Requiem sharks are of the family Carcharhinidae in the order Carcharhiniformes. They are Animal migration, viviparity sharks of warm seas (sometimes of Brackish water or fresh water) and include such species as the bull shark, lemon shark, blacktip shark, and whitetip reef shark.
Family members have the usual carcharhiniform characteristics. Their eyes are round, and one or two gill slits fall over the pectoral fin base. Most species are viviparous, the young being born fully developed. They vary widely in size, from as small as adult length in the Australian sharpnose shark, up to adult length in the oceanic whitetip shark.[Compagno, L.J.V. Family Carcharhinidae - Requiem sharks in Froese, R. and D. Pauly. Editors. 2010. FishBase. World Wide Web electronic publication, version (10/2013).] Scientists assume that the size and shape of their pectoral fins have the right dimensions to minimize transport cost.
According to the ISAF, requiem sharks are among the top five species involved in on humans;[ ISAF Statistics on Attacking Species of Shark ]
Etymology
The common name
requiem shark may be related to the French word for shark, requin, which is itself of disputed etymology. One derivation of the latter is from Latin
requiem ("rest"), which would thereby create a cyclic etymology (
requiem-requin-requiem), but other sources derive it from the Old French verb
reschignier ("to grimace while baring teeth").
The scientific name Carcharhinidae was first proposed in 1896 by D.S. Jordan and B.W. Evermann as a subfamily of Galeidae (now replaced by "Carcharhinidae").[Subfamily Carcharhininae Jordan & Evermann, 1896 (Family Galeidae), Bull.U.S.Nat.Mus., 48(1):28.] The term is derived from Greek κάρχαρος ( karcharos, sharp or jagged), and ῥί̄νη ( rhinē, rasp); both elements describe the jagged, rasp-like skin.
Evolutionary history
The oldest member of the family is
Archaeogaleus from the
Early Cretaceous (
Valanginian) of France.
Only a handful of records of the group are known from prior to the beginning of the
Cenozoic.
Modern carcharinid sharks have extensively diversified in
coral reef habitats.
Hunting strategies
Requiem sharks are extraordinarily fast and effective hunters. Their elongated, torpedo-shaped bodies make them quick and agile swimmers, so they can easily attack any prey. Some species are continually active, while others are capable of resting motionless for extended periods on the bottom. They have a range of food sources depending on location and species, including
Osteichthyes,
squid,
octopus,
lobster,
Turtle,
Marine mammal,
Seabird, other sharks and
Batoidea; smaller species tend to select a narrow range of prey, but some very large species, especially the
tiger shark (Galeocerdo cuvier), are virtually omnivorous. They are often considered the "garbage cans" of the seas because they will eat almost anything, even non-food items like trash. They are migratory hunters that follow their food source across entire oceans. They tend to be most active at night time, where their impressive eyesight can help them sneak up on unsuspecting prey. It is worth mentioning that the tiger shark, however, possibly belongs to the
Galeocerdonidae family.
[Pollerspöck, J.; Straube, N. Bibliography Database of Living/Fossil Sharks, Rays and Chimaeras (Chondrichtyes: Elasmobranchii, Holocephali)—List of Valid Extant Species; List of Described Extant Species; Statistic, World Wide Web Electronic Publication, Version 10/2021; . Available online: www.shark-references.com (accessed on 23 November 2021).] Most requiem sharks hunt alone, however some species like the whitetip reef sharks and
are cooperative feeders and will hunt in packs through coordinated, timed attacks against their prey. Some of the species have been shown to give specialized displays when confronted by divers or other sharks, which may be indicative of aggressive or defensive threat.
Classification
The 60 species of requiem shark are grouped into 11 genera:
[
]
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Genus Scoliodon J. P. Müller & Henle, 1838
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Genus Carcharhinus Blainville, 1816
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Blacknose shark Poey, 1860 (blacknose shark)
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Silvertip shark Rüppell, 1837 (silvertip shark)
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Bignose shark Stewart Springer, 1950 (bignose shark)
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Graceful shark Whitley, 1934 (graceful shark)
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Carcharhinus amblyrhynchos Bleeker, 1856 (grey reef shark)
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Pigeye shark J. P. Müller & Henle, 1839 (pigeye shark)
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Borneo shark Bleeker, 1858 (Borneo shark)
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Copper shark Günther, 1870 (copper shark)
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Spinner shark J. P. Müller & Henle, 1839 (spinner shark)
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Nervous shark Whitley, 1945 (nervous shark)
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Carcharhinus cerdale C. H. Gilbert, 1898 (Pacific smalltail shark)
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Carcharhinus coatesi Whitley, 1939 (Coates's shark)
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Whitecheek shark J. P. Müller & Henle, 1839 (whitecheek shark)
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Silky shark J. P. Müller & Henle, 1839 (silky shark)
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Creek whaler Whitley, 1943 (creek whaler)
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Galapagos shark Snodgrass & Edmund Heller, 1905 (Galapagos shark)
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Carcharhinus hemiodon J. P. Müller & Henle, 1839 (Pondicherry shark)
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Carcharhinus humani W. T. White & Simon Weigmann, 2014 (Human's whaler shark)
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Finetooth shark J. P. Müller & Henle, 1839 (finetooth shark)
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Carcharhinus leiodon Jack Garrick, 1985 (smoothtooth blacktip shark)
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Bull shark J. P. Müller & Henle, 1839 (bull shark)
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Blacktip shark J. P. Müller & Henle, 1839 (blacktip shark)
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Carcharhinus longimanus Poey, 1861 (oceanic whitetip shark)
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Hardnose shark J. P. Müller & Henle, 1839 (hardnose shark)
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Carcharhinus melanopterus Quoy & Gaimard, 1824 (blacktip reef shark)
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Dusky shark Lesueur, 1818 (dusky shark)
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Daggernose shark J. P. Müller & Henle, 1839 (daggernose shark)
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Carcharhinus perezi Poey, 1876 (Caribbean reef shark)
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Sandbar shark Nardo, 1827 (sandbar shark)
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Smalltail shark Camillo Ranzani, 1839 (smalltail shark)
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Blackspot shark Pietschmann, 1913 (blackspot shark)
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Night shark Poey, 1868 (night shark)
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Spot-tail shark J. P. Müller & Henle, 1839 (spot-tail shark)
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Carcharhinus tilstoni Whitley, 1950 (Australian blacktip shark)
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† Carcharhinus tingae
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Carcharhinus tjutjot Bleeker, 1852 (Indonesian whaler shark)
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Carcharhinus obsolerus White, Kyne, and Harris, 2019 (lost shark)
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Genus River shark Louis Agassiz, 1843
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Ganges shark J. P. Müller & Henle, 1839 (Ganges shark)
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Glyphis garricki Compagno, W. T. White & Last, 2008 (northern river shark)
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Speartooth shark J. P. Müller & Henle, 1839 (speartooth shark)
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Glyphis sp. not yet described (Mukah river shark)
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Genus Lamiopsis Theodore Gill, 1862
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Broadfin shark J. P. Müller & Henle, 1839 (broadfin shark)
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Lamiopsis tephrodes Fowler, 1905 (Borneo broadfin shark)
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Genus Whitenose shark Compagno & Garrick, 1983
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Genus Negaprion Whitley, 1940
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Negaprion acutidens Rüppell, 1837 (sicklefin lemon shark)
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Lemon shark Poey, 1868 (lemon shark)
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† Negaprion eurybathrodon Blake, 1862
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Genus Blue shark Cantor, 1849
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Genus Rhizoprionodon Whitley, 1929
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Milk shark Rüppell, 1837 (milk shark)
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Rhizoprionodon lalandii J. P. Müller & Henle, 1839 (Brazilian sharpnose shark)
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Rhizoprionodon longurio D. S. Jordan & C. H. Gilbert, 1882 (Pacific sharpnose shark)
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Rhizoprionodon oligolinx V. G. Springer, 1964 (grey sharpnose shark)
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Rhizoprionodon porosus Poey, 1861 (Caribbean sharpnose shark)
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Rhizoprionodon taylori Ogilby, 1915 (Australian sharpnose shark)
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Rhizoprionodon terraenovae J. Richardson, 1836 (Atlantic sharpnose shark)
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Genus Sliteye shark J. P. Müller & Henle, 1838
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Genus Triaenodon J. P. Müller & Henle, 1837
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Triaenodon obesus Rüppell, 1837 (whitetip reef shark)
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Genus † Physogaleus Cappetta, 1980
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† Physogaleus americanus Case, 1994
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† Physogaleus contortus Gibbes, 1849
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† Physogaleus hemmooriensis Reinecke & Hoedemakers, 2006
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† Physogaleus huberensis Case, 1981
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† Physogaleus latecuspidatus Muller, 1999
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† Physogaleus latus Storms, 1894
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† Physogaleus maltzani Winkler, 1875
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† Physogaleus onkensis Boulemia & Adnet, 2023
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† Physogaleus rosehillensis Case & Borodin, 2000
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† Physogaleus secundus Winkler, 1876
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† Physogaleus tertius Winkler, 1876
† = extinct
See also
Sources
External links
