Teleosteomorpha

Teleosteomorpha is an infraclass of ray-finned fishes containing all teleost fish and their closest extinct relatives. Also in this group are two diverse Mesozoic fish orders, the Aspidorhynchiformes and the Pachycormiformes. Several other non-teleostomorph teleosteans existed throughout the Mesozoic, although not as dominant as the two main clades in the group.

Shared morphological features of this group include a autosphenotic bone lacking a dermal component, the lack of a canal bearing part of the antorbital bone, the lack of vertebral centra fused into the occipital condyle in adult individuals, and each hypural (caudal fin support) being articulated with caudal rays.

The oldest known teleosteomorph is Prohalecites from the Triassic of Italy. The last surviving non-teleostean teleosteomorph was Belonostomus, which survived into the Late Paleocene.