''Chelmonops curiosus'', truncate coralfish, truncate butterflyfish, western talma or squareback 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 ...

from 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

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 ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Description

''Chelmonops curiosus'' has a very deep strongly compressed body, which is more than half its

standard 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 m ...

. It has a small head with a long, tapered snout and a tiny mouth at the end of its snout. There is a single, elongated

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 ...

with the separation between the spiny portion and the soft-rayed portion being hardly visible. The first spine is very small but as they progress towards the posterior they become longer and longer. In juveniles the soft part of the dorsal fin is rounded but it is pointed in adults and has a triangular profile when raised. 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 ...

is smaller than the dorsal fin. 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 se ...

is truncate. The background colour of this fish is steel grey with amounts of black shading different for each individual. They are marked with 4 vertical black bars with silver edged margins, becoming broader towards the tail. The

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s are black. In juveniles there is an ocellus on the soft part of the dorsal fin which fades as they become mature. The spiny part of the dorsal fin contains 11 spines while the soft part has 25-27 soft rays while the anal fin has 3 spines and 19-20 soft rays. This species 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

''Chelmonops curiosus'' is endemic to the seas of Australia where it is found along the south coast from

Victor Harbor, South Australia Victor Harbor is a town in the Australian state of South Australia located within the City of Victor Harbor on the south coast of the Fleurieu Peninsula, about south of the state capital of Adelaide city centre, Adelaide. The town is the large ...

and on the western coast as far north as

Shark Bay Shark Bay (Malgana: ''Gathaagudu'', "two waters") is a World Heritage Site in the Gascoyne region of Western Australia. The http://www.environment.gov.au/heritage/places/world/shark-bay area is located approximately north of Perth, on the ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Habitat and biology

''Chelmonops curiosus'' is found on coastal rocky reefs, seeming to prefer vertical rock faces, often where the water is turbid and they will use man-made structures such as pylons and jetties. The juveniles are frequently found swimming among seaweed beds. The adults are normally observed in pairs. This species is omnivorous and its diet comprises small worms, crustaceans, and algae. They breed in pairs. They appear to be

territorial A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal. In international politics, a territory is usually either the total area from which a state may extract power resources or a ...

, with each pair defending a territory.

Utilisation

''Chelmonops curiosus'' is occasionally collected for the aquarium trade. It is rarely exported from Australia.

Description

Distribution

Habitat and biology

Utilisation

References

Further reading