''Acanthurus achilles'', the Achilles tang, redtail surgeonfish or redspot surgeonfish, is a 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 ...

, the surgeonfishes, unicornfishes and tangs. This fish is found in the Pacific Ocean.

Taxonomy

''Acanthurus achilles'' was first formally described in 1803 by the English

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

George Shaw but Shaw did not give a type locality and no

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

is known. 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. This species is known to hybridise with ''

Acanthurus nigricans ''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, unic ...

''.

Etymology

''Acanthurus achilles'' has the

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''achilles'' which Shaw did not explain. It is thought that the name refers to

Achilles In Greek mythology, Achilles ( ) or Achilleus () was a hero of the Trojan War who was known as being the greatest of all the Greek warriors. The central character in Homer's ''Iliad'', he was the son of the Nereids, Nereid Thetis and Peleus, ...

, the mythical hero of the Trojan War, and may be an allusion to the sharp bony plates 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 ...

Description

''Acanthurus achilles'' has an elongated oval-shaped body with a steep dorsal profile to the head. The small, protrusible mouth is positioned low on the head with between 8 and 28 teeth fixed on each jaw, each having a flattened, serrated tip. The

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 ...

is supported by 9 spines and between 29 and 33 soft rays 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 ...

contains 3 spines and 26 to 29 soft rays. There is a single mobile spine on each side of the

which folds down into a slit. The

caudal 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 only ...

is concave. The overall colour is bluish-black with an irregular oval orange blotch on the rear of the body, a white bar on the gill cover, a wide orange bar on the caudal fin which also has a white posterior margin. There is a pale blue ring around just inside the snout tip. This species reaches a maximum

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 achilles'' is found in various reefs of Oceania, up to the islands of

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

and

Pitcairn The Pitcairn Islands ( ; Pitkern: '), officially Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islan ...

. The fish is also, although less commonly, found in the

Mariana Islands The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st pa ...

and even some reefs in southern Mexico and Guatemala] It is a benthopelagic species which inhabits the clear waters on the seaward side of reefs.

Biology

''Acanthurus achilles'' is herbivorous, grazing largely on Benthic zone, benthic

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

. They are territorial and monogamous.

References

External links

Achilles Tang care sheet at FishGeeks
{{Taxonbar, from=Q340279

achilles In Greek mythology, Achilles ( ) or Achilleus () was a hero of the Trojan War who was known as being the greatest of all the Greek warriors. The central character in Homer's ''Iliad'', he was the son of the Nereids, Nereid Thetis and Peleus, ...

Fauna of the Pitcairn Islands Fish of Mexican Pacific coast Fish of Hawaii Fish described in 1803 Fish of Guatemala