''Cryodraco'' is a genus 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 ...

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

, the

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

es. They 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 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...

. While ''C. antarcticus'' has minor commercial importance, ''C. atkinsoni'' and ''C. pappenheimi'' are of no interest 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 p ...

Taxonomy

''Cryodraco'' was first 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 "unisp ...

genus in 1900 by the Belgian

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Louis Dollo Louis Antoine Marie Joseph Dollo (; 7 December 1857 – 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 Othenio Ab ...

when he was describing ''Cryodraco antarctica''. Although

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

uses the genus name ''Cryodraco'',

Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously up ...

uses ''Pagetodes'' as the genus name and treats ''Cryodraco'' as a

synonym A synonym is a word, morpheme, or phrase that means precisely 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 a ...

, following Sheiko. The name ''Pagetodes'' was applied to a fish which was washed onto the bow of HMS ''Terror'' and frozen in place. The fish was carefully removed from the ice, allowing the ship's surgeon John Robertson to create a rough sketch, but a cat took the fish and ate it before it could be preserved in alcohol. In 1844 John Richardson described the genus ''Pagetodes'' from Robertson’s drawing in volume 2 of ''Ichthyology of the voyage of H. M. S. Erebus & Terror''. The genus name ''Cryodraco'' means "frost dragon". The name ''Pagetodes'' means "icebound" or "frozen".

Species

There are currently three recognized species in this genus: * '' Cryodraco antarcticus'' Dollo, 1900 – long-fingered icefish * '' Cryodraco atkinsoni'' Regan, 1914 * '' Cryodraco pappenheimi'' Regan, 1913 The genus has been treated as monotypic and the status of ''C. atkinsoni'' is arguable but samples of ''Cryodraco'' have clustered into two size ranges each containing both sexes which supports the proposition that there are two species. However, the status of ''C. pappenheimi'' is less clear; the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was deposited in the

Natural History Museum, Berlin The Natural History Museum () is a natural history museum located in Berlin, Germany. It exhibits a vast range of specimens from various segments of natural history and in such domain it is one of three major museums in Germany alongside Natur ...

and has been lost. From descriptions of this taxon it may not even belong in the genus ''Cryodraco''.

Characteristics

''Cryodraco'' icefishes have the spine on the snout reduced to a small knob. There are 3 or 4 spines on the operculum but none on the other operculum bones. There are 3 lateral lines which do not have any bony plates. The pelvic fins are long with the tips covered in thickened skin with the second pelvic fin ray being longer than the others. The first

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 ...

is small and is widely separated from the second dorsal fin. The caudal fin may be truncate or weakly emarginate. The largest species is C. antarcticus which has a maximum standard length of .

Distribution and habitat

''Cryodraco'' icefishes are found around in the Southern Ocean around Antarctica, occurring on the continental shelf as far north as the

South Shetland Islands The South Shetland Islands are a group of List of Antarctic and subantarctic islands, Antarctic islands located in the Drake Passage with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the n ...

and

South Orkney Islands The South Orkney Islands are a group of List of Antarctic and sub-Antarctic islands, islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula 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 ...

fishes.

Biology

''Cryodraco'' icefishes are of little importance to commercial fisheries and have been relatively little studied. They are predatory and analyses of stomach contents have shown they feed on fishes and krill.

References

External links

* {{Taxonbar, from=Q2155421 Channichthyidae Fish of the Southern Ocean Marine fish genera Perciformes genera Taxa named by Louis Dollo