Ischyrotherium

Ischyrotherium is an extinct genus named by Joseph Leidy in 1856 for fossils from the lignite deposits in Nebraska. Originally considered an herbivorous cetacean, Leidy then reassigned it to Sirenia as a relative of manatees, before Edward Drinker Cope reclassified it as a non-mammalian, suggesting the new name Ischyrosaurus to better identify its reptilian origins, as he considered it a sauropterygian.^[1][2][3] Ischyrotherium was found alongside material from the hadrosaur Thespesius and turtles Compsemys and Emys, and the fish Mylognathus.^[2] The name Ischyrosaurus was also used by John Whitaker Hulke for the sauropod now known as Ornithopsis manseli, as he was unaware it was preoccupied by Cope.^[4]

Ischyrotherium Temporal range: Late Cretaceous, Maastrichtian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Genus:	†Ischyrotherium Leidy, 1856
Species:	†I. antiquus
Binomial name
†Ischyrotherium antiquus Leidy, 1856
Synonyms
Ischyrotherium antiquum Leidy, 1860 Ischyrosaurus antiquum Cope, 1869

References

1. Leidy, J. (1856). "Notice of extinct Vertebrata, discovered by F. V. Hayden during the expedition to the Sioux country under the command of Lieut. G.K. Warren". Proceedings of the Academy of Natural Sciences of Philadelphia. 8: 89.
2. Leidy, J. (1860). "Extinct Vertebrata from the Judith River and Great Lignite Formations of Nebraska". Transactions of the American Philosophical Society. New Series. 11: 139–154. doi:10.2307/3231936. JSTOR 3231936.
3. Cope, E.D. (1869). "Synopsis of the extinct Batrachia, Reptilia, and Aves of the United States". Transactions of the American Philosophical Society. 14: 1–252. doi:10.2307/1005355. JSTOR 1005355.
4. Martill, D.M.; Earland, S.; Naish, D. (2006). "Dinosaurs in marine strata: evidence from the British Jurassic, including a review of the allochthonous vertebrate assemblage from the marine Kimmeridge Clay Formation (Upper Jurassic) of Great Britain". ColectivoArqueológico-Paleontológico Salense. Actas de las III Jornadas sobre Dinosaurios y su Entorno. pp. 1–31.