Neopterygii

Neopterygii (from Greek νέος neos, new, and πτέρυξ pteryx, fin) is a subclass of ray-finned fish (Actinopterygii). Only a few changes occurred during the evolution of neopterygians from the earlier actinopterygians. They appeared sometime in the Late Permian, before the time of the dinosaurs. The neopterygians were a very successful group of fish, because they could move more rapidly than their ancestors. Their scales and skeletons began to lighten during their evolution, and their jaws became more powerful and efficient. While electroreception and the ampullae of Lorenzini are present in all other groups of fish, with the exception of hagfish (although hagfish are not actinopterygians, they are agnathans), neopterygians have lost this sense, even if it has later been re-evolved within Gymnotiformes and catfishes, which possess nonhomologous teleost ampullae.[2]

Neopterygii Temporal range: Late Permian–recent PreꞒ Ꞓ O S D C P T J K Pg N
Siganus corallinus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
(unranked):	Actinopteri
Subclass:	Neopterygii Regan, 1923[1]
Infraclasses
Holostei Teleostei See text for orders.

A very important step in the evolution of the actinopterygian fishes is the origin of the neopterygians, with the acquisition of a better control of the movements of both dorsal and anal fins, resulting in an improvement in their swimming capabilities. They additionally acquired several modifications in the skull, which allowed the evolution of different feeding mechanisms and consequently the colonization of new ecological niches. All of these characters represented major improvements, resulting in Neopterygii becoming the dominant group of fishes (and, thus, taxonomically of vertebrates in general). Neopterygii also includes the teleosts, which compromise the vast majority of extant fishes.[3]