Hexanchiformes
Frilled shark, Chlamydoselachus anguineus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Subclass: Elasmobranchii Order: Hexanchiformes de Buen, 1926
Families
See text for families, genera and species

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Hexanchiformes is the order consisting of the most primitive types of sharks, and numbering just five extant species. Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens.(Allen, 45)

Hexanchiform sharks have only one dorsal fin, either six or seven gill slits, and no nictitating membrane in the eyes.

The frilled shark, Chlamydoselachus anguineus, is very different from the cow sharks, and it has been proposed that it be moved to its own order Chlamydoselachiformes.

Classification

Extant species

Family Chlamydoselachidae

• Chlamydoselachus
  • Frilled shark, Chlamydoselachus anguineus (Garman, 1884) [1]

Family Hexanchidae (cow sharks)

• Heptranchias
  • Sharpnose sevengill shark, Heptranchias perlo (Bonnaterre, 1788) [2]
• Hexanchus
  • Bluntnose sixgill shark, Hexanchus griseus (Bonnaterre, 1788)
  • Bigeyed sixgill shark, Hexanchus nakamurai (Teng, 1962)
• Notorynchus
  • Broadnose sevengill shark or spotted sevengill shark, Notorynchus cepedianus (Péron, 1807) [3]

Extinct species

Family Chlamydoselachidae

• Chlamydoselachus
  • Chlamydoselachus bracheri Pfeil, 1983
  • Chlamydoselachus gracilis Antunes & Cappetta, 2001
  • Chlamydoselachus goliath Antunes & Cappetta, 2001
  • Chlamydoselachus fiedleri Pfeil, 1983
  • Chlamydoselachus lawleyi Davis, 1887
  • Chlamydoselachus thomsoni Richter & Ward, 1990
  • Chlamydoselachus tobleri Leriche, 1929
• Thrinax
  • Thrinax baumgartneri Pfeil, 1983

Family Heptranchidae

• Heptranchias
  • Heptranchias ezoensis Applegate & Uyeno, 1968
  • Heptranchias howelii (Reed, 1946)
  • Heptranchias tenuidens (Leriche, 1938)

Family Hexanchidae

• Hexanchus
  • Hexanchus arzoensis (Debeaumont, 1960)
  • Hexanchus agassizi [4]
  • Hexanchus collinsonae Ward, 1979
  • Hexanchus gracilis (Davis, 1887) [5]
  • Hexanchus griseus “andersoni” “gigas” (Bonaterre, 1788)
  • Hexanchus hookeri Ward, 1979
  • Hexanchus microdon “agassizii” (Agassiz, 1843)
  • Hexanchus nakamurai “vitulus” Teng, 1962
• Notidanoides
• Notidanodon
  • Notidanodon antarcti Grande & Chatterjee, 1987
  • Notidanodon brotzeni Siverson, 1995
  • Notidanodon dentatus (Woodward, 1886)
  • Notidanodon lanceolatus (Woodward, 1886)
  • Notidanodon loozi (Vincent, 1876)
  • Notidanodon pectinatus (Agassiz, 1843)
• Notorynchus
  • Notorynchus aptiensis (Pictet, 1865)
  • Notorynchus intermedius Wagner
  • Notorynchus lawleyi Ciola & Fulgosi, 1983
  • Notorynchus munsteri (Agassiz, 1843)
  • Notorynchus serratissimus (Agassiz, 1844)
  • Notorynchus serratus (Agassiz, 1844)
• Paraheptranchias
  • Paraheptranchias repens (Probst, 1879)
  • Paranotidanus “Eonotidanus” contrarius (Munster, 1843)
  • Paranotidanus intermedius (Wagner, 1861)
  • Paranotidanus munsteri (Agassiz, 1843)
  • Paranotidanus serratus (Fraas, 1855)
• Pseudonotidanus
  • Pseudonotidanus semirugosus Underwood & Ward, 2004
• Weltonia
  • Weltonia ancistrodon (Arambourg, 1952)
  • Weltonia burnhamensis Ward, 1979

Family ?Mcmurdodontidae

• Mcmurdodus
  • Mcmurdodus featherensis White, 1968
  • Mcmurdodus whitei Turner, & Young, 1987

See also

• Time range of Hexanchiformes species

References

• Allen, Thomas B. The Shark Almanac. New York: The Lyons Press, 1999. ISBN 1-55821-582-4