Chondrichthyes

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
Domain:	Eukaryota
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]

Chondrichthyes (/kɒnˈdrɪkθi.iːz/; from Ancient Greek χόνδρος (khóndros) 'cartilage', and ἰχθύς (ikhthús) 'fish') is a class of jawed fish that contains the cartilaginous fish or chondrichthyians, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fish, which have skeletons primarily composed of bone tissue. Chondrichthyes are aquatic vertebrates with paired fins, paired nares, placoid scales, conus arteriosus in the heart, and a lack of opecula and swim bladders. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates.

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). Extant Chondrichthyes range in size from the 10 cm (3.9 in) finless sleeper ray to the over 10 m (33 ft) whale shark.