Actinopterygii

Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that constitutes nearly 99% of the over 30,000 living species of fish. The vast majority of extant actinopterygian species are teleosts, and by species count they dominate the subphylum Vertebrata, comprising over 50% of all living vertebrates. They are the most abundant nektonic aquatic animals and are ubiquitous throughout freshwater, brackish and marine environments from the deep sea to subterranean waters to the highest mountain streams. Extant species can range in size from Paed

Cheirolepis (from , 'hand' and 'scale') is an extinct genus of marine and freshwater ray-finned fish that lived in the Devonian period of Europe and North America. It is the only genus yet known within the family Cheirolepididae and the order Cheirolepidiformes. It was among the most basal of the Devonian actinopterygians and is considered the first to possess the "standard" dermal cranial bones seen in later actinopterygians.

Moythomasia (named for James Alan Moy-Thomas) is an extinct genus of early ray-finned fish from the Devonian period, known from fossils found in Europe and Australia.

Mimipiscis is a fossil genus of very primitive ray-finned fishes from the Upper Devonian Gneuda and Gogo formations of Western Australia.

Canobius (named for Canobie, the district where it was discovered) is an extinct genus of marine ray-finned fish that lived in the early Carboniferous period (Viséan) of Glencartholm, Scotland.

Nematoptychius is an extinct genus of ray-finned fish that lived from the Visean age of the Mississippian epoch (Early Carboniferous) to the Bashkirian age of the Pennsylvanian epoch (Late Carboniferous) in what is now Scotland, Belgium and France. left|thumb|Fossil skull of N. greenocki Its type species, Nematoptychius greenocki, was first described as Pygopterus greenocki by Ramsay Traquair.