Genus: Monacanthus, Filefishes, Spinetail Filefish

MONACANTHUS

FILEFISHES

Body deep, compressed; a long pointed snout; a small mouth that opens at front; teeth moderately strong, six in outer row on top jaws and six in a single row on bottom jaws; gill opening a short slit on side before pectoral base; 2 dorsal fins, 1st with II spines, 1st spine over rear 1/2 of eye, long, serrated at rear, toothed along front and sides, does not fold down into a deep groove, erectile, can be locked in position by small 2nd spine; none of dorsal fin rays elongate; pelvic fin rudiment evident as a prominent spine protruding from a group of enlarged scales, those scales flexible dorsoventrally; flap between pelvis and anus large; tail base of large juveniles and adults with 2-4 pairs of large spiny scales, those curved forwards in male; scales minute, innumerable, each with 1 or more spines, skin rough.

A tropical genus from the W Pacific and Atlantic, with 3 species, 2 species in the Greater Caribbean, 1 pan-Atlantic and 1 NW Atlantic.