''Patagonotothen brevicauda'', the Patagonian rockcod, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

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. It is native to oceans of the

Patagonian Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...

region, including

Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...

, the

Strait of Magellan The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and Tierra del Fuego to the south. The strait is considered the most important natural pass ...

, the

Beagle Channel Beagle Channel (; Yahgan: ''Onašaga'') is a strait in the Tierra del Fuego Archipelago, on the extreme southern tip of South America between Chile and Argentina. The channel separates the larger main island of Isla Grande de Tierra del Fuego fr ...

and the

Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouzet ...

Taxonomy

Described in 1905 by Swedish naturalist

Einar Lönnberg Axel Johann Einar Lönnberg (24 December 1865 – 21 November 1942) was a Swedish zoologist and conservationist. Lönnberg was born in Stockholm. He was head of the Vertebrate Department of the ''Naturhistoriska Riksmuseet'' (Swedish Natural Hi ...

with the nominate species name ''Patagonotothen brevicauda brevicauda'', the population from the Shag Rocks was described as ''P. brevicauda shagenisis'' by Soviet

ichthyologists Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October ...

A.V. Balushkin and Y.Y. Permetin in 1982. This taxon is regarded as a valid species by both

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.

and

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 ...

, '' Patagonotothen shagensis''.

Description

This species is a relatively small notothen, reaching a maximum length of up to . The depressed body is generally brownish. A series of yellowish-and-dark bands transverse the body. The bases of the

pectoral fins 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 ...

are outlined by dark lines, which are pale, as are the ventral areas. The back and anal parts are dark, with the latter having pale borders. Up to 19

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 ...

spines are present. The interorbital space is more depressed in males. This species is very similar to ''

Patagonotothen guntheri ''Patagonotothen guntheri'', the yellowfin notothen, is a species of notothen found in the Argentinian region of Patagonia, the Falkland Islands, the Burdwood Bank and the Shag Rocks (where it is found in abundance) west of South Georgia on the ...

'' (indeed, it was classified by authors such as H.H. DeWitt and J.-C. Hureau as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of ''P. guntheri''), but differs in several aspects such as

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 se ...

length in relation to head length (max. 35% vs max. 31%),

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

count (22-27 vs 26-39) and pectoral fin ray count (22-25 (mean 24.8) vs 23-26 (mean 23.0)). Between ''P. brevicauda'' and ''P. shagenisis'', the size of the interorbital space (16-20% of head length vs 11-15% of head length), the number of pectoral fin rays (usually 27 vs usually 25), and the number of

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

(51-53 vs 49-51) differentiate the two species.

Ecology

This

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 inhabits shallow, gravelly seabeds of depth range . This species is an

opportunistic Opportunism is the practice of taking advantage of circumstances – with little regard for principles or with what the consequences are for others. Opportunist actions are expedient actions guided primarily by self-interested motives. The term ...

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...

, mainly feeding on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...

, small

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

(such as the

squat lobster Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside ...

species ''

Munida gregaria ''Munida gregaria,'' commonly known as the gregarious squat lobster, is a species of squat lobster found along the eastern seaboard of the South Island of New Zealand, around the southern coast of Tasmania and in a few locations around the sou ...

'') and

copepods Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have p ...

Cephalopods A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...

bryozoans Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...

, mytilids,

hydrozoans Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialize ...

, thaliaceans,

isopods Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

and

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are mad ...

are also consumed to a lesser degree.

Commercial importance

This species 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 ...

, with only landed in 2011. However, this species once was commercially fished in large amounts, with landed in 1981 alone.

References

{{Taxonbar, from=Q11940475 brevicauda Taxa named by Einar Lönnberg Fish described in 1905