Ichthyodectiformes

{{Short description|Extinct order of ray-finned fishes}} {{Automatic taxobox | fossil_range = {{fossil range|Bathonian|65.5|Middle Jurassic-Early Paleocene}} | image = Ichthyodectidae2.jpg | image_caption = {{ordered list |style=text-align: left; |''Xiphactinus audax'' |''Ichthyodectes ctenodon'' |''Cladocyclus gardneri'' |''Chirocentrites'' sp.}} | image2 = Thrissops cf formosus 01.jpg | image2_caption = Fossil of ''Thrissops'' | taxon = Ichthyodectiformes | authority = Bardack & Sprinkle, 1969 | subdivision_ranks = Subgroups | subdivision = See text }}

'''Ichthyodectiformes''' is an extinct order of marine stem-teleost ray-finned fish. The order is named after the genus ''Ichthyodectes'', established by Edward Drinker Cope in 1870. Ichthyodectiforms are usually considered to be some of the closest relatives of the teleost crown group.<ref name="Nelson2016">{{cite book|last1=Nelson|first1=Joseph S.|last2=Grande|first2=Terry C.|last3=Wilson|first3=Mark V. H.|year=2016|title=''Fishes of the World''|edition=5th|publisher=John Wiley & Sons|isbn=978-1-118-34233-6}}</ref>

They were most diverse throughout the Cretaceous period, though basal forms like ''Thrissops, Occithrissops'' and ''Allothrissops'' are known from the Middle-Late Jurassic of Europe and North America. They were almost entirely wiped out by the Cretaceous-Paleogene extinction event, but a single species, ''Saurocephalus lanciformis'', appears to have survived into the earliest Paleocene (Danian).<ref>{{Cite journal |last=Boles |first=Zachary |last2=Ullmann |first2=Paul |last3=Putnam |first3=Ian |last4=Ford |first4=Mariele |last5=Deckhut |first5=Joseph |date=2024 |title=New vertebrate microfossils expand the chondrichthyan and actinopterygian fauna of the Maastrichtian–Danian Hornerstown Formation in New Jersey |journal=Acta Palaeontologica Polonica |language=en |volume=69 |doi=10.4202/app.01117.2023 |issn=0567-7920|doi-access=free }}</ref>

Most ichthyodectiforms ranged between {{convert|1|and|5|m|ft|sp=us}} 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'', 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.<ref>{{Cite journal |last1=Baños-Rodríguez |first1=Rocio Elizabeth |last2=González-Rodríguez |first2=Katia Adriana |last3=Wilson |first3=Mark V. H. |last4=González-Martínez |first4=Jorge Alberto |date=2020-06-01 |title=A new species of Heckelichthys from the Muhi Quarry (Albian–Cenomanian) of central Mexico |url=https://www.sciencedirect.com/science/article/pii/S0195667119304276 |journal=Cretaceous Research |language=en |volume=110 |article-number=104415 |doi=10.1016/j.cretres.2020.104415 |bibcode=2020CrRes.11004415B |s2cid=213275574 |issn=0195-6671|url-access=subscription }}</ref> There is evidence that at least one species, ''Xiphactinus audax'', may have been endothermic ("warm-blooded").<ref>{{cite journal |last1=Ferrón |first1=H. G. |title=Evidence of endothermy in the extinct macropredatory osteichthyan ''Xiphactinus audax'' (Teleostei, Ichthyodectiformes) |journal=Journal of Vertebrate Paleontology |date=2019 |volume=39 |issue=6 |article-number=e1724123 |doi=10.1080/02724634.2019.1724123|bibcode=2019JVPal..39E4123F |hdl=1983/e6d12da6-4f25-46ce-bb14-74fd2beddd82 |s2cid=216158318 |url=https://research-information.bris.ac.uk/en/publications/e6d12da6-4f25-46ce-bb14-74fd2beddd82 |hdl-access=free }}</ref> Another genus, ''Dugaldia'', may have been able to laterally open its mouth extremely wide in a manner akin to the modern sarcastic fringehead.<ref>{{Cite journal |last=Cavin |first=Lionel |last2=Berrell |first2=Rodney W. |date=2019-01-02 |title=Revision of Dugaldia emmilta (Teleostei, Ichthyodectiformes) from the Toolebuc Formation, Albian of Australia, with comments on the jaw mechanics |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2019.1576049 |journal=Journal of Vertebrate Paleontology |language=en |volume=39 |issue=1 |article-number=e1576049 |doi=10.1080/02724634.2019.1576049 |issn=0272-4634|url-access=subscription }}</ref>

==Systematics== The basal 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.

{{Div col}} {{Extinct}}'''Ichthyodectiformes'''<ref name="Nelson2016" /><ref name="Cavin2019">{{cite journal |last1=Cavin |first1=L. |last2=Berrell |first2=R. W. |title=Revision of ''Dugaldia emmilta'' (Teleostei, Ichthyodectiformes) from the Toolebuc Formation, Albian of Australia, with comments on the jaw mechanics |journal=Journal of Vertebrate Paleontology |date=2019 |volume=39 |issue=1 |article-number=e1576049 |doi=10.1080/02724634.2019.1576049|bibcode=2019JVPal..39E6049C |s2cid=190880286 }}</ref><ref name="Hacker2021">{{cite journal |last1=Hacker |first1=R. J. |last2=Shimada |first2=K. |title=A new ichthyodectiform fish (Actinopterygii: Teleostei) from the Arlington Member (mid-Cenomanian) of the Upper Cretaceous Woodbine Formation in Texas, USA |journal=Cretaceous Research |date=2021 |volume=123 |article-number=104798 |doi=10.1016/j.cretres.2021.104798|bibcode=2021CrRes.12304798H |s2cid=233806833 }}</ref> * {{Extinct}}''Africathrissops'' Taverne, 2010<ref name="Taverne2010">{{cite journal |last1=Taverne |first1=L. |title=Les Ichthyodectidae (Teleostei, Ichthyodectiformes) des schistes bitumineux de TAptien (Crétacé inférieur) de Guinée Équatoriale et du Gabon |journal=Bulletin de l'Institut Royal des Sciences Naturelles de Belgique |date=2010 |volume=80 |pages=115–143 |url=https://www.vliz.be/imisdocs/publications/ocrd/240420.pdf |language=fr}}</ref> * {{Extinct}}''Allothrissops'' Nybelin, 1964 * {{Extinct}}''Antarctithrissops'' Arratia ''et al.'', 2004<ref name="Arratia2004">{{cite journal |last1=Arratia |first1=G. |last2=Scasso |first2=R. A. |last3=Kiessling |first3=W. |title=Late Jurassic fishes from Longing Gap, Antarctic Peninsula |journal=Journal of Vertebrate Paleontology |date=2004 |volume=24 |issue=1 |pages=41–55 |doi=10.1671/1952-4 |bibcode=2004JVPal..24...41A |s2cid=85783766 |url=https://www.researchgate.net/publication/232669427|hdl=11336/91532 |hdl-access=free }}</ref> * {{Extinct}}''Ascalabothrissops''? Arratia, 2000<ref name="Arratia2000">{{cite journal |last1=Arratia |first1=G. |title=Remarkable teleostean fishes from the Late Jurassic of southern Germany and their phylogenetic relationships |journal=Fossil Record |date=2000 |volume=3 |issue=1 |pages=137–179 |doi=10.1002/mmng.20000030108|doi-access=free }}</ref> * {{Extinct}}''Capassoichthys'' Taverne, 2015<ref name="Taverne2018">{{cite journal |last1=Taverne |first1=L. |last2=Capasso |first2=L. |title=Osteology and phylogenetic relationships of ''Furloichthys bonarellii'' gen. and sp. nov. (Teleostei, Ichthyodectidae), a tropical fish from the Upper Cretaceous of central Italy |journal=Geo-Eco-Trop. |date=2018 |volume=42 |issue=1 |pages=75–88 |url=https://geoecotrop.be/uploads/publications/pub_421_06.pdf}}</ref> * {{Extinct}}''Carsothrissops'' d'Erasmo, 1946<ref>{{Cite journal |last=Palci |first=Alessandro |last2=Jurkovšek |first2=Bogdan |last3=Kolar-Jurkovšek |first3=Tea |last4=Caldwell |first4=Michael W. |date=2008-01-01 |title=New palaeoenvironmental model for the Komen (Slovenia) Cenomanian (Upper Cretaceous) fossil lagerstätte |url=https://ui.adsabs.harvard.edu/abs/2008CrRes..29..316P |journal=Cretaceous Research |volume=29 |pages=316–328 |doi=10.1016/j.cretres.2007.05.003}}</ref> * {{Extinct}}''Dugaldia'' Lees, 1990 * {{Extinct}}''Faugichthys'' Taverne & Chanet, 2000 * {{Extinct}}''Furloichthys'' Taverne & Capasso, 2018<ref name="Taverne2018" /> * {{Extinct}}''Occithrissops'' Schaeffer & Patterson, 1984 * {{Extinct}}''Ogunichthys'' Alvarado-Ortega & Brito, 2009 * {{Extinct}}''Pachythrissops''? Woodward, 1919 * {{Extinct}}''Prymnetes'' Cope, 1871<ref name="Blanco2007">{{cite journal |last1=Blanco-Piñón |first1=A. |last2=Alvarado-Ortega |first2=J. |title=Review of ''Vallecillichthys multivertebratum'' (Teleostei: Ichthyodectiformes), a Late Cretaceous (early Turonian) "Bulldog fish" from northeastern Mexico |journal=Revista Mexicana de Ciencias Geológicas |date=2007 |volume=24 |issue=3 |pages=450–466 |url=https://www.redalyc.org/pdf/572/57224312.pdf}}</ref> * {{Extinct}}''Thrissops'' Agassiz, 1843 * {{Extinct}}''Sultanuvaisia'' Nesov, 1981 * {{Extinct}}''Unamichthys'' Alvarado-Ortega, 2004 * {{Extinct}}''Verraesichthys'' Taverne, 2010 * {{Extinct}}'''Chuhsiungichthyidae'''? Yabumoto, 1994<ref>{{cite journal |last1=Kim |first1=H. |last2=Chang |first2=M. |last3=Wu |first3=F. |last4=Kim |first4=Y. |title=A new ichthyodectiform (Pisces, Teleostei) from the Lower Cretaceous of South Korea and its paleobiogeographic implication |journal=Cretaceous Research |date=2014 |volume=47 |pages=117–130 |doi=10.1016/j.cretres.2013.11.007|bibcode=2014CrRes..47..117K }}</ref><ref name=AO2024>{{Cite journal |last=Alvarado-Ortega |first=Jesús |date=2024-12-29 |title=Amakusaichthys benammii sp. nov., a Campanian long-nose ichthyodectiform fish from the Tzimol Quarry, Chiapas, southeastern Mexico |url=https://palaeo-electronica.org/content/2024/5295-a-long-nose-ichthyodectiform |journal=Palaeontologia Electronica |language=English |volume=27 |issue=3 |pages=1–37 |doi=10.26879/1444 |issn=1094-8074|doi-access=free }}</ref> ** {{Extinct}}''Chuhsiungichthys''? Lew, 1974 ** {{Extinct}}''Jinjuichthys''? Kim ''et al.'', 2014 ** {{Extinct}}''Mesoclupea''? Ping & Yen, 1933 * {{Extinct}}'''Bardackichthyidae'''? Hacker & Shimada, 2021 ** {{Extinct}}''Bardackichthys''? Hacker & Shimada, 2021<ref name=AO2024/> * {{Extinct}}'''Cladocyclidae''' Maisey, 1991 ** {{Extinct}}''Aidachar'' Nesov, 1981<ref name="Cavin2015">{{cite journal |last1=Cavin |first1=L. |last2=Boudad |first2=L. |last3=Tong |first3=H. |last4=Läng |first4=E. |last5=Tabouelle |first5=J. |last6=Vullo |first6=R. |title=Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco |journal=PLOS ONE |date=2015 |volume=10 |issue=5 |article-number=e0125786 |doi=10.1371/journal.pone.0125786|pmid=26018561 |pmc=4446216 |bibcode=2015PLoSO..1025786C |doi-access=free }}</ref> ** {{Extinct}}''Chirocentrites'' Heckel, 1849 ** {{Extinct}}''Chiromystus'' Cope, 1885 ** {{Extinct}}''Cladocyclus'' Agassiz, 1841 ** {{Extinct}}''Cladocynodon'' de Mayrinck ''et al.'', 2023<ref name="Mayrinck2023">{{cite journal |last1=de Mayrinck |first1=D. |last2=Ribeiro |first2=A. C. |last3=Assine |first3=M. L. |last4=Spigolon |first4=A. L. D. |title=A New Genus and Species of †Cladocyclidae (Teleostei: †Ichthyodectiformes) from the Lower Cretaceous "Batateira Beds", Barbalha Formation, Araripe Basin: The First Vertebrate Record in a Still Poorly Explored Fossil Site |journal=Diversity |date=2023 |volume=15 |issue=3 |page=413 |doi=10.3390/d15030413 |doi-access=free }}</ref> ** {{Extinct}}''Eubiodectes'' Hay, 1903 * {{Extinct}}'''Ichthyodectidae''' Crook, 1892 ** {{Extinct}}''Cooyoo'' Bartholomai & Less, 1987 ** {{Extinct}}''Ghrisichthys'' Cavin ''et al.'', 2013 ** {{Extinct}}''Ichthyodectes'' Cope, 1870 ** {{Extinct}}''Postredectes'' Kaddumi, 2009<ref name=":0">{{Cite book |last=Kaddumi |first=Hani F. |title=Fossils of the Harrana Fauna and the Adjacent Areas |publisher=Eternal River Museum of Natural History |year=2009 |location=Amman |chapter=Ichthyodectids of the late Maastrichtian sediments of the Muwaqqar Chalk Marl Formation of Harrana |oclc=709582892}}</ref> ** {{Extinct}}''Xiphactinus'' Leidy, 1870 * {{Extinct}}'''Heckelichthyidae''' Alvarado-Ortega, 2024<ref name=AO2024/> ** {{Extinct}}''Altamuraichthys''? Taverne, 2016 ** {{Extinct}}''Amakusaichthys'' Yabumoto ''et al.'', 2020 ** {{Extinct}}''Garganoichthys''? Taverne, 2009 ** {{Extinct}}''Heckelichthys'' Taverne, 2008 * {{Extinct}}'''Saurodontidae''' Cope, 1870<ref name=Cope1870>Cope, E. D. (1870). On the Saurodontidæ. ''Proceedings of the American Philosophical Society'' 11:529-538</ref><ref>Cope, E. D. (1873). On two new species of Saurodontidae. ''Proceedings of the Academy of Natural Sciences of Philadelphia'' 25:2-339</ref> ** {{Extinct}}''Gillicus'' Cope, 1875 ** {{Extinct}}''Gwawinapterus'' Arbour & Currie, 2011<ref name=fishjvp>Vullo, 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. {{doi|10.1080/02724634.2012.681078}}</ref> ** {{Extinct}}''Prosaurodon'' Stewart, 1999 ** {{Extinct}}''Saurocephalus'' Harlan, 1824 ** {{Extinct}}''Saurodon'' Hay, 1830 ** {{Extinct}}''Vallecillichthys'' Blanco & Cavin, 2003 ** {{Extinct}}''Wadiichthys'' Abu El-Kheir, 2026<ref>{{Cite journal|last1=Abu El-Kheir |first1=G. A. |last2=Marzouk |first2=A. |last3=Capasso |first3=L. |last4=Zahran |first4=E. |last5=Kasem |first5=A. M. |last6=Kamel |first6=A. |last7=Mousa |first7=M. K. |last8=Elbsebeshi |first8=A. |year=2026 |title=A new saurodontid fish from the Late Cretaceous of the Western Desert, Egypt |journal=Acta Palaeontologica Polonica |volume=71 |issue=1 |pages=85–94 |doi=10.4202/app.01277.2025 |doi-access=free }}</ref> {{Div col end}}

==References== {{Reflist}}

==External links== * {{Commons category-inline}} * {{Wikispecies-inline|Ichthyodectiformes}}

Category:Ichthyodectiformes Category:Prehistoric teleostei Category:Prehistoric ray-finned fish orders Category:Late Jurassic first appearances Category:Paleocene extinctions Category:Taxa described in 1969