Gymnacanthus Swainson, 1839
Body naked except for a few separate, thorny, bony plates under pectoral fin. Head broad or slightly compressed, usually covered with bony plates forming testa; 4 preopercular spines, the upper one long, straight, with some spinules on it. Vomer and palatine toothless. Slit behind fourth gill arch small or absent. Pelvic finrays 4. Lateral line without bony plates, 34-38 pores. Urogenital papilla simple, conical. Vertebrae 36-43.
Coastal marine. Feed on small bottom invertebrates and fishes. Eggs demersal, large, usually no more than a few hundreds. No commercial value.
Species 6; in Clofnam area 1.
Species of this genus in the program:
Gymnacanthus tricuspis