''Abralia veranyi'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 ...

in 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 ...

. Common names include the eye-flash squid, Verany's enope squid and the midwater squid. It is found in the Atlantic Ocean and the Mediterranean Sea. It undergoes a daily vertical migration from deep waters to near the surface.

Description

The midwater squid is a small species with a mantle length of about . It has a fin, four pairs of arms and two long tentacles. The tips of the arms bear four rows of suckers and there are three hooks on the club of each tentacle. The male has the fourth arm on the left modified into 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 ...

. This is used to store

spermatophore A spermatophore, from Ancient Greek σπέρμα (''spérma''), meaning "seed", and -φόρος (''-phóros''), meaning "bearing", or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especiall ...

s and transfer them into the mantle of the female during mating. The underside of the squid bears about 550 light-producing organs called

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. These are arranged in transverse rows each consisting of 4 to 6 large ones with many small ones in between. There are two large and three medium-sized photophores below each of the large eyes.Counterillumination
Retrieved 2012-04-25.''Abralia veranyi'' (Ruppell 1844)
The Tree of Life Web Project. Retrieved 2012-04-25.

Distribution

This species was first described from the Mediterranean Sea but is also found across much of the tropical and subtropical Atlantic Ocean. The range extends from

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and the West African coast to the

Bear Seamount The Bear Seamount is a guyot or flat-topped underwater volcano in the Atlantic Ocean. It is the oldest of the New England Seamounts, which was active more than 100 million years ago. It was formed when the North American Plate moved over the New ...

off

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

, the

Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...

, the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

, the

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 northern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. It has been found at depths of in the daytime but only at night. In 1921, a resident of

Funchal Funchal () officially Funchal City (), is the capital, largest city and a Municipality (Portugal), municipality in Portugal's Madeira, Autonomous Region of Madeira, bordered by the Atlantic Ocean. The city has a population of 105,795, making it ...

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 ...

, Senor de Noronha, gave an account of what is believed to be the first recording of the species from the Atlantic Ocean:A note on the occurrence and habits of a luminous squid ''Abralia veranyi'' at Madeira
S. Stillman Berry. Retrieved 2012-04-25.

Biology

The midwater squid remains at great depths where no light penetrates during the day, in order to avoid predators. However, it must rise to near the surface at night to feed on the small invertebrates that constitute its prey.

Counter-illumination camouflage

The midwater squid has

s on its underside. It is thought that their purpose is to make the squid less visible as a dark silhouette when viewed from below in dim light. 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 ...

produced provides

counter-illumination Counter-illumination is a method of active camouflage seen in marine animals such as firefly squid and midshipman fish, and in military prototypes, producing light to match their backgrounds in both brightness and wavelength. Marine animals of ...

, a form of

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

, which helps to break up the squid's outline.Midwater Squid, ''Abralia veranyi''
Smithsonian National Museum of Natural History. Retrieved 2012-04-25. The squid monitors the temperature of the water as a guide to regulating the emission spectra of the light it needs to emit to closely mimic the scintillating surface of the sea. In cold seas it mimics the blueish colour that sunlight produces at these depths and in warmer water, greener, moonlight colours are produced.

References

{{Taxonbar, from=Q3203106 Abralia Cephalopods described in 1844 Marine molluscs of Europe Cephalopods of Europe