Saturday, August 26, 2006

Indonesian scientists and others claim the "Hobbit" was only an aberrant pygmy

Here is the article from PNAS. Here is an interesting passage referring to the small size of the Hobbit (designated Homo floresiensis by some):

" Reduction in size on Flores is unsurprising in an ecosystem characterized by a humid climate, hilly topography, and abundant undergrowth of vegetation. Maintenance of body temperature alone can be a sufficient selective factor for small body size in such surroundings. Selection need only be sufficient to overcome limited levels of gene flow expected on an island separated by stretches of water constituting just filter barriers. Many of the surrounding regions (Peninsular Malaysia, the Andaman Islands, Sumatra, Java, Sulawesi, Papua, and Northern Australia) include populations relatively short in stature ... Diminutive body size does not in itself constitute convincing evidence for either isolation or speciation, because size fluctuations occur repeatedly in mammalian, including human, lineages. In living African pygmies, for example, spatial and genetic isolation manifestly is incomplete. "

In my view, the Hobbit was probably adapted to a rainforest environment, like most of the very short-statured peoples around the world. Also, as I have published, the most likely feature of the rainforest that is unique and probably results in a small skeletal size is low ultraviolet light, leading to low capacity for vitamin D production and development of bone mass.

(The Northern Australian pygmoids referred to in the quotation above are presumably the rainforest Aborigines of North Queensland. I measured ultraviolet light levels in the rainforest there some time ago. My report is here.)

It is interesting to see Australian Professors Thorne and Henneberg on the list of authors of the above paper. Professor Thorne is a noted physical anthropologist who lives here in Canberra and has been associated with the multiregional hypothesis of modern human origins, and Professor Henneberg is based in Adelaide and has presented his suggestion that the "Hobbit" individual was a case of microcephaly at a meeting of the Australasian Society for Human Biology (ASHB).

The above paper in PNAS argues that the Hobbit individual was an abnormal (microcephalic) person from a pygmoid population of modern humans. The suggestion that I made (from the floor) at the abovementioned meeting of the ASHB was that the Hobbit would turn out to be an extreme pygmoid type of Homo sapiens. This is close to the conclusion in the PNAS paper, except that I did not suggest that the individual was microcephalic, just an extreme type of pygmoid. Here and here are Internet references to my proposal.

John Hawks has also discussed this new PNAS paper at his anthropology blog.

I await further developments with interest.



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