Simoedosaurus
{{Short description|Extinct genus of reptiles}}
{{Italic title}}
{{Automatic taxobox
| name = Simoedosaurus
| fossil_range = Paleocene-Eocene
| image = Simoedosaurus lemoinei Cernay.JPG
| image_caption = Fossil
| taxon = Simoedosaurus
| authority = Gervais, 1877
| type_species = {{extinct}}Simoedosaurus lemoinei
| type_species_authority = Gervais, 1877
| subdivision_ranks = Other species
}}
Simoedosaurus is an extinct reptile known from the Paleocene of North America, Europe and western Asia,{{cite journal | vauthors = Averianov AO | date = 2005 | title = The first choristoderes (Diapsida, Choristodera) from the Paleogene of Asia. | journal = Paleontological Journal | volume = 39 | issue = 1 | pages = 79–84 }} and a member of the Choristodera, a group of aquatic reptiles that lived in the Northern Hemisphere from the Jurassic to the early Cenozoic.
A second species, S. dakotensis got its own genus, Kosmodraco, in 2022.{{cite journal | vauthors = Brownstein CD | title = High morphological disparity in a bizarre Paleocene fauna of predatory freshwater reptiles | journal = BMC Ecology and Evolution | volume = 22 | issue = 1 | pages = 34 | date = March 2022 | pmid = 35313822 | pmc = 8935759 | doi = 10.1186/s12862-022-01985-z | doi-access = free }}
Taxonomy
French paleontologist Paul Gervais described Simoedosaurus in 1877.
Though similar to and contemporaneous, Simoedosaurus is not closely related to the North American Champsosaurus, instead it appears to be most closely related to Tchoiria and Ikechosaurus from the Early Cretaceous of Asia. It therefore may represent a species that immigrated into North America from Asia in the wake of the Cretaceous-Tertiary mass extinction event, though the absence of choristoderes in the Late Cretaceous of Asia makes this merely a paleogeographical speculation.{{cite journal | vauthors = Matsumoto R, Evans SE | date = 2010 | title = Choristoderes and the freshwater assemblages of Laurasia. | journal = Journal of Iberian Geology | volume = 36 | issue = 2 | pages = 253–274 | doi = 10.5209/rev_JIGE.2010.v36.n2.11 | doi-access = free }}
Biology
Simoedosaurus was an aquatic predator, specialised to a fully aquatic lifestyle; though Champsosaurus might have still come ashore to lay eggs, ovovivipary is known in other choristoderes.{{cite journal | vauthors = Ji Q, Ji SA, Lu J, You H, Yuan CX | date = 2006 | title = Embryos of Early Cretaceous Choristodera (Reptilia) from the Jehol Biota in western Liaoning, China. | journal = Journal of the Paleontological Society of Korea | volume = 22 | issue = 1 | pages = 111–118 }} It in particular possesses broader, stronger jaws than other longirostrine choristoderes, including its closest relatives, suggesting that it was capable of tackling larger prey.{{cite journal | vauthors = Matsumoto R, Evans SE | title = Morphology and function of the palatal dentition in Choristodera | journal = Journal of Anatomy | volume = 228 | issue = 3 | pages = 414–29 | date = March 2016 | pmid = 26573112 | pmc = 5341546 | doi = 10.1111/joa.12414 }}
Simoedosaurus does occur in sites where aquatic crocodilians are present, including brevirostrine forms like Borealosuchus; the extent of competition between both groups, if there was any, is still unresolved.R. Matsumoto and S. E. Evans. 2010. Choristoderes and the freshwater assemblages of Laurasia. Journal of Iberian Geology 36(2):253-274
Like other neo-choristoderes it has nasal conchae, suggesting it could regulate its own body temperature, explaining its ability to live in cold waters.{{cite thesis | vauthors = Dudgeon TW | date = 2019 | title = The internal cranial anatomy of Champsosaurus lindoei and its functional implications | degree = Doctoral | publisher = Carleton University | url = https://curve.carleton.ca/6208eb7f-08f0-42a9-9a09-6d96779836fb }}
Range
The earliest records of Simoedosaurus are from the Early Paleocene (Puercan Land Mammal Age) of Saskatchewan. It persisted until the Late Palaecene in North America, and has also been found in the Late Paleocene of France. The youngest remains seem to occur in the Eocene of Kazakhstan.{{cite journal | vauthors = Averianov AO | date = 2005 | title = The first choristoderes (Diapsida, Choristodera) from the Paleogene of Asia. | journal = Paleontological Journal | volume = 39 | issue = 1 | pages = 79–84 }}
References
{{Reflist}}
{{Choristodera|S.}}
{{Taxonbar|from=Q2164813}}
Category:Extinct animals of Europe
Category:Extinct animals of North America