Actinopterygian node L: Supraorbital bones between nasal and dermosphenotic numerous and irregular, peg and socket articulation generally absent from dermal scutes.


These basal actinopterygians radiated in the Carboniferous and remained an extant clade of fish through to the Jurassic period. The palaeonisciforms' major defining morphological characteristics are their additional supraorbitals and their recognisably keystone-shaped dermosphenotic, which they both shared with more derived actinopterygians, indicating their possible evolution in an ancestral form linking the palaeoniscids with the later ray-finned fish.