SCORPAENIFORM

also called mail-cheeked fish, any member of the order Scorpaeniformes, a group of bony fishes that includes the sea robins, sculpins, and numerous other forms. They are characterized by a plate of bone running across each cheek. The scorpaeniforms are widespread throughout the oceans of the world. They are believed to have originated in warm marine waters but have invaded temperate and even Arctic and Antarctic seas as well as freshwaters of the Northern Hemisphere. The scorpaeniforms are a highly successful biological group, occurring in the sea from the midlittoral (coastal) zone down to depths of at least 4,000 metres (about 13,000 feet). They inhabit some deep freshwater lakes but are more abundant in cold streams and rivers. Atlantic flying gurnard (Dactylopterus volitans) The scorpaeniforms are often divided into six suborders, only two of which have more than one family; these are the Scorpaenoidei (three families) and the Cottoidei (seven families). The best known groups are the scorpion fishes and rockfishes (family Scorpaenidae); sea robins, or gurnards (Triglidae); flatheads (Platycephalidae); and sculpins (Cottidae). The flying gurnards (Dactylopteridae; see photograph), considered by some authorities to belong in this order but more often separated in the order Dactylopteriformes, are treated here for convenience. also called mail-cheeked fish (order Scorpaeniformes) any of a group of bony fishes that includes the sea robins, sculpins, and numerous other forms found worldwide. They are characterized by a plate of bone running across each cheek. Scorpaeniforms generally reach about 30 cm (1 foot) in length, although the deep-sea redfish can grow up to 90 cm long. Most scorpaeniforms are typically fishlike in appearance, with spiny rays and scales, but a number of them have truly odd shapes. The lumpfishes are fat and jellylike, usually without scales, and have no sharp spines on their fins. The sea robins, by contrast, have large, pointed heads and protuberant eyes as well as large pectoral and dorsal fins. The stonefish is an irregularly shaped, deep-bodied fish that is able to mimic its background so perfectly that it looks like an eroded piece of coral lying on the bottom. It is the most venomous of all the scorpaeniforms, with dorsal spines that inject poison. Turkey fishes also inhabit the tropical waters of the Indo-Pacific, but unlike the stonefish they are free swimmers and are brightly coloured with patterns of contrasting stripes to denote species. All have long, needlelike dorsal spines and can inflict extremely painful wounds. The flatheads are bottom dwellers that bury themselves on the bottom with only their eyes showing. Their varied diet includes fishes, mollusks, crustaceans, and worms. The largest of them, the dusky flathead (Platycephalus fuscus), is an important food fish in Australia. The sea robins, also bottom dwellers, have an interesting adaptation of their pectoral fins. The lower rays are long and thick and act as organs of taste and touch; they even make it possible for the fish to walk along the bottom, at the same time probing for food. Like the flatheads, sea robins feed on small fish, crustaceans, mollusks, and other bottom dwellers. The scorpaeniforms have adapted very well to fresh water, and sculpins are found in many lakes and rivers of the Northern Hemisphere. Some species remain in deep water year-round, while others use the bottom only to spawn. Additional reading Most of the information on the scorpaeniform fishes is found in short technical articles in scientific journals. The following works are broad in nature but contain substantial information on members of this order. E.S. Herald, Living Fishes of the World (1961, reprinted 1972), is a well-illustrated book for the general reader; N.B. Marshall, The Life of Fishes (1965), contains some sections on the biology of scorpaeniforms; G.V. Nikolskii, Special Ichthyology, 2nd rev. ed. (1961; trans. of the 2nd Russian ed. of 1954), deals especially with species commercially important in the former Soviet Union; B.W. Halstead, Poisonous and Venomous Marine Animals of the World, vol. 3 (1970), provides information on the venom of these fishes and its effects. P.H. Greenwood et al., Phyletic Studies of Teleostean Fishes, with a Provisional Classification of Living Forms, Bull. Am. Mus. Nat. Hist., 131: 339455 (1966); and C.T. Regan, The Osteology and Classification of the Teleostean Fishes of the Order Scleroparei, Ann. Mag. Nat. Hist., Series 8, 11:169184 (1913), are rather technical, but important, contributions to the study of the scorpaeniforms.