The eastern triangle butterflyfish (''Chaetodon baronessa''), also known as the baroness butterflyfish, 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, a butterflyfish 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 central Indo-West Pacific region from the

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and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

in the eastern

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 ...

to Fiji and

Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...

, north to southern Japan, south to New Caledonia and

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in Australia.

Description

It grows to a maximum of 16 cm long.The body has a pattern of alternating cream and grey-brown to purple chevron-shaped bars. There are three dark bars on the head, including one running across the eye.

Habitat and behaviour

The eastern triangle butterflyfish is found in seaward and

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons' ...

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. C ...

s. They usually swim around in pairs and are territorial. This species feeds exclusively on the polyps of the tubular ''

Acropora ''Acropora'' is a genus of small polyp stony coral in the phylum Cnidaria. Some of its species are known as table coral, elkhorn coral, and staghorn coral. Over 149 species are described. ''Acropora'' species are some of the major reef corals r ...

'' corals.

Phylogeny

The triangle butterflyfish (''C. triangulum'') is its western

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

, replacing ''C. baronessa'' in the

. The triangle butterflyfishes and the hooded butterflyfish (''C. larvatus'') form 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 ...

''Gonochaetodon''. If '' Chaetodon'' is split up as some researchers propose, this group might go into ''Megaprotodon'' as other high-backed and square-bodied species, but its exact relationships are still not well known.

References

External links

* {{Taxonbar, from=Q947271 Chaetodon Fish described in 1829 Taxa named by Georges Cuvier