Amphibians (class Amphibia), such as frogs, toads, salamanders, newts, and caecilians, are ectothermic (or cold-blooded) animals that either metamorphose from a juvenile water-breathing form, to an adult air-breathing form, or paedomorph and retain some juvenile characteristics. Mudpuppies and waterdogs are good examples of paedomorphic species. Though amphibians typically have four limbs, the caecilians are notable for being limbless.
This list of Anuran families shows all extant families of Anura. Anura is an order of animals in the class Amphibia that includes frogs and toads. There are around 5,280 species currently described in the order. The living Anurans are typically divided into three suborders: Archaeobatrachia, Mesobatrachia and Neobatrachia. This classification is based on such morphological features as the number of vertebrae, the structure of the pectoral girdle, and the morphology of tadpoles.
Scaphiopodidae is a toad family of American spadefoot toads. They are native to southern Canada and USA south to southern Mexico. Scaphiopodidae is a small family, comprising of only seven 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, this frog has hard, keratinous protrusion present on their feet, which helps them to dig.
The Western spadefoot toad (Spea hammondii) is a relatively smooth-skinned species of toad. Its eyes are pale gold with vertical pupils. It has a green or grey dorsum often with skin tubercles tipped in orange, and it is a whitish color on the ventrum. It has a wedge-shaped black spade on each hind foot. Adult toads are between 3.8 and 7.5 cm long. Juveniles western spadefoot toads look similar to adults, but have more distinct spotting.