''Acanthurus nigrofuscus'', the brown surgeonfish, blackspot surgeonfish, brown tang, dusky surgeon, lavender tang or spot-cheeked surgeonfish, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Acanthuridae Acanthuridae are a family of ray-finned fish which includes surgeonfishes, tangs, and unicornfishes. The family includes about 86 extant species of marine fish living in tropical seas, usually around coral reefs. Many of the species are brigh ...

, which includes the surgeonfishes, unicornishes and tangs. This species is a common and abundant fish occurring across a wide

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

range.

Taxonomy

''Acanthurus nigrofuscus'' was first formally described as ''Chaetodon nigrofuscus'' in 1775 by the Swedish-speaking Finnish

explorer Exploration is the process of exploring, an activity which has some Expectation (epistemic), expectation of Discovery (observation), discovery. Organised exploration is largely a human activity, but exploratory activity is common to most organis ...

, orientalist and

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Peter Forsskål Peter Forsskål, sometimes spelled Pehr Forsskål, Peter Forskaol, Petrus Forskål or Pehr Forsskåhl (11 January 1732 – 11 July 1763) was a Sweden, Swedish exploration, explorer, oriental studies, orientalist, natural history, naturalist, and ...

with its type locality given as

Jeddah Jeddah ( ), alternatively transliterated as Jedda, Jiddah or Jidda ( ; , ), is a List of governorates of Saudi Arabia, governorate and the largest city in Mecca Province, Saudi Arabia, and the country's second largest city after Riyadh, located ...

. The genus ''

Acanthurus ''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 ...

'' is one of two genera in the tribe

Acanthurini Acanthurini is a tribe of marine ray-finned fishes belonging to the family Acanthuridae and it is one of three tribes in the subfamily Acanthurinae. Taxonomy Acanthurini was first proposed as a taxon in 1839 by the French naturalist Charles Lucie ...

which is one of three tribes in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Acanthurinae ''Acanthurinae'' is a subfamily of marine ray-finned fishes belonging to the Family (biology), family Acanthuridae, found in the Indo-Pacific and the tropical Atlantic. These fishes commonly have the English names surgeonfishes or tangs. Taxono ...

which is one of two subfamilies in the family Acanthuridae.

Etymology

''Acanthuurus nigrofuscus'' was given the subspecific name, ''nigrofuscus'' combining ''nigro'', meaning "black", with ''fuscus'', meaning "dark" a reference to the dusky or brownish-black colour of this fish.

Description

''Acanthurus nigrofuscus'' has 9 spines and between 24 and 27 soft rays supporting its

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

while the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

is supported by 3 spines and 22 to 24 soft rays. The dorsal profile of the head his slightly humped. The overall colour varies from brown to purplish to bluish-brown marked with small orange spots on the head and breast. There are small black spots at the base of both the dorsal and anal fins, these fins have a pale blue margin. The spine on the

caudal peduncle Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

is contained within a patch of black pigment. There may or may not be sinuous horizontal lines of small blue dots. This species has a maximum published

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of .

Distribution and habitat

''Acanthurus nigrofuscus'' has a wide Indo-Pacific distribution from the coast of eastern Africa as far north as the Israeli Red Sea coast and south as far as far south as the

Aliwal Shoal The Aliwal Shoal is a rocky reef which is the remains of an ancient sand dune approximately off the coast of KwaZulu-Natal, South Africa. The reef is inhabited by many kinds of hard and soft corals and other marine invertebrates, and a variety of ...

in South Africa, across the Indian Ocean and into the Indian Ocean as far east as and the Pitcairn Islands and Hawaii, north as far as southern Japan and south as far as

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

. This is a numerous and common surgeonfish that is found in small

schools A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of ...

on sheltered coral and rocky reefs, frequently around isolated rocky reefs at depths down to .

Biology

''Acanthurus nigrofuscus'' grazes on benthic algae. Although typically encountered in small groups it will form large schools in oceanic areas, as well as gathering in large spawning aggregations. This is a relatively small surgeonfish and may be dominated by other larger species but the large schools they form can displace other grazing fish.

Symbiotic bacteria

''Acanthurus nigrofuscus'' has been found to be the host of an unusually large symbiotic bacteria discovered in its intestine, ''

Epulopiscium fishelsoni ''Candidatus Epulopiscium'' is a genus of Gram-positive bacteria that have a symbiotic relationship with surgeonfish. These bacteria are known for their unusually large size, many ranging from 0.2 - 0.7 mm (200–700 μm) in length. Until the di ...

'', this species has been found to grow as large as 600 by 80 μm, a little smaller than a printed hyphen, which controls the pH of its host's gut, thereby influencing its host's ability to digest food and absorb nutrients.

Utilisation

''Acanthurus nigrofuscus'' is taken as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

in some fisheries, and the flesh is consumed either raw or cooked. It is taken for the

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

trade.

References

External links

* {{Taxonbar, from=Q1536194 nigrofuscus Fish of Asia Fish of Palau Fish described in 1775 Taxa named by Peter Forsskål