens, she says, and justifies its classification as a separate species, Homo floresiensis.

Falk had expected to see something that looked like the brain of a chimpanzee, but says LB1's brain is sophisticated and unique, unlike other primate brain casts she has seen.

"It is a little, but highly evolved, brain that had been globally reorganized. It didn't get bigger, it got more complex. It got rewired and reorganized."

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