- Sharks
- Rays
- Skates
- Chimaeras
Chondrichthyes are characterized by their cartilaginous skeletons, lack of bone, and five to seven-gill slits on the sides of their heads. They are the oldest group of gnathostomes (jawed vertebrates) and have survived for over 400 million years. Chondrichthyes are found in all oceans and at all depths, from the shallows to the deep sea. They are predators and feed on a variety of animals, including fish, squid, crustaceans, and marine mammals.