Broadnose sevengill shark

Broadnose sevengill shark
Broadnose sevengill shark at Aquarium of the Bay
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Hexanchiformes
Family: Hexanchidae
Genus: Notorynchus
Species:
N. cepedianus
Binomial name
Notorynchus cepedianus
(Péron, 1807)
Range of the broadnose sevengill shark
Synonyms

Heptranchias haswelli* Ogilby, 1897
Heptranchias pectorosus Garman, 1884
Heptranchias spilotus Lahille, 1913
Notidanus ferox Perez Canto, 1886
Notidanus indicus Agassiz, 1838
Notidanus medinae Philippi, 1902
Notidanus wolniczkyi Philippi, 1902
Notorynchus macdonaldi Whitley, 1931
Notorynchus maculatus Ayres, 1855
Notorhynchus borealis Gill, 1864
Notorhynchus ocellatus Devincenzi, 1920
Squalus cepedianus Péron, 1807
Squalus platycephalus Tenore, 1809

* ambiguous synonym

The broadnose sevengill shark (Notorynchus cepedianus) is the only extant member of the genus Notorynchus, in the family Hexanchidae. It is recognizable because of its seven gill slits, while most shark species have five gill slits, with the exception of the members of the order Hexanchiformes and the sixgill sawshark. This shark has a large, thick body, with a broad head and blunt snout. The top jaw has jagged, cusped teeth and the bottom jaw has comb-shaped teeth. Its single dorsal fin is set far back along the spine towards the caudal fin, and is behind the pelvic fins. In this shark the upper caudal fin is much longer than the lower, and is slightly notched near the tip. Like many sharks, this sevengill is counter-shaded. Its dorsal surface is silver-gray to brown in order to blend with the dark water and substrate when viewed from above. In counter to this, its ventral surface is very pale, blending with the sunlit water when viewed from below. The body and fins are covered in a scattering of small black & white spots. In juveniles, their fins often have white margins.

It is also known as sevengill shark or simply sevengill and was formerly known as cow shark and mud shark; it is called sevengill due to its seven gill slits. Because of this, it was listed along with the sharpnose sevengill shark (Heptranchias perlo) by Guinness World Records as having the most gill slits.[2] It is similar to the sharpnose sevengill shark but the latter has a pointed snout and lacks spots on its dorsal surface.[3][4] The sevengill species are also related to ancient sharks as fossils from the Jurassic Period (200 to 145 million years ago) also had seven gills. As recently as the 1930s and 1940s, the shark was targeted by fisheries along the coast of California and, once the commercial fishery receded, recreational fishing of the shark started in the 1980s and 1990s.[5]

  1. ^ Finucci, B.; Barnett, A.; Cheok, J.; Cotton, C.F.; Kulka, D.W.; Neat, F.C.; Pacoureau, N.; Rigby, C.L.; Tanaka, S.; Walker, T.I. (2020). "Notorynchus cepedianus". IUCN Red List of Threatened Species. 2020: e.T39324A2896914. doi:10.2305/IUCN.UK.2020-3.RLTS.T39324A2896914.en. Retrieved 19 November 2021.
  2. ^ Glenday, Craig (2013). Guinness World Records 2013. Guinness World Records. p. 61. ISBN 978-0345547118.
  3. ^ Castro, Jose I.; Peebles, Diane Rome (2011). "The Sharks of North America". Oxford University Press. p. 38. ISBN 978-0195392944.
  4. ^ Van der Elst, Rudy (1993). A Guide to the Common Sea Fishes of Southern Africa. Struik. p. 55. ISBN 1868253945.
  5. ^ Cite error: The named reference FLMNH was invoked but never defined (see the help page).