Naso_tonganus

<i>Naso tonganus</i>

Naso tonganus

Species of surgeonfish

Naso tonganus, the bulbnose unicornfish, hump-nosed unicornfish, humphead unicornfish, or the humpnose unicorn, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This species is found in the Indo-Pacific. It is of value in commercial fisheries.

Quick Facts Naso tonganus, Conservation status ...

Taxonomy

Naso tonganus was first formally described as Naseus tonganus in 1835 by the French zoologist Achille Valenciennes with its type locality given as Tongatapu in Tonga.[2] This species is classified within the nominate subgenus of the genus Naso.[3] The genus Naso is the only genus in the subfamily Nasinae in the family Acanthuridae.[4]

Etymology

Naso tonganus has the specific name tonganus, a reference to its type locality of Tonga.[3]

Description

Naso tonganus has a dorsal fin which is supported by 5 spines and between 27 and 30 soft rays while the anal fin is supported by 2 spines and 26 to 28 soft rays.[5] There are between 22 and 46 teeth in each jaw. the number increasing as the fish grows, and these have serrated tips. The depth of the body fits into the standard length around 2.3 to 3 times, adults having less deep bodies than subadults. The adults have a bulging protuberance on the front of the head, in larger males this may extend beyond the mouth. The dorsal profile of the body is clearly convex underneath the spiny part of the dorsal fin. There is a pair of bony plates on either side of the caudal peduncle and each has a forward projecting point. The caudal fin is emarginate in juveniles and truncate in adults.[6] The overall colour is silvery to brownish-grey, shading to yellowish-grey on the ventral part of the body. There is an irregular pattern of pale and black spots below the spiny part of the dorsal fin. The dorsal fin is dark with a blue margin and there is a wide blackish submarginal band on the pectoral and caudal fins. Juveniles are covered in dense, dark spotting.[7] This species has attained a maximum published standard length of 60 cm (24 in).[5]

Distribution and habitat

Naso tonganus has a wide Indo-Pacific distribution. In the Western Indian Ocean it ranges from the eastern coast of Africa between Somalia and KwaZulu-Natal, Madagascar, the Comoros, the Seychelles and the Mascarenes.[6] It is found around the Maldives but appears to be absent from the continental coast of South Asia. It then occurs from Thailand east to the Samoan Islands, north to the Ryukyu Islands of southern Japan and south to Australia.[1] In Australia it has been recorded from Shark Bay to the North West Cape in Western Australia, the Ashmore Reef, the far north of the Great Barrier Reef and reefs in the Coral Sea as far south as Jervis Bay in New South Wales. It also occurs at Christmas Island and the Cocos (Keeling) Islands.[7] This species is often solitary but may be found in small groups on coral reefs where they feed on zooplankton and algae.[5]

References

  1. [1]
    Abesamis, R.; Clements, K.D.; Choat, J.H.; et al. (2012). "Naso tonganus". IUCN Red List of Threatened Species. 2012: e.T177951A1500716. doi:10.2305/IUCN.UK.2012.RLTS.T177951A1500716.en. Retrieved 7 January 2022.
  2. [2]
    Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Naso". Catalog of Fishes. California Academy of Sciences. Retrieved 28 July 2023.
  3. [3]
    Christopher Scharpf & Kenneth J. Lazara, eds. (12 January 2021). "Order ACANTHURIFORMES (part 2): Families EPHIPPIDAE, LEIOGNATHIDAE, SCATOPHAGIDAE, ANTIGONIIDAE, SIGANIDAE, CAPROIDAE, LUVARIDAE, ZANCLIDAE and ACANTHURIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Archived from the original on 10 January 2023. Retrieved 17 July 2023.
  4. [4]
    J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. pp. 497–502. ISBN 978-1-118-34233-6.
  5. [5]
    Froese, Rainer; Pauly, Daniel (eds.) (2023). "Naso tonganus" in FishBase. June 2023 version.
  6. [6]
    John E. Randall (2022). "Family Acanthuridae". In Phillip C Heemstra; Elaine Heemstra; David A Ebert; Wouter Holleman; John E Randall (eds.). Coastal Fishes of the Western Indian Ocean (PDF). Vol. 5. South African Institute for Aquatic Biodiversity. pp. 219–244. ISBN 978-1-990951-32-9. Archived (PDF) from the original on 2023-06-12. Retrieved 2023-07-17.
  7. [7]
    Bray, D.J. (2020). "Naso tonganus". Fishes of Australia. Museums Victoria. Retrieved 29 July 2023.
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