Coahuilasaurus, a new hadrosaur from Coahuila, Mexico

[Halichoeres]

Just the snoot:



Open access in Diversity: https://www.mdpi.com/1424-2818/16/9/531

[Newt]

Sweet! The Cerro del Pueblo is racking up on hadrosaurs.

Besides the new guy, there's a huge (ca. 11 m) individual referred to the kritosaurin saurolophine Kritosaurus navajovius; Latirhinus uitstlani, which could be a saurolophine or a lambeosaurine; plus the definite lambeosaurines Velafrons coahuilensis and Tlatolophus galorum. That's a pretty remarkable diversity of hadrosaurs for a unit that's still in the early stages of exploration, especially compared to some of the classic formations in the western US and Canada.

*EDIT* I really should have read the paper before posting. It seems part of the Cerro del Pueblo "Kritosaurus" material is the basis of Coahuilasaurus, and none of the rest can be definitely assigned to Kritosaurus, so it's off the list. Still, the formation's hadrosaur diversity is impressive.

[VD231991]

The recognition of Coahuilasaurus as distinct from Kritosaurus reminds me of the situation where Kritosaurus australis was once seen as a junior synonym of Secernosaurus before it was re-assessed as distinct and renamed Huallasaurus by Rozadilla et al. (2022). Given that the cladistic analysis by Longrich and colleagues finds Gryposaurus alsatei to be closely related to the South American kritosaurs, it is now obvious that some kritosaurs found in Laramidia are closely related to those from Patagonia. It'd be interesting to see if the specimen PASAC-1 from the Olmos Formation of Sabinas, northern Mexico is more closely related to Gryposaurus, Coahuilasaurus, and austrokritosaurins than to Kritosaurus because members of Austrokritosaurina are known from late Campanian to Maastrichtian deposits.

Rozadilla, S., Brissón-Egli, F., Agnolín, F.L., Aranciaga-Rolando, A.M., and Novas, F.E., 2022. A new hadrosaurid (Dinosauria: Ornithischia) from the Late Cretaceous of northern Patagonia and the radiation of South American hadrosaurids. Journal of Systematic Palaeontology 19 (17): 1207–1235. doi:10.1080/14772019.2021.2020917.