''Pagetopsis'' 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 ...

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 ...

Channichthyidae The crocodile icefish or white-blooded fish comprise a family (Channichthyidae) of notothenioid fish found in the Southern Ocean around Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populatio ...

, the

crocodile icefish The crocodile icefish or white-blooded fish comprise a family (Channichthyidae) of notothenioid fish found in the Southern Ocean around Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populatio ...

es. The species in this genus are found 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

''Pagetopsis'' was described as a genus in 1913 by the

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

ichthyologist

Charles Tate Regan Charles Tate Regan FRS (1 February 1878 – 12 January 1943) was a British ichthyologist, working mainly around the beginning of the 20th century. He did extensive work on fish classification schemes. Born in Sherborne, Dorset, he was educat ...

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 which had ''Champsocephalus macropterus'', which had been described by the Belgian-born British ichthyologist George Albert Boulenger in 1907, as its only species. The genus name is a combination of ''opsis'' with '' Pagetodes'', the name given by John Richardson in 1843 to an icefish frozen on the bow of HMS Terror which had been eaten by a cat before it could be preserved, Regan said that ''Pagetodes'' could not be used until that fish was rediscovered.

Species

There are currently two recognized species in this genus: * '' Pagetopsis macropterus'' (Boulenger, 1907) * '' Pagetopsis maculata'' Barsukov & Permitin, 1958

Characteristics

''Pagetopsis'' has a forward curving spine on the snout and a slightly protruding lower jaw. There are radiating ridge on the operculum ending in 3 or 4 spiny points, the other opercular bones lack spiny points. There are two lateral lines, neither having any bony plates, although the middle lateral line is restricted to 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 see ...

. The pelvic fin is fan shaped with a well developed membrane while the first

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 c ...

is large and tall and is contiguous with the second dorsal fin. The largest species is ''P. macropterus'' which attains a maximum total length of while the maximum total length of ''P. maculata'' is .

Distribution and habitat

''Pagetopsis'' Icefishes have a circumAntarctic distribution which extends as far north as the

South Shetland Islands The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 1 ...

and the South Orkney Islands. They are deep water demersal fishes which are at depths down to .

References

{{Taxonbar, from=Q2051203 Channichthyidae Taxa named by Charles Tate Regan