''Cryodraco antarcticus'', the long-fingered icefish, is a

demersal 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 ...

species 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 ...

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 ...

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. It occurs only in deep waters of 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

''Cryodraco antarcticus'' was first formally described in 1900 by the Belgian

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Louis Dollo Louis Antoine Marie Joseph Dollo (Lille, 7 December 1857 – Brussels, 19 April 1931) was a Belgian palaeontologist, known for his work on dinosaurs. He also posited that evolution is not reversible, known as Dollo's law. Together with the Austrian ...

with the type locality given as 71°22'S, 88°38'W, or 71°18'S, 88°02'W. It is 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 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 ...

''Cryodraco'', which is known as ''Pagetodes'' by some authorities.

Description

''Cryodraco antarcticus'' is pale greyish-brown with 5-6 dark cross-bars on its body and dusky-tipped

pelvic fins 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 ...

. It is distinguished by the elongate shape of its pelvic fins, which are blackish in the

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

juveniles. This species can grow up to .

Distribution and habitat

''Cryodraco antarcticus'' is found near the

South Orkney Islands The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

, the Weddell, Bellinghausen,

Ross Ross or ROSS may refer to: People * Clan Ross, a Highland Scottish clan * Ross (name), including a list of people with the surname or given name Ross, as well as the meaning * Earl of Ross, a peerage of Scotland Places * RoSS, the Republic of Sou ...

and

Davis Davis may refer to: Places Antarctica * Mount Davis (Antarctica) * Davis Island (Palmer Archipelago) * Davis Valley, Queen Elizabeth Land Canada * Davis, Saskatchewan, an unincorporated community * Davis Strait, between Nunavut and Gre ...

seas at depths of 90 to 600 m (295 to 1970 ft).

Biology

''Cryodraco antarcticus'' feeds on

fishes Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

and

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 Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...

(studies from 1982 to 1984 revealed mostly fishes and

Antarctic krill Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 ind ...

). The

larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

have a long late winter

phase. It is closely related to the blackfin icefish (''Chaenocephalus aceratus'') but differs in a number of

meristic Meristics is an area of ichthyology and herpetology which relates to counting quantitative features of fish and Reptile, reptiles, such as the number of fins or scales. A meristic (countable trait) can be used to describe a particular species of fi ...

characteristics. They are similar in size, colouration and body shape, as well as sharing a many biological characters, including breeding behaviour, and diet. They seem to occupy very similar niches in the ecosystem of the southern

Scotia Arc The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea. The northern border, the North Scotia Ridge, comprises (from west to east) Isla de los Estados at the tip of Tierra del Fuego, the Burdwood, Davis, ...

. ''C. antarcticus'' is, however, less numerous than the blackfin icefish and does not share its habitats. ''C. antarcticus'' appears to replace its relative in deeper areas and higher Antarctic waters.

Fisheries

''Cryodraco antarcticus'' is of minor importance to

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

References

{{Taxonbar, from=Q2659751 antarcticus Fish described in 1900 Fish of the Southern Ocean Fauna of Antarctica Taxa named by Louis Dollo