{{Short description|Species of fish}} {{Speciesbox | image = Twospot bristletooth (Ctenochaetus binotatus) (36604859314).jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref name= iucn>{{cite iucn |author=Clements, K.D. |author2=Choat, J.H. |author3=Abesamis, R. |author4=McIlwain, J. |author5=Myers, R. |author6=Nanola, C. |author7=Rocha, L.A. |author8=Russell, B. |author9=Stockwell, B. |display-authors=3 |date=2012 |title=''Ctenochaetus binotatus'' |article-number=e.T177955A1501829 |doi=10.2305/IUCN.UK.2012.RLTS.T177955A1501829.en |access-date=19 November 2021}}</ref> | taxon = Ctenochaetus binotatus | authority = J. E. Randall, 1955 | synonyms = {{Specieslist | Ctenochaetus oculocoeruleus | Fourmanoir, 1966 }} | synonyms_ref = <ref name = Fishbase>{{FishBase|Ctenochaetus|binotatus|month=June|year=2023}}</ref> }}
'''''Ctenochaetus binotatus''''', the '''twospot bristletooth''' or '''twospot surgeonfish''', is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes unicornfishes and tangs. This species has a wide Indo-Pacific distribution.
==Taxonomy== ''Ctenochaetus binotatus'' was first formally described in 1955 by the American ichthyologist John Ernest Randall with its type locality given as Batangas Bay, off the island of Luzon, in the Philippines.<ref name = CofF>{{Cof genus|genus=Ctenochaetus|access-date=4 October 2023}}</ref> The genera ''Ctenochaetus'' and ''Acanthurus'' make up the tribe Acanthurini, which is one of three tribes in the subfamily Acanthurinae, which is one of the two subfamilies in the family Acanthuridae.<ref name = Nelson5>{{cite book |title=Fishes of the World |edition=5th |author1=J. S. Nelson |author2=T. C. Grande |author3=M. V. H. Wilson |year=2016 |pages= 497–502 |publisher=Wiley |ISBN= 978-1-118-34233-6 }}</ref>
==Etymology== The specific name of this species, ''binotatus'', meaning "twice marked", is a reference to the two black spots present on the flanks, one at the axil of the soft-rayed part of the dorsal fin and the other at the rear of the anal fin.<ref name = ETYFish>{{cite web | url = https://etyfish.org/acanthuriformes2/ | title = Order ACANTHURIFORMES (part 2): Families EPHIPPIDAE, LEIOGNATHIDAE, SCATOPHAGIDAE, ANTIGONIIDAE, SIGANIDAE, CAPROIDAE, LUVARIDAE, ZANCLIDAE and ACANTHURIDAE | work = The ETYFish Project Fish Name Etymology Database | editor1= Christopher Scharpf | editor2 = Kenneth J. Lazara | name-list-style = amp |date = 12 January 2021 | access-date = 4 October 2023 | publisher = Christopher Scharpf and Kenneth J. Lazara}}</ref>
==Description== ''Ctenochaetus binotatus'' has a dorsal fin which is supported by 8 spines and between 24 and 27 soft rays; for the anal fin the figures are 3 and between 22 and 25 respectively.<ref name = Fishbase/> The depth of the body is more than half of its standard length. In adults, the caudal fin is lunate.<ref name = WIOF>{{cite book |author=John E. Randall |chapter=Family Acanthuridae |pages=219–244 |title=Coastal Fishes of the Western Indian Ocean |volume=5 |editor1=Phillip C Heemstra |editor2=Elaine Heemstra |editor3=David A Ebert |editor4=Wouter Holleman |editor5=John E Randall |year=2022 |isbn=978-1-990951-32-9 |publisher=South African Institute for Aquatic Biodiversity |url=https://saiab.ac.za/wp-content/uploads/2022/11/1._wiof_volume_5_text.pdf |access-date=2023-07-17 |archive-date=2023-06-12 |archive-url=https://web.archive.org/web/20230612092043/https://saiab.ac.za/wp-content/uploads/2022/11/1._wiof_volume_5_text.pdf |url-status=live }}</ref> The overall colour is brown, but the head and chest are marked with pale spots, and there are pale lines horizontal lines along the flanks. The eyes are blue, and there is an obvious dark spot at the rear axils of both the dorsal and anal fins.<ref name = FofA>{{cite web |author=Bray, D.J. |year=2018 |title=''Ctenochaetus binotatus'' |work=Fishes of Australia |access-date=4 October 2023 |url=https://fishesofaustralia.net.au/home/species/1033 |publisher=Museums Victoria}}</ref> This species has a maximum published total length of {{cvt|22|cm}}.<ref name = Fishbase/>
==Distribution and habitat== ''Ctenochaetus binotatus'' has a wide Indo-Pacific distribution. It can be found across the Indian Ocean, from the eastern African coast between Kenya and Sodwana Bay in South Africa <ref name = WIOF/> all the way to the Andaman Sea, although it is absent off some Asian coasts. In the Pacific Ocean, it can be found as far east as the Tuamotu Islands and Mangareva, and everywhere between southern Japan and New South Wales.<ref name = iucn/> It is found at depths of {{cvt|60|m}} in areas of coral and rubble, deep lagoons and seaward reefs.<ref name = Fishbase/>
==Biology== ''Ctenochaetus binotatus'' is typically found singly. These fishes feed by scooping up the film of detritus and single-celled algae, such as the dinoflagellate ''Gambierdiscus toxicus'', which is a producer of the ciguatera toxin. This species is a link in the ciguatera chain.<ref name = Fishbase/>
==Utilisation== ''Ctenochaetus binotatus'' is traded in the aquarium industry. It is also used as a food fish in some areas, e.g. Thailand.<ref name = iucn/>
==References== {{Reflist}}
==External links== {{Commons category|Ctenochaetus binotatus}} {{Portal|Fish|marine biology|marine life}} *http://www.marinespecies.org/aphia.php?p=taxdetails&id=219655 * {{SealifePhotos|219655}}
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binotatus Category:Fish described in 1955 Category:Taxa named by John Ernest Randall