To be absolutely scientifically correct, the one you've got is a Lowveld African Bullfrog, Pyxicephalus edulis. It looks exactly like those found in Kruger National Park, South Africa. Others, like the one in the following photo, are not Pyxicephalus adspersus either, but we lump them into the "Dwarf" category because they don't get above 5 inches or so and the Taxonomy scientists haven't gotten around to the Pyxicephalus genus yet.