''Chaetodon xanthocephalus'', known commonly as the Yellowhead 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

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

in the

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Chaetodontidae. It is found in the Indian Ocean.

Description

The yellowhead butterflyfish has a pearly white body with a golden-yellow band of colour on the head, along the dorsal and ventral parts of the body and on the fins. The white is broken by greyish blue

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s. It has a short black vertical bar running through the eyes and a thin yellow line on the rear of the operculum. The orange dorsal and anal fins have light blackmarks on their lower rear parts and yellow margins. The caudal fin is light grey also edged in yellow. 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 ...

contains 13-14 spines and 21-26 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 3 spines and 21-23 soft rays. The yellowhead butterflyfish attains a maximum

total 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 ...

of .

Distribution

The yellowhead butterflyfish is widespread throughout the

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waters of the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

. It occurs from Somalia to

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in South Africa and Madagascar, east as far as Sri Lanka, western Thailand and northwestern

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

Habitat and biology

The yellowhead butterflyfish is found at depths between 1 and 30m. Usually solitary, but may form loose shoals of 5-6 individuals and usually found around isolated coral heads. Territorial and aggressive to other chaetodonts; omnivorous. They form pairs for breeding and the females swell up when ready to spawn, the eggs are scattered into the water and the male fertilises them. The spherical eggs float and after what is probably a period of 28-30 hours they hatch. After hatching the larvae develops a bony plate over its head, these larvae are called tholichthys, and they are pelagic for quite a long period. They slowly mature into juveniles. It is the tholichthys phase of their life cycle that makes it so difficult to breed butterflyfish in captivity.

Systematics

The yellowhead butterflyfish was first formally described in 1833 by the

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

naturalist Edward Turner Bennett (1797–1836) with the type locality given as

Ceylon Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

. It belongs to the large

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 ...

''Rabdophorus'' which might warrant recognition as a distinct

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 ...

. It has been recorded hybridising with saddle butterflyfish (''C. ephippium'').

References

External links

*http://www.marinespecies.org/aphia.php?p=taxdetails&id=218721 *http://www.fishbase.org/summary/7794 *http://eol.org/pages/213607/details * {{Taxonbar, from=Q2612982 Chaetodon Fish described in 1833