Chondrichthyes

Cartilaginous fishes Temporal range: Early Silurian (Aeronian) - Present
Example of cartilaginous fishes: Elasmobranchii above, Holocephali below.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Infraphylum:	Gnathostomata
Clade:	Eugnathostomata
Class:	Chondrichthyes Huxley, 1880
Living subgroups and incertae sedis
Subclass Elasmobranchii Division Selachii Order Carcharhiniformes Order Lamniformes Order Orectolobiformes Order Heterodontiformes Order Squaliformes Order Echinorhiniformes Order Squatiniformes Order Pristiophoriformes Order Hexanchiformes Division Batomorphi Order Myliobatiformes Order Rajiformes Order Rhinopristiformes Order Torpediniformes Subclass Holocephali Superorder Holocephalimorpha Order Chimaeriformes Incertae sedis †Bandringa †Delphyodontos †Listracanthidae †Mcmurdodontidae †Nanocetorhinus †Plesioselachus †Psammodontiformes †Omalodontiformes

Chondrichthyes (/kɒnˈdrɪkθiiːz/; from Ancient Greek χόνδρος (khóndros) 'cartilage' and ἰχθύς (ikhthús) 'fish') is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, 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, and conus arteriosus in the heart. 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) which lack opercula, and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Extant chondrichthyans range in size from the 10 cm (3.9 in) finless sleeper ray to the over 10 m (33 ft) whale shark.