''Lampadioteuthis megaleia'' is a small, colorful

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 ...

, the only species in the only genus in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

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 ...

Lampadioteuthidae. It is sometimes known as the wonderful firefly squid. It was formerly classified in the

Lycoteuthidae The Lycoteuthidae are a family of squid comprising three known genera. They are small muscular squid, characterised by a lack of hooks and by photophores present on the viscera, eyeballs and tentacles. They inhabit tropical and subtropical seas w ...

, but differs from them mainly by having a

hectocotylus A hectocotylus (: hectocotyli) is one of the 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 may use it merel ...

in the males and by the possession of a rostrum on 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 ...

Description

''Lampadioteuthis megaleia'' is a small squid which grows to a mantle length of 40 mm. In males the right ventral

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 ...

is hectocotylized with an enlarged protective membrane over the mid-arm. It has four ocular

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, arranged as three in a

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 ...

line and one positioned laterally. 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 ...

have five photophores which are set on a stalk. There are circular anal photophores on either side of the

rectum The rectum (: rectums or recta) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. Before expulsion through the anus or cloaca, the rectum stores the feces temporarily. The adult ...

, single elongated branchial photophores lie at the base of each gill, there are no abdominal photophores and a single photophore is situated to the rear of the abdomen between the inner surface of mantle and the

viscera In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...

. There are a lot of functional

chromatophores Chromatophores are cells that produce color, of which many types are Biological pigment, pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals an ...

which are covered by a violet pigmented external skin. The males have a penis.

Distribution

''Lampadioteuthis megaleia'' occurs in the subtropical North Atlantic Ocean in the

Gulf Stream The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude (North Carolin ...

and the northern

Sargasso Sea The Sargasso Sea () is a region of the Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it is the only one without land boundaries. It is distinguished from other parts of the Atlantic Oc ...

and in the southwestern Pacific Ocean. Its type locality is the

Kermadec Islands The Kermadec Islands ( ; ) are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are in total area and uninhabit ...

, in the South Pacific Ocean, In the eastern North Atlantic it has been reported from between the

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

and Spain south to 25°N while in the western North Atlantic it has been recorded at 40°N.

Habitat and biology

''Lampadioteuthis megaleia'' is found in the upper

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 ...

epipelagic The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

zones. Little is known about its life history but the violet pigmentation in the skin lying over its photophores is assumed to act as a colour filter which enables the

bioluminescence Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorgani ...

to be a closer match to the colour of the sun or moonlight downwelling from the surface. The photophores of species of squid in the genus ''

Lycoteuthis ''Lycoteuthis'' is a genus containing two species of squid: '' Lycoteuthis springeri'' and '' Lycoteuthis lorigera''. They are small animals which grow up to in length. These squid live in the deep sea at depths of up to 3000 metres, making ho ...

'' have a very similar type of detached filter. Small, less than 8mm in mantle length, subadults have been found which are very similar to adults, except that some of the body proportions differ, the size of the photophores and only having the large photophore at the base of each tentacle. The

paralarva Coleoidea or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea ...

are

planktonic Plankton are the diverse collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they pro ...

References

{{Taxonbar, from=Q3201562 Enoploteuthoidea Cephalopods described in 1916 Monotypic cephalopod genera Bioluminescent molluscs