What class of fish includes sharks, rays, and chimaeras?

What class of fish includes sharks, rays, and chimaeras? The answer is Chondrichthyes, the class of jawed cartilaginous fishes.

Unlike bony fishes, chondrichthyans have skeletons made primarily of cartilage. The class is divided into Elasmobranchii, which includes sharks, rays, skates, and sawfish, and Holocephali, the group containing chimaeras, also called ghost sharks. Their skin commonly bears tooth-like dermal denticles, giving many species a sandpaper-like texture.

A common mix-up is treating sharks as the whole group. Sharks are only one lineage within the broader cartilaginous-fish class; rays and skates are close relatives, while chimaeras belong to a separate surviving branch. Chondrichthyans also differ from most bony fishes in lacking a swim bladder, although they use other adaptations, including oily livers and lift from their fins, to control buoyancy.

Their reproduction is varied: fertilization is internal, and species may lay eggs, give birth to live young, or retain embryos internally until birth. The group includes both familiar coastal predators and specialized deep-sea forms.