The Spot-naped Butterflyfish (''Chaetodon oxycephalus''), also known as the pig-face butterflyfish, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 h ...

. a

butterflyfish The butterflyfish are a group of conspicuous tropical marine fish of the family Chaetodontidae; the bannerfish and coralfish are also included in this group. The approximately 129 species in 12 genera are found mostly on the reefs of the Atla ...

belonging to the

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

Chaetodontidae. It is found in the Indo- West Pacific region from Sri Lanka to

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

, north to

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

and the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. It grows to a maximum of long. The body is white with thin vertical lines on the sides and a large black area in the upper back. Very similar to the

Lined Butterflyfish The lined butterflyfish (''Chaetodon lineolatus'') is a species of marine ray-finned fish. a butterflyfish belonging to the family Chaetodontidae, one of the largest species in the genus ''Chaetodon''. It has a wide range from the Red Sea to Sou ...

(''C. lineolatus''), its vertical black eyestripe is broken above the eye and there are additional black and orange lines and spots in the yellow

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

and

caudal 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. The Spot-naped Butterflyfish belongs to the large subgenus ''Rabdophorus'' which might warrant recognition as a distinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

. In this group, it seems to be member of a lineage also containing species such as the Lined Butterflyfish, or the peculiar Black-wedged Butterflyfish (''C. falcula'') and Pacific Double-saddle Butterflyfish or "False Falcula" (''C. ulietensis''). These four differ wildly in shape, but all have bluish vertical lines on a white body with yellow behind, and black on back and

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 see ...

in addition to the typical eyestripe of ''Chaetodon''. The Blue-cheeked Butterflyfish (''C. semilarvatus'') seems to be a far more basal lineage of ''Rabdophorus'' relative to them, but it also has the tell-tale blue vertical lines. ''C. oxycephalus'' is found in coral-rich areas and clear waters of seaward

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...

s at 10–40 m depth. It feeds on coral polyps and sea anemones.

References

External links

* Chaetodon Fish of Palau Fish described in 1853 {{Chaetodontidae-stub