Seychelles butterflyfish
Encyclopedia
The Seychelles Butterflyfish, Chaetodon madagaskariensis, is a species
of butterflyfish
(family
Chaetodontidae). It is found in the Indian Ocean
from eastern Africa
(as far south as Port Elizabeth in South Africa) east to Cocos-Keeling Islands and Christmas Island
, north to Sri Lanka
. The Seychelles Butterflyfish is found in areas of rich coral growth on seaward reef
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. There are a series of dark grey chevron lines on the sides of the body, partly broken into spots. Between the eyes and the start of the dorsal fin
there is a black patch rimmed with white. The base of the caudal fin is white, followed by an orange patch and a white rim.
(C. paucifasciatus) and Atoll Butterflyfish
es (C. mertensii), and the more distant Pearlscale Butterflyfish
(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
Exornator, or considered a distinct subgenus Rhombochaetodon. According to various DNA sequence
studies, some older and more singular lineages. These include species such as the Asian Butterflyfish (C. argentatus), the Blue-striped Butterflyfish (C. fremblii) and Burgess' Butterflyfish (C. burgessi). C. burgessi is in fact so peculiar that it was placed in a monotypic
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.
But the expanded group is of unclear relationships to species like the Speckled Butterflyfish
(C. citrinellus) and the Four-spotted Butterflyfish (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 phylogenetically, their position towards Rhombochaetodon is unresolved, and ultimately it might be better to merge both Rhombochaetodon and Roaops in Exornator. If the genus Chaetodon
is split up, Exornator might become a subgenus of Lepidochaetodon or a separate genus.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of butterflyfish
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. Found mostly on the reefs of the Atlantic, Indian and Pacific Oceans, there are approximately 120 species in 10 genera...
(family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Chaetodontidae). It is found in the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
from eastern Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
(as far south as Port Elizabeth in South Africa) east to Cocos-Keeling Islands and Christmas Island
Christmas Island
The Territory of Christmas Island is a territory of Australia in the Indian Ocean. It is located northwest of the Western Australian city of Perth, south of the Indonesian capital, Jakarta, and ENE of the Cocos Islands....
, north to Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
. The Seychelles Butterflyfish is found in areas of rich coral growth on seaward reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
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. There are a series of dark grey chevron lines on the sides of the body, partly broken into spots. Between the eyes and the start of the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
there is a black patch rimmed with white. The base of the caudal fin is white, followed by an orange patch and a white rim.
Systematics
C. madagaskariensis is one of the "crowned" butterflyfishes. These form a group of largely allopatric species sharing the overall color pattern of dark forward-pointing chevrons 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 EritreanEritrean butterflyfish
The Eritrean Butterflyfish or Crown Butterflyfish, Chaetodon paucifasciatus, is a species of butterflyfish . It is essentially just known from the Red Sea and the Gulf of Aden, but has been reported from East Africa....
(C. paucifasciatus) and Atoll Butterflyfish
Atoll butterflyfish
The Atoll Butterflyfish, Chaetodon mertensii, is a species of butterflyfish . It is found in the Pacific Ocean from the Ryukyu Islands to the Philippines and extending to Lord Howe Island, Rapa Iti and the Tuamotus....
es (C. mertensii), and the more distant Pearlscale Butterflyfish
Pearlscale butterflyfish
The Pearlscale Butterflyfish is a species of butterflyfish also known as Yellow-tailed Butterflyfish or Philippines Chevron Butterflyfish...
(C. xanthurus).
The "crowned" Chaetodon are a clearly recognizable clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
, but their further relationships are otherwise less clear. They were often placed in the subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Exornator, or considered a distinct subgenus Rhombochaetodon. According to various DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
studies, some older and more singular lineages. These include species such as the Asian Butterflyfish (C. argentatus), the Blue-striped Butterflyfish (C. fremblii) and Burgess' Butterflyfish (C. burgessi). C. burgessi is in fact so peculiar that it was placed in a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
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.
But the expanded group is of unclear relationships to species like the Speckled Butterflyfish
Speckled butterflyfish
Chaetodon citrinellus is a species of butterflyfish . It is commonly known as the Speckled Butterflyfish or Citron Butterflyfish...
(C. citrinellus) and the Four-spotted Butterflyfish (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 phylogenetically, 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
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 might warrant recognition as distinct genera.Several subgenera...
is split up, Exornator might become a subgenus of Lepidochaetodon or a separate genus.