Charles Oxnard and colleagues have a paper out in PLoS ONE in which they present new data supporting their contention that Homo floresiensis is in fact a member of our own species affected by hypothyroid cretinism. In an earlier and highly controversial study they drew the same conclusion based on cranial data; this new paper looks at the rest of the skeleton.
Using principal components analysis and non-metric multi-dimensional scaling the authors say they have confirmed that H. floresiensis clusters with hypothyroid cretins and is clearly separated from both unaffected modern humans and chimpanzees:
We therefore conclude that LB1 and LB6, at least, are, most likely, endemic cretins from a population of unaffected Homo sapiens. This is consistent with recent hypothyroid endemic cretinism throughout Indonesia, including the nearby island of Bali.
So are Oxnard et al. right to conclude that the floresiensis morphology is the result of human disease or are their critics right to maintain that it represents a completely new species? I don’t know and, to be honest, I don’t really have a vested interest one way or another. I suppose I’d quite like it to be a new species, but either way it’s a fascinating discovery.
Obendorf P. J., Oxnard C. E., Kefford B. J. 2008. Are the small human-like fossils found on Flores human endemic cretins? Proceedings of the Royal Society Series B 275:1287-1296.
Oxnard C., Obendorf P. J., Kefford B. J. 2010. Post-cranial skeletons of hypothyroid cretins show a similar anatomical mosaic as Homo floresiensis. PLoS ONE 5(9):e13018 DOI: 10.1371/journal.pone.0013018