''Pagothenia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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 h ...

es, 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 ...

Nototheniidae : ''In some scientific literature, the term "cod icefish" is used to identify members of this family. This should not be confused with the term "icefish," which refers to the "white-blooded" fishes of the family Channichthyidae. See Icefish (disam ...

, the notothens or cod icefishes. These fishes occur 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 ...

Taxonomy

''Pagothenia'' was formally described as a

monotypic 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 ...

genus in 1936 by the American zoologists

John Treadwell Nichols John Treadwell Nichols (June 11, 1883 – November 10, 1958) was an American ichthyologist and ornithologist. Life and career Nichols was born in Jamaica Plain, Boston, Massachusetts, the son of Mary Blake (Slocum) and John White Treadwell Nic ...

and Francesca Raimonde La Monte with 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 specime ...

being ''P. antarctica'' which Nichols and La Monte were describing as a new species. ''P. antarctica'' was subsequently shown to be a synonym of ''P. brachysoma'' which was described by the German zoologist in 1912. ''P. brachysoma'' is now regarded as a junior synonym of ''Notothenia phocae'' which was described in 1844 by the

naval surgeon A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often in reference to Royal Navy's medical personnel during the Age of Sail. Ancient uses Speciali ...

, Arctic explorer and naturalist John Richardson. Some authorities place this genus in the subfamily Trematominae, but the 5th edition of '' Fishes of the World'' does not include subfamilies in the Nototheniidae. Nichols and La Monte did not explain the etymology of the generic name but it may be a compound of the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

words ''pagos'' which means "frost", being the root of the word pagophilia for someone who thrives or prefers to live in ice, and ''thenia'' which means "coming from" possibly a reference to the occurrence of ''P. antarctica'' under ice, the

types Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allo ...

being captured through a seal hole in crevasse filled with water.

Species

The recognized species in this genus are: * '' Pagothenia borchgrevinki'' ( Boulenger, 1902) (bald notothen) * '' Pagothenia phocae'' ( Richardson, 1844) (stocky rockcod)

Characteristics

''Pagothenia'' have oblong bodies which are compressed towards the tail. They have a moderately sized mouth with the maxilla reaching to just beyond the front of the eye. The jaws are equipped with rows of small, sharp, conical teeth, larger at the front of the mouth and forming a single row at its back. The body is clothed in small, slightly

ctenoid A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as ...

and non ctenoid scales with a largely naked head. The lateral lines are rather vague and may, or may not, have tubed scales. The rounded

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 ...

has 16-17 branched rays. The

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 ...

s are longer than the pelvic fins. The bald notothen reaches a maximum

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

of while the stocky rock off is smaller with a maximum

of .

Distribution, habitat and biology

''Pagothenia'' are found in the Southern Ocean around Antarctica where they are cryopelagic, living on the underside of the sea ice. The juveniles have been found among

krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...

swarms. The adults feed on krill and copepods. They spawn annually and have a long pelagic larval phase.

References

{{Taxonbar, from=Q2391164 Nototheniidae Perciformes genera Fish of the Southern Ocean Taxa named by John Treadwell Nichols Taxa named by Francesca LaMonte