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Squaliformes

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

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

All members of the family Eptomeridae and Dalatiidae and Zameus squamulosus possess photophores, luminous organs, and exhibit intrinsic bioluminescence [3]. Bioluminescence evolved once in Squaliformes, approximately 111-153 million years ago, and helped the Squaliformes radiate and adapt to the deep sea[3][4]. The common ancestor of Dalatiidae, Etmopteridae, Somniosidae, and Oxynotidae possessed a luminous organ and used bioluminescence for camouflage by counterillumination [3][5]. Counterillumination is an active form of camouflage in which an organism emits light to match the intensity of downwelling light to hide from predators below.[6] Currently, bioluminescence provides different functions for Squaliformes based on the family. Dalatiidae and Zameus squamulosus possess simple photophores and use bioluminescence for ventral counter-illumination[5]. Etmopteridae possess more complex photophores [7]and utilize bioluminescence for ventral counter illumination as well as species recognition [8].

Classification

Family Centrophoridae Bleeker, 1859 (gulper sharks)

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

Family Echinorhinidae Theodore Gill, 1862 (bramble 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)

References

  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. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 64. ISBN 978-0-12-547665-2.
  3. ^ a b c Flammesbeck, C. K., J. Pollerspöck, F. D. B. Schedel, N. J. Matzke, and N. Straube (2018). "Of teeth and trees: a fossil tip dating approach to infer divergence times of extinct and extant squaliform sharks". 2dh Annual Conference of the European Elasmobranch Association: 57.CS1 maint: multiple names: authors list (link)
  4. ^ Davis, M. P., J. S. Sparks, and W. L. Smith (2016). "Repeated and widespread evolution of bioluminescence in marine fishes". PLoS ONE. 11 (6): e0155154. doi:10.1371/journal.pone.0155154. PMC 4898709. PMID 27276229.CS1 maint: multiple names: authors list (link)
  5. ^ a b Straube, N., C. Li, J. M. Claes, S. Corrigan, and G. J. P. Naylor (2015). "Molecular phylogeny of squaliformes and first occurrence of bioluminescence in sharks". BMC Evolutionary Biology. 15: 62. doi:10.1186/s12862-015-0318-0. PMC 4434831. PMID 25880916.CS1 maint: multiple names: authors list (link)
  6. ^ Hastings, J. W. (1971). "Light to hide by: ventral luminescence to camouflage the silhouette". Science. 173: 1016–1017.
  7. ^ Claes, J. M., and J. Mallefet. (2009). "Bioluminescence of sharks: first synthesis". Kerala: Research Signpost: 51–65.CS1 maint: multiple names: authors list (link)
  8. ^ Claes, J. M., D. E. Nilsson, J. Mallefet, and N. Straube (2015). "The presence of lateral photophores correlates with increased speciation in deep-sea bioluminescent sharks". Royal Society Open Science. 2 (7): 150219. doi:10.1098/rsos.150219. PMC 4632593. PMID 26587280.CS1 maint: multiple names: authors list (link)
  9. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Centrophoridae" in FishBase. January 2009 version.
  10. ^ Hamlett, W.C., ed. (1999). Sharks, Skates, and Rays: The Biology of Elasmobranch Fishes. JHU Press. pp. 16–17. ISBN 978-0-8018-6048-5.
  11. ^ {{FishBase_family| family=Echinorhinidae
  12. ^ Froese, Rainer, and Daniel Pauly, eds. (2011). "Etmopteridae" in FishBase. February 2011 version.
  13. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Oxynotidae" in FishBase. January 2009 version.
  14. ^ Murray, Brent William; Wang, John Y.; Yang, Shih-Chu; Stevens, John D.; Fisk, Aaron; Svavarsson, Jörundur (2008). "Abstract". Marine Biology. 153 (6): 1015–1022. doi:10.1007/s00227-007-0871-1.
  15. ^ "Family Somniosidae - Sleeper sharks". Fish Base. Retrieved 29 December 2012.
  16. ^ Simon, Matt (2012-07-05). "Footnotes: Lazy Sharks, Humiliated Seals, and Googlers Eating Dog Food | Wired Opinion". Wired. Retrieved 2012-07-05.
  17. ^ Froese, Rainer, and Daniel Pauly, eds. (2009). "Squalidae" in FishBase. January 2009 version.
  18. ^ National Geographic June 1998
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Squaliformes: Brief Summary

provided by wikipedia EN

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

Members of the order have two dorsal fins, which usually possess spines, they usually have a sharp head, no anal fin or nictitating membrane, and five to seven gill slits. In most other respects, however, they are quite variable in form and size. Most species of the squaliform order live in a saltwater or brackish waters. They are found worldwide, from northern to tropical waters, and from shallow coastal seas to the open ocean.

All members of the family Eptomeridae and Dalatiidae and Zameus squamulosus possess photophores, luminous organs, and exhibit intrinsic bioluminescence . Bioluminescence evolved once in Squaliformes, approximately 111-153 million years ago, and helped the Squaliformes radiate and adapt to the deep sea. The common ancestor of Dalatiidae, Etmopteridae, Somniosidae, and Oxynotidae possessed a luminous organ and used bioluminescence for camouflage by counterillumination . Counterillumination is an active form of camouflage in which an organism emits light to match the intensity of downwelling light to hide from predators below. Currently, bioluminescence provides different functions for Squaliformes based on the family. Dalatiidae and Zameus squamulosus possess simple photophores and use bioluminescence for ventral counter-illumination. Etmopteridae possess more complex photophores and utilize bioluminescence for ventral counter illumination as well as species recognition .

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN