given historical ranges of different species, what kinds of frogs could have been present for the plague of frogs in exodus?
Fantastic question. Let's assume that the Egyptians considered toads and frogs to be different organisms, and therefore the stories referring to frog plagues indeed mean frogs other than Bufonidae (I think this is a reasonable assumption). If this is the case, there are basically two key candidates: Ptychadena nilotica and Pelophylax saharicus. Ptychadena have the edge over Pelophylax because they are somewhat more tolerant of drier habitats. Sometimes they occur in huge densities, so that every step sends dozens springing away. Both can lay enormous clutches, many thousands of eggs, and in a particularly wet year, I could easily imagine a boom in froglet development that would cause a 'plague'. And because the frogs would be trying to disperse, but heading into habitat that is too dry for them to persist long-term, you would quickly have a lot of dead frogs.
