Ichthyodectiformes is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

order of marine stem- teleost ray-finned fish. The order is named after the genus ''

Ichthyodectes ''Ichthyodectes'' is an extinct genus of ichthyodectid fish which lived during the Late Cretaceous. Fossils of the species included have been found from Canada to Texas. Description ''Ichthyodectes ctenodon'' was a ichthyodectid around in ...

'', established by

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

in 1870. Ichthyodectiforms are usually considered to be some of the closest relatives of the teleost

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

. They were most diverse throughout the Cretaceous period, though basal forms like ''

Thrissops ''Thrissops'' (from el, θρῐ́ξ , 'hair' and el, ὄψις 'look') is an extinct genus of stem-teleost fish from the Jurassic and Cretaceous periods. Its fossils are known from the Solnhofen Limestone, as well as the Kimmeridge Clay. ''T ...

Occithrissops ''Occithrissops'' is an extinct genus of prehistoric ray-finned fish of the Jurassic, described from Sundance Formation. The genus name of ''Occithrissops'' refers to the occidental occurrence of the genus and its relationship to '' Thrissops'' ...

'' and ''

Allothrissops ''Allothrissops'' is an extinct genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarch ...

'' are known from the Middle- Late Jurassic of Europe and North America. Most ichthyodectiforms ranged between 1 and 5 meters (3–15 ft) in length. Most of known taxa were predators, feeding on smaller fish; in several cases, larger ichthyodectiforms preyed on smaller members of the order. Some species had remarkably large teeth, though others, such as ''

Gillicus arcuatus ''Gillicus'' was a relatively small, 2-metre long ichthyodectiform fish that lived in the Western Interior Seaway, in what is now central North America, during the Late Cretaceous. Description Like its larger relative, ''Ichthyodectes ctenodon ...

'', had small ones and sucked in their prey. '' Heckelichthys preopercularis'' is a rare example of non-predatory ichthyodectiform, more likely to be microphagous, fed on small particles. There is evidence that at least one species, ''

Xiphactinus audax ''Xiphactinus'' (from Latin and Greek for "sword-ray") is an extinct genus of large (Shimada, Kenshu, and Michael J. Everhart. "Shark-bitten Xiphactinus audax (Teleostei: Ichthyodectiformes) from the Niobrara Chalk (Upper Cretaceous) of Kansas." ...

'', may have been endothermic ("warm-blooded").

Systematics

The

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

phylogeny is badly resolved, leading to many ichthyodectiforms that are simply known to be rather primitive, but where nothing certain can be said about their precise relationships. Ichthyodectiformes * '' Africathrissops'' Taverne, 2010 * ''

'' Nybelin, 1964 * '' Altamuraichthys'' Taverne, 2016 * '' Antarctithrissops'' Arratia ''et al.'', 2004 * '' Ascalabothrissops''? Arratia, 2000 * '' Capassoichthys'' Taverne, 2015 * '' Dugaldia'' Lees, 1990 * '' Faugichthys'' Taverne & Chanet, 2000 * '' Furloichthys'' Taverne & Capasso, 2018 * '' Garganoichthys'' Taverne, 2009 * ''

'' Schaeffer & Patterson, 1984 * '' Ogunichthys'' Alvarado-Ortega & Brito, 2009 * ''

Pachythrissops ''Pachythrissops'' is an extinct genus of ray-finned fish. It contains two species, ''P. laevis'' from the Purbeckian of England and ''P. propterus'' from the Tithonian of Germany. A third species, ''P. vectensis'', has been reassigned to the ...

''? Woodward, 1919 * ''

Prymnetes ''Prymnetes'' is an extinct genus of prehistoric bony fish that lived during the Late Cretaceous epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: ...

'' Cope, 1871 * ''

'' Agassiz, 1843 * ''

Sultanuvaisia ''Sultanuvaisia'' is an extinct genus of ichthyodectiform teleost ray-finned fish from the Late Cretaceous of Kyzyl Kum, central Asia. It was named by Lev Nesov in 1981. At first, he tentatively described the fossil material as jaw fragments o ...

'' Nesov, 1981 * '' Verraesichthys'' Taverne, 2010 * Chuhsiungichthyidae Yabumoto, 1994 ** ''

Chuhsiungichthys ''Chuhsiungichthys'' is an extinct genus of ichthyodectiform ray-finned fish that lived in freshwater environments in what is now Yunnan, China, and Kyushu, Japan during the Cretaceous. It differs from its sister genus, ''Mesoclupea'', primarily ...

'' Lew, 1974 ** '' Jinjuichthys'' Kim ''et al.'', 2014 ** ''

Mesoclupea ''Mesoclupea showchangensis'' is an extinct ichthyodectiform ray-finned fish that lived in freshwater environments in what is now China during the Early Cretaceous epoch. It differs from its sister genus, '' Chuhsiungichthys'', primarily by hav ...

'' Ping & Yen, 1933 * Bardackichthyidae Hacker & Shimada, 2021 ** ''

Amakusaichthys ''Amakusaichthys'' is an extinct genus of Ichthyodectiformes, ichthyodectiform fish which lived during the Late Cretaceous, known from only one species ''A. goshouraensis''. Fossils are known from Kumamoto Prefecture in Japan. Discovery Fossi ...

''? Yabumoto ''et al.'', 2020 ** '' Bardackichthys'' Hacker & Shimada, 2021 ** '' Heckelichthys''? Taverne, 2008 * Cladocyclidae Maisey, 1991 ** '' Aidachar'' Nesov, 1981 ** ''

Chirocentrites ''Chirocentrites'' is an extinct genus of Ichthyodectidae. References * Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth ...

'' Heckel, 1849 ** '' Chiromystus'' Cope, 1885 ** ''

Cladocyclus ''Cladocyclus'' (derived from the Greek κλάδος/kládos ("branch") and κύκλος/kýklos ("circle")) is an extinct genus of Ichthyodectidae. It was a predatory fish of about in length, found in the Albian Romualdo and Crato Formations ...

'' Agassiz, 1841 ** ''

Eubiodectes ''Eubiodectes'' is an extinct genus of prehistoric bony fish that lived during the Cenomanian. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People ...

'' Hay, 1903 * Ichthyodectidae Crook, 1892 ** ''

Cooyoo ''Cooyoo'' ("fish" in the Yirandhali language) is an extinct genus of ichthyodectid fish known from the Lower Cretaceous. It contains a single species, ''C. australis'', known from the Albian-aged Toolebuc and Allaru Formations of Queensland, ...

'' Bartholomai & Less, 1987 ** '' Ghrisichthys'' Cavin ''et al.'', 2013 ** ''

'' Cope, 1870 ** '' Postredectes'' Kaddumi, 2009 ** ''

Xiphactinus ''Xiphactinus'' (from Latin and Greek for "sword-ray") is an extinct genus of large (Shimada, Kenshu, and Michael J. Everhart. "Shark-bitten Xiphactinus audax (Teleostei: Ichthyodectiformes) from the Niobrara Chalk (Upper Cretaceous) of Kansas." ...

'' Leidy, 1870 * Saurodontidae Cope, 1870 Cope, E. D. (1870). On the Saurodontidæ. ''Proceedings of the American Philosophical Society'' 11:529-538 Cope, E. D. (1873). On two new species of Saurodontidae. ''Proceedings of the Academy of Natural Sciences of Philadelphia'' 25:2-339 ** ''

''? Yabumoto ''et al.'', 2020 ** '' Gillicus'' Cope, 1875 ** ''

Gwawinapterus ''Gwawinapterus beardi'' is a species of saurodontid ichthyodectiform fish from the Late Cretaceous period of British Columbia, Canada. While initially described as a very late-surviving member of the pterosaur family Istiodactylidae, further ex ...

'' Arbour & Currie, 2011Vullo, R., Buffetaut, E. and Everhart, M.J. (2012). "Reappraisal of ''Gwawinapterus beardi'' from the Late Cretaceous of Canada: a saurodontid fish, not a pterosaur." ''Journal of Vertebrate Paleontology'', 32(5): 1198-1201. ** '' Heckelichthys''? Taverne, 2008 ** '' Prosaurodon'' Stewart, 1999 ** ''

Saurocephalus ''Saurocephalus'' (from el, σαῦρος , 'lizard' and el, κεφαλή 'head') is an extinct genus of ray-finned fishes within the family Saurodontidae.Maisey, J. G.1991. ''Santana Fossils, an Illustrated Atlas''. New Jersey, T.F.H. Public ...

'' Harlan, 1824 ** ''

Saurodon ''Saurodon'' (from el, σαῦρος , 'lizard' and el, ὀδούς 'tooth') is an extinct genus of ichthyodectiform fish from the Cretaceous. ''Saurodon leanus'' is known to occur as early as the late Coniacian through the Santonian, in the ...

'' Hay, 1830 ** '' Unamichthys'' Alvarado-Ortega, 2004 ** '' Vallecillichthys'' Blanco & Cavin, 2003

References

Prehistoric ray-finned fish orders Late Jurassic first appearances Late Cretaceous extinctions {{paleo-rayfinned-fish-stub