Pipidae

The Pipidae are a family of primitive, tongueless frogs. The thirty species in the family Pipidae are found in tropical South America (genus Pipa) and sub-Saharan Africa (four other genera).

These frogs are exclusively aquatic and have numerous morphological modifications befitting their habitat. For example, the feet are completely webbed, the body is flattened, and a lateral line system is present. In addition, pipids possess highly modified ears for producing and receiving sound underwater. They lack a tongue or vocal cords, instead having bony rods in the larynx that help produce sound. They range from 4 to 19 centimeters (1.6 to 7.5 in) in body length.

The fossil record for pipids is relatively good with twelve extinct species known. Six of these are placed in the extant genus Xenopus, the remainder in extinct genera. These fossils are known from Africa, South America, and Middle East back to the Lower Cretaceous.