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Convergent evolution of a eusuchian-type secondary palate within Shartegosuchidae. (American Museum novitates, no. 3901)

Show simple item record Dollman, Kathleen N. Clark, James Matthew, 1956- Norell, Mark. Xu, Xing, 1969- Choiniere, Jonah N. Mongolian-American Museum Paleontological Project. Mongolyn Shinzhlėkh Ukhaany Akademi. 2018-06-19T15:13:18Z 2018-06-19T15:13:18Z 2018-06-18
dc.description 23 pages : illustrations (some color), color map ; 26 cm. en_US
dc.description.abstract Shartegosuchids are a poorly known, early-branching group of Asian and North American crocodylomorphs. Shartegosuchids have been hypothesized to have eusuchian-type secondary palates, but a paucity of described material makes assessing this difficult. Our fieldwork in western Mongolia recovered cranial material of a new Shartegosuchus specimen from the Ulan Malgait Formation, which we CT-scanned and digitally reconstructed to investigate its palatal morphology. We then incorporated this new anatomical information into a revised phylogenetic dataset to assess its affinities. Our study confirms that Shartegosuchus has a posteriorly placed choana that is fully enclosed by the pterygoids, but differs from Eusuchia in possessing a secondary palatal fenestra and reduced palatine bones. Shartegosuchus, together with Adzhosuchus, Fruitachampsa, and Nominosuchus, forms the monophyletic group Shartegosuchidae. Shartegosuchidae is nested within a larger clade Shartegosuchoidea, and this clade is an earlier-diverging lineage than Eusuchia, showing that a eusuchian-type secondary palate evolved multiple times in crocodylomorphs, including very early in the group's evolutionary history. The co-occurrence of Nominosuchus in the Ulan Malgait Formation and the Shishigou Formation allows us to assign an early Oxfordian age to Shartegosuchus. The independent evolution of a eusuchian-type secondary palate in an oreinorostral group suggests that the link between platyrostry and a closed secondary palate has been overstated. en_US
dc.language.iso en_US en_US
dc.publisher American Museum of Natural History. en_US
dc.relation.ispartofseries American Museum novitates;no.3901.
dc.subject Shartegosuchus asperopalatum. en_US
dc.subject Palate. en_US
dc.subject Nasal fossa. en_US
dc.subject Convergence (Biology) en_US
dc.subject Shartegosuchidae. en_US
dc.subject Shartegosuchoidea. en_US
dc.subject Phylogeny. en_US
dc.subject Crocodylomorpha. en_US
dc.subject Crocodilians. en_US
dc.subject Govʹ-Altaĭ Aĭmag (Mongolia) en_US
dc.subject Mongolia. en_US
dc.title Convergent evolution of a eusuchian-type secondary palate within Shartegosuchidae. (American Museum novitates, no. 3901) en_US
dc.title.alternative Convergent evolution in Shartegosuchidae palate. en_US

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  • American Museum Novitates
    Novitates (Latin for "new acquaintances"), published continuously and numbered consecutively since 1921, are short papers that contain descriptions of new forms and reports in zoology, paleontology, and geology. New numbers are published at irregular intervals.

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