''Onychoteuthis'' 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 ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

in the family

Onychoteuthidae The hooked squid, family (biology), family Onychoteuthidae, currently comprise about 20–25 species (several known from only single life stages and thus unconfirmed), in six or seven genus, genera. They range in mature mantle (mollusc), mantle l ...

. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

is '' Onychoteuthis bergii''. While the genus is found worldwide in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

oceans, they can also occur in the

North Pacific Ocean North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' ...

. There were previously considered to be four species in the genus but there are now considered to be roughly 10. These squid are frequently observed in the surface waters at night and they are often caught using dipnet at nightlight stations. The young squid are usually the only specimens captured using standard midwater trawls, the older squid are apparently able to avoid the trawls. They can, however be collected from the air as individuals are able to leap high out of the water, sometimes even landing on the deck of a ship.

Anatomy

Most

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

belonging to the genus have a mantle length of under 200 mm, however the larger members may measure over 300 mm. The species in this genus have a densely muscular, cylindrical mantle which is tapered posteriorly into a pointed tail. Their skin is smooth and has no warts or wrinkles. The

gladius ''Gladius'' () is a Latin word properly referring to the type of sword that was used by Ancient Rome, ancient Roman foot soldiers starting from the 3rd century BC and until the 3rd century AD. Linguistically, within Latin, the word also came t ...

can be seen through the skin along the midline of the back. The fins are rhomboid in shape, heart shape or arrow shaped and are pointed posteriorly. The species of ''Onychoteuthis'' have 8-10 prominent nuchal folds. Their

tentacular club All cephalopods possess flexible limbs extending from their heads and surrounding their cephalopod beak, beaks. These appendages, which function as muscular hydrostats, have been variously termed arms, legs or tentacles. Description In ...

s have 2 central series of 19-27 large, strong hooks on their

manus Manus may refer to: Relating to locations around New Guinea *Manus Island, a Papua New Guinean island in the Admiralty Archipelago ** Manus languages, languages spoken on Manus and islands close by ** Manus Regional Processing Centre, an offshore ...

and the adults either have no lateral sucker series no marginal series of suckers. or they are vestigial. The

chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...

ous rings of the suckers on the

arms Arms or ARMS may refer to: *Arm or arms, the upper limbs of the body Arm, Arms, or ARMS may also refer to: People * Ida A. T. Arms (1856–1931), American missionary-educator, temperance leader Coat of arms or weapons *Armaments or weapons **Fi ...

is smooth, with no teeth. They have

photophore A photophore is a specialized anatomical structure found in a variety of organisms that emits light through the process of boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generated through a mut ...

s in their mantle cavity with a small one placed anteriorly on the

ink sac An ink sac is an anatomical feature that is found in many cephalopod mollusks used to produce the defensive cephalopod ink. With the exception of nocturnal and very deep water cephalopods, all Coleoidea (squid, octopus and cuttlefish) which dwell ...

, another near the anus; a large one placed posteriorly on the intestine and a bilobed photophore located on the ventral surface of each eye.

Species

The following species are included in the genus: *'' Onychoteuthis aequimanus'' Gabb, 1868 *''

Onychoteuthis banksii ''Onychoteuthis banksii'', the common clubhook squid, is a species of squid in the family Onychoteuthidae. It is the type species of the genus '' Onychoteuthis''. This species was thought to have a worldwide distribution but with the revision of ...

'' ( Leach, 1817), common clubhook squid *'' Onychoteuthis bergii'' Lichtenstein, 1818 *'' Onychoteuthis borealijaponica''

Okada Okada (written: 岡田 literally "hill rice-paddy") is a Japanese surname. Notable people with the name include: *, Japanese painter * Doris Okada Matsui, American politician of the Democratic Party *, Japanese painter in the Edo period *, Japanese ...

, 1927, boreal clubhook squid *'' Onychoteuthis compacta'' (

Berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit although many pips or seeds may be present. Common examples of berries in the cul ...

, 1913) *'' Onychoteuthis horstkottei'' Bolstad, 2010 *'' Onychoteuthis lacrima'' Bolstad & Seki, 2008 *''

Onychoteuthis meridiopacifica ''Onychoteuthis meridiopacifica'' is a species of squid in the family Onychoteuthidae. Males become mature at 40 mm, and the species is believed to reach a maximum mantle (mollusc), mantle length of 90 mm, the smallest species in the ge ...

'' Rancurel & Okutani, 1990 *'' Onychoteuthis mollis'' ( Appellöf, 1891) *'' Onychoteuthis prolata'' Bolstad, Vecchione &

Young Young may refer to: * Offspring, the product of reproduction of a new organism produced by one or more parents * Youth, the time of life when one's age is low, often meaning the time between childhood and adulthood Music * The Young, an America ...

, 2008 There are also two species which are considered '' taxa inquirendum'' and up to 11 which are classed as '' nomen dubia''.

References

{{Taxonbar, from=Q3166929 Hooked squid Cephalopod genera Bioluminescent molluscs