Neoselachii

The Neoselachii are an important group of cartilaginous fish in the subclass Elasmobranchii, class Chondrichthyes. 

The group is important because it includes all living  sharks, skates,  and rays. They rapidly diversified during the Upper Triassic.

The group is descended from a primitive type of shark in the Devonian period.Underwood C.J. 2006. Diversification of the Neoselachii (Chondrichthyes) during the Jurassic and Cretaceous (PDF). Paleobiology 32 (2): 215–235. 

 References 

Category:Sharks
Category:Rays