A review on the Fauna of the Superorder Batoidea (Elasmobranchii, Pisces) in the East Asia

The living cartilaginous fishes, class Chondrichthyes, may comprise about 900 described species, and include approximately 170 genera and 50 families (Compagno, 1991). At present the Chondrichthyes consists of two subclasses, the Holocephali and the Elasmobranchii. The dominant subclass Elasmobranchii includes modem sharks and rays, the former is more diverse than the latter in higher taxa but have fewer species. The superorder Batoidea, batoids or rays, is speciose with about 500 species in six orders, fourteen families and about 60 genera. (omitted)