Whip-lash squid | |
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Mastigoteuthis flammea | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Cephalopoda |
Order: | Oegopsida |
Superfamily: | Chiroteuthoidea |
Family: | Mastigoteuthidae Verrill, 1881 [1] |
Genera | |
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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 described by Verill in 1881, it was later lowered by Chun (1920) to a subfamily (Mastigoteuthinae) of the Chiroteuthidae. However, Roper et al. (1969) raised it back to the family level, and this has not been changed since. The taxonomy of this family is extremely unstable, and there have been at times one genus, [2] two genera and four subgenera(Salcedo-Vargas & Okutani, 1994), two genera and several 'groups' (Salcedo-Vargas, 1997), five genera [3] and one species with an uncertain placement, or six genera. [4]
Mastigoteuthids range in size from quite small species in the genus Mastigoteuthis , to relatively gigantic sizes in the genus Idioteuthis . However most are rather small, from 3–15 centimetres total mantle length. Their most distinctive features are their extremely elongate tentacles —which retract into membranous lateral sheaths of the fourth (and largest) arms —and their very large ovate fins, which may occupy up to 80% of the mantle length in some species. It is from these 'whip-like' tentacles that their common name derives. Unlike most other squid, the club of the mastigoteuthid tentacle is not significantly (usually not at all) broader than the rest of the tentacle and is covered in very small suckers—in some species, invisible to the naked eye—which impart an extremely sticky property to the clubs, themselves answering for 70% or more of the tentacle's length in some species.
Many species also possess photophores (bioluminescent organs) which may be located on either the skin, the surface of the eyeball, or the eyelid. These photophores have a "lens" of chromatophores, pigment cells which may allow the squid to modify the colour of the light produced by the photophores. The mantle of some species is adorned with conical or hemispherical tubercles. Most species have arm suckers that possess sharp or blunt conical teeth, which are either larger or present only on the distal side, however some species, such as Mastigoteuthis inermis , have smooth sucker rings with no teeth at all (however, the validity of this species is uncertain at the present time). Coloration is typically a rich reddish brown or dark purple.
Species in the genus Echinoteuthis and Idioteuthis are known to have expanded tentacular clubs as paralarvae (for both species) or adults (Idioteuthis).
Members of this family have scarcely been observed in life, but at least two species ( Mastigopsis hjorti and Magnoteuthis magna ) are known to hover above the ocean bottom in a vertical orientation, the head pointing downward. The squid use their large fins to maintain this orientation and use both their extended tentacles like fly paper, held rigidly at a constant distance apart: this has been termed the "tuning fork" position. Prey items apparently consist primarily of benthic crustaceans.
Although mastigoteuthids possess ink sacs (which could suggest forays into shallower, lit waters), all observations have been over the bottom in deep water. Deep-sea squids commonly possess ink. The squid seem to lack the ability of rapid jet propulsion and instead rely on their large fins.
This family is taxonomically little understood, but there have many recent advances in its systematics. With many species represented by single, damaged, and juvenile specimens, this group is still creating controversy in the taxonomic community. Salcedo-Vargas and Okutani (1994) reclassified the family and eliminated the genus Echinoteuthis, added two subgenera, and reduced the number of species to eight. Three years later, after the careful examination of skin tubercles and photophores, Salcedo-Vargas eliminated his subgenera, and increased the number of species to 17 (Salcedo-Vargas, 1997).
According to the World Register of Marine Species the classification of the Mastigoteuthidae is: [1]
The taxa listed above with an asterisk (*) are taxon inquirendum and needs further study to determine if it is a valid taxon or a synonym.
The validity of several species remains to be reviewed, and the placement of the species Mastigotragus pyrodes in a separate genus should be assessed with genetics.
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 Pacific, and Indo-Pacific. The family is represented by approximately 12 species and four subspecies in four genera, two of which are monotypic. They are sometimes known collectively as whip-lash squid, but this common name is also applied to the Mastigoteuthidae, which are sometimes treated as a subfamily (Mastigoteuthinae) of Chiroteuthidae.
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, comprised around half of the world's cephalopod catch annually.
Oegopsida is one of the two orders of squid in the superorder Decapodiformes, in the class Cephalopoda. Together with the Myopsina, 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.
Taoniinae is a subfamily containing ten genera of glass squids.
Taningia danae, the Dana octopus squid, is a species of squid in the family Octopoteuthidae. It is one of the largest known squid species, reaching a mantle length of 1.7 m (5.6 ft) and total length of 2.3 m (7.5 ft). The largest known specimen, a mature female, weighed 161.4 kg (356 lb).
Magnapinna talismani is a species of bigfin squid known only from a single damaged specimen. It is characterised by small white nodules present on the ventral surface of its fins.
Idioteuthis cordiformis is a species of whip-lash squid found in tropical regions of the west Pacific Ocean. The species is commonly known as the 'love-heart squid' because the species name cordiformis is Latin for 'heart shaped'. Recently, this species has been found to consume small birdbeak dogfish.
Idioteuthis latipinna is a species of whip-lash squid. It is the type species of the genus Idioteuthis. Richard E. Young and Michael Vecchione consider I. latipinna to be a junior synonym of I. cordiformis and the World Register of Marine Species states that it is a taxon inquirendum.
Idioteuthis okutanii is a species of whip-lash squid. Richard E. Young and Michael Vecchione consider I. okutanii to be a junior synonym of I. hjorti.
Idioteuthis is a genus of whip-lash squid containing at least one species. Some teuthologists consider it synonymous with Mastigoteuthis, but genetics have confirmed the placement of this genus as distinct from all other genera in this family. The placement of Idioteuthis within the Mastigoteuthidae remains uncertain.
Mastigoteuthis is a genus of whip-lash squid containing at least seven valid species. Some teuthologists consider Idioteuthis synonymous with this taxon.
Echinoteuthis is a genus of whip-lash squid containing approximately three to five species. Some teuthologists consider Idioteuthis synonymous with this taxon.
Magnoteuthis is a genus of whip-lash squid containing at least three species. Some teuthologists consider Idioteuthis or Mastigoteuthis synonymous with this taxon, but it is genetically and morphologically distinct.
Mastigopsis is a genus of whip-lash squid containing one single species, Mastigopsis hjorti. Some teuthologists consider Idioteuthis synonymous with this taxon; however, genetic results indicate that this genus is not closely related with Idioteuthis but actually closer to Magnoteuthis.
Echinoteuthis atlantica is a species of whip-lash squid from the family Mastigoteuthidae. It occurs in the eastern North and South Atlantic Ocean. This squid is red in colour and similar to Echinoteuthis famelica of the Pacific but differs in having a well developed protective membrane on the tentacular club which is absent on E. famelica. The presence on this membrane on Echinoteuthis glaukopis from the Indian Ocean suggests that this may be a synonym of E. atlantica, in which case glaukopis has priority.
Mastigoteuthis psychrophila is a species of whip-lash squid. It was first described by Kir Nazimovich Nesis in 1977, based on four individuals found in Antarctic waters. The largest was 143 mm long. The squid's tentacles are 15 mm in diameter, with 0.15 mm diameter club suckers. Integumental photophores are present upon the head, arms and fins. Although uncertain, it is believed to have more than two series of photophores on the arms, differing from other species in the M. agassizii group. However, this species, like the rest of the family, is badly in need of revision.
Magnoteuthis microlucens is a species of squid; the most common species of Mastigoteuthis around the main Hawaiian Islands.
Teuthowenia megalops, sometimes known as the Atlantic cranch squid, is a species of glass squid from the subarctic and temperate waters of the northern Atlantic Ocean. They are moderately sized squid with a maximum mantle length of 40 cm (16 in). Their very large eyes are the source for the specific name megalops. Like other members of the genus Teuthowenia, they are easily recognizable by the presence of three bioluminescent organs (photophores) on their eyeballs.
Mastigotragus is a genus of whip-lash squid containing a single species, Mastigotragus pyrodes. This species was originally placed within Mastigoteuthis, but has been subsequently separated from other species in that genus due to multiple morphological characters. This genus is characterized by a lack of antitragus in the funnel-locking cartilage, larger sucker rings on the tentacles, a particular photophore morphology, and relatively large eyelid photophore. This genus is Latin for 'whip-lash goat'.
Chiroteuthoidea is a superfamily of squid in the order Oegopsida. They are the sister group to the Pholidoteuthoidea.