"Hobbit" Humans Were Diseased Cretins, Study Suggests
for National Geographic News
|March 6, 2008|
The fossils of hobbit-like humans discovered on the Indonesian island of Flores in 2003 may have been severely malnourished modern humans, a controversial new study suggests.
The hypothesis is the latest in a string of diseases proposed to explain the small-bodied fossils.
The scientists who originally discovered the remains hailed them as representing a heretofore unknown species, Homo floresiensis, that lived at the same time as modern humans 18,000 years ago.
Since then researchers have squared off against each other, poring over skeletal traits, regional histories, and the medical literature to argue for or against the unique-species designation.
Peter Obendorf of RMIT University in Melbourne, Australia, decided to enter the fray after noticing the hobbits looked similar to people with a disorder of the thyroid gland called cretinism.
Cretinism can cause dwarfing and mental retardation, and is related to nutritional deficiencies, primarily a lack of iodine.
"Very quickly I found there were some quite surprising similarities between the dwarf cretins and these little people of Flores," Obendorf said.
Disease of the Week?
Among the key similarities are a particular type of arrested bone growth that leads to shorter but thicker bones, a twisting of the arm bone, and certain features in the wrist and skull.
The findings are based on a comparison of images and descriptions of the Flores remains with previously published data on dwarf cretins.
Obendorf and colleagues Charles Oxnard from the University of Western Australia and Ben Kefford at RMIT University did not study the original hobbit fossils.
Their analysis was published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences.
Several scientists called the paper an unsuccessful attempt to explain away the hobbit with yet another disease and pointed out features they believe uphold the unique-species designation.
One of these scientists is Matthew Tocheri, an anthropologist at the Smithsonian Institution in Washington, D.C.
"New hypotheses of hobbit pathology arise every week, and they will continue to disappear just as quickly afterward," he commented via email.
Tocheri said his data published last year in Science refutes the claim put forth by Obendorf's team that a particular hobbit wrist bone called the trapezoid is actually separated into pieces.
Obendorf's team speculates this type of separation may be associated with cretinism and that a piece of the trapezoid is missing in the hobbit.
Tocheri said the bone lines up too well with other wrist bones to be missing a piece, and he added that it resembles those of chimpanzees and gorillas.
No documented evidence of this feature's association with cretinism exists, he noted.
Dean Falk, an anthropologist at Florida State University, has a bone to pick with the team's measurement of an indentation on the skull where the pituitary gland fits.
Cretinism leads to the enlargement of this gland.
"We think the thing the whole paper rests on is the claim about having a large pituitary and therefore the cradle it sits in, the pituitary fossa," she said.
Obendorf's team measured this indentation based on a 2-D picture of a 3-D skull reconstruction created by Falk's team and found it is 0.5 inch (12.9 millimeters) long.
Falk and colleagues measured the fossa in their 3-D reconstruction and found it is only 0.35 inch (9 millimeters) long and likely shorter.
Even if this latter measurement is correct, however, Obendorf said their measurement "doesn't blow us out of the water. What it means is this particular point of evidence is not as strong."
Sick and Abandoned
Falk's colleagues Charles Hildebolt and Kirk Smith at the Mallinckrodt Institute of Radiology in St. Louis, Missouri, also took issue with other interpretations of the skull and teeth.
Hildebolt suggested that defending the new-species designation comes with the territory.
"Any new fossil find such as this historically is met with skepticism," he said.
Obendorf argues that the new-species hypothesis has been weak from the beginning.
For one, he said, small-bodied modern humans were on the nearby island of Timor at least 42,000 years ago and made stone tools similar to those associated with the hobbits.
(See a National Geographic magazine feature: "Flores Find: The People That Time Forgot.")
More detailed studies of features such as wrist and teeth bones, he said, support the suggestion the hobbit was a diseased modern human.
From his perspective, that disease was cretinism. A malnourished 30-year-old cretin, he said, would become burdensome to a hunter-gatherer society on Flores.
"At some stage they would either be left in some suitable environment or just become estranged and find themselves left alone dying in a cave," he said.
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