Galapagos ringtail damselfish, Southern whitetail major
Body oval, compressed; 1 pair of nostrils; margin of preopercle serrated; margin of bone under eye serrated, without notch it and the bone before it; mouth small, protrusible; teeth in single row, long and close-set; lower gill rakers 11 (10-12); a single continuous dorsal fin, XII, 15 (14-16); anal rays II, 13 (rarely 14); pectoral rays 20-21 (rarely 22); no projecting short spines at upper and lower base of tail fin; caudal fin bluntly forked; scales are moderately large and rough; body scaled, head largely scaled (snout scaled to nostrils), as are the basal parts of the median fins; lateral-line scales 20 (rarely 19); lateral line incomplete, ends under end of dorsal fin base.
Dark brown with darker scale outlines, often with white band on caudal peduncle, also with a blue iris and white or yellow outer edge of pectoral fin. Juvenile dark with red nape, upper back and spiny dorsal, and a dark ocellus at rear base of dorsal fin.
Size: grows to 17 cm.
Habitat: common along rocky shores.
Depth: 0-15 m.
Resident populations in the Galapagos Islands, Malpelo and Cocos, vagrants on the coast of Costa Rica and in the Pearl Islands, Panama.