Marquesan Surgeonfish

Acanthurus reversus has its dorsal fin supported by 9 spines and 24 or 25 soft rays while the anal fin is supported by 3 spines and 23 or 24 soft rays. Its overall colour is brown, although the posterior may be clearly paler than the anterior. There is an elongated orange spot running from the upper end of the gill slit With its, posterior have being surrounded by a blue band that reaches beyond the pectoral fin. There is an indistinct orange line at the base of both the dorsal and anal fins and the soft-rayed part of the dorsal fin has 3 dark horizontal bands while the anal fin has a blue margin. The caudal fin is light yellow with a wide black band to its rear, this narrows as it reaches the filamentous part of the lobes. Juveniles are yellow and have blue margins on their dorsal and anal fins. The maximum published total length of the Marquesas surgeonfish is 34 cm (13 in).

== References ==

Acanthurus reversus Is endemic to the Marquesas Islands in French Polynesia. There is a record of an individual from Takaroa Atoll in the Tuamotu Archipelago but this is thought to have referred to a vagrant. The Marquesas surgeonfish is found singly or in small groups on inshore reefs at depths between 4 and 25 m (13 and 82 ft).

Acanthurus reversus was given the specific name reversus, this means "reversed" and refers to the reversed pattern if colours on the caudal fin of this species in comparison to the closely related A. olivaceus.