Latirhinus
From Latin latus (broad) and Greek rhis (nose); meaning "broad nose"
Latirhinus is an extinct genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous of Mexico. The type species, Latirhinus uitstlani, was named in 2012 on the basis of a partial skeleton from the Campanian-age Cerro del Pueblo Formation. The specific name uitstlani means "southern" in the Náhuatl language of Mexico, a reference to the species' southern occurrence in the Cretaceous landmass Laramidia. The genus name refers to the broad narial region inferred from an arcuate skull fragment identified in the original description as a partial nasal; that element was subsequently reidentified as a fragment of right jugal belonging to a much larger hadrosaurid and removed from the holotype, leaving the skull of Latirhinus effectively unknown.
Under dispute
Latirhinus uitstlani was originally described as a saurolophine and was later recovered at the base of Hadrosauridae in a clade with Aquilarhinus, but both of those placements rested on an arcuate skull fragment interpreted as a partial nasal, since reidentified as a fragment of right jugal from a much larger hadrosaurid and excluded from the holotype. Ramírez-Velasco and colleagues (2021) reassigned the species to Lambeosaurinae on a rediagnosis of the recomposed holotype, and two independent parsimony analyses published in 2022, one of them co-authored by the original describer, recovered it within Lambeosaurinae. Those two analyses differ on how deeply it nests: Serrano-Brañas and Prieto-Márquez left its relationships within the subfamily unresolved, while Ramírez-Velasco recovered it within Lambeosaurini alongside Magnapaulia and Velafrons. The composition of the holotype itself remains contested, the 2021 and 2022 studies disagreeing over which elements of the bonebed belong to the type individual.
Diagnosis
- Coracoid oval in shape and poorly developed laterally, with an elongate biceps tuberosity
- Rounded dorsal margin of the coracoid in medial view (convergent with basally branching hadrosauroids)
- Well developed and medially pronounced subcoracoid tuberculum
- Low sternal process of the coracoid (convergent with basally branching hadrosauroids)
- Rounded, slightly anteroposteriorly compressed bump on the scapular glenoid process
- Trapezoid lateroventral corner of the humeral deltopectoral crest, abruptly expanded anteriorly into two lobes protruding medially and laterally
Species
Latirhinus uitstlani Prieto-Márquez & Serrano-Brañas, 2012
Type species
From the Náhuatl language of Mexico, 'uitstlani' meaning 'southern', in reference to the species' occurrence in the southern part of the Late Cretaceous landmass Laramidia.
- Holotype
- IGM 6583, IGM 12713, IGM 12714 , Instituto de Geología, Universidad Nacional Autónoma de México
- Material
- IGM 6583 in part, comprising 14 caudal vertebrae, left coracoid, proximal fragment of left scapula, both humeri and ulnae, right metacarpals III and IV, left manual phalanx II-1, preacetabular process of left ilium, both femora, tibiae, and fibulae, and left astragalus; IGM 12713, ten associated partial dorsal vertebrae; IGM 12714, left and right metatarsals III and IV, both proximal phalanges III-1, and a left proximal pedal phalanx II-1
- Horizon
- Cerro del Pueblo Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
- Locality
- Ejido Presa San Antonio, Coahuila, Mexico
References
- Prieto-Márquez, A.; Serrano-Brañas, C. I. (2012). Latirhinus uitstlani, a 'broad-nosed' saurolophine hadrosaurid (Dinosauria, Ornithopoda) from the late Campanian (Cretaceous) of northern Mexico. Historical Biology 24(6): 607-619. Informa UK Limited. doi:10.1080/08912963.2012.671311 prieto-márquez2012a
-
Prieto-Márquez, A.; Wagner, J. R.; Lehman, T. (2020). An unusual 'shovel-billed' dinosaur with trophic specializations from the early Campanian of Trans-Pecos Texas, and the ancestral hadrosaurian crest. Journal of Systematic Palaeontology 18(6): 461-498. Informa UK Limited. doi:10.1080/14772019.2019.1625078
Described Aquilarhinus as a close relative, uniting both near Hadrosauridae's base.
prieto-márquez2020a -
Ramírez-Velasco, A. A.; Espinosa-Arrubarrena, L.; Alvarado-Ortega, J. (2021). Review of the taxonomic affinities of Latirhinus uitstlani, an emblematic Mexican hadrosaurid. Journal of South American Earth Sciences 110: 103391. Elsevier BV. doi:10.1016/j.jsames.2021.103391
Reidentified the supposed nasal as a jugal, recomposed the holotype and reassigned the species from Saurolophinae to Lambeosaurinae.
ramírez-velasco2021b -
Serrano-Brañas, C. I.; Prieto-Márquez, A. (2022). Taphonomic attributes of the holotype of the lambeosaurine dinosaur Latirhinus uitstlani from the late Campanian of Mexico: implications for its phylogenetic systematics. Journal of South American Earth Sciences 114: 103689. Elsevier BV. doi:10.1016/j.jsames.2021.103689
Revised the holotype composition and diagnosis on taphonomic grounds and recovered the species within Lambeosaurinae in a parsimony analysis.
serrano-brañas2022a -
Ramírez-Velasco, A. A. (2022). Phylogenetic and biogeography analysis of Mexican hadrosauroids. Cretaceous Research 138: 105267. Elsevier BV. doi:10.1016/j.cretres.2022.105267
Recovered the species within Lambeosaurini alongside Magnapaulia and Velafrons.
ramírez-velasco2022a -
Jiménez-Moreno, F. J.; Ramírez-Velasco, A. A.; Ocampo-Cornejo, P.; Velázquez-Castro, J.; Palomino-Merino, R. (2025). First population analysis in Hadrosauroid dinosaurs (Ornithopoda: Iguanodontia: Hadrosauroidea). Evolving Earth 3: 100072. Elsevier BV. doi:10.1016/j.eve.2025.100072
Estimated body mass and population density for the species in a comparative analysis of hadrosauroid populations.
jiménez-moreno2025a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Treats Latirhinus as a lambeosaurine.
jones2026a