[2] All the species occur in freshwater habitats in tropical Africa and the Nile River system, mainly swampy, shallow floodplains and estuaries.

Cladistia, polypterids and their fossil relatives, are considered the sister group to all other extant ray-finned fishes (Actinopteri).

The oldest polypterids are around 100 million years old, from the early Late Cretaceous of South America and Africa.

Bichirs have a number of other primitive characteristics, including fleshy pectoral fins superficially similar to those of lobe-finned fishes.

[citation needed] Polypterid reproduction consists of the female laying anywhere from 100 to 300 eggs over the span of a few days, and subsequent fertilization by the male.

They are facultative air-breathers, accessing surface air to breathe when the water they inhabit is poorly oxygenated.

In addition to the extinct genus Bawitius, the two living genera, Polypterus and Erpetoichthys, have 14 extant species:[12] Erpetoichthys calabaricus P. retropinnis P. congicus P. ansorgii P. endlicheri P. bichir P. mokelembembe P. ornatipinnis P. weeksii P. teugelsi P. palmas P. senegalus P. delhezi P. polli Order Polypteriformes Suborder Polypterioidei Clade Salamandrophysida