Acanthurus nigricauda | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Acanthuriformes |
Family: | Acanthuridae |
Genus: | Acanthurus |
Species: | A. nigricauda |
Binomial name | |
Acanthurus nigricauda | |
Synonyms | |
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Acanthurus nigricauda, the epaulette surgeonfish, black-barred surgeonfish, eye-line surgeonfish, shoulderbar surgeonfish, white-tail surgeonfish or blackstreak surgeonfish, [3] is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. It is native to the Indo-Pacific region.
Acanthurus nigricauda was first formally described as a subspecies of Acanthurus gahhm in 1929 by the German zoologists Paul Georg Egmont Duncker and& Erna Mohr with its type locality given as Massau Island in the St Matthias Islands northeast of New Ireland in the Bismarck Archipelago in Papua New Guinea. [4] It was confirmed as a separate valid species by John E. Randall in 1987. [5] The genus Acanthurus is one of two genera in the tribe Acanthurini which is one of three tribes in the subfamily Acanthurinae which is one of two subfamilies in the family Acanthuridae. [6]
Acanthuurus nigricauda was given the subspecific name, nigricauda meaning "black tail", because its dark brown caudal peduncle distinguished it from the nominate A. g, gahhm. Duncker and Mohr originally described this taxon as a subspecies of that species. [7]
Acanthurus nigricauda is a laterally compressed, deep-bodied fish reaching a maximum length of 40 cm (16 in). The profile of the head is convex, the eyes are fairly prominent and there are two pairs of nostrils just in front of the eyes. The dorsal fin has 9 spines and 25 to 28 soft rays, and the anal fin has 3 spines and 23 to 26 soft rays. The caudal fin is crescent-shaped. The body is covered with tiny scales giving it a smooth appearance, and the lateral line is indistinct. The head is usually paler than the body, which is a uniform shade but varies in colour from pale grey to dark brown or nearly black, depending on the fish's mood. [3] There is a bold black streak behind the eye, the "epaulette", which extends as far as the operculum, and a slender black line in front of the pair of sharp "scalpels" on the caudal peduncle. The dorsal fin is yellowish with a black line with blue edge at the margin, and the anal fin is grey with a blue margin. The pectoral fins have an orange base and are banded in grey, yellow and translucent, and the caudal fin has a white base and a dark outer portion bordered with blue. [8] [3] A. nigricauda can be distinguished from the similar doubleband surgeonfish (Acanthurus tennenti) by the single "epaulette" behind its head. [3]
Acanthurus nigricauda occurs in the tropical and subtropical Indian Ocean and the western and central Pacific Ocean. Its range extends from East Africa and Madagascar to the Tuamoto Islands, and from southern Japan to Northern and Eastern Australia and New Caledonia. [8] It occurs over sandy and rocky bottoms, in bays, lagoons and on reef slopes, at depths down to about 30 m (100 ft). Unlike most other members of its genus, it is seldom found over coral. [3]
Acanthurus nigricauda is a schooling fish and forms shoals, sometimes in association with the orange-band surgeonfish (Acanthurus olivaceus). [3] It feeds by grazing on the algal film that grows over sandy areas in the vicinity of coral or rock substrates, [9] but the proportion of algae in its stomach is low, and it mostly subsists on the organic detritus that gets trapped in the film. [3]
The sexes are separate in this species, and both sexes become mature at a length of about 15 cm (6 in). Large aggregations of fish occur at breeding time, with both sexes liberating their gametes into the water column. The scalpels on the caudal peduncle are retractable and are very sharp; they are displayed when the tail is thrust to the side and are used to slash at rival fish and for protection against predators. Juvenile fish are shorter and more deep-bodied than adults. They are deep brown at first, with a yellowish, unnotched caudal fin, and gradually change colour as they reach a length of between 5 and 10 cm (2 and 4 in). [3]
Acanthurus is a genus of marine ray-finned fish belonging to the family Acanthuridae, which includes the surgeonfishes, unicornfishes and tangs, found in the Atlantic, Indian and Pacific Ocean. They are found in tropical oceans, especially near coral reefs, with most species in the Indo-Pacific but a few are found in the Atlantic Ocean. As other members of the family, they have a pair of spines, one on either side of the base of the tail which are dangerously sharp.
The sohal surgeonfish or sohal tang, is a species of marine ray-finned fish belonging to the family Acanthuridae, which includes the surgeonfishes, unicornfishes and tangs. This fish is found in the northwestern Indian Ocean.
Acanthurus achilles, the Achilles tang, redtail surgeonfish or redspot surgeonfish, is a marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This fish is found in the Pacific Ocean.
Acanthurus leucosternon, commonly known as the blue surgeonfish, powder blue tang or powder-blue surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indian Ocean.
The doctorfish tang, also known as the doctorfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. These fishes are found in the western Atlantic Ocean.
Acanthurus mata, the pale surgeonfish, blue-lined surgeonfish, mata surgeonfish, striped surgeonfish, tailring surgeon, white-tail lancet or yellowmask surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indo-Pacific region.
Acanthurus olivaceus, the orange-band surgeonfish, the orange-shoulder surgeonfish or the orangebar tang, is a species of marine ray-finned fish belonging to the family Acanthuridae, this family includes the surgeonfishes, unicornfishes and tangs. It lives in the tropical waters of the Indo-west Pacific.
Naso lituratus, the clown unicornfish, orangespined unicornfish, black-finned unicornfish, Pacific orangespined unicornfish, blackfinned unicornfish or stripefaced unicornfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This fish is found in the eastern Indian Ocean and western Pacific Ocean.
Acanthurus nigroris, the bluelined surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, which includes the surgeonfishes, unicornfishes and tangs. This species and A. nigros have been regarded as synonymous with the combined taxon having a wide Indo-Pacific distribution, if treated as a separate valid species it is confined to the United States Pacific islands.
Acanthurus tristis, the Indian Ocean mimic surgeonfish, blackcheek surgeonfish or yellowspot surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae which includes the surgeonfishes, unicornfishes and tangs. This species is found in the eastern Indian Ocean.
Acanthurus nigricans, the goldrim surgeonfish, velvet surgeon, whitecheek surgeonfish, yellow-banded surgeonfish or yellowrimmed surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found from the central Indo-Pacific area to the eastern Pacific coast, Hawaii included.
Acanthurus maculiceps, the white-freckled surgeonfish, yellow-freckled surgeonfish, pale-lined surgeonfish,spotted-faced surgeonfish or earbar surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indo-West Pacific region.
Acanthurus blochii, the ringtail surgeonfish or dark surgeonfish, is a marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This fish is found in the Indo-Pacific.
Acanthurus auranticavus, the ringtail surgeonfish or orange-socket surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indo-West Pacific.
Acanthurus bariene, the bariene surgeonfish, black-spot surgeonfish, or eye-spot surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indo-Pacific.
Acanthurus fowleri, Fowler's surgeonfish or the horseshoe surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes or tangs. This fish is found in the Western Pacific Ocean.
Acanthurus gahhm, the black surgeonfish, monk surgeonfish or lined surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes or tangs. This fish is found in the western Indian Ocean.
Acanthurus leucocheilus, the palelipped surgeonfish or the white-spine surgeonfish is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes or tangs. This fish is found in the Indo-Pacific region.
Prionurus is a genus of marine ray-finned fishes belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs, although some of the species in this genus are called sawtails or doctorfish. The species in this genus are found in the Pacific Ocean with one species, P. biafraensis, found in the Atlantic Ocean.
The grey-head surgeonfish is a species of marine ray-finned fish belonging to the family Acanthuridae which includes the surgeonfishes. unicornfishes and tangs. This species has a wide Indo-Pacific distribution.