Flatfish entire order was John Roxborough Norman's "Monograph of the Flatfishes" published in 1934. New species are described with some regularity and undescribed species likely remain. Hybrids are well known in flatfishes. The Pleuronectidae, of marine fishes, have the largest number of reported hybrids. Two of the most famous intergeneric hybrids are between the European plaice ("Pleuronectes platessa") and European flounder ("Platichthys flesus") in the Baltic Sea, and between the English sole ("Parophrys vetulus") and starry flounder ("Platichthys stellatus") in Puget Sound. The offspring of the latter species pair is popularly known as the hybrid sole and was initially believed to
American smooth flounder American smooth flounder The American smooth flounder ("Pleuronectes putnami") is a flatfish of the family Pleuronectidae. It is a demersal fish that inhabits shallow inshore salt and brackish waters at depths of up to . Its native habitat is the temperate waters of the northwestern Atlantic, from Ungava Bay in Quebec, Canada to Rhode Island, United States. It can grow up to in length. The American smooth flounder is a right-eyed flatfish, resembling the winter flounder in shape and appearance. Its upper side, including the fins, ranges in colour from dark grey to brown or almost black, and may be