Acanthuridae are a

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 ...

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 ...

which includes surgeonfishes, tangs, and unicornfishes. The family includes about 86

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

species of marine fish living in tropical seas, usually around

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s. Many of the species are brightly colored and popular in aquaria.

Etymology and taxonomic history

The name of the family is derived from the Greek words ''akantha'' and ''oura'', which loosely translate to "thorn" and "tail", respectively. This refers to the distinguishing characteristic of the family, the "

scalpel A scalpel or bistoury is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, podiatry and various handicrafts. A lancet is a double-edged scalpel. Scalpel blades are usually made of hardened and tempered ...

" found 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 ...

. In the early 1900s, the family was called Hepatidae.

Subfamilies and genera

Acanthuridae contains the following

subfamilies and genera: * Subfamily Nasinae Fowler &

Bean A bean is the seed of some plants in the legume family (Fabaceae) used as a vegetable for human consumption or animal feed. The seeds are often preserved through drying (a ''pulse''), but fresh beans are also sold. Dried beans are traditi ...

, 1929 ** Genus '' Naso'' Lacépède, 1801 * Subfamily Acanthurinae Bonaparte, 1835 ** Tribe Acanthurini Bonaparte, 1839 *** Genus '' Acanthurus'' Forsskål 1775 *** Genus '' Ctenochaetus''

Gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

, 1884 ** Tribe Prionurini

J. L. B. Smith James Leonard Brierley Smith (26 September 1897 – 8 January 1968) was a South African ichthyology, ichthyologist, organic chemist, and university professor. He was the first to identify a taxidermied fish as a coelacanth, at the time thought t ...

, 1966 *** Genus '' Prionurus'' Lacépède, 1804 ** Tribe Zebrasomini Winterbottom, 1993 *** Genus '' Paracanthurus'' Bleeker, 1863 *** Genus '' Zebrasoma'' Swainson, 1839

Evolution and fossil record

There are several extinct genera known from fossils dating from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Eocene genera

A particularly large diversity of fossil surgeonfish is known from the Monte Bolca '' lagerstatte'' of Italy. These represent some of the earliest representatives of the individual tribes within the Acanthuridae. *†'' Acanthuroides'' Blot & Tyler, 1990 *†'' Eorandallius'' Blot & Tyler, 1990 (='' Naseus''

Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

, 1842 (preocc.)) *†'' Frigosorbinia'' Bannikov & Tyler, 2012 *†'' Gazolaichthys'' Blot & Tyler, 1990 *†'' Lehmanichthys'' Blot & Tyler, 1990 *†'' Metacanthurus'' Blot & Tyler, 1990 *†'' Metaspisurus'' Blot & Tyler, 1990 *†'' Padovathurus'' Tyler, 2005 *†'' Pesciarichthys'' Blot & Tyler, 1990 *†'' Proacanthurus'' Blot & Tyler, 1990 *†'' Protozebrasoma'' Sorbini & Tyler, 1998 *†'' Sorbinithurus'' Tyler, 1999 *†'' Tauichthys'' Tyler, 1999 *†'' Tylerichthys'' Blot, 1980

Oligocene genera

*†'' Arambourgthurus'' Tyler, 2000 *†'' Caprovesposus'' Daniltshenko, 1960 *†'' Glarithurus'' Tyler & Micklich, 2011 *?†'' Eonaso'' Blot, 1984

Miocene genera

*†'' Marosichthys'' Whitley, 1951

Morphology

The distinctive characteristic of the family is that they have scalpel-like modified scales, one or more on either side of the peduncle of the tail. The spines are dangerously sharp and may seriously injure anyone who carelessly handles such a fish. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

, anal, and

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 ...

s are large, extending for most of the length of the body. The mouths are small and have a single row of teeth adapted to grazing on algae. Surgeonfishes sometimes feed as solitary individuals, but they often travel and feed in schools. Feeding in schools may be a mechanism for overwhelming the highly aggressive defense responses of small territorial

damselfish Damselfish are those fish within the subfamilies Abudefdufinae, Chrominae, Lepidozyginae, Pomacentrinae, and Stegastinae within the family Pomacentridae. Most species within this group are relatively small, although the four largest speci ...

es that vigorously guard small patches of algae on coral reefs. Most species are fairly small, with a maximum length of , but some in the genus ''Acanthurus'', some in the genus ''Prionurus'', and most species in the genus ''Naso'' may grow larger; the whitemargin unicornfish (''Naso annulatus'') is the largest species in the family, reaching a length of up to . These fishes may grow quickly in aquaria, so average growth size and suitability should be checked before adding them to any marine aquarium. A larval acanthurid, known as an acronurus, looks strikingly different from the juvenile and adult forms of the same individual. It is mostly transparent and tends to have a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

lifestyle, living in open water for an extended period of time before settling on the ocean bottom near the shore, where it develops into the juvenile and ultimately the adult form.

Symbiotic bacteria

Acanthurids are the only known hosts of the bacteria of the genus '' Epulopiscium'' bacteria. These bacteria affect the digestion of surgeonfishes enabling them to digest the algae in their diet.

In the aquarium

Tangs are very sensitive to disease in the home aquarium. However, if the tang is fed enough algae and the aquarium is properly maintained disease should not be a problem. It is usually necessary to quarantine the animals for a period before introducing them to the aquarium. Adults range from in length and most grow quickly even in aquaria. When considering a tang for an aquarium it is important to consider the size to which these fish can grow. Larger species such as the popular Pacific blue tang surgeonfish (of ''

Finding Nemo ''Finding Nemo'' is a 2003 American animated comedy-drama adventure film produced by Pixar Animation Studios for Walt Disney Pictures. The film was directed by Andrew Stanton, co-directed by Lee Unkrich, and produced by Graham Walters, from ...

'' fame), '' Naso'' or lipstick tang, lined surgeonfish, Sohal surgeonfish and Atlantic blue tang surgeonfish can grow to and require swimming room and hiding places. Many also suggest adding aggressive tangs to the aquarium last as they are territorial and may fight and possibly kill other fish. Tangs primarily graze on

macroalgae Seaweed, or macroalgae, refers to thousands of species of Macroscopic scale, macroscopic, Multicellular organism, multicellular, ocean, marine algae. The term includes some types of ''Rhodophyta'' (red), ''Brown algae, Phaeophyta'' (brown) and ...

from genera such as ''

Caulerpa ''Caulerpa'' is a genus of seaweeds in the family Caulerpaceae (among the green algae). They are unusual because they consist of only one cell with many cell nucleus, nuclei, making them among the biggest single cells in the world. Referring to ...

'' and ''

Gracilaria ''Gracilaria'', also known as irish moss or ogonori, is a genus of red algae in the family Gracilariaceae. It is notable for its economic importance as an agarophyte meaning that it is used to make agar, as well as its use as a food for humans ...

'', although they have been observed in an aquarium setting to eat meat-based fish foods. A popular technique for aquarists is to grow macroalgae in a

sump Sump may refer to: * An infiltration basin used to manage surface runoff water and recharge underground aquifers * Sump (cave), a permanently flooded section of a cave, where an underground flow of water exits the cave into the earth such that t ...

or refugium. This technique not only is economically beneficial, but serves to promote enhanced water quality through

nitrate Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...

absorption. The growth of the algae can then be controlled by feeding it to the tang.

Gallery

File:Acanthurus achilles1.jpg, Achilles tang, ''Acanthurus achilles'' File:A. dussumieri 2.jpg, Eyestripe surgeonfish, ''Acanthurus dussumieri'' File:Acanthurus leucosternon 01.JPG, Powderblue surgeonfish, ''Acanthurus leucosternon'' File:Acanthurus tennenti Kreisdorn-Doktorfisch3.jpg, Doubleband surgeonfish, ''Acanthurus tennenti'' File:Ctenochaetus strigosus 1.jpg, Kole tang, ''Ctenochaetus strigosus'' File:Naso vlamingii - Masken-Nasendoktorfisch imponierend.jpg, Bignose unicornfish, ''Naso vlamingii'' File:Nasounicornis-Blauklingen.jpg, Bluespine unicornfish, ''Naso unicornis'' File:Acanthuridae - Zebrasoma desjardinii.JPG, Red Sea sailfin tang, ''Zebrasoma desjardinii'' File:A. olivaceus.jpg, Orangespot surgeonfish, ''Acanthurus olivaceus'' File:Paletten-Doktorfisch Münster.JPG, Regal tang, ''Paracanthurus hepatus'' in an aquarium

References

External links

* * * {{Authority control Acanthuriformes families Marine fish families Taxa named by Charles Lucien Bonaparte Articles which contain graphical timelines