Neopterygii

Neopterygii (from Greek νέος neos 'new' and πτέρυξ pteryx 'fin') is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year.

Fossil evidence for crown group neopterygians goes back at least 251 million years to the Induan stage of the Early Triassic epoch, however, one study incorporating morphological data from fossils and molecular data from nuclear and mitochondrial DNA, places this divergence date at least 284 mya (million years ago), during the Artinskian stage of the Early Permian. Another study suggests an even earlier split (360 myr ago, near the Devonian-Carboniferous boundary).