The Pipidae are a family of primitive, tongueless frogs. The 30 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 cm (1.6 to 7.5 in) in body length.