Squaliformes

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Squaliformes
Temporal range: Late Jurassic–Recent[1]
Spiny dogfish.jpg
Spiny dogfish, Squalus acanthias
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Squaliformes
Goodrich, 1909

Squaliformes is an order of sharks that includes about 126 species in seven families.

Members of the order have two dorsal fins, which usually possess spines, no anal fin or nictitating membrane, and five gill slits. In most other respects, however, they are quite variable in form and size. They are found worldwide, from polar to tropical waters, and from shallow coastal seas to the open ocean.[2]

Classification[edit]

Family Centrophoridae Bleeker, 1859 (gulper sharks)

Family Dalatiidae (J. E. Gray, 1851) (kitefin sharks)

Family Etmopteridae Fowler, 1934 (lantern sharks)

Family Oxynotidae Gill, 1872 (rough sharks)

Family Somniosidae D. S. Jordan, 1888 (sleeper sharks)

Family Squalidae Blainville, 1816 (dogfish sharks)

Family Image Common name Genera Species Description
Centrophoridae Acanthidium quadrispinosum.jpg Gulper sharks 2 20 Gulper sharks are usually deepwater fish. While some, such as the gulper shark Centrophorus granulosus, are found worldwide and fished commercially, others are uncommon and little-known. Their usual prey is other fish; some are known to feed on squid, octopus, and shrimp. Some species live on the bottom (benthic), while others are pelagic. They are ovoviviparous, with the female retaining the egg-cases in her body until they hatch.[3] They are small to medium sharks, ranging from 79 centimetres (2.59 ft) to 164 centimetres (5.38 ft) in adult body length.
Dalatiidae Dalatias licha1.jpg Kitefin sharks 7 10 Kitefin sharks are small, under 2 m (6.6 ft) long, and are found worldwide. They have cigar-shaped bodies with narrow heads and rounded snouts. Several species have specialized bioluminescent organs.[4] The term kitefin shark is also used as the common name for the type species of the family, Dalatias licha.
Etmopteridae Centroscyllium nigrum by garman.jpg Lantern sharks 5 45 Lantern sharks are deep water fish with light-producing photophores on their bodies. The members of this family are small, under 90 cm (35 in) long, and are found worldwide.[5]
Oxynotidae Oxynotus bruniensis drawing.jpg Rough sharks 1 5 Rough sharks are characterised by two large dorsal fins, each with a sharp spine, and with the first fin placed far forward above the head. Their bodies are compressed, giving them a triangular cross-section. Their skins are even rougher and more prickly than the dogfishes (below). Rough sharks are small to medium in size, ranging from 49 centimetres (1.61 ft) to 150 centimetres (4.9 ft) in adult body length, depending on species. They are deep water sharks possessing a luminous organ which live in Atlantic and western Pacific oceans.[6]
Somniosidae Somniosus microcephalus.jpg Sleeper sharks 7 20 Sleeper sharks are a poorly studied[7] deep-sea shark found in all oceans.[8] They contain anti-freeze to survive in cold temperatures, and may feed on colossal squid. In Iceland they are hunted for food. They are allowed to rot for months until the poisonous anti-freeze degrades, and they are safe to eat.[9]
Squalidae Squalus acanthias.jpg Dogfish sharks 2 30 Dogfish sharks have two dorsal fins, each with smooth spines, but no anal fin. Their skin is generally rough to the touch.[10] These sharks are characterized by teeth in upper and lower jaws similar in size; caudal peduncle with lateral keels; upper precaudal pit usually present; and a caudal fin without subterminal notch. Unlike nearly all other shark species, dogfish possess venom, which coats its dorsal spines and is mildly toxic to humans. Their livers and stomachs contain also the compound squalamine, which possesses the property of reduction of small blood vessel growth in humans.[11]

References[edit]

  1. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Squaliformes" in FishBase. January 2009 version.
  2. ^ Stevens, J. & Last, P.R. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 64. ISBN 0-12-547665-5. 
  3. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Centrophoridae" in FishBase. January 2009 version.
  4. ^ Hamlett, W.C., ed. (1999). Sharks, Skates, and Rays: The Biology of Elasmobranch Fishes. JHU Press. pp. 16–17. ISBN 0-8018-6048-2. 
  5. ^ Froese, Rainer, and Daniel Pauly, eds. (2011). "Etmopteridae" in FishBase. February 2011 version.
  6. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Oxynotidae" in FishBase. January 2009 version.
  7. ^ "Abstract". Springer Links. Retrieved 29 December 2012. 
  8. ^ "Family Somniosidae - Sleeper sharks". Fish Base. Retrieved 29 December 2012. 
  9. ^ Simon, Matt. "Footnotes: Lazy Sharks, Humiliated Seals, and Googlers Eating Dog Food | Wired Opinion". Wired.com. Retrieved 2012-07-05. 
  10. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Squalidae" in FishBase. January 2009 version.
  11. ^ National Geographic June 1998

Further reading[edit]