; subclass Actinopterygii, order Pleuronectiformes)
A large family of marine flatfish, comprising the true flounders which have the eyes on the right side, the dorsal fin starting above the upper eye, a fairly large mouth with distinct teeth, and the right pectoral and pelvic fins mostly larger than the left ones. The family includes many commercially important species, e.g. Reinhardtius hippoglossoides (Greenland halibut), 1 m, which has been heavily overfished in the N. Atlantic (catches are now restricted); Platichthys flesus (flounder), 50 cm; and Pseudopleuronectes americanus (Atlantic winter flounder), 60 cm. There are about 100 species, distributed in the Atlantic and Pacific.
Subjects: Zoology and Animal Sciences.