Mounted skeleton of X. audax at the American Museum of Natural History
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
†Ichthyodectiformes
Family:
†Ichthyodectidae
Subfamily:
†Ichthyodectinae
Genus:
†Xiphactinus Leidy, 1870
Type species
†Xiphactinus audax
Leidy, 1870
Species[1]
† X. audaxLeidy, 1870
† X. vetusLeidy, 1856
Synonyms
List of synonyms[2][3]
Synonyms of X. audax
Saurocephalus audax Cope, 1870
Saurocephalus thaumas Cope, 1870
Portheus molossus Cope, 1871
Portheus thaumas Cope, 1871
Portheus lestrio Cope, 1873
Portheus mudgei Cope, 1874
Portheus lowii Stewart, 1898
Xiphactinus molossus Stewart, 1898
Xiphactinus thaumas Stewart, 1898
Xiphactinus brachygnathus Stewart, 1899
Xiphactinus lowii Stewart, 1900
Xiphactinus gaultinus Newton, 1877
Xiphactinus mantelli Newton, 1877
Megalodon sauroides Agassiz, 1835
Megalodon? lewesiensis Mantell, 1836
Hypsodon lewesiensis Agassiz, 1843
Portheus mantelli Newton, 1877
Portheus daviesi Newton, 1877
Synonyms of X. vetus
Polygonodon vetus Leidy, 1856
Polygonodon rectus Emmons, 1858
Mossasaurus rectus Emmons, 1858[a]
Portheus angulatus Cope, 1872
Xiphactinus angulatus Schwimmer et al., 1992
Xiphactinus (from Latin and Greek for "sword-ray"), colloquially referred to as the X-fish, is an extinct genus of large predatory marine bony fish that lived during the late Albian to the late Maastrichtian.[4] The genus grew up to 5–6 metres (16–20 ft) in length, and superficially resembled a gargantuan, fanged tarpon.[1][5]
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),[6][7] and Cretaceous formations all over the East Coast (most notably Georgia, Alabama, North Carolina, and New Jersey) in the United States,[6][3] as well as Europe, Australia,[8] the Kanguk and Ashville Formations of Canada,[6] La Luna Formation of Venezuela and the Salamanca Formation in Argentina.[6][4][9]
^ abVavrek, M.J.; Murray, A.M.; Bell, P.R. (2016). "Xiphactinus audax Leidy, 1870 from the Puskwaskau Formation (Santonian to Campanian) of northwestern Alberta, Canada and the distribution of Xiphactinus in North America". Vertebrate Anatomy Morphology Palaeontology. 1 (1): 89–100. doi:10.18435/B5H596.
^Bardack, D. (1965). "Anatomy and evolution of chirocentrid fishes". The University of Kansas Paleontological Contributions. 10: 1–88. hdl:1808/3814.
^ abSchwimmer, David R.; Stewart, J. D.; Williams, G. Dent (1997). "Xiphactinus vetus and the Distribution of Xiphactinus Species in the Eastern United States". Journal of Vertebrate Paleontology. 17 (3): 610–15. doi:10.1080/02724634.1997.10011007. JSTOR 4523841.
^ abDe Pasqua, Julieta J.; Agnolin, Federico L.; Bogan, Sergio (2020). "First record of the ichthyodectiform fish Xiphactinus (Teleostei) from Patagonia, Argentina". Alcheringa: An Australasian Journal of Palaeontology. 44 (2): 327–331. doi:10.1080/03115518.2019.1702221. S2CID 216170146.
^Lionel Cavin; Peter L. Forey; Samuel Giersch (2013). "Osteology of Eubiodectes libanicus (Pictet & Humbert, 1866) and some other ichthyodectiformes (Teleostei): phylogenetic implications". Journal of Systematic Palaeontology. 11 (2): 115–177. doi:10.1080/14772019.2012.691559. S2CID 83807640.
^ abcdXiphactinus at Fossilworks.org
^Haines, Tim; Chambers, Paul (2005). The complete guide to prehistoric life (First ed.). Buffalo, N.Y.: Firefly Books. p. 134. ISBN 978-1-55407-181-4. The first Xiphactinus fossil was found during the 1850s in Kansas.
^Vavrek, Matthew J.; Murray, Alison M.; Bell, Phil R. (2016-02-04). "Xiphactinus audax Leidy 1870 from the Puskwaskau Formation (Santonian to Campanian) of northwestern Alberta, Canada and the distribution of Xiphactinus in North America". Vertebrate Anatomy Morphology Palaeontology. 1: 89. doi:10.18435/B5H596.
^Carrillo-Briceño, J., Alvarado-Ortega, J. & Torres, C. (2012). 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
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Skeletal remains of Xiphactinus have come from the Carlile Shale and Greenhorn Limestone of Kansas (where the first Xiphactinus fossil was discovered...
fed on small particles. There is evidence that at least one species, Xiphactinus audax, may have been endothermic ("warm-blooded"). The basal phylogeny...
fish Xiphactinus audax with the skeleton of another bony fish, Gillicus arcuatus inside the larger one. Another excellent skeleton of Xiphactinus audax...
was also a filter-feeder. Gillicus was also eaten by its own relative, Xiphactinus. One particular 13 foot (4.0 m) long fossil specimen contains a nearly...
specimen found with the stomach stuffed with the extinct herring Xyne grex) Xiphactinus (a 4-meter-long specimen was found with a perfectly preserved skeleton...
Pachyrhizodus, Enchodus, and the massive 4-to-5-metre (13 to 16 ft) long Xiphactinus, larger than any modern bony fish. Other sea life included invertebrates...
R.; Stewart, J. D.; Williams, G. Dent (1997). "Xiphactinus vetus and the Distribution of Xiphactinus Species in the Eastern United States". Journal of...
to the sea, bitten off by some large predator such as a mosasaur or a Xiphactinus, or was crushed off by larger adults while herding on the shore. However...
The museum's fossil collection includes a 20-foot mosasaur, a 14-foot Xiphactinus fish, Pteranodon specimens, fossil birds, and numerous other late Cretaceous...
and consists of a partial vertebral column with skeletal remains of a Xiphactinus as stomach contents and partial jaws with about 150 teeth visible. This...
such as Enchodus, Protosphyraena, Stratodus, and the ichthyodectids Xiphactinus and Saurodon. Mosasaurus is known from late Maastrichtian deposits in...
"Unicerosaurus" (Armstrong, 1987, identified this fossil as belonging to a fish Xiphactinus). Studies over the years had concluded that the fossil "human" footprints...
Enchodus, Cimolichthys, Saurocephalus, Saurodon, Gillicus, Ichthyodectes, Xiphactinus, Protosphyraena and Martinichthys; and the sharks Cretoxyrhina, Cretolamna...
surface. Hesperornis hunt for fish until they themselves are hunted by Xiphactinus. Nostoceras hatchlings are at the mercy of the tides and juvenile Pyroraptor...
of partial wing bones, as well as a tooth from the prehistoric fish Xiphactinus, which Marsh mistakenly believed to belong to this new pterosaur (all...
warm waters frequented by sharks, small mosasaurs, and fish such as Xiphactinus. Spiral-shelled ammonites and invertebrates of the marine shelf are also...
specimens, which were accompanied by teeth that belonged to the fish Xiphactinus, which Marsh assumed that these teeth belonged to the pterosaur specimens...
silicoflagellates. 115 Ma First monotreme mammals. 114 Ma Earliest bees. 112 Ma Xiphactinus, a large predatory fish, appears in the fossil record. 110 Ma First hesperornithes...
large predatory fish were present in the seas at that time, most notably Xiphactinus. Several fish were of close relation to modern day fish including primitive...
swordfish-like Protosphyraena, as well as the predatory fishes Pachyrhizodus, Xiphactinus, Ichthyodectes, Gillicus, Leptecodon, Enchodus and Cimolichthys, the...
ichthyodectiform fish was Xiphactinus, which measured up to 6.1 m (20 ft) long. Ichthyodectes reached 3 m (9.8 ft) long, twice lesser than Xiphactinus. The largest...
body and large eyes, suggest Enchodus was a predatory species. XiphactinusXiphactinus is an extinct genus of large predatory marine bony fish of the...
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