Abstract

BUCHY, Marie-Céline; FREY, Eberhard; STINNESBECK, Wolfgang  and  LOPEZ-OLIVA, José Guadalupe. Cranial anatomy of a Maastrichtian (Upper Cretaceous) mosasaur (Squamata, Mosasauridae) from north-east Mexico. Rev. mex. cienc. geol [online]. 2007, vol.24, n.1, pp.89-103. ISSN 2007-2902.

We here describe ihefirsl mosasaur from Mexico known by significanl cranial remains, from ihe late Early Maastrichtian Méndez Formation of Nuevo León, north-east Mexico. The specimen comprises a fragmentary skull and parts of the mandibles. Some anatomical features suggest a juvenile animal. The skull possesses a rostral tuberosity on the premaxilla, as well as a combination of features known from different mosasaur genera, like its frontopremaxillary suture situated caudal to the external naris, its prefrontal and postorbitofrontal being in contact lateral to the orbit, associated with the supra- and infrastapedial processes of its quadrate which almost contact one another. Despite being clearly distinct from any hitherto described mosasaur, the affinities of this specimen with other mosasaurs remain obscure, not only because of incompleteness, but also because of the poorly understood biological significance of the characters used for the classification of Mosasauridae.

Keywords : Mosasauridae; Early Maastrichtian; Méndez Formation; north-east Mexico.

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