page_title: Hexanchiformes
section_title: Extinct species
hierarchical_section_title: Hexanchiformes / Classification / Extinct species
caption_attribution_description: Notidanodon sp. fossil at the Geological Museum, Copenhagen.
context_page_description: The Hexanchiformes are the order consisting of the most primitive types of sharks, and numbering just seven extant species. Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens.
  Hexanchiform sharks have only one dorsal fin, either six or seven gill slits, and no nictitating membrane in the eyes. Shark teeth similar to those modern hexanchids are known from Devonian deposits in Antarctica and Australia, as well as Permian deposits in Japan. If these are in fact hexanchids, this may be the only extant order of elasmobranchs to have survived after the Permian extinction.
  The frilled sharks of the genus Chlamydoselachus are very different from the cow sharks, and have been proposed to be moved to a distinct order, Chlamydoselachiformes.
context_section_description: Family Chlamydoselachidae
  Chlamydoselachus Garman, 1884
  Chlamydoselachus bracheri Pfeil, 1983
  Chlamydoselachus fiedleri Pfeil, 1983
  Chlamydoselachus garmani Welton, 1983
  Chlamydoselachus goliath Antunes & Cappetta, 2002
  Chlamydoselachus gracilis Antunes & Cappetta, 2002
  Chlamydoselachus keyesi Mannering & Hiller, 2008
  Chlamydoselachus landinii Carrillo-Briceño, Aguilera & Rodriguez, 2014
  Chlamydoselachus lawleyi Davis, 1887
  Chlamydoselachus tatere Consoli, 2008
  Chlamydoselachus thomsoni Richter & Ward, 1990
  Chlamydoselachus tobleri Leriche, 1929
  Proteothrinax Pfeil, 1983
  Proteothrinax baumgartneri Pfeil, 1983
  Family Crassonotidae
  Crassodontidanus Kriwet & Klug, 2011
  Crassodontidanus serratus Fraas, 1855
  Crassodontidanus wiedenrothi Thies, 1983
  Notidanoides Maisey, 1986
  Notidanoides muensteri Agassiz, 1843
  Notidanus Cuvier, 1816
  Notidanus amalthei Oppel, 1854
  Notidanus atrox Ameghino, 1899 
  Notidanus intermedius Wagner, 1862
  Notidanus nikitini Chabakov & Zonov, 1935
  Pachyhexanchus Cappetta, 1990
  Pachyhexanchus pockrandti Ward & Thies, 1987
  Family Hexanchidae
  Gladioserratus Underwood, Goswami, Prasad, Verma & Flynn, 2011
  Gladioserratus aptiensis Pictet, 1864
  Gladioserratus dentatus Guinot, Cappetta & Adnet, 2014
  Gladioserratus magnus Underwood, Goswami, Prasad, Verma & Flynn, 2011
  Heptranchias Rafinesque, 1810
  Heptranchias ezoensis Applegate & Uyeno, 1968
  Heptranchias howellii Reed, 1946
  Heptranchias karagalensis Kozlov in Zhelezko & Kozlov, 1999
  Heptranchias tenuidens Leriche, 1938
  Hexanchus Rafinesque, 1810
  Hexanchus agassizi  Cappetta, 1976
  Hexanchus andersoni Jordan, 1907
  Hexanchus casieri Kozlov, 1999
  Hexanchus collinsonae Ward, 1979
  Hexanchus gracilis Davis, 1887
  Hexanchus hookeri Ward, 1979
  Hexanchus microdon Agassiz, 1843
  Hexanchus tusbairicus Kozlov in Zhelezko & Kozlov, 1999
  Notidanodon Cappetta, 1975
  Notidanodon brotzeni Siverson, 1995
  Notidanodon dentatus Woodward, 1886
  Notidanodon lanceolatus Woodward, 1886
  Notidanodon loozi Vincent, 1876
  Notidanodon pectinatus Agassiz, 1843
  Notorynchus Ayres, 1855
  Notorynchus borealus Jordan & Hannibal, 1923
  Notorynchus kempi Ward, 1979
  Notorynchus lawleyi Cigala Fulgosi, 1983
  Notorynchus primigenius Agassiz, 1843
  Notorynchus serratissimus Agassiz, 1843
  Notorynchus subrecurvus Oppenheimer, 1907
  Pachyhexanchus Cappetta, 1990
  Pachyhexanchus pockrandti Ward & Thies, 1987
  Paraheptranchias Pfeil, 1981
  Paraheptranchias repens Probst, 1879
  Pseudonotidanus Underwood & Ward, 2004
  Pseudonotidanus semirugosus Underwood & Ward, 2004
  Welcommia Cappetta, 1990
  Welcommia bodeuri Cappetta, 1990
  Welcommia cappettai Klug & Kriwet, 2010
  Weltonia Ward, 1979
  Weltonia ancistrodon Arambourg, 1952
  Weltonia burnhamensis Ward, 1979
  Family Mcmurdodontidae ?
  Mcmurdodus White, 1968
  Mcmurdodus featherensis White, 1968
  Mcmurdodus whitei Turner, & Young, 1987
  Family Orthacodontidae
  Occitanodus Guinot, Cappetta & Adnet, 2014
  Occitanodus sudrei Guinot, Cappetta & Adnet, 2014
  Orthacodus Woodward, 1889
  Orthacodus longidens Agassiz, 1843
  Sphenodus Agassiz, 1843
  Sphenodus alpinus Gümbel, 1861
  Sphenodus longidens Agassiz, 1843
  Sphenodus lundgreni Davis, 1890
  Sphenodus macer Quenstedt, 1852
  Sphenodus nitidus Wagner, 1862
  Sphenodus planus Agassiz, 1843
  Sphenodus rectidens Emmons, 1858
  Sphenodus robustidens Seguenza, 1900
  Sphenodus tithonius Gemmellaro, 1871
  Sphenodus virgai Gemmellaro, 1871
caption: Notidanodon sp. fossil at the Geological Museum, Copenhagen
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