''Naso tuberosus'', the humpnose unicornfish, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Acanthuridae Acanthuridae are the family of surgeonfishes, tangs, and unicornfishes. The family includes about 86 extant species of marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular in aq ...

, the surgeonfishes, unicornfishes and tangs. This species occurs in the Indian Ocean but it may be more widespread.

Taxonomy

''Naso tuberosus'' was first formally described in 1801 by the French naturalist

Bernard Germain de Lacépède Bernard-Germain-Étienne de La Ville-sur-Illon, comte de Lacépède or La Cépède (; 26 December 17566 October 1825) was a French naturalist and an active freemason. He is known for his contribution to the Comte de Buffon's great work, the ...

with its type locality given as Mauritius. This species is classified within the nominate

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

'' Naso''. The

''Naso'' is the only genus in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Nasinae in the family Acanthuridae.

Etymology

''Naso tuberosus'' has the specific name ''tuberosus'', meaning "lumpy", a reference to the bulging protuberance on the front of its head.

Description

''Naso tuberosus'' has a

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

which is supported by 5 spines and between 26 and 29 soft rays while the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is supported by 2 spines and 26 to 28 soft rays. There are between 30 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 Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

around 2.3 to 2.7 times, adults having less deep bodies than subadults. The adults have a bulging protuberance on the front of the head, this never extends beyond the mouth. The dorsal profile of the body is weakly convex underneath the spiny part of the dorsal fin. There is a pair of bony plates on either side of the

caudal peduncle Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

and each has a keel with a forward projecting point. The caudal fin is very emarginate in juveniles and slightly emarginate in adults. The overall colour is greyish with small blackish spots on the upper part of the body. A large black spot is located underneath and to the front of the base of the

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s. This species has attained a maximum published standard length of .

Distribution and habitat

''Naso tuberosus'' is an uncommon species found in the Indian Ocean, it may occur in the western Pacific Ocean but this many, if not all records, outside the Pacific Ocean may refer to ''Naso tonganus''. The humpnose unicornfish has been recorded from the eastern coast of Africa from Somalia as far south as

Sodwana Bay Sodwana Bay is a bay in South Africa on the KwaZulu Natal north coast, between St. Lucia and Lake Sibhayi. It is in the Sodwana Bay National Park, and the Maputaland Marine Reserve, and is a popular recreational diving destination. The term is co ...

in South Africa, the

Comoro Islands The Comoro Islands or Comoros ( Shikomori ''Komori''; ar, جزر القمر , ''Juzur al-qamar''; french: Les Comores) form an archipelago of volcanic islands situated off the southeastern coast of Africa, to the east of Mozambique and northw ...

, Madagascar, the Seychelles, the

Mascarenes The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of the islands belonging to the Republic of Mauritius as well as the French department of Réunion. Their ...

and from Yemen. It has also been found at

Rottnest Island Rottnest Island ( nys, Wadjemup), often colloquially referred to as "Rotto", is a island off the coast of Western Australia, located west of Fremantle. A sandy, low-lying island formed on a base of aeolianite limestone, Rottnest is an A-class ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

and from the

Cocos (Keeling) Islands ) , anthem = "''Advance Australia Fair''" , song_type = , song = , image_map = Australia on the globe (Cocos (Keeling) Islands special) (Southeast Asia centered).svg , map_alt = Location of the Cocos (Keeling) Islands , map_caption = ...

. This species is found mainly on coral reefs where it grazes on algae of the genus ''

Caulerpa ''Caulerpa'' is a genus of seaweeds in the family Caulerpaceae (among the green algae). They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world. A species in the Mediterran ...

''.

References

{{Taxonbar, from=Q2276575 tuberosus Fish described in 1801 Taxa named by Bernard Germain de Lacépède