The Scaphiopodidae are a family of American spadefoot toads, which are native to North America. The family is small, comprising only seven different species. The American spadefoot toads are of typical shape to most fossorial (or burrowing) frogs. They are round, with short legs and protruding eyes. As suggested by their name, these frogs have hard, keratinous protrusions present on their feet, which help them to dig. Like most fossorial frogs, they dig backwards into the ground. They differ from true toads because they have vertical pupils and no parotoid gland. The American spadefoot toads are terrestrial when not underground. They are dully colored, usually a grey or dull green or brown, to aid in camouflage in their arid habitats. Taxonomy The American spadefoot toads were previously included in a broader circumscription of the family Pelobatidae, which then united Palaearctic and Neoarctic spadefoot toads in the same family. However, the American spadefoot genera were split off into Scaphiopodidae, with the Pelobatidae restricted to the European spadefoot toads in the genus Pelobates. The Scaphiopodidae contains two genera, both in North America: Southern spadefoot toads, Scaphiopus (Holbrook, 1836) Western spadefoot toads, Spea (Cope, 1866) Despite the common name and current distribution of the family, fossil evidence indicates that it once had a much larger distribution that at least reached eastern Asia. The extinct genus †Prospea is the earliest known member of this family, and is only known from Paleocene sediments in Mongolia. Appearance Similar to other burrowing frogs, American spadefoot toads are about 2-3 inches in length with round, stocky bodies and eyes that bulge from their heads. The name “spadefoot” is derived from the keratinous bone in its hind legs that allow it to burrow within soil. The skin of the toad is grey or brown in appearance and smooth to the touch. Location and environment Spadefoot toads are generally found in arid climates, where they spend the majority of their lives underground, generally beneath perennial ponds, creek beds, or other moisture-retaining areas. During years of sufficient rainfall, the toads surface to breed and lay eggs. The two main species of spadefoot toads are found in different locations across North America. The eastern spadefoot is the only species found east of the Mississippi River, ranging from New England to southern Florida. The Great Basin spadefoot and the plains spadefoot are both found in Western Canada and the northwestern U.S., but the