As I mentioned once or twice, a debate I follow whose duration seems destined to be measured in geologic time is the one over Homo floresiensis - the "hobbits" of Flores Island, Indonesia.
Round 257 or so (I lose count) is based on a new paper in the Proceedings of the Royal Society.
"Are the small human-like fossils found on Flores human endemic cretins?"
Peter J. Obendorf, Charles E. Oxnard and Ben J. Kefford.
The point: "We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens."
In English: the fossils of the main specimen, LB1, indicate "congenital hypothyroidism."
The entire paper is online at the link above.
My take: I'm not about to wade into the details of a debate whose fine points are pretty much understood only by Ph.D.s. I will note only the problem I've had with all the non-species explanations, that they are based entirely, or almost entirely, on LB1. This is inescapable, since LB1's is the only cranium and the only near-complete skeleton we have, but it also means everyone is generalizing from one specimen. The new-species researchers are more likely to cite features of the other, less complete, specimens that appear in multiple individuals. That does not mean the new-species people are right (although the scientific romantic in me can't help but hope they are), only that I don't think anything is definitive yet. This is not going to be settled until we have more fossils, especially craniums (crania?).
I also note that, as a general rule, the idea that such cretins grew to maturity, which these fossils show they did, seems unlikely in a primitive hunter-gatherer culture. Such cultures tend not to expend the effort to keep marginally functional members alive and well-fed. It's not a hard rule, but it's something else to think about.