These are fish which have cartilige rather than bones in their body. Examples including sharks, rays and guitarfishes. Found worldwide, there are about 1000 species worldwide.
“Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nostrils, scales...Chondrichthyes
“The subclass Holocephali ("complete heads") is a taxon of cartilaginous fishes, of which the...Holocephali
“Elasmobranchii is the subclass of cartilaginous fish that includes skates, rays (batoidea), and...Elasmobranchii
“Template:Otheruses4 Chimaeras are cartilaginous fish in the order Chimaeriformes. They are...Chimaera