Is the hobbit human debate over? I doubt it, but the below, from Wiley-Blackwell, puts a strong notch on the side of those who believe "Homo floresiensis" represents a new human species.
Researchers from Stony Brook University Medical Center in New York have confirmed that Homo floresiensis
is a genuine ancient human species and not a descendant of healthy
humans dwarfed by disease. Using statistical analysis on skeletal
remains of a well-preserved female specimen, researchers determined the
"hobbit" to be a distinct species and not a genetically flawed version
of modern humans. Details of the study appear in the December issue of Significance, the magazine of the Royal Statistical Society, published by Wiley-Blackwell.
In
2003 Australian and Indonesian scientists discovered small-bodied,
small-brained, hominin (human-like) fossils on the remote island of
Flores in the Indonesian archipelago. This discovery of a new human
species called Homo floresiensis has spawned much debate with
some researchers claiming that the small creatures are really modern
humans whose tiny head and brain are the result of a medical condition
called microcephaly.
Hobbit skull with brain region highlighted
(Image courtesy of Kirk E. Smith of the Mallinckrodt Institute of Radiology of Washington University, via Science-AAAS)
Researchers William Jungers, Ph.D., and
Karen Baab, Ph.D. studied the skeletal remains of a female (LB1),
nicknamed "Little Lady of Flores" or "Flo" to confirm the evolutionary
path of the hobbit species. The specimen was remarkably complete and
included skull, jaw, arms, legs, hands, and feet that provided
researchers with integrated information from an individual fossil.
The
cranial capacity of LB1 was just over 400 cm, making it more similar to
the brains of a chimpanzee or bipedal "ape-men" of East and South
Africa. The skull and jawbone features are much more primitive looking
than any normal modern human. Statistical analysis of skull shapes show
modern humans cluster together in one group, microcephalic humans in
another and the hobbit along with ancient hominins in a third.
Due
to the relative completeness of fossil remains for LB1, the scientists
were able to reconstruct a reliable body design that was unlike any
modern human. The thigh bone and shin bone of LB1 are much shorter than
modern humans including Central African pygmies, South African KhoeSan
(formerly known as 'bushmen") and "negrito" pygmies from the Andaman
Islands and the Philippines. Some researchers speculate this could
represent an evolutionary reversal correlated with "island dwarfing."
"It is difficult to believe an evolutionary change would lead to less
economical movement," said Dr. Jungers. "It makes little sense that
this species re-evolved shorter thighs and legs because long hind limbs
improve bipedal walking. We suspect that these are primitive retentions
instead."
Further analysis of the remains using a regression
equation developed by Dr. Jungers indicates that LB1 was approximately
106 cm tall (3 feet, 6 inches)—far smaller than the modern pygmies
whose adults grow to less than 150 cm (4 feet, 11 inches). A
scatterplot depicts LB1 far outside the range of Southeast Asian and
African pygmies in both absolute height and body mass indices.
"Attempts to dismiss the hobbits as pathological people have failed
repeatedly because the medical diagnoses of dwarfing syndromes and
microcephaly bear no resemblance to the unique anatomy of Homo floresiensis," noted Dr. Baab.
