Cladistia

Cladistia refers to an order of primitive, freshwater African fishes that possess scales, a head skeleton, and pectoral arches resembling extinct species. These fish, including the bichir and reedfish, are characterized by their ability to breathe air in addition to extracting oxygen from water using rudimentary gills. This adaptation, involving lungs derived from the ventral side of the endoderm, may have originated in the Silurian Period.12

Bichirs, belonging to the genus Polypterus, are typically elongated with fleshy pectoral fins, rounded tails, and thick, ganoid scales. They inhabit African river and lake systems and forage at night for various small prey. While some classifications place them with chondrosteans, others suggest a closer relation to crossopterygians, but most recognize them as a distinct clade, Cladistia.2