TETRAODONTIFORM

any member of the order Tetraodontiformes, a group of primarily tropical marine fishes that evolved from the Perciformes (the typical advanced spiny-rayed fishes) during the Eocene Period of the Cenozoic Era, about 50,000,000 years ago. Included are the triggerfishes, puffers, and porcupine fishes. The approximately 320 species of modern tetraodontiforms are notable for a high degree of diversity in anatomical structure and way of life. The great diversity evident among the 11 families of the order is also seen within some families, but not in others. Members of the deepwater, bottom-dwelling Triacanthodidae, the most primitive family, for example, range from relatively normal configurations to weirdly specialized forms with extremely long tubular snouts; the shallow-water members of the Triacanthidae, closely related and derived from the Triacanthodidae, are of rather uniform configuration. Likewise, the balistids are rather uniform in body plan; but monacanthids, which evidently evolved from them, include a series of species ranging from the normal to the exceedingly elongated and highly specialized. any member of the order Tetraodontiformes, a group of bony, primarily tropical, marine fishes containing about 320 species in 11 families. Included within the order are the triggerfishes, puffers, and porcupine fishes. Most tetraodontiforms, which constitute about 5 percent of all tropical fish, are bottom dwellers, and they have developed a number of specializations for acquiring food. Teeth, for example, are well developed and in some species form parrotlike beaks with which to scrape at rock and corals or to crush mollusks and crustaceans. Boxfishes blow jets of water onto the bottom floor to expose burrowing worms and other invertebrates. Members of the superfamily Triacanthodidae (spikefishes and triple spines) have long snouts, with which to poke into holes and crevices, and rudimentary teeth, probably as a result of feeding on the scales of other bottom-dwelling fishes. Some species eat spiny sea urchins, clams, and even oysters. The huge ocean sunfish, which has massive teeth, feeds extensively on jellyfishes and other soft-bodied invertebrates. Tetraodontiforms are distinguished by a small gill slit on the side of the head, a small mouth, and massive teeth. Their scales may be overlapping (triacanthoids and balistoids), sutured (ostraciontoids), or developed as sharp spines (puffers and diodontoids). The skin is sometimes thick and hard. Tetraodontiforms swim by rowing their soft dorsal and anal fins; their pectoral fins vibrate constantly, giving them great control. Tetraodontiforms have little commercial value, although their flesh may be esteemed by local groups. Many species are poisonous during certain times of the year. These fishes have to be carefully cleaned prior to cooking. Of the nonpoisonous varieties, the flesh of certain triggerfishes and trunkfishes is considered particularly delectable. The skins of boxfishes and puffers are often dried as curios. Additional reading J.E. Bhlke and C.C.G. Chaplin, Fishes of the Bahamas and Adjacent Tropical Waters, 2nd ed. (1992), includes an excellent combination of scientific and popular accounts of the Caribbean tetraodontiforms, with all of the species well illustrated. Bruce W. Halstead, Poisonous and Venomous Marine Animals of the World, vol. 2, Vertebrates, 2nd rev. ed. (1988), contains a comprehensive review of the poisonous properties of the tetraodontiforms, with numerous illustrations of poisonous species. James C. Tyler, A Monograph on Plectognath Fishes of the Superfamily Triacanthoidea (1968), is a technical monograph on the two most generalized families of tetraodontiforms but also includes general accounts of the way of life, the distribution, and the relationships of these families, as well as an extensive bibliography on related articles.