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| Prognathodon cipactli Rivera-Sylva, Sánchez-Uribe, Guzmán-Gutierrez, Rodríguez, Rangel-Morelos, & Longrich, 2026 |
Abstract
Mosasaurs staged a major radiation at the end of the Cretaceous period before perishing at the Cretaceous-Paleogene boundary. Although mosasaurs are well-known from the Late Cretaceous of North America, relatively little is known about the mosasaurids of Mexico. In 2001 the largely complete skull of a mosasaurid was collected from outcrops of the Early Maastrichtian Mendez Formation at Rancho Las Barretas, 10 kilometers northeast of Linares. Although much of the skeleton was reported to have been present, only the skull was collected and the quarry has not been relocated. The specimen was described and figured in 2007 by Buchy et al. (2007) and reported as an indeterminate mosasaurid. Although the specimen has suffered some erosion after exposure in the desert, it includes most of the skull. We redescribe this specimen and show that it represents a derived species of Prognathodon, P. cipactli sp. nov. The specimen shows specializations for an apex predator niche, including a a short rostrum with robust jaws and teeth, suggesting that specialization for taking large prey preceded the evolution of large size in prognathodontins. The specimen enhances our understanding of the fossil record and paleoecology of the Western Interior Seaway during the Late Cretaceous, showing how prognathodontins successfully exploited the top predator niche globally in the Maastrichtian.
Keywords: Mosasauridae • Prognathodon • Maastrichtian • Mexico • Mendez Formation
Prognathodon cipactli sp. nov.
Rivera-Sylva, Héctor E.; Sánchez-Uribe, Iván E.; Guzmán-Gutierrez, José Rubén; Rodríguez, Rosalba Lizbeth Nava; Rangel-Morelos, Adolfo A. and Longrich, Nicholas. 2026. A New Species of Prognathodon (Squamata: Mosasauridae) from the Early Maastrichtian of Nuevo León, Mexico. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. DOI: doi.org/10.1127/njgpa/1303 [Mar 9, 2026]
