''Onychoteuthis'' is a genus of

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

in the family

Onychoteuthidae The hooked squid, family Onychoteuthidae, currently comprise about 20–25 species (several known from only single life stages and thus unconfirmed), in six or seven genera. They range in mature mantle length from 7 cm to a suggested length ...

. The type species is '' Onychoteuthis bergii''. While the genus is found worldwide in tropical and

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

oceans, they can also occur in the North Pacific Ocean. 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 belonging to the genus have a

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

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 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 clubs have 2 central series of 19-27 large, strong hooks on their manus and the adults either have no lateral sucker series no marginal series of suckers. or they are vestigial. The

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

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 photophores 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 ''Onychoteuthis'' is a genus of squid in the family Onychoteuthidae. The type species is ''Onychoteuthis bergii''. While the genus is found worldwide in tropical and subtropical oceans, they can also occur in the North Pacific Ocean. There were p ...

'' Gabb, 1868 *'' Onychoteuthis banksii'' ( 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 * , Japa ...

, 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 are strawberries, raspb ...

, 1913) *''

Onychoteuthis horstkottei ''Onychoteuthis'' is a genus of squid in the family Onychoteuthidae. The type species is ''Onychoteuthis bergii''. While the genus is found worldwide in tropical and subtropical oceans, they can also occur in the North Pacific Ocean. There were p ...

'' Bolstad, 2010 *'' Onychoteuthis lacrima'' Bolstad & Seki, 2008 *'' Onychoteuthis meridiopacifica'' Rancurel & Okutani, 1990 *'' Onychoteuthis mollis'' ( Appellöf, 1891) *'' Onychoteuthis prolata'' Bolstad, Vecchione & Young, 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 Squid Cephalopod genera Bioluminescent molluscs