Large buckler scales with posteriorly directed processes present along bases of dorsal and anal fins. Also known as John dory and St. Peter fish.
Two genera, Zenopsis and Zeus, with about five species.
Order GASTEROSTEIFORMES (55)—sticklebacks. Pelvic girdle never attached directly to the cleithra; supramaxillary, orbitosphenoid, and basisphenoid absent; postcleithrum a single bone or absent; branchiostegal rays 1-5; body often with armor of dermal plates; mouth usually small.
As noted in greater detail in Nelson (1994), some authors have recognized the Gasterosteoidei and Syngnathoidei in separate but related orders (either under the ordinal name Gasterosteiformes or Syngnathiformes), while McAllister (1968) felt that they belonged to separate lineages. Although evidence for the monophyly is not strong, I accept the view ofJohnson and Patterson (1993) and earlier studies by T. W. Pietsch and R. A. Fritzsche that they are probably each other's closest relatives. Bowne (1994) reviews the systematics and morphology of Gasterosteiformes. The Indostomidae is moved from Syngnathoidei to Gasterosteoidei following the conclusions of Britz and Johnson (2002).
Two suborders with 11 families, 71 genera, and 278 species. About 21 species are restricted to freshwater and another 42 species are found in brackish water (some being variously diadromous or at least able to commonly enter freshwater and marine water).
Suborder Gasterosteoidei. Upper jaw protractile, ascending process of pre-maxilla well developed; postcleithrum absent; circumorbital bones, in addition to lachrymal, present; nasals and parietals present; anterior vertebrae not elongate; kidneys produce a gluelike substance used by males to construct a nest of plant material (condition in some species unknown); supracleithrum absent in Aulorhynchus, Spinachia, and Gasterosteus wheatlandi.
Four families, nine genera, and about 14 species (see comment on number of species under Gasterosteidae).
Family HYPOPTYCHIDAE (289)—sand eel. Marine; Japan and Korea to Sea of Okhotsk.
Body elongate, scutes and scales absent; spines absent; dorsal and anal fins posteriorly placed, each with about 20 soft rays; pelvic girdle and fins absent; pectoral fin rays nine; caudal fin with 13 principal rays (11 branched); four branchiostegal rays; circumorbital ring incomplete; premaxillary teeth present in males but absent in females; about 29 pairs of pleural ribs, epipleurals absent; vertebrae about 55-57; hypural plate divided into upper and lower halves (all other gasterosteioids have a fused hypural plate except Gasterosteus, which also has a split hypural). Maximum length about 8.5 cm.
One species, Hypoptychus dybowskii.
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