Overview

Brief Summary

Requiem sharks - the Carcharhinids - are distributed throughout temperate and tropical oceans with several species occurring worldwide. Habitats are oceanic beyond the continental shelf (oceanic whitetip sharks, Carcharhinus longimanus) and inland into freshwater rivers and lakes (bull sharks, Carcharhinus leucas). Some species tend to associate with bottom while others range throughout the water column. All carcharhinids are viviparous or ovoviviparous (Compagno, 1984).

Carcharhinid sharks are a valuable resource worldwide. They are utilized for their flesh, fins, oil, and skin, and are taken recreationally (Bonfil, 1994). Some species are known to travel long distances, occasionally crossing oceans, and are considered to be a resource shared between regions and nations.

Carcharhinidae genera can be difficult to identify due to similar body shape, color, and overlapping distributions; particularly Carcharhinus species and Rhizoprionodon species. There are a number of shark identification keys and field guides that are invaluable for carcharhinid identifications and those works are fundamental for providing a format for accurate identifications (Bigelow and Schroeder, 1948; Baughman and Springer, 1950; Springer, 1950; Casey, 1964; Clark and von Schmidt, 1965; Schwartz and Burgess, 1975; Hoese and Moore, 1977; Boschung, 1979; Garrick, 1982, 1985; Castro, 1983; Compagno, 1984; Gar­ man, 1997; McEachran and Fechhelm, 1998).

Members of Carcharhinidae are variously distinguished by the presence of precaudal pits; lack of spiracles (present on tiger sharks and occurring rarely on lemon sharks, Compagno, 1988); bladelike teeth with single cusps; first dorsal fin origin usually above pectoral fin or slightly posterior to pectoral fin inner corner (except on the blue shark with the dorsal fin base midpoint closer to pelvic fin origin than pectoral fin axil); second dorsal fin smaller than first dorsal fin and above anal fin (second dorsal fin and first dorsal fin almost equal size on lemon sharks); fifth gill slit over or posterior to pectoral fin origin; no fleshy keels along sides of caudal peduncle (except on tiger sharks and blue sharks); well­ developed nictitating membrane along eye socket lower margin.

  • Grace, Mark. Field Guide to Requiem Sharks (Elasmobranchiomorphi: Carcharhinidae) of the Western North Atlantic. Mississippi Laboratories, Southeast Fisheries Science Center NOAA, National Marine Fisheries Service. 2001
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Distribution

Distribution: global. Gill openings 5, the fifth behind origin of pectoral fin. Small to large sharks with round eyes, internal nictitating eyelids, no nasoral grooves or barbels, usually no spiracles. Teeth usually bladelike with one cusp. Development usually viviparous.
  • MASDEA (1997).
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Source: World Register of Marine Species

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records: 3968
Specimens with Sequences: 3081
Specimens with Barcodes: 1990
Species: 81
Species With Barcodes: 77
Public Records: 884
Public Species: 44
Public BINs: 41
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Barcode data

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Wikipedia

Requiem shark

Spinner shark, Carcharhinus brevipinna, from the Gulf of Mexico
Lemon shark, Negaprion brevirostris, at Tiger Beach, Bahamas

Requiem sharks, Carcharhinidae, are a family of sharks in the order Carcharhiniformes, containing migratory, live-bearing sharks of warm seas (sometimes of brackish or fresh water) such as the blacknose shark, the blacktip shark, the blacktail reef shark, and the blacktip reef shark.

The name may be related to the French word for shark, requin, itself of disputed etymology (chien de mer or Latin requiem ("rest"), which would thereby create a cyclic etymology: requiem-requin-requiem).[2]

Family members have the usual carcharhiniform characteristics. Their eyes are round, and the pectoral fins are completely behind the five gill slits. Most species are viviparous, the young being born fully developed. They vary widely in size, from as small as 69 cm (2.26 ft) adult length in the Australian sharpnose shark, up to 5.5 m (18 ft) adult length in the tiger shark.[3]

Requiem sharks are responsible for a large proportion of attacks on humans; however, due to the difficulty in identifying individual species, a degree of inaccuracy exists in attack records.[4]

Classification[edit]

The 60 species of requiem shark are grouped into 12 genera:[3]

† = extinct

References[edit]

  1. ^ Guillaume Guinot, Henri Cappetta and Sylvain Adnet (2014). "A rare elasmobranch assemblage from the Valanginian (Lower Cretaceous) of southern France". Cretaceous Research 48: 54–84. doi:10.1016/j.cretres.2013.11.014. 
  2. ^ "Requiem Shark" by Erik Tierney (accessed 28 November 2007).
  3. ^ a b 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).
  4. ^ ISAF Statistics on Attacking Species of Shark[dead link]
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