Xiphactinus: Difference between revisions

{{Short description|Extinct genus of ray-finned fishes}}

| image = Xiphactinus audax fossil, Tellus Science MuseumAMNH.jpg

| image_caption = Mounted skeleton of ''X. audax'' at the [[Tellus ScienceAmerican Museum]], [[Georgiaof (U.S.Natural state)|GeorgiaHistory]]

| subdivision = *{{extinct}} '''''X. audax''''' {{small|Leidy, 1870}}

'''''Xiphactinus''''' (from [[Latin]] and [[Greek language|Greek]] for "[[sword]]-ray") is an [[Extinction (biology)|extinct]] genus of large predatory marine [[Teleost|bonyray-finned fish]] that lived during the late [[Albian]] to the late [[Maastrichtian]].<ref name=Julieta20/> The genus grew up to {{convert|5|-|6|m|ft|1}} in length, and superficially resembled a gargantuan, fanged [[tarpon]].<ref name=Vavrek16>{{cite journal|author1=Vavrek, M.J.|author2=Murray, A.M.|author3=Bell, P.R.|year=2016|title=''Xiphactinus audax'' Leidy, 1870 from the Puskwaskau Formation (Santonian to Campanian) of northwestern Alberta, Canada and the distribution of ''Xiphactinus'' in North America|journal=Vertebrate Anatomy Morphology Palaeontology|volume=1|issue=1|pages=89–100|doi=10.18435/B5H596|doi-access=free}}</ref><ref>{{Cite journal|author1=Lionel Cavin |author2=Peter L. Forey |author3=Samuel Giersch |year=2013 |title=Osteology of ''Eubiodectes libanicus'' (Pictet & Humbert, 1866) and some other ichthyodectiformes (Teleostei): phylogenetic implications |journal=Journal of Systematic Palaeontology |volume=11 |issue=2 |pages=115–177 |doi=10.1080/14772019.2012.691559 |s2cid=83807640 }}</ref> It is a member of the extinct order [[Ichthyodectiformes]], which represent close relatives of modern [[teleosts]].

The species ''Portheus molossus'' described by Cope is a [[junior synonym]] of ''X. audax''. Skeletal remains of ''Xiphactinus'' have come from the [[Carlile Shale]] and [[Greenhorn Limestone]] of [[Kansas]] (where the first ''Xiphactinus'' fossil was discovered during the 1850s in the [[Niobrara Chalk]]),<ref name="FWXiphactinus">[httphttps://www.fossilworkspaleobiodb.org/cgi-binclassic/bridge.plcheckTaxonInfo?a=taxonInfo&taxon_no=35308 ''Xiphactinus''] at [[Fossilworks]].org</ref><ref name="comguide">{{cite book|last=Haines|first=Tim|title=The complete guide to prehistoric life|year=2005|publisher=Firefly Books|location=Buffalo, N.Y.|isbn=978-1-55407-181-4|edition=First|author2=Chambers, Paul|page=[https://archive.org/details/isbn_9781554071258/page/134 134]|quote=The first ''Xiphactinus'' fossil was found during the 1850s in Kansas.|url-access=registration|url=https://archive.org/details/isbn_9781554071258/page/134}}</ref> and Cretaceous formations all over the [[East Coast of the United States|East Coast]] (most notably [[Georgia (U.S. state)|Georgia]], [[Alabama]], [[North Carolina]], and [[New Jersey]]) in the [[United States]],<ref name="FWXiphactinus" /><ref name=Schwimmeretal1997>{{cite journal |doi=10.1080/02724634.1997.10011007 |first1=David R. |last1=Schwimmer |first2=J. D. |last2=Stewart |first3=G. Dent |last3=Williams |year=1997 |title=''Xiphactinus vetus'' and the Distribution of ''Xiphactinus'' Species in the Eastern United States |journal=[[Journal of Vertebrate Paleontology]] |volume=17 |issue=3 |pages=610–15 |jstor=4523841|bibcode=1997JVPal..17..610S }}</ref> as well as [[Europe]], [[Australia]],<ref>{{cite journal |title=Xiphactinus audax Leidy 1870 from the Puskwaskau Formation (Santonian to Campanian) of northwestern Alberta, Canada and the distribution of Xiphactinus in North America |journal=Vertebrate Anatomy Morphology Palaeontology |date=2016-02-04 |volume=1 |doi=10.18435/B5H596 |url=https://www.researchgate.net/publication/292983703|doi-access=free |last1=Vavrek |first1=Matthew J. |last2=Murray |first2=Alison M. |last3=Bell |first3=Phil R. |page=89 }}</ref> the [[Kanguk Formation|Kanguk]] and [[Ashville Formation]]s of [[Canada]],<ref name="FWXiphactinus" /> [[La Luna Formation]] of [[Venezuela]] and the [[Salamanca Formation]] in [[Argentina]].<ref name="FWXiphactinus" /><ref name=Julieta20>{{cite journal |title=First record of the ichthyodectiform fish Xiphactinus (Teleostei) from Patagonia, Argentina |journal=Alcheringa: An Australasian Journal of Palaeontology |date=2020 |doi=10.1080/03115518.2019.1702221 |url=https://www.tandfonline.com/doi/figure/10.1080/03115518.2019.1702221?scroll=top&needAccess=true|last1=De Pasqua |first1=Julieta J. |last2=Agnolin |first2=Federico L. |last3=Bogan |first3=Sergio |volume=44 |issue=2 |pages=327–331 |bibcode=2020Alch...44..327D |s2cid=216170146 }}</ref><ref>Carrillo-Briceño, J., Alvarado-Ortega, J. & Torres, C. (2012). [http://www.sbpbrasil.org/revista/edicoes/15_3/08_CarrilloBriceno_et_al.pdf Primer registro de ''Xiphactinus'' Leidy, 1870, (Teleostei: Ichthyodectiformes) en el Cretácico Superior de América del Sur (Formación La Luna, Venezuela)]. ''[[Revista Brasileira de Paleontologia]]'' 15(3):327-335</ref>

Species of ''Xiphactinus'' were voracious predatory fish. At least a dozen specimens of ''X. audax'' have been collected with the remains of large, undigested or partially digested prey in their stomachs. In particular, one {{convert|4.2|m|ft|1}} fossil "'''Fish-Within-A-Fish'''" specimen was collected by [[George F. Sternberg]] with another, nearly perfectly preserved {{convert|1.9|m|ft}} long ichthyodectid ''[[Gillicus arcuatus]]'' inside of it. The larger fish apparently died soon after eating its prey, most likely owing to the smaller prey's struggling and rupturing an organ as it was being swallowed. This fossil is on display at the Sternberg Museum of Natural History in [[Hays, Kansas]].<ref>Konishi, T., Newbrey, M. G., & Caldwell, M. W. (2014). A small, exquisitely preserved specimen of ''Mosasaurus missouriensis'' (Squamata, Mosasauridae) from the upper Campanian of the Bearpaw Formation, western Canada, and the first stomach contents for the genus. Journal of Vertebrate Paleontology, 34(4), 802–819. https://doi.org/10.1080/02724634.2014.838573</ref>

Like many other species in the Late Cretaceous oceans, a dead or injured individual was likely to be scavenged by sharks (''[[Cretoxyrhina]]'' and ''[[Squalicorax]]''). The remains of a ''Xiphactinus'' were found within a large specimen of ''[[Cretoxyrhina]]'' collected by Charles H. Sternberg. The specimen is on display at the University of Kansas Museum of Natural History.

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[[Category:IchthyodectidaeIchthyodectiformes]]

[[Category:PrehistoricCretaceous fish of Australia]]