''Prognathodes dichrous'', the bicolor butterflyfish, also known as the bastard cunningfish or hedgehog 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 Atlant ...

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 found in the South Atlantic Ocean.

Description

''Prognathodes dichrous'' is largely brown in colour with the upper rear quarter of the body being white, including the dorsal 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 se ...

The dorsal fin contains 12 spines and 19 soft rays while the anal fin has 3 spines and 15 soft rays. This species attains a maximum total length of . There is a white eye ring, too.

Distribution

''Prognathodes dichrous'' is found in the southeastern Atlantic Ocean where it is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the waters around the

British Overseas Territories The British Overseas Territories (BOTs), also known as the United Kingdom Overseas Territories (UKOTs), are fourteen dependent territory, territories with a constitutional and historical link with the United Kingdom. They are the last remna ...

of Ascension and

Saint Helena Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constitu ...

islands.

Habitat and biology

''Prognathodes dichrous'' is a species of deeper water, normally found between but ar Hummock Point it can be seen in water as shallow as . It is found in caves and under overhangs, as well as on

seamounts A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

. It is normally encountered in pairs, although shoals have also been recorded, which browse on benthic invertebrates over rocky areas. This is an oviparous species which

spawns Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

as pairs.

Systematics

''Prognathodes dichrous'' was first formally described in 1869 by the German-born British zoologist Albert Günther (1830–1914) with the type locality given as St Helena. Its closest relative appears to be the rather similar ''

Prognathodes obliquus ''Prognathodes obliquus'', the oblique butterflyfish is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It is endemic to St Paul Rocks in the southwestern Atlantic Ocean off Brazil. Destruction of it ...

'' which is

to St Paul Rocks off Brazil.

References

{{Taxonbar, from=Q2238095 dichrous Fish described in 1869 Taxa named by Albert Günther