About Naso brevirostris (Cuvier, 1829)
Naso brevirostris (Cuvier, 1829) has 6 spines and between 27 and 29 soft rays supporting its dorsal fin. Its anal fin is supported by 2 spines and 27 to 29 soft rays. The depth of this fish’s body is 2 to 2.7 times smaller than its standard length. Its snout is very short, very steep, and almost vertical. Subadult and adult individuals grow a long, tapering bony protuberance in front of their eyes. This protuberance can extend past the mouth by as much as the length of the head, and it first appears as a bump in individuals that reach around 10 cm (3.9 in) in total length. Each side of the caudal peduncle has a pair of bony plates with poorly developed keels. The shape of the caudal fin ranges from truncate to slightly rounded. The overall body color of Naso brevirostris is light bluish-grey to olive-brown, and it has a distinct color phase where the front quarter of the body is pale, with a sharp boundary between this pale area and the rest of the body. Thin, vertical dark grey lines mark the middle of the fish’s flanks; these lines break up into small spots on the lower body. The head is marked either with small dark spots or a lattice of lines. The protuberance is marked with diagonal black lines. The membrane of the operculum is white, the edges of the lips are pale blue, and the caudal fin is mostly whitish. This species has a maximum published total length of 60 cm (24 in). Naso brevirostris is widespread across the Indian and Pacific Oceans. Its range extends from the Red Sea south along the eastern coast of Africa as far as Durban, South Africa, and east across the Indian Ocean into the Western Pacific Ocean. In the Pacific, its range extends east to the Pitcairn Islands and the Hawaiian Islands, north to southern Japan, and south to Australia. In Australia, the species is distributed from Ningaloo Reef around the northern tropical coasts to the northern Great Barrier Reef and the Coral Sea, reaching as far south as Moreton Bay in Queensland. It is also found around Lord Howe Island in the Tasman Sea. In the eastern Pacific, it occurs around the Galápagos Islands. These fish inhabit lagoon and seaward reefs, at depths down to 46 m (151 ft).
