Editing Filefish (section)

==Description==
Appearing very much like their close relatives the triggerfish, filefish are [[rhomboid]]-shaped, with beautifully elaborate cryptic patterns. Deeply keeled bodies give a false impression of size when the fish are viewed facing the flanks. Filefish have soft, simple fins, with comparatively small pectoral fins and truncated, fan-shaped tail fins; a slender, retractable spine crowns the head. Although usually two of these spines occur, the second spine is greatly reduced, being used only to lock the first spine in the erect position. That gives rise to the family name Monacanthidae, from the [[Greek language|Greek]] ''monos'' meaning "one" and ''akantha'' meaning "thorn". Some species also have recurved spines on the base of the tail ([[caudal peduncle]]).

[[File:Monocanthus chinensis1.jpg|thumb|left| This fan-bellied leatherjacket, ''[[Monacanthus chinensis]]'', was photographed in nearshore water, on the northeast coast of Taiwan.]]

The small terminal mouths of filefish have specialized incisor teeth on the upper and lower jaws. The upper jaw hase four teeth in the inner series and six in the outer series. The lower jaw has four to six in an outer series only. The snout is tapered and projecting, and the eyes are located high on the head. Filefish have rough non-overlapping scales with small spikes, which is why they are called filefish. Although scaled, some filefish have such small scales that they appear scaleless. Like the triggerfish, filefish have small [[gill]] openings and greatly elongated pelvic bones, creating a "dewlap" of skin running between the bone's sharply keeled termination and the belly. The pelvis is articulated with other bones of the "pelvic girdle" and is capable of moving upwards and downwards in many species to form a large dewlap, which is used to make the fish appear much deeper in the body than is actually the case. Some filefish erect their dorsal spine and pelvis simultaneously to make removing them from a cave more difficult for predators.

The largest filefish species is the [[scrawled filefish]] (''Aluterus scriptus'') at up to {{convert|110|cm|abbr=on}} in length. Most species are less than {{convert|60|cm|abbr=on}} in length. Marked [[sexual dimorphism]] is seen in some species, with the sexes possessing different coloration, different body shapes; the males have larger caudal spines and bristles than females.

[[File:Scrawled Filefish.jpg|thumb|''[[Aluterus scriptus]]'' grows up to {{convert|110|cm|in|abbr=on}} in length]]