''Chaetodon andamanensis'', commonly known as the Andaman butterflyfish, 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 ...

, 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 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 ...

Chaetodontidae. It is native to the Indian Ocean.

Description

''Chaetodon andamanensis'' is an overall bright yellow colour apart from a black band which runs from the top of the head and through the eyes, and a black

ocellus A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...

on the caudal peduncle. The dorsal fin contains 1:4 spines and 18 soft rays while the anal fin has 4 spines and 16-18 soft rays. This species attains a maximum total length of }.

Distribution

''Chaetodon andamanensis'' is found in the eastern Indian Ocean where it has been recorded from Sri Lanka, southwestern India, the

Andaman Islands The Andaman Islands () are an archipelago in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a maritime boundary between th ...

, the

Nicobar Islands The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of the Indian s ...

, the Maldives; the

Mergui Archipelago The Mergui Archipelago (also Myeik Archipelago or ''Myeik Kyunzu''; my, မြိတ်ကျွန်းစု) is located in far southern Myanmar (Burma) and is part of the Tanintharyi Region. It consists of more than 800 islands, varying in ...

in Myanmar, the

Similan Islands The Similan Islands ( th, หมู่เกาะสิมิลัน, , , Malay: ''Pulau Sembilan'') is an archipelago in the Andaman Sea off the coast of, and part of, Phang Nga Province in southern Thailand. It is the maritime border betw ...

of Thailand and

Weh Island Weh Island (Indonesian: Pulau Weh), often known as Sabang after the city of which the island is administrated, is a small active volcanic island to the northwest of Sumatra, 45 minutes by fast regular ship or 2 hours by ferry from mainland, ...

off 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 ...

in Indonesia.

Habitat and biology

''Chaetodon andamanensis'' is found in rock or coral reef habitats close to the shoreline or on the outer slopes. They can be solitary but are typically encountered in pairs or small aggregations. Their diet is mostly coral

polyps A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary polyps, the aboral (opposite to oral) end is ...

. It is an oviparous species which forms pairs for breeding. it is thought that this species is a slow breeding fish which must have live branching coral to reproduce. They are found at depths between .

Systematics

''Chaetodon andamanensis'' was first formally described in 1999 by Rudie Kuiter and Helmut Debelius with the type locality given as

Great Nicobar Great Nicobar is the southernmost and largest of the Nicobar Islands of India, north of Sumatra. History The Nicobar Island has been well known to Indian mariners since the time of the seafaring Cholas https://www.britannica.com/place/Nicobar- ...

. Many authorities consider the Andaman butterflyfish a local colour

morph Morph may refer to: Biology * Morph (zoology), a visual or behavioral difference between organisms of distinct populations in a species * Muller's morphs, a classification scheme for genetic mutations * "-morph", a suffix commonly used in tax ...

of '' Chaetodon plebeius''. Like the other butterflyfishes with angular yellow bodies with black eyestripes and a single differently-colored patch, it belongs in the

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 ...

''Tetrachaetodon''. Among this group it seems to be the most basal living species. If ''

Chaetodon ''Chaetodon'' is a tropical fish genus in the family Chaetodontidae. Like their relatives, they are known as "butterflyfish". This genus is by far the largest among the Chaetodontidae, with about 90 living species included here, though most migh ...

'' is split up, this subgenus would be placed in ''Megaprotodon''.

References

{{Taxonbar, from=Q2256004 Fish of Thailand Fish described in 1999 Fish of the Indian Ocean andamanensis