Abdomen with a well-developed median keel extending from throat to origin of anal fin. Dorsal fin advanced in position, with a strongly serrated spine; pectoral spines as long as or slightly longer than dorsal spine, strong, denticulated along their inner edge; pelvic fins small; anal fin low, long; adipose fin very small (Ref. 4792). Single, oval-shaped patch of teeth on each side of palate; eye large (Ref. 12693).