Review of the taxonomic affinities of Latirhinus uitstlani, an emblematic Mexican hadrosaurid

Abstract This work presents a detailed study of the bones from the holotype of Latirhinus uitstlani. A Mexican hadrosaurid species known informally as “Isauria”, discovered by Don Ramon Lopez, from the Upper Cretaceous Cerro del Pueblo Formation of Coahuila. The results indicate that this Campanian species from the Ejido Presa San Antonio is a chimera or Frankenstein. Its holotype originally includes bones that were individually misinterpreted, belonging to individuals of different sizes, identifiable to saurolophines and lambeosaurines, even, one bone coming from a different locality. Therefore, after classifying the components of the holotype, we rediagnosed L. uitstlani from its pectoral appendicular bones and pelvic bones, confirming their validity as a species. It was also reclassified as a member of the Lambeosaurine subfamily rather than to Saurolophine, and with an estimated body length of 8.72 m. In addition, we identified a large saurolophine, represented by three specimens, and a small lambeosaurine from the same locality of L. uitstlani, along with a small saurolophine from the Cerro de los Dinosaurios area, originally including in the holotype.