Chondrichthyes

Chondrichthyes (/kɒnˈdrɪkθi.iːz/; from Ancient Greek χόνδρος (khóndros) 'cartilage', and ἰχθύς (ikhthús) 'fish') is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fishes, which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. Extant chondrichthyes range in size from the 10 cm (3.9 in) finless sleeper ray to the 10 m (32 ft) whale shark.

Cartilaginous fishes Temporal range: 439–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Silurian (Aeronian) - Present
Example of cartilaginous fishes: Elasmobranchii at the top of the image and Holocephali at the bottom of the image.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Infraphylum:	Gnathostomata
Clade:	Eugnathostomata
Class:	Chondrichthyes Huxley, 1880
Living subclasses and orders
Subclass Elasmobranchii Superorder Selachimorpha Order Carcharhiniformes Order Lamniformes Order Orectolobiformes Order Heterodontiformes Order Squaliformes Order Squatiniformes Order Pristiophoriformes Order Hexanchiformes Superorder Batoidea Order Myliobatiformes Order Rajiformes Order Rhinopristiformes Order Torpediniformes Subclass Holocephali Superorder Holocephalimorpha Order Chimaeriformes Incertae sedis †Acanthorhachis[1] †Bandringa[2] †Delphyodontos[3] †Listracanthus[4] †Nanocetorhinus[5] †Plesioselachus[6] †Psammodontiformes †Xiphodolamia[7]

The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class).

Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates.