Naso (fish)

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Genus of fishes

title: "Naso (fish)" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["naso-(fish)", "acanthuridae", "extant-eocene-first-appearances", "marine-fish-genera", "taxa-named-by-bernard-germain-de-lacépède"] description: "Genus of fishes" topic_path: "general/naso-fish" source: "https://en.wikipedia.org/wiki/Naso_(fish)" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Genus of fishes ::

| fossil_range = Eocene to present{{Cite journal | last = Sepkoski | first = Jack | author-link = | title = A compendium of fossil marine animal genera | journal = Bulletins of American Paleontology | volume = 364 | issue = | pages = 560 | year = 2002 | url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class | doi = | id = | access-date = 2008-01-08 }} | image = Bluespine Unicornfish, Emily Bay, Kingston 2899, Norfolk Island imported from iNaturalist photo 173453689 (cropped).jpg | image_caption = Bluespine unicornfish (N. unicornis) | taxon = Naso | parent_authority = Fowler & Bean, 1929 | authority = Lacépède, 1801 | type_species = Acanthurus fronticornis | type_species_authority = Lacepède, 1801 | synonyms = {{collapsible list|bullets = true|title=List | Atulonotus J. L. B. Smith, 1955 | Axinurus Cuvier, 1829 | Callicanthus Swainson 1839 | Cyphomycter Fowler & Bean, 1929 | Keris Valenciennes, 1835 | Monoceros Bloch & Schneider, 1801 | Nasonus Rafinesque, 1815 | Priodon
Quoy & Gaimard, 1825 | Priodontichthys Bonaparte, 1831 | Prionolepis J. L. B. Smith, 1931 | Rhinodactylus J. L. B. Smith, 1957 | synonyms_ref = | subdivision_ranks = Species | subdivision = 20., see text

Naso is a genus of marine ray-finned fishes belonging to the family, Acanthuridae, the unicornfishes, surgeonfishes and tangs. The fishes in this genus are known commonly as unicornfishes because of the "rostral protuberance", a hornlike extension of the forehead present in some species.

Unicorn fish are popular with spearfishermen and may be cooked by grilling them whole. Unicornfish primarily live around coral reefs and eat mostly algae.

This genus is distributed across the Indo-Pacific from Africa to Hawaii.

Taxonomy

Naso was first proposed as a genus in 1801 by Bernard Germain de Lacépède when he described Naso fronticornis as a new species from Jeddah and Mauritius. In 1917 David Starr Jordan designated Naso fronticornis as the type species of the genus Naso. within the family Acanthuridae.

Etymology

Naso means "nose" referring to the fleshy protuberance on the forehead of N. fronticornis (=unicornis). The subgenus Axinurus comes from axino and oura, meaning axe-tail, potentially referring to the presence of a single tail spine on each side as opposed to two in the subgenus Naso.

Distribution

Naso unicornfishes are found in the Indo-Pacific region from the eastern coast of Africa to the Galápagos Islands.

Characteristics

Naso unicornfishes have a pointed snout and a rhomboidal or oval shaped body, with some species possessing a long protuberance on the forehead, typically present in both males and females. The caudal peduncle is slender and there are 1 or 2 anteriorly directed sharp, blade-shaped spines mounted on bony plates on each side. The caudal fin varies from slightly rounded to highly emarginate. In some species there are long filaments at the tips of the lobes of the caudal fin, sometimes restricted to males. The dorsal fins of these fishes are supported by between 4 and 7 spines and between 24 and 31 soft rays while the anal fin contains 2 spines and 23 to 30 soft rays. There is a single spine and 3 soft rays in the pelvic fins and between 16 and 19 soft rays in the pectoral fins.

The species in the genus Naso vary in size from a maximum published standard length of 30 cm in the slender unicorn (N. minor) to a maximum published total length of 100 cm in the whitemargin unicornfish (N. annulatus).

There are two subgenera which are distinguished by the number of keels on the caudal peduncle with the nominate subgenus, Naso having a pair on each side of the peduncle while the subgenus Axinurus has a single keel on each side.

Biology

Naso unicornfishes differ from other acanthurids in that they eat zooplankton rather than grazing on algae or detritus and that they tend to live at greater ranges of depth.

Cephalic horn function

Some species exhibit a large horn on the forehead. It is uncertain what the purpose of this horn is. One explanation postulates that is a result of sexual selection, ie serving a purpose in competition and communication, which may be within or between the sexes, or both. Alternatively, it has been hypothesized that they instead perform a hydrodynamic function, assisting the species that exhibit them with precision movements. This is because both fast swimming "scombriform" shaped species and small species typically lack the horn, while it is only the large relatively slow-swimming species which display the horn.

Molecular phylogenetics show that horns independently evolved multiple times within the genus, and only ever evolved in benthic feeding species. Similarly, benthic-feeding also evolved multiple times independently. In addition, pelagic feeding and the fast-swimming "scombriform" body shape appear to be plesiomorphic traits. This is because the basalmost species in Naso are the pelagic feeding "scombriform" species in the subgenus Axinurus, and because every other acanthurid genus comprises predominantly benthic feeders.

In some species, both males and females display such a horn. In at least some species where this is the case, such as the bluespine unicornfish, the horn is slightly sexually dimorphic, being slightly larger in males. In other species, such as the humpback unicornfish, the horn is almost completely absent in females.

Species

Naso is divided into two subgenera and 20 species are classified within it: ::data[format=table title="Subgenus ''Naso'' Lacepède, 1801"]

SpeciesCommon nameImage
Naso annulatuswhitemargin unicornfish[[File:Whitemargin Unicornfish, Nausicaá imported from iNaturalist photo 51203063 (cropped).jpg
Naso brachycentronhumpback unicornfish[[File:Naso brachycentron 295997177 (cropped).jpg
Naso brevirostrisspotted unicornfish[[File:Naso brevirostris.jpg
Naso caesiusgray unicornfish[[File:Corl0234 (28009711442).jpg
Naso eleganselegant unicornfish[[File:Pez unicornio elegante (Naso elegans), mar Rojo, Egipto, 2023-04-17, DD 78.jpg
Naso fagenihorseface unicornfish[[File:Naso fageni 43445931.jpg
Naso hexacanthussleek unicornfish[[File:Sleek Unicornfish, Berau, ID-KI, ID imported from iNaturalist photo 459819459.jpg
Naso lituratusorangespine unicornfish[[File:Orangespine unicornfish (Naso lituratus).jpg
Naso lopezielongated unicornfish[[File:Elongate unicornfish in Night coloration (Naso lopezi) (42955826600).jpg
Naso maculatusspotted unicornfish
Naso mcdadeisquarenose unicornfish[[File:Naso mcdadei.png
Naso reticulatusreticulated unicornfish[[File:Naso reticulatus 57 cm.png
Naso tergusTaiwanese unicornfish
Naso tonganusbulbnose unicornfish[[File:Naso tonganus LyleVail.jpg
Naso tuberosushumpnose unicornfish[[File:Naso tuberosus Réunion.jpg
Naso unicornisbluespine unicornfish[[File:Bluespine Unicornfish, Kingston, Norfolk Island imported from iNaturalist photo 120509443 (cropped).jpg
Naso vlamingiibignose unicornfish[[File:Naso vlamingii 261420630 (cropped).jpg
::

::data[format=table title="Subgenus ''Axinurus'' Cuvier 1829"]

SpeciesCommon nameImage
Naso caeruleacauda J. E. Randall, 1994blue unicornfish[[File:Bluetail unicornfish (Naso caeruleacauda).jpg
Naso minor (J. L. B. Smith, 1966)slender unicornfish[[File:Naso minor, Romblon, Filipinas.jpg
Naso thynnoides (G. Cuvier, 1829)oneknife unicornfish[[File:BozuHG.jpg
::

References

References

  1. {{Cof family
  2. Dayton, C.. (2001). "Genetic evolution among selected members of the genus ''Naso'' (Nasinae), "unicornfishes" from Guam". Marine Biology.
  3. "Fishing at the tip of the spear in Guam".
  4. (5 November 2022). "Unicorn Fish the weird but delicious fish". The Arena Media Brands, LLC.
  5. "Acanthuridae (Surgeonfishes/Tangs)". Kasper Hareskov Tygesen.
  6. Borden, W. C.. (1998). "Phylogeny of the unicornfishes (''Naso'', Acanthuridae) based on soft anatomy". Copeia.
  7. Lacépède's name was an unnecessary replacement of ''Chaetodon unicornis'' described by Peter Forsskål in 1775 from Jeddah.{{Cof genus|genus=Naso|access-date=11 July 2023}}
  8. (2016). "Fishes of the World". Wiley.
  9. [[John E. Randall]]. (2022). "Coastal Fishes of the Western Indian Ocean". South African Institute for Aquatic Biodiversity.
  10. John E. Randall. (1994). "Unicornfishes of the Subgenus ''Axinurus'' (Perciformes: Acanthuridae: ''Naso''), with Description of a New Species". Copeia.
  11. DeMartini, Edward E.. (July 2016). "Sexual Dimorphisms in the Bluespine Unicornfish, Naso unicornis (Acanthuridae): External Metrics for Movement Ecology and Life History". Copeia.
  12. (July 2004). "Patterns of lineage diversification in the genus Naso (Acanthuridae)". Molecular Phylogenetics and Evolution.
  13. (12 January 2021). "Order Acanthuriformes (part 2): Families Ephippidae, Leiognathidae, Scatophagidae, Antigoniidae, Siganidae, Caproidae, Luvaridae, Zanclidae and Acanthuridae". Christopher Scharpf and Kenneth J. Lazara.
  14. {{FishBase genus. (2023)

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