Cladistia is a subclass of bony fishes whose only living members are the bichirs of tropical Africa. Their major synapomorphies are a dorsal fin with independent rays, and a posteriorly elongated parasphenoid.

Cladistia are the earliest diverging branch of living Actinopterygii, and are thought to have diverged from the Actinopteri, the group which includes all other living ray finned fish, by the Carboniferous. However, the fossil range for the only extant order (Polypteriformes) is comparatively young, only reaching as far back as the mid-Cretaceous of South America and Africa, and the two extant genera of bichir only diverged around the Miocene.

Aside from bichirs, other extinct fish groups thought to be members of the group include the Scanilepiformes, known from Triassic (and possibly Permian) of the Northern Hemisphere. The Guildayichthyiformes of Carboniferous North America are also sometimes considered cladistians, but this is thought to be dubious, with other authorities placing them as a stem-group to Neopterygii.

Based on work done by Near et al (2017) and Lund (2000):