''Scarus'' is a genus of parrotfishes. With 52 currently recognised

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,Froese, R. and D. Pauly, Eds
''Scarus''.
FishBase. 2013. it is by far the largest parrotfish genus. The vast majority are found at

reefs A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave eros ...

in the

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 ...

, but a small number of species are found in the warmer parts of the eastern Pacific and the western

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

, with a single species, '' Scarus hoefleri'' in the eastern Atlantic. The genus name ''Scarus'' comes from the Greek word σκάρος (''skáros''), which refers to parrotfishes.

Evolution

''Scarus'' is most closely related to its sister genus '' Chlorurus''. Most recent phylogenetic analyses find that the two genera diverged during the

late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

(

Messinian The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the fir ...

). In both genera, most of their diversification occurred some time later, within the last 3.5 million years during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 Most ''Scarus'' species occur in reef habitats. However, some of the more basal species such as '' S. zufar'' occur in rockier, more peripheral habitats, suggesting that this may be the ancestral habitat type for the genus. A 2012 phylogenetic analysis of 45 ''Scarus'' species recovered 10 major

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

clades.

Description

Adults of most species reach maximum lengths of between , but the rainbow parrotfish (''Scarus guacamaia'') can grow to lengths of and is the second largest species of parrotfish after the humphead parrotfish. ''S. guacamaia'' weighs a hundred times more than the smallest ''Scarus'' species '' Scarus iseri'', which only reaches a maximum length of 27 cm. In comparison to its sister genus ''Chlorurus'', ''Scarus'' species in general have less obtuse head profiles, less extensive cheek areas, and smaller dental plates, although a few relatively basal species of ''Scarus'' are exceptions to this. This may possibly reflect comparatively lower biting power, and a disparity in the ability to excavate

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

reef subtrata.

Sexual dichromatism

Most ''Scarus'' species are very colourful, and most are sexually dichromatic, with strikingly different initial (male and female) and terminal (male only) phases. However in a few species, initial phase and terminal phase colouration remains the same. Examples of such sexually monochromatic species include '' S. guacamaia'', '' S. coelestinus'', '' S. perrico'', '' S. niger'', and '' S. coeruleus''.

Ecology

''Scarus'' species are important herbivores in reef ecosystems, feeding predominantly on algae and dead coral. In the process, they facilitate bioerosion and create sediment. Lifespan varies across different species. More short-lived species, such as the common parrotfish ('' S. psittacus''), live for up to 6 years. Other species are more long-lived; the endangered greenback parrotfish ( ''S. trispinosus'') has been recorded living for over 20 years, and is the largest herbivorous reef fish in the South Atlantic. Its close relative, the midnight parrotfish ('' S. coelestinus''), has been recorded reaching 31 years of age. Such large bodied and long-lived species are highly vulnerable to over-exploitation by fisheries. Many species within the genus are

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

with each other, and often are sympatric with their sister species; ''Scarus'' frequently underwent sympatric speciation through adaptive radiation.

Species

There are currently 52 recognised species in this genus:

In political thought

Cesare Ripa Cesare Ripa (, Perugia – Rome) was an Italian Renaissance scholar and iconography, iconographer. Life Little is known about his life. The scant biographical information that exists derives from his one very successful work: the ''Iconologia ...

's Renaissance iconography, the ''scarus'' fish symbolised civil "Union," i.e. the joining of individuals into a collective body.

Plutarch Plutarch (; , ''Ploútarchos'', ; – 120s) was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo (Delphi), Temple of Apollo in Delphi. He is known primarily for his ''Parallel Lives'', ...

had written that ''scarus'' fish "swim together in shoals and ingeniously and heroically free each other when caught in a net." The ''scarus'' thus "denoted reciprocal assistance in the fight for survival."Hont, I. ''Jealousy of Trade: International Competition and the Nation-State in Historical Perspective''. Harvard UP: 2005, pp. 21-22.

References

{{Authority control Extant Rupelian first appearances Marine fish genera Taxa named by Peter Forsskål Rupelian genus first appearances Taxonomy articles created by Polbot