The Seychelles butterflyfish (''Chaetodon madagaskariensis'') is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

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 Atlan ...

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

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 ...

from eastern

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

(as far south as

Port Elizabeth Gqeberha (), formerly Port Elizabeth and colloquially often referred to as P.E., is a major seaport and the most populous city in the Eastern Cape province of South Africa. It is the seat of the Nelson Mandela Bay Metropolitan Municipality, S ...

in South Africa) east to

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 = ...

and

Christmas Island Christmas Island, officially the Territory of Christmas Island, is an Australian external territory comprising the island of the same name. It is located in the Indian Ocean, around south of Java and Sumatra and around north-west of the ...

, north to

Sri Lanka 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 ...

. The Seychelles butterflyfish is found in areas of rich coral growth on 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 component, abiotic processes—deposition (geology), deposition of ...

s, at 10–40 m depth. It grows to a maximum of 13 cm (more than 5 in) long. The body color is silver at the head, becoming white towards the tail, with a triangular orange patch covering the posterior and 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 a series of dark grey

chevron Chevron (often relating to V-shaped patterns) may refer to: Science and technology * Chevron (aerospace), sawtooth patterns on some jet engines * Chevron (anatomy), a bone * ''Eulithis testata'', a moth * Chevron (geology), a fold in rock lay ...

lines on the sides of the body, partly broken into spots. Between the eyes and the start of 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 c ...

there is a black patch rimmed with white. The base of the

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 ...

is white, followed by an orange patch and a white rim.

Systematics

The Seychelles butterflyfish was first formally described in 1923 by the

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and ...

Ernst Ahl (1898-1945) with the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

given as Mauritius. The specific name is sometimes spelt ''madagascarensis'' but Ahl’s original should be used. ''C. madagaskariensis'' is one of the "crowned" butterflyfishes. These form a group of largely

allopatric Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

species sharing the overall color pattern of dark forward-pointing

s on silvery hues, (usually) a black-and-white crown spot and yellow to red hindparts to a stunning degree; they differ in the exact combination of hues and some small pattern details. Other members of this lineage are the closely related Eritrean (''C. paucifasciatus'') and atoll butterflyfishes (''C. mertensii''), and the more distant

pearlscale butterflyfish The pearlscale butterflyfish (''Chaetodon xanthurus''), also known as yellow-tailed butterflyfish, crosshatch butterflyfish or Philippines chevron butterflyfish is a species of marine ray-finned fish, a butterflyfish belonging to the family Chae ...

(''C. xanthurus''). The "crowned" ''Chaetodon'' are a clearly recognizable clade, but their further relationships are otherwise less clear. They were often placed 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 betw ...

''Exornator'', or considered a distinct subgenus ''Rhombochaetodon''. According to various

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

studies, some older and more singular lineages. These include species such as the

Asian butterflyfish ''Chaetodon argentatus'', the Asian butterflyfish, three band butterflyfish or black pearlscaled butterflyfish, is a species of marine ray-finned fish a butterflyfish belonging to the family Chaetodontidae. It is native to the western Pacific O ...

('' C. argentatus''), the

blue-striped butterflyfish The bluestripe butterflyfish or blue-striped butterflyfish (''Chaetodon fremblii'') is a species of butterflyfish (family Chaetodontidae) found in the waters surrounding the Hawaiian Islands. The fish is endemic to Hawaii where it is common on sha ...

('' C. fremblii'') and

Burgess' butterflyfish Burgess' butterflyfish (''Chaetodon burgessi''), also known as the black & white butterflyfish or black-barred butterflyfish, is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It occurs in the wester ...

('' C. burgessi''). ''C. burgessi'' is in fact so peculiar that it was placed in a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

subgenus ''Roaops''. But recognition of this would probably result in several other small or monotypic subgenera becoming justified, and the older ''Rhombochaetodon'' would be the more conveniently apply to the entire

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, vi ...

. But the expanded group is of unclear relationships to species like the

speckled butterflyfish ''Chaetodon citrinellus'' is a species of butterflyfish (family Chaetodontidae). It is commonly known as the speckled butterflyfish or citron butterflyfish. It is found in the Indo-Pacific: the Red Sea, East Africa to the Hawaiian, Marquesan and ...

(''C. citrinellus'') and the

four-spotted butterflyfish The four-spotted butterflyfish or fourspot butterflyfish (''Chaetodon quadrimaculatus'') is a species of butterflyfish ( family Chaetodontidae) found in the Pacific Ocean from the Ryukyus, Ogasawara (Bonin) Islands and Taiwan to the Hawaiia ...

(''C. quadrimaculatus''). These might be members of the subgenus ''Exornator'' – the lineages around the spot-banded butterflyfish (''C. punctatofasciatus'') – and ''C. citrinellus'' certainly looks somewhat similar to these. Yet

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

ally, their position towards ''Rhombochaetodon'' is unresolved, and ultimately it might be better to merge both ''Rhombochaetodon'' and ''Roaops'' in ''Exornator''. If the genus ''

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, ''Exornator'' might become a subgenus of ''Lepidochaetodon'' or a separate genus.

References

External links

* {{Taxonbar, from=Q582693 Seychelles butterflyfish Fauna of Seychelles Fish of the Indian Ocean Marine fauna of East Africa Seychelles butterflyfish