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March 3, 2005 Thursday 11:03 PM Eastern Time
SECTION: DOMESTIC NEWS
LENGTH: 771 words
HEADLINE: 'Hobbit' Brain Supports Species Theory
BYLINE: JOSEPH B. VERRENGIA; AP Science Writer
BODY:
Scientists working with powerful imaging computers say the
spectacular "Hobbit" fossil recently discovered in Indonesia had
distinctive brain features that could justify its classification as a
separate - and tiny - human ancestor.
The new report, published Thursday in the online journal Science
Express, seems to support the idea of a sophisticated human dwarf
species marooned for eons while modern man proliferated.
The new research produced a computer-generated model that compared
surface impressions on the inside of the fossil skull with brain
casts of modern and ancient humans, as well as chimps and other
primates.
The scientists said the model shows that the 3-foot specimen,
nicknamed Hobbit, had a brain unlike anything they had seen before in
the human lineage. The brain is chimplike in size, about 417 cubic
centimeters.
Yet the Hobbit's brain shared wrinkled surface features with the much
larger brains of both modern humans and Homo erectus, a tool-making
ancestor that lived in southeast Asia more than 1 million years ago.
Some of those brain features are consistent with higher cognitive
traits.
These brain features coincide with physical evidence of advanced
behaviors, such as hunting, firemaking and the use of stone tools,
which were found alongside the bones in a cave on the remote
equatorial island of Flores. To some, this suggests an organized
society of tiny hunters flourished on the island for millennia at a
time when modern humans dominated the planet.
"This is a unique creature," said Florida State University
anthropologist Dean Falk, who led the study. "We found amazing,
specialized features across the surface from front to back."
"These findings are consistent with the kinds of sophisticated
behaviors that are hypothesized" for the Hobbit, Falk said, but she
stopped short of saying the Hobbit was a tool-maker.
In October, scientists from Indonesia and Australia caused an
international sensation with their report of a trove of tiny fossils.
As many as eight individuals were represented in layers that were
dated from 95,000 to 12,000 years ago. The Hobbit skeleton was the
most complete specimen and contained the only skull.
In a project funded by the National Geographic Society, Falk and
researchers from Washington University in St. Louis created a
three-dimensional computer model of the brain using CT scans of the
interior of the Hobbit's skull. Known as virtual endocasts, these
images show the wrinkles, vessels and other surface features that
made faint impressions on the skull's lining.
They compared that model with the brains of chimps, a female Homo
erectus, a contemporary woman, a pygmy and a European specimen of a
person with a small-brain syndrome known as microcephaly.
Scientists say its brain shape is most closely associated with that
of Homo erectus. However, it also reflects some features of modern
humans,
including:
-A fissure near the back of the brain known as the lunate sulcus,
similarly found in the modern human brain. "I almost fell over seeing
this feature in something so small," Falk said.
-A swollen temporal lobe, the mid-brain area between the ears where
hearing, memory, image identification and emotions are processed.
-A part of the frontal lobe near the eyes that is thought to be
involved in planning and initiative-taking.
Such advanced brain features were especially surprising because the
rest of the skeleton has more primitive traits like coarse teeth and
an apelike pelvis similar to human ancestors that emerged in Africa
some 4 million years ago.
"It's a really strange combination of traits," said Michael J.
Morwood of the University of New England in Australia, one of the
Hobbit's excavators. "It is a new, diminutive human species."
Whether the Hobbit evolved into a dwarfed form of Homo erectus or
hails from another, older human cousin is unknown, he said.
Other human evolution specialists were split over the new report.
Katerina Semendeferi of the University of California-San Diego
described it as a "cutting edge study." While the Hobbit brain does
not fit neatly into an evolutionary pattern, she said it is too much
to expect that all species would have brain sizes that would neatly
transition in size from ape to modern human.
But some experts dismissed the brain-scan study as "trivial."
Primatologist Robert Martin, provost of the Field Museum in Chicago,
said the Hobbit probably was a modern human that suffered from a form
of microcephaly.
But Falk said the Hobbit brain was quite different from the brain of
a modern human with abnormal brain growth, or a human pygmy.
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