Bailey, Reeve M. Formerly, Division of Fishes, Museum of Zoology, University of Michigan, Ann Arbor, Michigan.
Last reviewed:July 2015
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A small extinct order of teleostean bony fishes. Members of the order Ctenothrissiformes (see illustration) are of particular interest because they seem to be on or near the main evolutionary line leading from the generalized, soft-rayed salmoniforms to the spiny-rayed beryciforms and perciforms, which are the dominant groups among higher bony fishes. Individuals lack fin spines, but they share the following characters with primitive beryciforms: pelvic fins that are thoracic, with seven or eight rays, and pectoral fins that are placed well up on the flank; a subocular shelf; a scaly opercle; a beryciform-like premaxilla; maxillary teeth; an orbitosphenoid; and 17 branched caudal rays. Except for the last three, these features persist in generalized members of the Perciformes and indicate a major evolutionary trend away from typical soft-rayed fishes. The scales are ctenoid or cycloid, and there are nine branchiostegals. Ctenothrissiform fishes also lack a mesocoracoid. See also: Beryciformes; Perciformes; Salmoniformes; Scale (zoology); Teleostei
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