Chondrichthyes (Cartilaginous Fish)
General description:
The class Chondrichthyes comprises almost 1050 extant species of cartilaginous fishes, encompassing skates, sharks, rays, and chimaeras
Diagnostic description:
Skeletons formed of calcified cartilage rather than bone.
The skin ia covered with placoid scalesor denticles.
True teeth, which are shed and replaced regularly in modern species.
The males of all but the oldest fossil species have a pelvic clasper, used in courtship and mating. It is formed of the pelvic meta-pterygium - the basal cartilage of the pelvic fin.
Identification: