Batoidei

Batoidei 

a suborder of fishes of the order Selachii; some ichthyologists consider Batoidei to be an order. The skin is naked or covered with spines, and the skeleton is cartilaginous. The head and body are flattened dorsoventrally; in most species the head and body are fused together with the pectoral fins, which form a disk. The five pairs of gill slits are located on the ventral side of the body, and the dorsal fins, if present, are on the tail.

There are ten families (according to some taxonomists, 15), including Rhinobatidae (guitarfishes), Pristidae (sawfishes; with the single genus Pristis), Rajidae (skates), Dasyatidae (stingrays), Myliobatidae (eagle rays), Mobulidae (mantas), and Potamotrygonidae.

Most species inhabit the coastal areas of tropical and subtropical seas; some, including the skates, are present in temperate and cold seas. There also are freshwater forms, for example, the Potamotrygonidae, which live in the rivers of South America. Ten species of skates and stingrays are found in the USSR—in the Barents, White, and Black seas, as well as in the seas of the Far East.

The fishes are usually viviparous or ovoviviparous; only skates lay eggs. The eggs take 4½ to 15 months to develop. Fecundity ranges from one to several dozen fry. Most species feed on bottom-dwelling animals; guitarfishes and eagle rays mostly eat mollusks.

Fishes of the suborder Batoidei are commercially valuable. They are fished primarily off the coast of Western Europe. The flesh of many species is used as food, and the fins are highly valued. An oil used in industry is pressed from the liver.

REFERENCES

Promyslovye ryby SSSR. Opisanie ryb. [Moscow] 1949. (Text to an atlas.)
Andriiashev, A. P. Ryby severnykh morei SSSR. Moscow-Leningrad, 1954.
Nikol’skii, G. V. Chastnaia ikhtiologiia, 3rd ed. Moscow, 1971.
Lindberg, G. U. Opredelitel’i kharakteristika semeistv ryb mirovoi fauny. Leningrad, 1971.
Zhizn’zhivotnvkh, vol.4, part 1. Moscow, 1971.

G. U. LINDBERG