An order of fishes also known as Lampridiformes and Allotriognathi. Although the families of Lampriformes appear very dissimilar, they share the following combination of characters that distinguish them from other orders of actinopterygian (ray-finned) fishes: notably compressed body, often ribbonlike; no true spines in fins, rays only; thoracic pelvic fins, if present; swim bladder, if present, physoclistous; and small cycloid scales, commonly absent. In addition, lampriforms have a unique type of protrusible upper jaw, by which the premaxilla excludes the maxilla from the gape, and the maxilla, instead of having a ligamentous attachment to the ethmoid and palatine bones, slides in and out with the highly protractile premaxilla. Most species are large and colorful; some have inspired sea-serpent stories.