''Naso tergus'' 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 was first formally described in 2011 from off of the coast of

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

after several specimens were collected.

Taxonomy

''Naso tergus'' was first formally described in 2011 by Ho-Hsuan Ching, Shen Kang-Ning and Chang Chi-Wei with its type locality given as off Nanfango in

Ilan Ilan may refer to: Organization *ILAN, Israeli umbrella organization for the treatment of disabled children Given name *Ilan (name), a Hebrew/Israeli name * Ilan Bakhar, a retired Israeli footballer *Ilan Araújo Dall'Igna, a Brazilian footballer ...

in nortrheastern Taiwan at a depth of . 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 tergus'' was originally described as a cryptic species which hid among closely related fishes and bore a morphological resemblance to the subadults of those species. The authors chose the Latin word ''tergus'' as its specific name, this name means "hide". However, it means "hide" as a noun, i.e. the hide of an animal, rather than the verb which means to conceal.

Description

''Naso tergus'' has a moderately elongated and compressed body, described as having a slender body and head compared to its congeners. It has a relatively large head with a smoothly sloping dorsal profile with a relatively small mouth. The

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 ...

is supported by 6 spines and between 26 and 30 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 ...

has 2 spines and 26 to 28 soft rays supporting it. There is a pair of elliptical bony plates on each 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 ...

. There are between 100 and 120 teeth on the lower jaw and between 90 and 110 on the upper jaw. The overall color of the body is brownish. This is a relatively small unicornfish with a standard length that may not exceed .

Distribution

''Naso tergus'' has been recorded from Taiwan, southern Japan and the Philippines as depths between .

References

{{Taxonbar, from=Q13875833 Acanthuridae tergus Fish of Taiwan Fish of the Pacific Ocean Fish described in 2011