I don't konw the exact distributions of both of them but I was under the impression that they occured separately. Maybe someone here knows and will chime in.
I think the only obvious difference between the two is the more exaggerated peristome on hamata. If that was taken away, the plants look similar enough to me to not be considered different species.
One thing I don't understand is why with many species, people are eager to make "species" out of them quite readily, with the exception of alata. I can think of 6 different forms off the top of my head that look radically different (much more than just a more exaggerated peristome) and they are all considered exactly the same. Does anyone have pics of hamata/tentaculata flowers?
@llepardggecko: It could probably survive in them temporarily, but will not survive in the long run. I can't give you specifics as I don't grow it, but I would avoid those temps if possible, and if not, wouldn't keep the plant in them for more than maybe 3 months tops (assuming you have all the other variables correct)