There are 41 species in the family, found in tropical South America (genus Pipa) and sub-Saharan Africa (the three other genera).

For example, the feet are completely webbed, the body is flattened, and a lateral line system is present in adults.

[1] In addition, pipids possess highly modified ears for producing and receiving sound under water.

The oldest known crown group pipids are Oumtkoutia and Pachycentrata from the Upper Cretaceous of Morocco and Niger, respectively.

Furthermore, the composition of this crown clade (in terms of which extinct taxa are included) depends on whether or not the topology is constrained to reflect the molecular tree.