Comb-toothed sharks

Comb-toothed sharks
	Six gill shark
Systematics
Subclass :	Euselachii
Subclass :	Plate gill (Elasmobranchii)
without rank:	Sharks (selachii)
Superordinate :	Squalomorphii
Order :	Hexanchiformes
Family :	Comb-toothed sharks
Scientific name
	Hexanchidae
	Gray , 1851

The comb- toothed sharks (Hexanchidae) are a family of sharks from the order of the Hexanchiformes ; the alternative name gray sharks is not unique because it is also used for the requiem sharks .

anatomy

They have six ( Hexanchus ) or seven ( Heptranchias and Notorynchus ) gill slits , which is considered a primitive feature. Their mouth is below, the teeth of the lower and upper jaw are toothed, those of the lower jaw are much larger. They only have one dorsal fin that is positioned far back .

distribution

The sharks live worldwide in temperate to tropical areas of the Atlantic , Pacific and Indian Oceans , on the continental slopes and the coasts of islands also at greater depths.

Way of life

Comb-toothed sharks eat very large prey, like other sharks, rays , large bony fish and crustaceans . The young hatch in the mother's body or shortly after they have laid eggs ( ovoviviparia ).

species

There are three genera and five types:

Genus: Heptranchias Rafinesque, 1810
- Pointed-nosed seven-gill shark ( Heptranchias perlo (Bonnaterre, 1788) )
Genus: six-gill sharks ( Hexanchus Rafinesque, 1810 )
- Blunt-nosed six-gill shark ( Hexanchus griseus (Bonnaterre, 1788) )
- Bigeye six-gill shark ( Hexanchus nakamurai Teng, 1962 )
- Hexanchus vitulus Springer & Waller, 1969
Genus: Notorynchus Ayers, 1855
- Broad-nosed seven-gill shark ( Notorynchus cepedianus (Péron, 1807) )

literature

Joseph S. Nelson: Fishes of the World , John Wiley & Sons, 2006, ISBN 0-471-25031-7 .

Individual evidence

↑ Daly-Engel, TS, Baremore, IE, Grubbs, RD, Gulak, SJB, Graham, RT & Enzenauer, MP (2018): Resurrection of the sixgill shark Hexanchus vitulus Springer & Waller, 1969 (Hexanchiformes, Hexanchidae), with comments on its distribution in the northwest Atlantic Ocean. Marine Biodiversity, February 2018.

Web links

Commons : Hexanchidae - collection of images, videos and audio files

Crested sharks on Fishbase.org (English)

[Daly-Engel-1] Daly-Engel, TS, Baremore, IE, Grubbs, RD, Gulak, SJB, Graham, RT & Enzenauer, MP (2018): Resurrection of the sixgill shark Hexanchus vitulus Springer & Waller, 1969 (Hexanchiformes, Hexanchidae), with comments on its distribution in the northwest Atlantic Ocean. Marine Biodiversity, February 2018.