Merriam-Webster says both definitions are correct.There is a difference between "the tropics", which refers to latitude (just as it would with the temperate zone, or the tundra [which is also used to refer to an ecosystem, not just a latitude]), with "tropical", meaning the warm and humid areas that are common within the tropics. But that is not the only ecosystem found there.
There are several flaws with this argument:
First, and perhaps least important, modern English language dictionaries are not arbiters of what is “correct”. With perhaps over a billion native-speakers, who knows how many secondary speakers, over a million words, and usage on every continent and hundreds of countries worldwide, dictionaries only report common usage. As you well-know, common use or common knowledge does not make anything “correct”.
Of special importance, however is what the dictionary actually says. I went back to Merriam-Webster [online - I've no idea what versions anyone else consulted.
http://www.merriam-webster.com/dictionary/tropical], and found the following as the only relevant alternate definition for “tropical”:
b: of, being, or characteristic of a region or climate that is frost-free with temperatures high enough to support year-round plant growth given sufficient moisture
That definition includes anything between the tropics of Cancer and Capricorn which does not experience frost [or “winter”]. This means cloud forest, lowland rain forest, coral reef, swamp, river, or desert. Depending on the particular location, it could also include paramo or puna. Nowhere does it say “warm” or “humid”.
And NONE of this negates the simple fact that by the primary definition:
a: of, relating to, occuring in, or suitable for use in the tropics
even locations which experience frost [or “winter”] are STILL “tropical” if they are between the tropics. This:
”There is a difference between "the tropics", which refers to latitude ..., with "tropical", meaning the warm and humid areas that are common within the tropics.” is also a false distinction, given the primary definition [from Merriam-Webster] of ”
tropical a: of, relating to, occuring in, or suitable for use in the tropics”. This is the only definition provided in two Oxford dictionaries [”coming from, found in or typical of the tropics”], while a third adds “
resembling the tropics, especially in being very hot and humid: some plants thrived in last year’s tropical summer heat”. It does in fact say “hot” and “humid”, but note that this is figurative and is used to compare situations outside of the tropics to sterotypical views about situations inside the tropics.
And third, how do you reconcile dictating that a “tropical” location is not “tropical”, without specifying exactly what you mean? You can't. If you wish to say “not tropical lowland rainforest”, then that's what you must say. However, even that would not be true, because there certainly are plethodontids in tropical lowland rainforests and other tropical lowland habitats [eg.
Bolitoglossa colonnea, B.striatula, B.yucatana, B.mulleri, B.dofleini, many
Oedipina spp. - just to name a few].
or the tundra [which is also used to refer to an ecosystem, not just a latitude]
I have never heard “tundra” used to indicate a latitude, much less “just” a latitude.
Regarding the actual selection of species, my goal was to restrict the selection of animals to a smaller subset which includes potential species, not to dictate that all in that category were suitable, so I could have worded my recommendations better than I did. In terms of habitat availability, this environment is plenty big enough. Most of us house our animals in small plastic boxes or terraria of less then four square feet and two feet of height. This habitat is five feet, just front to rear, with multiple places where most of that appears to be terrestrial or riparian. As has been said by most though, the main concern would likely be temperature. Given a relatively cool room temperature, and heating mainly of the water itself, there could be some rather large gradients in there. That would require testing. The trouble remains though, that suitable species might simply not be legally or ethically available.