Osteichthyes

Osteichthyes are a taxonomic superclass of fish, also called bony fish, that includes the ray-finned fish (Actinopterygii) and lobe finned fish (Sarcopterygii). The split between these two classes occurred around 440 million years ago.  The Osteichthyes are paraphyletic with land vertebrates. This is why some classification schemes put the tetrapods into the Osteichthyes.  Osteichthyes are the most various group of vertebrates, consisting of over 29,000 species, making them the largest superclass of vertebrates in existence today.

 Taxonomy 
Osteichthyes has two classes. They are the Actinopterygii and Sarcopterygii.

 Actinopterygii – these are the ray-finned fishes.
 Sarcopterygii – these are the lobe-finned fishes. There are only a few sarcopterygians that are still alive today. Most of them have gone extinct.