Heteroteuthis dispar
Encyclopedia
Heteroteuthis dispar, also known as the odd bobtail, is a small deep water squid found in the North Atlantic Ocean
and the Mediterranean Sea
.
, which is found in the central North Pacific Ocean
. It has not been possible to compare the two species side by side and so it is unclear whether they are identical. DNA sequencing
should eventually clarify this issue.
south to the coastal fringes of West Africa
, across to Bermuda
, the Caribbean Sea
and the eastern fringes of the United States north to Maryland
. The western and eastern Atlantic populations may be isolated.
in the male. Arm 3 has two or three greatly enlarged suckers at the proximal end and a few moderate sized ones at the distal end. Arms 3 and 4 are longer than the others. In the female, arms 1 and 2 have no suckers on the distal ends. The tentacles are retractable, slender and whip-like, with a short club with eight rows of microscopically small suckers.
The funnel is found under the head and the locking apparatus has a deep, curved groove and an angled posterior pit. The mantle
margin is detached from the head, and the neck cartilage is either free or fused. On the underside, the mantle shield is confined to the anterior part of the mantle. The fins are quite short and are attached to the posterior part of the mantle from which they bulge forwards. The mantle length in the adult female is about 25 millimetres.
or sperm package which is transferred to the female before she is sexually mature. She stores it and makes use of it at the optimal time for fertilisation. The spermatophore is large, constituting about 3% of her weight, and therefore disadvantageous to her. This reproductive practice may be due to the fact that finding a mate deep in the ocean at the appropriate time is difficult.
This species is found in the mesopelagic zone of the ocean at depths down to 1600 metres. Spawning takes place on the bottom and the paralarva
e live at even greater depths, down to 3000 metres. Adults often live in groups at depths of 200 to 300 metres, often in areas where shrimp
s are found. Predators
that feed on this squid include dolphin
s (Grampus griseus), the velvet belly lantern shark
(Etmopterus spinax), the blackmouth catshark
(Galeus melastomus), the small-spotted catshark
, (Scyliorhinus canicula), the swordfish
(Xiphias gladius) and tuna
(Thunnus alalunga).
Heteroteuthis dispar can be bioluminescent
, emiting light from photophore
s containing bacterial symbionts
. A large photophore is found on the underside and contains two pores through which the luminescent material is extruded. An iridescent shutter cover helps to filter and control the light. The squid can also secrete bioluminescent mucous from glands near the ink sac
. This can be released into the water through the funnel and the glowing cloud is believed to blind or confuse predators for long enough for the squid to make its escape.
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
.
Taxonomy
Heteroteuthis dispar is a deep sea species of squid and relatively little is known about it because of the difficulty of observing it in situ. Its description is very similar to that of Heteroteuthis hawaiiensisHeteroteuthis hawaiiensis
Heteroteuthis hawaiiensis is a species of bobtail squid native to the central and western Pacific Ocean. It occurs in waters off Hawaii, Bonin, the Ryukyu Islands, Indonesia, and the Great Australian Bight. H. hawaiiensis may also be present in Banc Combe in the southwestern Pacific at depths of...
, which is found in the central North Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. It has not been possible to compare the two species side by side and so it is unclear whether they are identical. DNA sequencing
DNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
should eventually clarify this issue.
Distribution
Heteroteuthis dispar is found in the Mediterranean Sea and across the Atlantic Ocean. The range includes a broad swathe from southwest IrelandIreland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
south to the coastal fringes of West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...
, across to Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
, the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
and the eastern fringes of the United States north to Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
. The western and eastern Atlantic populations may be isolated.
Description
There are five pairs of appendages. Arms 1 and 2 are fused at the base and each is a hectocotylusHectocotylus
A hectocotylus is one of the arms of the male of most kinds of cephalopods that is modified in various ways to effect the fertilization of the female's eggs. It is a specialized, extended muscular hydrostat used to store spermatophores, the male gametophore...
in the male. Arm 3 has two or three greatly enlarged suckers at the proximal end and a few moderate sized ones at the distal end. Arms 3 and 4 are longer than the others. In the female, arms 1 and 2 have no suckers on the distal ends. The tentacles are retractable, slender and whip-like, with a short club with eight rows of microscopically small suckers.
The funnel is found under the head and the locking apparatus has a deep, curved groove and an angled posterior pit. The mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
margin is detached from the head, and the neck cartilage is either free or fused. On the underside, the mantle shield is confined to the anterior part of the mantle. The fins are quite short and are attached to the posterior part of the mantle from which they bulge forwards. The mantle length in the adult female is about 25 millimetres.
Biology
The male Heteroteuthis dispar produces a spermatophoreSpermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
or sperm package which is transferred to the female before she is sexually mature. She stores it and makes use of it at the optimal time for fertilisation. The spermatophore is large, constituting about 3% of her weight, and therefore disadvantageous to her. This reproductive practice may be due to the fact that finding a mate deep in the ocean at the appropriate time is difficult.
This species is found in the mesopelagic zone of the ocean at depths down to 1600 metres. Spawning takes place on the bottom and the paralarva
Paralarva
Paralarvae is the term used to describe the young planktonic stages of cephalopods, between hatchling and subadult. It is used to differentiate it from the term 'larva' used in animals which undergo true metamorphosis. They have been observed only on members of the orders Octopoda and Teuthida.The...
e live at even greater depths, down to 3000 metres. Adults often live in groups at depths of 200 to 300 metres, often in areas where shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
s are found. Predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
that feed on this squid include dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s (Grampus griseus), the velvet belly lantern shark
Velvet belly lantern shark
The velvet belly lantern shark is a species of dogfish shark in the family Etmopteridae. One of the most common deepwater sharks in the northeastern Atlantic Ocean, the velvet belly is found from Iceland and Norway to Gabon and South Africa at a depth of...
(Etmopterus spinax), the blackmouth catshark
Blackmouth catshark
The blackmouth catshark is a species of catshark, family Scyliorhinidae, common in the northeastern Atlantic Ocean from Iceland to Senegal, including the Mediterranean Sea. It is typically found over the continental slope at depths of , on or near muddy bottoms. The youngest sharks generally...
(Galeus melastomus), the small-spotted catshark
Small-spotted catshark
The small-spotted catshark or lesser spotted dogfish, Scyliorhinus canicula, is a cat shark of the family Scyliorhinidae found on the continental shelves and uppermost slopes off Norway and the British Isles south to Senegal, including the Mediterranean between latitudes 63° N and 12° N. Its...
, (Scyliorhinus canicula), the swordfish
Swordfish
Swordfish , also known as broadbill in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood...
(Xiphias gladius) and tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
(Thunnus alalunga).
Heteroteuthis dispar can be bioluminescent
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
, emiting light from photophore
Photophore
A photophore is a light-emitting organ which appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors...
s containing bacterial symbionts
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
. A large photophore is found on the underside and contains two pores through which the luminescent material is extruded. An iridescent shutter cover helps to filter and control the light. The squid can also secrete bioluminescent mucous from glands near the ink sac
Ink sac
With the exception of nocturnal and very deep water cephalopods, all coeloids which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink to confuse predators. This sac is a muscular bag which originated as an extension of the hind gut...
. This can be released into the water through the funnel and the glowing cloud is believed to blind or confuse predators for long enough for the squid to make its escape.