''Nototheniops'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 ...

es 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 ...

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. The species in this genus are native to 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 ...

Taxonomy

''Nototheniops'' Was first formally described as a

subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...

of the genus ''

Lepidonotothen The grey rockcod (''Lepidonotothen squamifrons''), also known as the grey notothen, stripe-eyes notothen or stripe-eyed rockcod, is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is n ...

'' in 1976 by the

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

ichthyologist 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, 35,800 species of fish had been described as of March 2 ...

Arkady Vladimirovich Balushkin Arkady () is a Slavic masculine given name, ultimately derived from the Greek language, Greek name Αρκάδιος, meaning “from Arcadia (region), Arcadia”. Endeared versions of the name are ''Arkasha''. The Latin equivalent is Arcadius (disa ...

. The genus has been considered to be

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 ...

by some authorities with ''N. larseni'' as the only species. Some authorities place this genus in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Nototheniinae, but the 5th edition of ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'' does not include subfamilies in the Nototheniidae. The specific name is a compound of ''

Notothenia ''Notothenia'' is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes with the species in this genus often having the common name of rockcod. They are native to the Southern Ocean and other w ...

'', which this genus is closely related to and ''ops'' meaning "eyes" referring to its larger eyes.

Species

The recognized species in this genus are: * '' Nototheniops larseni'' ( Lönnberg, 1905) * '' Nototheniops loesha'' (Balushkin 1976) * '' Nototheniops nybelini'' ( Balushkin, 1976) * '' Nototheniops tchizh'' (Balushkin, 1976)

Characteristics

''Nototheniops'' differs from the closely related ''Lepidonotothen'' and ''

Lindbergichthys ''Lindbergichthys'' is a genus of marine ray-finned fishes belonging to the family Nototheniidae, the notothens or cod icefishes. Froese, R. and D. Pauly. Editors. (2021). FishBase. Lindbergichthys Balushkin, 1979. Accessed through: World Registe ...

'' by having the area to front of the eye. the preorbital, and the snout scaled with unscaled eyes. There is a single

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

, the upper one, which consists of tubed scales. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s are roughly equal in length or longer than the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s. The first and second spines of 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 ...

are roughly equal in height but are taller than the third spine. The last spine of the first dorsal fin is connected to the first ray of the second dorsal fin by a membrane. There are 14-15 branch fin rays in the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. The front of the jaws have a band of small, sharp, conical teeth which reduces to a single series towards the rear of the jaws becoming uniserial, these back teeth and the outer row of the front teeth are a little bigger than the inner row. The largest recorded

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

in this genus is in ''N. larseni''.

Distribution, habitat and biology

''Nototheniops'' are found in the Southern Ocean off the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martin 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 Antarctica. ...

and in the subantarctic islands and seamounts, especially in the Atlantic and Indian sectors. They are found at depths between . The larvae and juveniles are

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

and it is thought they may have a long pelagic phase which helps dispersal, settling to a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

lifestyle as adults. They feed on

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

such as

krill Krill ''(Euphausiids)'' (: krill) are small and exclusively marine crustaceans of the order (biology), order Euphausiacea, found in all of the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small ...

, hyperiid amphipods and

mysid Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in thi ...

s, juveniles feeding on

copepods Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (living in the water column), some are benthic (living on the sediments), several species have ...

References

{{Taxonbar, from=Q675148 Nototheniidae Taxa named by Arkady Vladimirovich Balushkin