[D] Huehuecanauhtlus tiquichensis [sG] [T]
Ramírez-Velasco, Benammi, Prieto-Márquez, Ortega & Hernández-Rivera 2012
Cretaceous Late Santonian
Ornithischia Ornithopoda Hadrosauridae
Barranca Los Bonetes locality, Tuzantla, Michoacán, Mexico
Huehuecanauhtlus tiquichensis gen. et sp. nov. is the southernmost diagnostic basal hadrosauroid in the Americas. The holotype and referred material of this taxon came from Santonian strata in the Michoacán State, southwestern Mexico. Huehuecanauhtlus tiquichensis is diagnosed on the basis of a combination of dental, axial, and appendicular characters, including the following: at least two teeth exposed on the occlusal plane of the dentary and maxilla; seven sacral vertebrae; tall neural spines of caudal vertebrae; supraacetabular process long; and short and trapezoidal (in lateral view) postacetabular process.
It differs from other hadrosauroids in having an ilium with extreme ventral deflection of the preacetabular process. Maximum parsimony cladistic analysis placed H. tiquichensis as a closely related outgroup to Hadrosauridae. The occurrence of H. tiquichensis in the Santonian of North America may be explained as a dispersal event from Asia to North America that occurred no later than the Albian or, alternatively, as a vicariant event of a most recent common ancestor widespread in both landmasses.
IGM 6253 represented by fragmentary skull (partial left maxilla and dentary fragment) and postcranial skeleton including four cervical vertebrae, nine dorsal vertebrae, four dorsal neural spines, one dorsal diapophysis, five right dorsal ribs, seven left dorsal ribs, seven sacral neural spines, seven sacral diapophyses, one caudal diapophysis, three caudal vertebrae, two caudal neural spine, eight fragmentary ossified tendons, left and right partial ilium, and left and right partial pubis.
IGM 6254, is represented by fragment of left dentary, two teeth, and one cervical prezygapophysis
The generic name is derived from Náhuatl (group of dialects related to the Aztecan languages) huehuetl, meaning -ancient- and canauhtli, meaning -duck- in reference to its hadrosauroid affinities. The specific name, tiquichensis, honors the town of Tiquicheo, for the generosity and hospitality of its people during the fieldwork season.