Actinopterygii

The Actinopterygii is the class of ray-finned fishes.

The ray-finned fishes get their name from the fact their fins are webs of skin held by bony or horny spines ("rays"). This is different from the fleshy fins of the fish in the Sarcopterygii. Ray-finned fish  first appeared in the Silurian period.

Actinopterygians are the largest class of vertebrates. There are nearly 25,000 species. They can be found in both fresh water and marine environments from the deep sea to the highest mountain streams. 

Most of the living species are teleosts, which are late-comers to the fish domain. The first teleosts are in the Mesozoic era, yet now they make up 96% of all fish.

 Taxonomy 

 Chondrostei (bichirs and sturgeons)
 Neopterygii
 Holostei (gars and bowfins)
 Teleostei
 Osteoglossomorpha
 Elopomorpha (eels) 
 Clupeomorpha (herrings, anchovies)
 Ostariophysi (goldfish, minnows, catfish, electric eels)
 Protacanthopterygii (salmon, trout, pike)
 Stenopterygii
 Cyclosquamata
 Scopelomorpha
 Lampridiomorpha
 Polymyxiomorpha
 Paracanthopterygii (cod, anglerfish)
 Acanthopterygii (mullets, flying fishes, sticklebacks, seahorses, flatfish, cichlids, mackerel, tuna, perch)

 References