Is providing some sort of heat source over the water basin necessary? I've been thinking, that these frogs live in savannahs which likely don't have a lot of natural cover from the sun, so the puddles/ponds they spend much of their time in probably gets warmed up pretty well. But, in some parts of their habitat, the temperatures can get rather cool, down to the low 70s.

The room I keep my Pyxie in stays within around 75-77 degrees during this time of year, but can drop to 70 or a little below during the height of winter. That's of course not to say I keep the frog herself at said temps- actual habitat temps are low 80s during the day, low to high 70s (depending on season) at night. My Pyxie always deposits waste in her water so I've a 60W ceramic heat emitter (in a dimmer lamp) over the basin. Seems to aid digestion, especially from tougher food items like Dubias, or mistakenly ingested substrate.

Is there any exact temperature requirement for water, or is room temperatures just fine for it? I know in the case of horned frogs it is commonly utilized as a "cooling spot."