Squid

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Squid is the cephalopod of two commands Myopsida and Oegopsida, previously considered the two subordues of the Teuthida order, but recent research shows Teuthida to be paraphyletic. The two orders currently consist of about 304 species. Like other cephalopods, squid have different heads, bilateral symmetry, mantles, and arms. Squid, like squid, has eight arms arranged in pairs and two, usually longer, tentacles.

Video Squid

Taxonomy

Squid is a member of the Cephalopoda class, the Coleoidea subclass, two commands, Myopsida and Oegopsida (including giant squid like Architeuthis dux ). Valid teuthids are the largest cephalopoda order with about 300 species classified into 29 families.

Orders Myopsida and Oegopsida are classified in superorder Decapodiformes (from Greek for "ten feet"). Two other orders of decapodiform cepalopoda are also called squid, although they are taxonomically different from the squid and are distinctly recognizable in its anatomical features. They are the frilly squid of the Sepiolida order and the ram squid from the Spirulida monotypic order. Vampire squid, however, is more closely related to octopus than squid.

• Cephalopoda Class
  • Subclass Nautiloidea: nautilus
  • Coleoidea subclass: squid, octopus, squid
    • Superorder Octopodiformes
    • Superorder Decapodiformes
      • Ã,? Boletzkyida message
      • Spirulida message: ram ram squid
      • Sepiid message: squid
      • Sepiolian message: tail squid
      • Myopsida messages
        • The Australiteuthidae family
        • The Loliginidae family: beaches, squid, and grass squid
      • Message Oegopsida
        • The Ancistrocheiridae family: sharp squid
        • The Architeuthidae family: the giant squid
        • The Bathyteuthidae deepsea squid
        family
        • The Batoteuthidae family: bush-club squid
        • The Brachioteuthidae Family
        • The Chiroteuthidae family
        • The Chtenopterygidae family: squid combs
        • The Cranchiidae family: glass squid, including colossal squid
        • Family Cycloteuthidae
        • The Enoploteuthidae Family
        • The Gonatidae family: squid armhook
        • Histioteuthidae's family: squid gem
        • The Joubiniteuthidae family: Joubin squid
        • The Lepidoteuthidae family: Grimaldi scaly squid
        • The Lycoteuthidae Family
        • The Magnapinnidae family: big squid
        • The Mastigoteuthidae family: whip squid
        • The Neoteuthidae Family
        • Family Octopoteuthidae
        • The Ommastrephidae family: flying squid
        • The Onychoteuthidae family: the hooked squid
        • The Pholidoteuthidae Family
        • The Promachoteuthidae family
        • Family Psychroteuthidae: glacial squid
        • The Pyroteuthidae family: squid fire
        • The Thysanoteuthidae family: rhomboid squid
        • The Walvisteuthidae Family
          • Parateuthis tunicata ( incertae sedis )
        • Family Plesioteuthididae ( incertae sedis )
Evolution

Squid has been distinguished from their ancestral molluscs so that the body plan has been antero-posterior condensed and extended dorso-ventral. What was previously probably the ancestor's leg was transformed into a complex set of tentacles and highly developed sense organs, including eyes that advanced similarly to vertebrates.

The ancestor's shell has disappeared, with only the internal gladius, or pen, remaining. The pen is a feather-shaped internal structure that supports the squid's mantle and serves as a site for muscle attachment. It is made from materials such as chitin.


Maps Squid





Description

The main body mass is covered in a mantle, which has a swimming fin on each side. These fins, unlike other marine organisms, are not the main source of driving in most species.

The skin is covered in chromatophores, which allow the squid to change color to fit its surroundings, making it practically invisible. The lower part is also almost always lighter from the upper side, to provide camouflage from both prey and predator.

Below the body is an opening to the mantle cavity, which contains the gills (ctenidia) and openings to the excretory and reproductive systems. In front of the mantle cavity lies the siphon, which the squid use to move through the right jet propulsion. In the form of this movement, water is sucked into the mantle cavity and removed from the siphon with a fast and powerful jet. Siphon direction can be changed, to fit the direction of the trip.

Inside the cavity of the coat, outside the siphon, lies the visceral mass, which is covered by a thin membrane epidermis. Below are all major internal organs.

Squid is a strong swimmer and certain species can "fly" for short distances out of the water.

Nervous system

Giant axons, which may be diameter up to 1 mm (0.04 inches) in some larger species, conserve the mantle and control part of the jet propulsion system.

Like squid, squid exhibit a relatively high intelligence among invertebrates. For example, the Humboldt squid group hunts cooperatively, using active communication. (See Cephalopod intelligence.)

Reproductive System

In women, the ink sac is hidden from view by a pair of white nidamental glands, which lie anteriorly to the gills. Also, the nidamental accessory glands of red spots are present. Both organs are linked to the manufacture of nutrients and egg shells. Women also have a large translucent ovary, located toward the posterior mass of the visceral.

Males do not have these organs, but instead have large testes in the ovaries, and spermatophoric glands and sacs. In adult males, these sacs may contain spermatophores, which are placed inside a woman's mantle during mating.

Shallow water species from continental plates and epipelagic/mesopelagic zones are characterized by the presence of hectocotyli, a specially modified arm used to fertilize female eggs. The deepest sea squid lacks hectocotyli and has a longer penis; Ancistrocheiridae and Cranchiinae are exceptions. Giant squid of the genus Architeuthis is unusual because they have large penis and modified end of arm, though whether the latter is used for spermatophore transfer is uncertain. Elongation penis has been observed in deep water species Onykia ingens ; when erect, the penis may be as long as the mantle, head, and arm are combined. Thus, sea squid has the best known penis length compared to the size of the body of all moving animals, secondly throughout the animal kingdom only for certain sessile barnacles.

Digestive System

Like all squid, squid has a complicated digestive system. The abdominal muscle is found approximately at the midpoint of the visceral mass. From there, the bolus moves into the caecum for digestion. The serum, a long white organ, is found next to the ovary or testes. In adult squid, more priority is given to reproduction such as stomach and cecum often wrinkled during the next stage of life. Finally, food into the liver (or digestive glands), is found at the end of the siphon, for absorption. Solid waste is removed from the rectum. Beside the rectum is an ink sac, which allows the squid to quickly remove black ink into the mantle cavity.

Cardiovascular system

Squid has three hearts. Two branchial hearts feed the gills, each encircling the larger systemic heart that pumps blood throughout the body. Squid blood contains a copper-rich protein hemocyanin to transport oxygen. A slightly greenish heart is surrounded by a kidney sac - the main excretory system. The kidneys are difficult to identify and stretch from the heart (located on the posterior side of the ink sac) to the liver. The systemic heart consists of three chambers, the lower ventricle, and the upper two auricles.

Head

An eight-armed bear head and two tentacles, each muscular hydrostatic shape containing many suckers along the edges. This tentacle does not grow back if it is cut off. In adult males, one and a half basal left ventricular tentacles are fragmented - and end up with joint solids rather than suckers. It is used for sexual intercourse.

Its mouth is equipped with sharp and sharp beaks that are mostly made of chitin and crosslinking proteins, and are used to kill and tear the prey into manageable parts. Its beak is very strong, but it contains no minerals, unlike teeth and jaws of many other organisms, including marine species. The captured whales often have unbearable squid beaks in their stomachs. The mouth contains a radula (common rough tongue for all molluscs except bivalves).

Eyes, on either side of the head, each containing a hard lens. The image is focused by changing the position of the lens, as in the camera or telescope, rather than changing the shape of the lens, as in the human eye.

Calamari seems to have limited hearing.

Size

The majority is not more than 60 centimeters (24 inches) in length, although the giant squid can reach 13 m (43 ft).

In 1978, the sharp and curved claws on the squid cup of squid tentacles cut the rubber layer on the stomach of the USS Stein . Its size suggested the largest squid known at the time.

In 2003, large specimens of many but poorly understood species, Mesonychoteuthis hamiltoni (giant squid), were discovered. This species can grow up to 14 m (46 ft) in length, making it the largest invertebrate. Squid has the largest eyes in the animal world. The Kraken is a legendary tentacle monster that may be based on the appearance of a real giant squid.

In February 2007, the New Zealand fishing vessel caught a large squid weighing 495 kg (1,091 lb) and measuring about 10 m (33 ft) off the coast of Antarctica. This specimen is the largest cephalopod ever documented scientifically.



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Commercial fishing

According to FAO, catches of cephalopods for 2002 were 3,173,272 tons (6,995867 ÃÆ' - 10 ⁹ Ã, lb). Of this number, 2,189,206 tons, or 75.8 percent, are squid. The following table lists the catch of squid fish that exceeded 10,000 tonnes (22,000,000 lb) in 2002.



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As food

Many species are popular as food in diverse cuisines such as America, Basque, Canada, China, Egypt, England, Philippines, Greece, Italy, Japan, Korea, Portugal, Spain, Tunisia, Turkey, and Vietnam.

In English-speaking countries, squid as a food is often marketed using the Italian word squid . Cuttlefish are found abundantly in certain areas, and provide large catches for fisheries. The body can be filled intact, cut into pieces, or sliced ​​into rings. Arms, tentacles, and inks are also edible; the only part that is not eaten is the beak and gladius (pen). Squid is a good source of food for zinc and manganese, and is rich in copper, selenium, vitamin B ₁₂ , and riboflavin.



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See also

• Paralarva



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References




src: www.tepapa.govt.nz




External links

• CephBase: Teuthida
• Colossal Squid at New Zealand Te Papa Tongarewa Museum
• Squid market mates, spawn (video)
• Scientific American - Giant Squid
• Cephalopoda page
• The Octopus News Magazine Online

Source of the article : Wikipedia