Template:Short description Template:Use dmy dates Template:Redirect2 Template:Distinguish Template:Automatic taxobox Parrotfish (named for their mouths, which resemble a parrot's beak) are a clade of fish placed in the tribe Scarini of the wrasse family (Labridae).<ref>Template:Cite journal</ref> Traditionally treated as their own family (Scaridae), genetic studies have found them to be deeply nested within the wrasses, and they are now treated as a subfamily (Scarinae) or tribe (Scarini) of them.<ref name =Westneat/> With roughly 95 species, this group's largest species richness is in the Indo-Pacific. They are found in coral reefs, rocky coasts, and seagrass beds, and can play a significant role in bioerosion.<ref name=j1/><ref name=j2/><ref name=j3/>
TaxonomyEdit
Traditionally, the parrotfishes have been considered to be a family level taxon, Scaridae. Although phylogenetic and evolutionary analyses of parrotfishes are ongoing, they are now accepted to be a clade in the wrasses closely related to the tribe Cheilini, and are now commonly referred to as scarine labrids (tribe Scarini, family Labridae).<ref name="Westneat" /><ref name=":4">Template:Cite journal</ref> Some authorities have preferred to maintain the parrotfishes as a family-level taxon,<ref name="Randall2007">Randall, J. E. (2007). Reef and Shore Fishes of the Hawaiian Islands. Template:ISBN</ref> resulting in Labridae not being monophyletic (unless split into several families).
The following taxonomic placement is based on Bellwood et al (2019):<ref name=":4" />
- Tribe Scarini<ref name=":4" />
- Subtribe Scarina
- genus Bolbometopon Smith, 1956 (1 species)
- genus Cetoscarus Smith, 1956 (2 species)
- genus Chlorurus Swainson, 1839 (18 species)
- genus Hipposcarus Smith, 1956 (2 species)
- genus Scarus Forsskål, 1775 (53 species)
- Subtribe Sparisomatina
- genus Calotomus Gilbert, 1890 (5 species)
- genus Cryptotomus Cope, 1870 (1 species)
- genus Leptoscarus Swainson, 1839 (1 species)
- genus Nicholsina Fowler, 1915 (3 species)
- genus Sparisoma Swainson, 1839 (15 species)
- Subtribe Scarina
Some sources retain the Scaridae as a family, placing it alongside the wrasses of the family Labridae and the weed whitings Odacidae in the order Labriformes, part of the Percomorpha. They also do not support the division of the Scaridae into two subfamilies.<ref name="Nelson5">Template:Cite book</ref> However, as such a placement is paraphyletic, they are placed within the wrasses by Eschmeyer's Catalog of Fishes.<ref name=":13">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Fossil remains of parrotfishes are known dating back to the Early Miocene of Java, Indonesia.<ref name=":4" />
DescriptionEdit
Parrotfish are named for their dentition,<ref>Ostéologie céphalique de deux poissons perroquets (Scaridae: Teleostei) TH Monod, JC Hureau, AE Bullock - Cybium, 1994 - Société française d'ichtyologie</ref> which is distinct from other fish, including other labrids. Their numerous teeth are arranged in a tightly packed mosaic on the external surface of their jaw bones, forming a parrot-like beak with which they rasp algae from coral and other rocky substrates<ref name=EoF/> (which contributes to the process of bioerosion).
Maximum sizes vary within the group, with the majority of species reaching Template:Convert in length. However, a few species reach lengths in excess of Template:Convert, and the green humphead parrotfish can reach up to Template:Convert.<ref>{{#invoke:Cite taxon|main|fishbase|genus=|species=|subspecies=}}</ref> The smallest species is the bluelip parrotfish (Cryptotomus roseus), which has a maximum size of Template:Convert.<ref>{{#invoke:Cite taxon|main|fishbase|genus=|species=|subspecies=}}</ref><ref name=Lieske/><ref>Shah, A.K. (2016). Template:Url. The Online Guide to the Animals of Trinidad and Tobago. The University of the West Indies. Accessed 11 March 2018.</ref>
Protective mucusEdit
Some parrotfish species, such as the queen parrotfish (Scarus vetula), secrete a mucus cocoon, particularly at night.<ref name=UV>Cerny-Chipman, E. "Distribution of Ultraviolet-Absorbing Sunscreen Compounds Across the Body Surface of Two Species of Scaridae." DigitalCollections@SIT 2007. Accessed 2009-06-21.</ref> Prior to going to sleep, some species extrude mucus from their mouths, forming a protective cocoon that envelops the fish, presumably hiding its scent from potential predators.<ref>Langerhans, R.B. "Evolutionary consequences of predation: avoidance, escape, reproduction, and diversification. Template:Webarchive" pp. 177–220 in Elewa, A.M.T. ed. Predation in organisms: a distinct phenomenon. Heidelberg, Germany, Springer-Verlag. 2007. Accessed 2009-06-21.</ref><ref name=biochem/> This mucus envelope may also act as an early warning system, allowing the parrotfish to flee when it detects predators such as moray eels disturbing the membrane.<ref name=biochem/>
The skin itself is covered in another mucous substance which may have antioxidant properties helpful in repairing bodily damage,<ref name="UV" /><ref name="biochem" /> or repelling parasites, in addition to providing protection from UV light.<ref name="UV" />
FeedingEdit
Most parrotfish species are herbivores, feeding mainly on epilithic algae.<ref name=":2">Template:Cite journal</ref><ref name=Bellwood>Template:Cite journal</ref><ref name=Bonaldo2018>Bonaldo, R.M. & R.D. Rotjan (2018). The Good, the Bad, and the Ugly: Parrotfishes as Coral Predators. in Hoey, A.S. & R.M. Bonaldo, eds. Biology of Parrotfishes. CRC Press. Template:Isbn</ref> A wide range of other small organisms are sometimes eaten, including invertebrates (sessile and benthic species, as well as zooplankton), bacteria and detritus.<ref>Template:Cite journal</ref> A few mostly larger species such as the green humphead parrotfish (Bolbometopon muricatum) feed extensively on living coral (polyps).<ref name=EoF/><ref name=Bellwood/><ref name=Bonaldo2018/> None of these are exclusive corallivores, but polyps can make up as much as half their diet<ref name=Bonaldo2018/> or even more in the green humphead parrotfish.<ref name=":2"/> Overall it has been estimated that fewer than one percent of parrotfish bites involve live corals and all except the green humphead parrotfish prefer algae-covered surfaces over live corals.<ref name=Bonaldo2018/> Nevertheless, when they do eat coral polyps, localized coral death can occur.<ref name=Bonaldo2018/> Their feeding activity is important for the production and distribution of coral sands in the reef biome, and can prevent algal overgrowth of the reef structure. The teeth grow continuously, replacing material worn away by feeding.<ref name=Lieske/> Whether they feed on coral, rock or seagrasses, the substrate is ground up between the pharyngeal teeth.<ref name=Bonaldo2018/><ref>Template:Cite book</ref> After they digest the edible portions from the rock, they excrete it as sand, helping create small islands and the sandy beaches. The humphead parrotfish can produce Template:Convert of sand each year.<ref name=Thurman/> Or, on average (as there are so many variables i.e. size/species/location/depth etc.), almost Template:Convert per parrotfish per day. While feeding, parrotfish must be cognizant of predation by one of their main predators, the lemon shark.<ref>Template:Cite book</ref> On Caribbean coral reefs, parrotfish are important consumers of sponges.<ref>Template:Cite journal</ref> An indirect effect of parrotfish grazing on sponges is the protection of reef-building corals that would otherwise be overgrown by fast-growing sponge species.<ref name=":0">Template:Cite journal</ref><ref name=":1">Template:Cite journal</ref>
Analysis of parrotfish feeding biology describes three functional groups: excavators, scrapers and browsers.<ref name=":2"/> Excavators have larger, stronger jaws that can gouge the substrate,<ref name=":3">Template:Cite journal</ref> leaving visible scars on the surface.<ref name=":2" /> Scrapers have less powerful jaws that can but infrequently do leave visible scraping scars on the substrate.<ref name=":2" /><ref name=":3" /> Some of these may also feed on sand instead of hard surfaces.<ref name=":2" /> Browsers mainly feed on seagrasses and their epiphytes.<ref name=":2" /> Mature excavating species include Bolbometopon muricatum, Cetoscarus, Chlorurus and Sparisoma viride.<ref name=":2" /> These excavating species all feed as scrapers in early juvenile stages, but Hipposcarus and Scarus, which also feed as scrapers in early juvenile stages, retain the scraping feeding mode as adults.<ref name=":2" /><ref name=":3" /> Browsing species are found in the genera Calotomus, Cryptotomus, Leptoscarus, Nicholsina and Sparisoma.<ref name=":2" /> Feeding modes reflect habitat preferences, with browsers chiefly living in the grassy seabed, and excavators and scrapers on coral reefs.<ref>Environmental Biology of Fishes 28: 189–214, 1990</ref><ref name=":2" />
Recently, the microphage feeding hypothesis challenged the prevailing paradigm of parrotfish as algal consumers by proposing that:
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Most parrotfishes are microphages that target cyanobacteria and other protein-rich autotrophic microorganisms that live on (epilithic) or within (endolithic) calcareous substrata, are epiphytic on algae or seagrasses, or endosymbiotic within sessile invertebrates.<ref>Template:Cite journal</ref>{{#if:|{{#if:|}}
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Microscopy and molecular barcoding of coral reef substrate bitten by scraping and excavating parrotfish suggest that coral reef cyanobacteria from the order Nostocales are important in the feeding of these parrotfish.<ref>Georgina M Nicholson, Kendall D Clements, Micro-photoautotroph predation as a driver for trophic niche specialization in 12 syntopic Indo-Pacific parrotfish species, Biological Journal of the Linnean Society, Volume 139, Issue 2, June 2023, Pages 91–114, https://doi.org/10.1093/biolinnean/blad005</ref> Additional microscopy and molecular barcoding research indicates that some parrotfish may ingest microscopic biota associated with endolithic sponges.<ref>Nicholson, G.M., Clements, K.D. A role for encrusting, endolithic sponges in the feeding of the parrotfish Scarus rubroviolaceus? Evidence of further trophic diversification in Indo-Pacific Scarini. Coral Reefs (2024). https://doi.org/10.1007/s00338-024-02482-z</ref>
Life cycleEdit
Most tropical species form large schools when feeding and these are often grouped by size. Harems of several females presided over by a single male are normal in most species, with the males vigorously defending their position from any challenge.Template:Citation needed As pelagic spawners, parrotfish release many tiny, buoyant eggs into the water, which become part of the plankton. The eggs float freely, settling into the coral until hatching.Template:Citation needed
Sex changeEdit
The development of parrotfishes is complex and accompanied by a series of changes in sex and colour (polychromatism). Most species are sequential hermaphrodites, starting as females (known as the initial phase) and then changing to males (the terminal phase). In many species, for example the stoplight parrotfish (Sparisoma viride), a number of individuals develop directly to males (i.e., they do not start as females). These directly developing males usually most resemble the initial phase, and often display a different mating strategy than the terminal phase males of the same species.<ref name=Bester2009>Bester, C. Stoplight parrotfish. Template:Webarchive Florida Museum of Natural History, Ichthyology Department. Accessed 15-12-2009</ref> A few species such as the Mediterranean parrotfish (S. cretense) are secondary gonochorists. This means that some females do not change sex (they remain females throughout their lives), the ones that do change from female to male do it while still immature (reproductively functioning females do not change to males) and there are no males with female-like colors (the initial phase males in other parrotfish).<ref name=Afonsoa/><ref name=Girolamo1999>Template:Cite journal</ref><ref>Template:Cite journal</ref> The marbled parrotfish (Leptoscarus vaigiensis) is the only species of parrotfish known not to change sex.<ref name=Lieske/> In most species, the initial phase is dull red, brown, or grey, while the terminal phase is vividly green or blue with bright pink, orange or yellow patches.<ref name=Lieske/><ref name=Randall2007/> In a smaller number of species the phases are similar,<ref name=Lieske/><ref name=Randall2007/> and in the Mediterranean parrotfish the adult female is brightly colored, while the adult male is gray.<ref name=Debelius1997>Template:Cite book</ref> In most species, juveniles have a different color pattern from adults. Juveniles of some tropical species can alter their color temporarily to mimic other species.<ref>Cardwell JR1, Liley NR.Gen Comp Endocrinol. 1991 Jan;81(1):7-20</ref> Where the sexes and ages differ, the remarkably different phases often were first described as separate species.<ref name=Randall2007/> As a consequence early scientists recognized more than 350 parrotfish species, which is almost four times the actual number.<ref name=Bester2009/>
The sex change in parrotfishes is accompanied by changes in circulating steroids. Females have high levels of estradiol, moderate levels of T and undetectable levels of the major fish androgen 11-ketotestosterone. During the transition from initial to terminal coloration phases, concentrations of 11-ketotestosterone rise dramatically and estrogen levels decline. If a female is injected with 11-ketotestosterone, it will cause a precocious change in gonadal, gametic and behavioural sex.Template:Citation needed
Economic importanceEdit
A commercial fishery exists for some of the larger species, particularly in the Indo-Pacific,<ref name=Lieske/> but also for a few others like the Mediterranean parrotfish.<ref>Template:Cite journal</ref> Protecting parrotfishes is proposed as a way of saving Caribbean coral reefs from being overgrown with seaweed<ref>Morelle, Rebecca (1 November 2007) Parrotfish to aid reef repair. BBC</ref> and sponges.<ref name=":0" /><ref name=":1" /> Despite their striking colors, their feeding behavior renders them highly unsuitable for most marine aquaria.<ref name=Lieske/>
A new study has discovered that the parrotfish is extremely important for the health of the Great Barrier Reef; it is the only one of thousands of reef fish species that regularly performs the task of scraping and cleaning inshore coral reefs.<ref>Template:Cite journal</ref>
GalleryEdit
- Scarus globiceps mâle.jpg
Scarus globiceps (male)
- Parrotfish turquoisse.jpg
- Bolbometopon muricatum.jpg
- Viridescent Parrotfish - Calotomus viridescens.jpg
- Cetoscarus ocellatus Great Barrier Reef.jpg
- Chlorurus sordidus by Jaroslaw Barski.jpg
- Hipposcarus longiceps.jpg
- Queen parrotfish Scarus vetula (2442375123).jpg
- Stoplight-parrotfish.jpg
Timeline of generaEdit
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bar:periodtop from: -65.5 till: -55.8 color:paleocene text:Paleocene from: -55.8 till: -33.9 color:eocene text:Eocene from: -33.9 till: -23.03 color:oligocene text:Oligocene from: -23.03 till: -5.332 color:miocene text:Miocene from: -5.332 till: -2.588 color:pliocene text:Plio. from: -2.588 till: -0.0117 color:pleistocene text:Pleist. from: -0.0117 till: 0 color:holocene text:H.
bar:eratop from: -65.5 till: -23.03 color:paleogene text:Paleogene from: -23.03 till: -2.588 color:neogene text:Neogene from: -2.588 till: 0 color:quaternary text:Q.
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bar:period from: -65.5 till: -55.8 color:paleocene text:Paleocene from: -55.8 till: -33.9 color:eocene text:Eocene from: -33.9 till: -23.03 color:oligocene text:Oligocene from: -23.03 till: -5.332 color:miocene text:Miocene from: -5.332 till: -2.588 color:pliocene text:Plio. from: -2.588 till: -0.0117 color:pleistocene text:Pleist. from: -0.0117 till: 0 color:holocene text:H.
bar:era from: -65.5 till: -23.03 color:paleogene text:Paleogene from: -23.03 till: -2.588 color:neogene text:Neogene from: -2.588 till: 0 color:quaternary text:Q.
</timeline>
ReferencesEdit
Further readingEdit
- Hoey and Bonaldo. The Biology of Parrotfishes
- Monod, Th., 1979. "Scaridae". pp. 444–445. In J.C. Hureau and Th. Monod (eds.) Check-list of the fishes of the north-eastern Atlantic and of the Mediterranean (CLOFNAM). UNESCO, Paris. Vol. 1.
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- Bullock, A.E. and T. Monod, 1997. "Myologie céphalique de deux poissons perroquets (Teleostei: Scaridae)". Cybium 21(2):173–199.
- Template:Cite journal
External linksEdit
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