''Paracaesio xanthura'', the yellowtail blue snapper, the false fusilier, gold-backed fusilier, Pedley's fusilier or Southern fusilier, 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 snapper 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 ...

Lutjanidae Lutjanidae, or snappers are a family of perciform fish, mainly marine, but with some members inhabiting estuaries, feeding in fresh water. The family includes about 113 species. Some are important food fish. One of the best known is the red snapp ...

. It is native to the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region.

Description

''Paracaesio xanthura'' has a fusiform and moderately deep body. It has large eyes which are separated by a convex area, and a short snout which has a length equal to the diameter of the eye. The upper and lower jaws are roughly equal in length and are equipped with an outer row of canine-like teeth and an inner band of small bristle-like teeth. The

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 ...

has 10 spines and 10-11 soft rays while the anal fin has 3 spines and 8-9 soft rays. This species attains a maximum total length of . This species is bright blue with a vivid yellow band which runs along its back and extends onto the

caudal peduncle 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 ...

and 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 ...

Distribution

''Paracaesio xanthura'' has a wide Indo-Pacific distribution. It is found from Kenya to South Africa on the coast of eastern Africa through the Indian Ocean, including Madagascar,

Comoros Islands The Comoro Islands or Comoros (Shikomori ''Komori''; ar, جزر القمر , ''Juzur al-qamar''; french: Les Comores) form an archipelago of volcanic islands situated off the southeastern coast of Africa, to the east of Mozambique and northwe ...

, Seychelles, Mauritius and

Réunion Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...

as well as the

Gulf of Aden The Gulf of Aden ( ar, خليج عدن, so, Gacanka Cadmeed 𐒅𐒖𐒐𐒕𐒌 𐒋𐒖𐒆𐒗𐒒) is a deepwater gulf of the Indian Ocean between Yemen to the north, the Arabian Sea to the east, Djibouti to the west, and the Guardafui Channe ...

, the Maldives and

Chagos Islands The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archi ...

, Sri Lanka and southern India. In the Pacific, it is found as far north as southern Japan, south to Australia and from the

Andaman Sea The Andaman Sea (historically also known as the Burma Sea) is a marginal sea of the northeastern Indian Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and west side of the Malay Peninsula, and separated from ...

in the west east to the

Austral Islands The Austral Islands (french: Îles Australes, officially ''Archipel des Australes;'' ty, Tuha'a Pae) are the southernmost group of islands in French Polynesia, an overseas country of the French Republic in the South Pacific. Geographically, ...

. In Australia it is found on the

Houtman Abrolhos The Houtman Abrolhos (often called the Abrolhos Islands) is a chain of 122 islands and associated coral reefs, in the Indian Ocean off the west coast of Australia, about west of Geraldton, Western Australia. It is the southernmost true coral ...

and the offshore reefs off northwestern

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 ...

, as well as the northern

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

south to Montague Island in

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

and east to

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

in the

Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...

Habitat and biology

''Paracaesio xanthura'' is associated with reefs and is found over rocky substrates where it occasionally forms large aggregations. It feeds mainly on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and is found at depths between .

Systematics and etymology

''Paracaesio xanthura'' was first formally described in 1869 as ''Caseio xanthurus'' by the

Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...

herpetologist Herpetology (from Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and rept ...

and

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

Pieter Bleeker with the type locality given as Nosy-Bé off Madagascar. When Bleeker created the

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 ...

Paracaesio ''Paracaesio'' is a genus marine ray-finned fishes, snappers belonging to the family Lutjanidae. They are native to the Indian Ocean and the western Pacific Ocean, with these currently recognized species: * '' Paracaesio brevidentata'' W. T. Whit ...

'' ''C. xanthoura'' was its only species and so was the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

monotypy In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

, subsequently other species were added. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''xanthura'' means "yellow tail", a reference to the yellow caudal peduncle and tail.

Utilisation

''Paracaesio xanthura'' is considered to be a good food fish in some parts of its range and it is mostly taken using handlines and longlines. The catch is sold either fresh or frozen.

References

{{Taxonbar, from=Q2123949 xanthura Fish of the Indian Ocean Marine fish of South Africa Marine fish of Northern Australia Fish described in 1869