:Scarus

Scarus is most closely related to its sister genus Chlorurus. Most recent phylogenetic analyses find that the two genera diverged during the late Miocene (Messinian).{{Cite journal |last1=Choat |first1=John. H. |last2=klanten |first2=Oya. S. |last3=Van Herwerden |first3=Lynne |last4=Robertson |first4=D. Ross |last5=Clements |first5=Kendall D. |date=November 2012 |title=Patterns and processes in the evolutionary history of parrotfishes (Family Labridae): Evolutionary History of Parrotfishes |url=https://academic.oup.com/biolinnean/article-lookup/doi/10.1111/j.1095-8312.2012.01959.x |journal=Biological Journal of the Linnean Society |language=en |volume=107 |issue=3 |pages=529–557 |doi=10.1111/j.1095-8312.2012.01959.x}} In both genera, most of their diversification occurred some time later, within the last 3.5 million years during the Pliocene.{{Cite journal |last1=Smith |first1=Lydia L. |last2=Fessler |first2=Jennifer L. |last3=Alfaro |first3=Michael E. |last4=Streelman |first4=J. Todd |last5=Westneat |first5=Mark W. |date=October 2008 |title=Phylogenetic relationships and the evolution of regulatory gene sequences in the parrotfishes |journal=Molecular Phylogenetics and Evolution |language=en |volume=49 |issue=1 |pages=136–152 |doi=10.1016/j.ympev.2008.06.008 |pmc=3418665 |pmid=18621133|bibcode=2008MolPE..49..136S }} In contrast, coral reefs in their modern form were established much earlier, during the Miocene.

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 clades.

Adults of most species reach maximum lengths of between {{convert|30|and(-)|50|cm|in|abbr=on}}, but the rainbow parrotfish (Scarus guacamaia) can grow to lengths of {{convert|1.2|m|ft|abbr=on}} 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 reef subtrata.

Most Scarus species are very colourful, and most are sexually dichromatic, with strikingly different initial (male and female) and terminal (male only) phases.{{Cite journal |last1=RANDALL |first1=JOHN E. |last2=CHOAT |first2=J. HOWARD |date=1980-12-01 |title=Two new parrotfishes of the genus Scarus from the Central and South Pacific, with further examples of sexual dichromatism |url=https://academic.oup.com/zoolinnean/article-abstract/70/4/383/2658767?redirectedFrom=fulltext |journal=Zoological Journal of the Linnean Society |volume=70 |issue=4 |pages=383–419 |doi=10.1111/j.1096-3642.1980.tb00856.x |issn=0024-4082}} 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.{{Cite book |last1=Hoey |first1=Andrew S. |url=https://www.taylorfrancis.com/books/9781482224023 |title=Biology of Parrotfishes |last2=Bonaldo |first2=Roberta M. |date=2018-03-05 |publisher=CRC Press |isbn=978-1-315-11807-9 |editor-last=Hoey |editor-first=Andrew S. |edition=1 |location=Boca Raton, FL: CRC Press, Taylor & Francis Group, [2018]{{!}} “A Science Publishers book.” {{!}} Includeu bibliographical references and index. |language=en |doi=10.1201/9781315118079 |editor-last2=Bonaldo |editor-first2=Roberta M.}}

File:Scarus coelestinus 57202825.jpg with S. guacamaia in Florida, two extremely closely related species. Unlike most Scarus species, these two are not sexually dimorphic. Due to their similar appearance and sympatric distribution, they were often thought to be colour phases of the same species until the 1960s.{{Cite journal |last=Randall |first=John E. |date=1963 |title=Notes on the Systematics of Parrotfishes (Scaridae), with Emphasis on Sexual Dichromatism |url=https://www.jstor.org/stable/1441337?origin=crossref |journal=Copeia |volume=1963 |issue=2 |pages=225–237 |doi=10.2307/1441337 |issn=0045-8511}}]]

Scarus species are important herbivores in reef ecosystems, feeding predominantly on algae and dead coral.{{Cite journal |last=Frydl |first=Paul |date=1979 |title=The Effect of Parrotfish (Scaridae) on Coral in Barbados, W. I |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/iroh.19790640603 |journal=Internationale Revue der gesamten Hydrobiologie und Hydrographie |language=en |volume=64 |issue=6 |pages=737–748 |doi=10.1002/iroh.19790640603 |issn=1522-2632}} In the process, they facilitate bioerosion and create sediment.{{Cite journal |last1=Freitas |first1=Matheus O. |last2=Previero |first2=Marília |last3=Leite |first3=Jonas R. |last4=Francini-Filho |first4=Ronaldo B. |last5=Minte-Vera |first5=Carolina V. |last6=Moura |first6=Rodrigo L. |date=2019-08-30 |title=Age, growth, reproduction and management of Southwestern Atlantic's largest and endangered herbivorous reef fish, Scarus trispinosus Valenciennes, 1840 |journal=PeerJ |language=en |volume=7 |pages=e7459 |doi=10.7717/peerj.7459 |doi-access=free |pmid=31531268 |pmc=6718160 |issn=2167-8359}}

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.{{Cite journal |last1=Jones |first1=David Delane |last2=Rivera Hernández |first2=Jesús M. |last3=Shervette |first3=Virginia R. |date=2021-05-01 |title=Princess parrotfish Scarus taeniopterus age, growth, maturity, and transition |url=https://link.springer.com/article/10.1007/s10641-021-01097-5 |journal=Environmental Biology of Fishes |language=en |volume=104 |issue=5 |pages=581–595 |doi=10.1007/s10641-021-01097-5 |bibcode=2021EnvBF.104..581J |issn=1573-5133}} Such large bodied and long-lived species are highly vulnerable to over-exploitation by fisheries.

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

{{Space}}

There are currently 52 recognised species in this genus:

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

{{Reflist}}

{{Taxonbar|from=Q258514}}

{{Authority control}}

Category:Extant Rupelian first appearances

Category:Marine fish genera

Category:Taxa named by Peter Forsskål

Category:Rupelian genus first appearances

Category:Taxonomy articles created by Polbot