''Enoploteuthis leptura'', the hooked enope squid, is a species of

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 ...

from 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 ...

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

. It is 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 ...

of the

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 ...

Enoploteuthis ''Enoploteuthis'' is a genus of squid in the family Enoploteuthidae, being the type genus. ''Enoploteuthis'' is a genus with a relatively high number of species, most of which were described in the late 20th and early 21st century. They have bee ...

'', which is in turn the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

of the Enoploteuthidae.

Description

''Enoploteuthis leptura'' have hooks on their

arm In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between ...

s, less on arms I-III than on arms IV, the males have many tiny papillae covering the oral surfaces of arms I-III. In males right arm IV is

hectocotylised A hectocotylus (: hectocotyli) is one of the cephalopod limb, arms of male cephalopods that is specialized to store and transfer spermatophores to the female. Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male ma ...

and has a flap created by an expansion of the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

protective membrane and there are about six pairs of hooks on the distal third of the arm on the opposite side to the flap. On the dorsal side the protective membrane expands a little to create a series of small flaps on the other side of the arm from the large flap made by the ventral membrane. The

tentacles In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

are long and slender and the

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 ...

is narrow with two rows of hooks on its manus, a ventral series having 6-7 large hooks and a dorsal series with 4-5 smaller hooks. The

dactylus The dactylus is the tip region of the tentacular club of cephalopods and of the leg of some crustaceans (see arthropod leg). In cephalopods, the dactylus is narrow and often characterized by the asymmetrical placement of suckers (i.e., the vent ...

has 10-15 suckers in two series and there is a long, thin carpal cluster. The ventral mantle has six series of complex

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 on the anterior

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, Exoskeleton, shell, germ or Peel (fruit), rind. Etymology The term is derived from ''integumentum'', which is Latin for "a coverin ...

with a seventh series which curves either to the left or right to join with one of the nearby series and so does not extend to the anterior mantle margin. On the ventral, anterior edge of the mantle there is a discontinuous row of photophoresin which the gaps correspond to the spaces between the series of photophores on the mantle. The ventral surface of the head has six series of photophoresin which the outermost series are interrupted by a ventral window in the skin. There are no photophores between these ventral windows and the photophores on the eyelids. They grow to a mantle length of 92mm.

Distribution

''Enoploteuthis leptura'' has been recorded from the

Gulf of Guinea The Gulf of Guinea (French language, French: ''Golfe de Guinée''; Spanish language, Spanish: ''Golfo de Guinea''; Portuguese language, Portuguese: ''Golfo da Guiné'') is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez i ...

, the eastern and western central Atlantic Ocean from

Bermuda Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest. Bermuda is an ...

and

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

in the north to Brazil and southwestern Africa in the south. The

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

species ''

Enoploteuthis magnoceani ''Enoploteuthis magnoceani'' is a subspeciesof ''Enoploteuthis leptura'' from the Family (biology), family Enoploteuthidae. Some authorities consider ''Enoploteuthis magnoceani'' as being its own species, and has been observed in the Indo-Pacific ...

'' is considered by some authorities to be a subspecies of ''E. leptura''.

Habitat and Biology

''Enoploteuthis leptura''is a

mesopelagic The mesopelagic zone (Greek language, Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light ...

squid which occurs in the warmer water areas of the Atlantic. Increment analysis of statolith growth of specimens collected from the Gulf of Guinea showed that it has a short life span of approximately 6 months with individuals attaining sexual maturity in 45–60 days in males and 80–90 days in females. The maximum age is 153 days for mature males and they had grown to 72mm mantle length with females living to 143 days and attaining a mantle length of 92mm. Spawning occurs throughout much of the year up to September in the Gulf of Guinea with two peaks occurring in January and June–July. This species is a vertical diel migrant, i.e. they spend the day at depths and move upwards towards the water surface at night to feed.

References

{{Authority control Enoploteuthidae Cephalopods described in 1817