Wednesday, January 10, 2024

[Paleontology • 2024] Varanosuchus sakonnakhonensis • New Cretaceous neosuchians (Crocodylomorpha) from Thailand bridge the evolutionary history of atoposaurids and paralligatorids


Varanosuchus sakonnakhonensis 
Pochat-Cottilloux, Lauprasert, Chanthasit, Manitkoon, Adrien, Lachambre, Amiot & Martin, 2024

วาราโนซูคัส สกลนครเอนซิส  || DOI: 10.1093/zoolinnean/zlad195


Abstract
The origin of modern crocodylians is rooted in the Cretaceous, but their evolutionary history is obscure because the relationships of outgroups and transitional forms are poorly resolved. Here, we describe a new formVaranosuchus sakonnakhonensis gen. nov., sp. nov., from the Early Cretaceous of Thailand that fills an evolutionary gap between Paralligatoridae and Atoposauridae, two derived neosuchian lineages with previously unsettled phylogenetic relationships. Three individuals, including a complete skull and associated postcranial remains, allow for a detailed description and phylogenetic analysis. The new taxon is distinguished from all other crocodylomorphs by an association of features, including a narrow altirostral morphology, a dorsal part of the postorbital with an anterolaterally facing edge, a depression on the posterolateral surface of the maxilla, and fully pterygoid-bound choanae. A phylogenetic analysis confirms the monophyly and taxonomic content of Atoposauridae and Paralligatoridae, and we underline the difficulty in reaching a robust definition of Eusuchia. Furthermore, we put forward further arguments related to the putative terrestrial ecology with semi-aquatic affinities of atoposaurids based on their altirostral snout morphology and osteoderm ornamentation.

Atoposauridae, CT scan, Neosuchia, Phu Sung, Sao Khua, Thailand

Varanosuchus sakonnakhonensis gen. nov., sp. nov.

 



Yohan Pochat-Cottilloux, Komsorn Lauprasert, Phornphen Chanthasit, Sita Manitkoon, Jérôme Adrien, Joël Lachambre, Romain Amiot and Jeremy E Martin. 2024. New Cretaceous neosuchians (Crocodylomorpha) from Thailand bridge the evolutionary history of atoposaurids and paralligatorids. Zoological Journal of the Linnean Society. zlad195. DOI: 10.1093/zoolinnean/zlad195

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