''Macrourus'' is a small

benthopelagic The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

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 ...

rattail Grenadiers or rattails are generally large, brown to black gadiform marine fish of the subfamily Macrourinae, the largest subfamily of the family Macrouridae. Found at great depths from the Arctic to Antarctic, members of this subfamily are am ...

s 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 ...

Macrouridae Macrouridae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a singl ...

General features

The species in the genus ''Macrourus'' have large broad heads which are over four times as deep as it is long with a snout which varies from rounded to bluntly pointed, with a substantial modified spiny scale at its tip. They have a strong, suborbital ridge that extends onto

preopercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bon ...

and ends with a sharp point. The eyes have a diameter of around one third of the length of the head. It has small teeth which are set in in moderate to broad bands in the

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

which taper posteriorly and ending well short of the ends of the lips; the mandibular band is either 3 or 4 teeth wide at the

symphysis A symphysis (, pl. symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together ...

, narrowing to 1 row posteriorly and extending to about the end of the lips. They have a serrated spiny

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 ...

ray; 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 ...

usually has 8 or 9 rays. The anus is at 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 ...

, there is no

photophore A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

. Their maximum size is probably around .

Habitat, distribution and biology

The species of ''Macrourus'' are found on the upper- to middle

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

which are restricted to cold temperate and polar waters in both the North and South Atlantic as well as in the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

. They are found at depths from around to greater than . They normally prefer temperatures of between , although one species, the Antarctic roughhead ('' Macrourus whitsoni''), has been collected at temperatures which were slightly below .

Fisheries

''Macrourus'' species are important food fishes in the North Atlantic and off the Patagonian coast of Argentina. They are normally considered as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

in the north eastern Atlantic but they are landed and the weight of catches landed between 1990 and 2015 varied from almost none to 4,000 tonnes.

Taxonomy and species

There is a controversy about the identification of 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 ...

of this genus; ''Macrourus rupestris'' was named as the type species by

Bloch Bloch is a surname of German origin. Notable people with this surname include: A–F * (1859-1914), French rabbi *Adele Bloch-Bauer (1881-1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter * (born 1972), German motor journal ...

but this name is a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of '' Coryphaenoides rupestris''. In 1917

Jordan Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...

proposed that ''Macrourus berglax'' be designated the type species, but this also lacks clarity as Sundevall was of the view that the fish named as ''berglax'' by Gunnerus was in fact ''C. rupestris'' and that ''M. berglax'' should be named ''M. fabricii''. This is still to be resolved by the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

. There are currently five recognized species in this genus: * ''

Macrourus berglax ''Macrourus berglax'', the roughhead grenadier or onion-eye grenadier, is a species of marine ray-finned fish in the family Macrouridae. It is a deep-water fish found in the Atlantic Ocean. Description The roughhead grenadier can reach a length ...

'' Lacépède, 1801 (Roughhead grenadier) * '' Macrourus caml'' P. J. McMillan, Iwamoto, A. L. Stewart & P. J. Smith, 2012 (Caml Grenadier)McMillan, P., Iwamoto, T., Stewart, A. & Smith, P.J. (2012). "A new species of grenadier, genus ''Macrourus'' (Teleostei, Gadiformes, Macrouridae) from the southern hemisphere and a revision of the genus." ''Zootaxa'' 3165: 1-24. * '' Macrourus carinatus'' ( Günther, 1878) (Ridge scaled rattail) * '' Macrourus holotrachys'' Günther, 1878 (Bigeye grenadier) * '' Macrourus whitsoni'' (

Regan The family name Regan, along with its cognates O'Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ''ri'' ...

, 1913) (Whitson's grenadier)

References

Macrouridae {{Gadiformes-stub