Cow shark

Cow shark
Cow sharks
Temporal range: Upper Jurassic–Recent
[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Hexanchiformes
Family: Hexanchidae
J. E. Gray, 1851
Genera

See text

Cow sharks, or the Hexanchidae, are a family of sharks characterized by an additional pair or pairs of gill slits. There are currently known to be four species in three genera, Heptranchias, Hexanchus and Notorynchus,.[2][3]

Cow sharks are considered the most primitive of all the sharks, because their skeletons resemble those of ancient extinct forms, with few modern adaptations. Their excretory and digestive systems are also unspecialised, suggesting that they may resemble those of primitive shark ancestors. Their most distinctive feature, however, is the presence of a sixth, and, in two genera, a seventh, gill slit, in addition to the five found in all other sharks.[4] They range from 1.4 metres (4.6 ft) to over 5.5 metres (18 ft) in adult body length.

Cow sharks are ovoviviparous, with the mother retaining the egg-cases in her body until they hatch. They feed on relatively large fish of all kinds, including other sharks, as well as on crustaceans and carrion.

There are just four species of cow shark, in three genera:[1]

  • Heptranchias Rafinesque, 1810
    • Heptranchias perlo (Bonnaterre, 1788) (Sharpnose sevengill shark)
  • Hexanchus Rafinesque, 1810
    • Hexanchus griseus (Bonnaterre, 1788) (Bluntnose sixgill shark)
    • Hexanchus nakamurai Teng, 1962 (Bigeyed sixgill shark)
  • Notorynchus Ayres, 1855
    • Notorynchus cepedianus (Péron, 1807) (Broadnose sevengill shark)

References

  1. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2011). "Hexanchidae" in FishBase. February 2011 version.
  2. ^ Allen, 45
  3. ^ Compagno, L., Dando, M. and Fowler, S. Sharks of the World Princeton Field Guides ISBN 0-691-12072-2
  4. ^ Matt's, J. & Last P.R. (1998). Paxton, J.R. & Eschmeyer, W.N.. ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 61. ISBN 0-12-547665-5. 

External links



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Look at other dictionaries:

  • cow shark — n. any of a family (Hexanchidae, order Hexanchiformes) of primitive sharks, having six or seven gill slits …   English World dictionary

  • cow shark — noun large primitive shark widely distributed in warm seas • Syn: ↑six gilled shark, ↑Hexanchus griseus • Hypernyms: ↑shark • Member Holonyms: ↑Hexanchus, ↑genus Hexanchus * * * …   Useful english dictionary

  • cow shark — pilkasis šešiažiaunis ryklys statusas T sritis zoologija | vardynas taksono rangas rūšis atitikmenys: lot. Hexanchus griseus angl. blunt nosed six gilled shark; brown shark; bull shark; bulldog shark; cow shark; gray shark; six gilled shark rus.… …   Žuvų pavadinimų žodynas

  • cow shark — any of several sharks constituting the family Hexanchidae, having six or seven gill openings on each side of the head. * * * …   Universalium

  • seven-gilled cow shark — pilkasis septynžiaunis ryklys statusas T sritis zoologija | vardynas taksono rangas rūšis atitikmenys: lot. Heptranchias perlo angl. Mediterranean shark; perlon shark; seven gilled cow shark; seven gilled shark; sharp nosed shark rus. пепельная… …   Žuvų pavadinimų žodynas

  • Shark — Taxobox name = Shark fossil range = Late Devonian Recent image width = 250px image caption = Grey reef shark, Carcharhinus amblyrhynchos regnum = Animalia phylum = Chordata subphylum = Vertebrata classis = Chondrichthyes subclassis =… …   Wikipedia

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  • Cow sharks — Taxobox name = Cow sharks image width = 250px regnum = Animalia phylum = Chordata classis = Chondrichthyes subclassis = Elasmobranchii ordo = Hexanchiformes familia = Hexanchidae familia authority = Gray, 1851 subdivision ranks = Genera and… …   Wikipedia

  • cow sharks — Notidanian No ti*da ni*an, n. [Gr. ? back + ? comely.] (Zo[ o]l.) Any one of several species of sharks of the family {Notidanid[ae]}, or {Hexanchid[ae]}. Called also {cow sharks}. See {Shark}. [1913 Webster] …   The Collaborative International Dictionary of English

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