The rubyfish (''Plagiogeneion rubiginosum''), also known as the cosmopolitan rubyfish, red ruby or ruby rover, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

, belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Emmelichthyidae Emmelichthyidae is a small Family (biology), family of small to medium-sized Marine (ocean), marine ray-finned fishes known commonly as redbaits, rovers, bonnetmouths or rubyfishes. The Emmelichthyidae are poorly known even among researchers who ...

, the rovers, bonnetmouths and rubyfishes. This species is found from the southeastern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

off

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

through the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

to the southwestern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

around

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. This species is commercially important.

Taxonomy

The rubyfish was first formally described in 1875 as ''Therapon rubiginosus'' by the English-born New Zealand

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

and

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

Frederick Hutton with its type locality given as the coast of

Otago Otago (, ; ) is a regions of New Zealand, region of New Zealand located in the southern half of the South Island and administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local go ...

in New Zealand. In 1890

Henry Ogg Forbes Henry Ogg Forbes (30 January 1851 – 27 October 1932) was a Scottish explorer, ornithologist, and botanist. He also described a new species of spider, '' Thomisus decipiens''. Biography Forbes was the son of Rev Alexander Forbes M.A. (1821� ...

reclassified ''T. rubiginosus'' in a new

monospecific genus 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 "unispe ...

'' Plagiogeneion'' making this species the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

of that genus. ''Plagiogeneion'' is classified withion the family Emmelichthyidae in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Acanthuriformes Acanthuriformes is a large, diverse order of mostly marine ray-finned fishes, part of the Percomorpha clade. In the past, members of this clade were placed in the suborders Acanthuroidea and Percoidea of the order Perciformes, but this treatment ...

Etymology

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 ...

''rubiginosum'' means "rusty" and refers to the overall reddish colour of this fish. As Forbes's generic name ''Plagiogeneion'' is neuter the ending of Hutton's specific name had to be altered to ''-um''.

Description

The rubyfish has a moderately elongated body with a single continuous

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

and a strongly forked

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

, with a highly protrusible mouth. The dorsal fin is supported by 12 or 13 spines and 10 or 11 soft rays while the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 3 spines and 10 soft rays. The body has a depth of between 27% and 34% of the

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

. The head and upper body are red with a silvery lower body and blackish tips to the caudal fin. This species reaches a maximum published

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of .

Distribution and habitat

The rubyfish is found in the southeastern Atlantic over the Vema Seamount to the west of

Cape Town Cape Town is the legislature, legislative capital city, capital of South Africa. It is the country's oldest city and the seat of the Parliament of South Africa. Cape Town is the country's List of municipalities in South Africa, second-largest ...

, and

Walvis Bay Walvis Bay (; ; ) is a city in Namibia and the name of the bay on which it lies. It is the List of cities in Namibia, second largest city in Namibia and the largest coastal city in the country. The city covers an area of of land. The bay is a ...

in Namibia. In the Indian Ocean it is found off

Algoa Bay Algoa Bay is a maritime bay in the Eastern Cape, South Africa. It is located on the east coast, east of the Cape of Good Hope. Algoa Bay is bounded in the west by Cape Recife and in the east by Cape Padrone. The bay is up to deep. The harbour ...

in the

Eastern Cape The Eastern Cape ( ; ) is one of the nine provinces of South Africa. Its capital is Bhisho, and its largest city is Gqeberha (Port Elizabeth). Due to its climate and nineteenth-century towns, it is a common location for tourists. It is also kno ...

, around

Île Saint-Paul is an island forming part of the French Southern and Antarctic Lands (, TAAF) in the Indian Ocean, with an area of . The island is located about south of the larger Île Amsterdam , northeast of the Kerguelen Islands, and southeast of Réuni ...

and

Île Amsterdam (), also known as Amsterdam Island or New Amsterdam (), is an island of the French Southern and Antarctic Lands in the southern Indian Ocean that together with neighbouring Île Saint-Paul to the south forms one of the five districts of the t ...

and east to southern Australia and New Zealand. In Australia its range extends from West of

Bunbury, Western Australia Bunbury () is a coastal city in the Australian state of Western Australia, approximately south of the state capital, Perth. It is the state's third most populous city after Perth and Mandurah, with a population of approximately 75,000. Loca ...

, along the tempareate southern coast to

Cape Byron Cape Byron is the easternmost point of the mainland of Australia, located in New South Wales. It is about east of the town of Byron Bay, New South Wales and projects into the Pacific Ocean at 28.6335° S, 153.6383° E. A lighthouse is situated t ...

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

, including

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

. It is a

bathydemersal Demersal fish, also known as groundfish, live and feed on or near the bottom of ocean, seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 T ...

fish found at depths of from , near sand or mud bottoms, typically in the vicinity of the edge of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

and around

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

s. The juveniles are

epipelagic The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

and as they mature the descend into deeper waters.

Biology

The rubyfish

spawn Spawn or spawning may refer to: * Spawning, the eggs and sperm of aquatic animals Arts, entertainment and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** ''Spawn: Armageddon' ...

s in late spring up to early summer. It is a long lived species which has been estimated to reach 85 years of age. The adults prey on larger

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

caught near the bottom.

Fisheries

Rubyfish is an important species for major fisheries in New Zealand and the South Pacific. In some area, this species is fished for over deep sea seamounts. The catch is sold fresh or as frozen fish and it is reputed to be highly palatable.

References

* Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{Taxonbar, from=Q2449394

Rubyfish The rubyfish (''Plagiogeneion rubiginosum''), also known as the cosmopolitan rubyfish, red ruby or ruby rover, is a species of marine ray-finned fish, belonging to the Family (biology), family Emmelichthyidae, the rovers, bonnetmouths and rubyfish ...

Fish described in 1875 Taxa named by Frederick Hutton (scientist)