Huehuecanauhtlus tiquichensis, new Santonian hadrosauroid

[Jay <jayp.nair@yahoo.com>]

Huehuecanauhtlus tiquichensis

Ramírez-Velasco AA, Benammi M, Prieto-Márquez A, Ortega JA, Hernández-Rivera R 
(2012) Huehuecanauhtlus tiquichensis, a new hadrosauroid dinosaur 
(Ornithischia: Ornithopoda) from the Santonian (Late Cretaceous) of Michoacán, 
Mexico. Canadian Journal of Earth Sciences 49(2): 379-395.
http://www.nrcresearchpress.com/doi/abs/10.1139/e11-062


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.