Convergent evolution of a eusuchian-type secondary palate within Shartegosuchidae

Title Variants

Alternative: Convergent evolution in Shartegosuchidae palate

Related Titles

Series: American Museum novitates, number 3901

By

Dollman, Kathleen N. , author

Clark, James Matthew, 1956- , author
Norell, Mark A. , author
Xu, Xing, 1969- , author
Choiniere, Jonah N. , author

Type

Book

Material

Published material

Publication info

New York, NY American Museum of Natural History [2018]

Notes

Caption title.

"June 18, 2018."

Specimen collected during the 2010 installment of the American Museum of Natural History-Mongolian Academy of Sciences Paleontological Expedition.

Supplemental material available online in a separate file.

Local PDF available in high- and low-resolution versions.

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.

Subjects

Convergence (Biology) , Crocodilians , Crocodylomorpha , Evolution , Govʹ-Altaĭ Aĭmag , Jurassic , Mongolia , Nasal fossa , Palate , Paleontology , Phylogeny , Reptiles , Reptiles, Fossil , Shartegosuchidae , Shartegosuchoidea , Shartegosuchus asperopalatum

Call Number

QL1 .A436 no.3901 2018

Language

English

Identifiers

DOI: https://doi.org/10.1206/3901.1
OCLC: 1040694876