The Spot-tailed Butterflyfish, ''Chaetodon ocellicaudus'', is a

species In biology, a species is the basic unit of 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 the appropriate s ...

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 central Indo- west Pacific region from

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

, north to the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

and

Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the Caro ...

Micronesia Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...

. It grows to a maximum of long. Nearly identical to the Black-backed Butterflyfish (''C. melannotus''), it differs only in the shape of the black mark on the caudal peduncle, in lacking a black mark on the chest, a lighter back, and in having an average of 14 rather than 15

pectoral 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 ...

rays. ''C. ocellicaudus'' belongs to the large

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 between t ...

''Rabdophorus'' which might warrant recognition as a distinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

. In this group, it appears to be a close relative of the Black-backed Butterflyfish and somewhat less close to the Yellow-dotted Butterflyfish (''C. selene''). These are all of oval shape, silvery with yellow fins and snout, ascending diagonal stripes, and black markings around the eyes, on the caudal peduncle, and sometimes on the back. Next closest seem the Saddle Butterflyfish (''C. ephippium'') and the Dotted Butterflyfish (''C. semeion''), but these are already so distant that their ancestors must have diverged from those soon after the ''Rabdophorus'' lineage started to diversify. The Spot-tailed Butterflyfish is found at depths between 3 and 15 m in

coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...

. They occur in coral-rich areas of reef flats,

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'') a ...

s and seaward reefs. Juveniles tend to keep inshore. Adults are usually seen in pairs. These fish feed on soft

coral polyp Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

s (e.g. ''

Litophyton viridis ''Litophyton'' is a genus of soft corals in the family Nephtheidae. Species The World Register of Marine Species includes the following species in the genus: *'' Litophyton acuticonicum'' (Verseveldt, 1974) *'' Litophyton amentaceum'' (Studer, ...

'' and species of the genera ''

Clavularia Clavularia is a genus of corals in the family Clavulariidae. They are often referred by the common names star polyps or clove polyps. Species There are 69 accepted species in this genus: * '' Clavularia alba'' (Grieg, 1888) * '' Clavularia arc ...

'', '' Nephthia'' and '' Sarcophyton'').

References

External links

* Chaetodon Fish described in 1831 Taxa named by Georges Cuvier {{Chaetodontidae-stub