Oegopsida is one of the two

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

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

superorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Decapodiformes Decapodiformes is a superorder of Cephalopoda comprising all cephalopod species with ten limbs, specifically eight short arms and two long tentacles. It is hypothesized that the ancestral coleoid had five identical pairs of limbs, and that one ...

, in the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differentl ...

Cephalopod 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 ...

a. Together with the

Myopsina Myopsida is one of the four orders of squid. It consists of two families: the monotypic '' Australiteuthis'' and the diverse and commercially important Loliginidae (~50 species). Some taxonomists classify this taxon as a suborder of the order ...

, it was formerly considered to be a suborder of the order Teuthida, in which case it was known as Oegopsina. This reclassification is due to Oegopsina and Myopsina not being demonstrated to form a clade. The Oegopsida are an often pelagic squid, with some nerito-oceanic species associated with sea mounts. They consist of 24

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

and 69

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. They have these characters in common: the head is without tentacle pockets, eyes lack a corneal covering, arms and tentacle clubs may have hooks, the buccal supports are without suckers, and oviducts in females are paired. Two families, the

Bathyteuthidae ''Bathyteuthis'' is the singular genus of squid in the family Bathyteuthidae, encompassing three species. ''Bathyteuthis'' species are found scattered throughout the world’s oceans at mesopelagic to bathypelagic depths, commonly between 700 ...

and

Chtenopterygidae ''Chtenopteryx'' is a genus of small, muscular, midwater squid in the monotypic family Chtenopterygidae. Four species are presently recognized in the genus, but more are believed to exist. These squid occupy tropical to subtropical The subt ...

, which have features characteristic of the

Myopsida Myopsida is one of the four orders of squid. It consists of two families: the monotypic ''Australiteuthis'' and the diverse and commercially important Loliginidae (~50 species). Some taxonomists classify this taxon as a suborder of the order Te ...

while retaining others common to the Oegopsina, are sometimes placed in the

Bathyteuthoidea The Bathyteuthoidea are small, mesopelagic to bathypelagic squid that in some ways resemble myopsid squid, such as ''Loligo'' and in others the pelagic oegopsid squid. Its two families, the Bathyteuthidae and Chtenopterygidae, each containing ...

. The Oegopsida differ from the coastal Myopsida, characterised by the genus ''

Loligo ''Loligo'' is a genus of squid and one of the most representative and widely distributed groups of myopsid squid. The genus was first described by Jean Baptiste Lamarck in 1798. However, the name had been used earlier than Lamarck ( Schneider, ...

'', which have corneal coverings over the eyes and tentacle pockets, but lack hooks, have no suckers on the buccal supports, and a single oviduct. Oegopsid squid are the only decapods that lack a pocket for the tentacles. Otherwise, they share different characters with different decapod groups. Like the Bathyteuthoidea and Myopsida, the Oegopsida have a brachial canal, which is absent in other forms. As with the

Spirulidae ''Spirula spirula'' is a species of deep-water squid-like cephalopod mollusk. It is the only extant member of the genus ''Spirula'', the family Spirulidae, and the order Spirulida. Because of the shape of its internal shell, it is commonly kn ...

and

Idiosepiidae Idiosepiidae is a family of mollusc in the class Cephalopoda. This family appears to be related to the cuttlefish in the order Sepiida and the bobtail squid in the order Sepiolida but the exact placement of this family within the Decapodiforme ...

, the Oegopsida lack suckers on the buccal supports, and like the Bathyteuthoidea, Idiosepiidae, and Spirulidae, they have no circular muscle on the suckers. *Order Oegopsida **Family Ancistrocheiridae **Family

Architeuthidae The giant squid (''Architeuthis dux'') is a species of deep-ocean dwelling squid in the family Architeuthidae. It can grow to a tremendous size, offering an example of abyssal gigantism: recent estimates put the maximum size at around Trac ...

**Family

**Family Batoteuthidae **Family

Brachioteuthidae Brachioteuthidae is a family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of ...

**Family

Chiroteuthidae The Chiroteuthidae are a family of deep-sea squid, generally small to medium in size, rather soft and gelatinous, and slow moving. They are found in most temperate and tropical oceans, but are known primarily from the North Atlantic, North Pac ...

**Family

**Family Cranchiidae **Family

Cycloteuthidae The Cycloteuthidae are a family in the order Oegopsida, comprising two genera. While physically dissimilar, molecular evidence supports the relatedness of the genera. The family is found primarily in mesopelagic tropical to subtropical waters. ...

**Family

Enoploteuthidae The Enoploteuthidea are a family of squid comprising approximately 40 species in four genera. Most species have a mantle length ranging from 3–13 cm. Hooks are present on all arms and tentacles. The family is best known for the large arr ...

**Family

Gonatidae The Gonatidae, also known as armhook squid, are a family of moderately sized squid. The family contains about 19 species in three genera, widely distributed and plentiful in cold boreal waters of the Pacific Ocean. At least one species is known f ...

**Family

Histioteuthidae Histioteuthidae is a family of Oegopsid squid. The family was previously considered to be monotypic but the World Register of Marine Species assigns two genera to this family. The species classified under Histioteuthidae are mostly weakly musc ...

**Family

Joubiniteuthidae ''Joubiniteuthis portieri'', also known as Joubin's squid from the monotypic family Joubiniteuthidae and genus ''Joubiniteuthis''. It is a rare, small squid which occurs in the mesopelagic to bathypelagic zones and which has a worldwide distrib ...

**Family

Lepidoteuthidae ''Lepidoteuthis grimaldii'', also known as the Grimaldi scaled squid, is a large squid growing to 1 m in mantle length. It is named after the Grimaldi family, reigning house of Monaco. Prince Albert I of Monaco was an amateur teuthologist ...

**Family

Lycoteuthidae The Lycoteuthidae are a family of squid comprising four known genera in two subfamilies. They are small muscular squid characterised by a lack of hooks and by photophores present on the viscera, eyeballs and tentacles. They inhabit tropical an ...

**Family

Magnapinnidae Bigfin squids are a group of rarely seen cephalopods with a distinctive morphology. They are placed in the genus ''Magnapinna'' and family Magnapinnidae. Although the family is known only from larval, paralarval, and juvenile specimens, some a ...

**Family

Mastigoteuthidae The Mastigoteuthidae, also known as whip-lash squid, are a family of small deep-sea squid. Approximately 20 known species in six genera are represented, with members found in both the mesopelagic and bathypelagic zone of most oceans. Originally d ...

**Family

Neoteuthidae The Neoteuthidae are a family (biology), family of squid comprising four monotypic genus, genera. They are thought to be the closest relatives to the famous giant squid (''Architeuthis dux''). Species * ''Alluroteuthis'' ** ''Alluroteuthis antar ...

**Family

Octopoteuthidae The Octopoteuthidae are a family of squid comprising two genera. The family is characterized by tentacles which cease to grow after the paralarval stage, and the use of a penis, instead of a hectocotylus A hectocotylus (plural: ''hectocotyli' ...

**Family

Ommastrephidae Ommastrephidae is a family of squid containing three subfamilies, 11 genera, and over 20 species. They are widely distributed globally and are extensively fished for food. One species, '' Todarodes pacificus'', comprises around half of the world ...

**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 ...

**Family

Pholidoteuthidae ''Pholidoteuthis'' is a genus of squid in the monotypic family Pholidoteuthidae, comprising at least two species. The defunct genus ''Tetronychoteuthis'' was previously incorporated into Pholidoteuthidae based upon a singular taxon known as ''Te ...

**Family Promachoteuthidae **Family Psychroteuthidae **Family Pyroteuthidae **Family Thysanoteuthidae **'' Parateuthis tunicata'' (''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'') These families group into a number of different

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s but these have not yet been formally given names. These groupings are: *Architeuthids **Architeuthidae **Neoteuthidae *Brachioteuthids **Brachioteuthidae *Chiroteuthids **Batoteuthidae **Chiroteuthidae **Joubiniteuthidae **Magnapinnidae **Mastigoteuthidae **Promachoteuthidae *Cranchiids **Cranchiidae *Cycloteuthids **Cycloteuthidae *Enoploteuthids **Ancistrocheiridae **Enoploteuthidae **Lycoteuthidae **Pyroteuthidae *Gonatids **Gonatidae *Histioteuthids **Histioteuthidae **Psychroteuthidae *Lepidoteuthida **Lepidoteuthidae **Octopoteuthidae **Pholidoteuthidae *Ommastrephids **Ommastrephidae *Onychoteuthids **Onychoteuthidae *Thysanoteuthids **Thysanoteuthidae

References

External links

* Squid {{Squid-stub