Theropod teeth from the Upper Cretaceous of central Spain: Assessing the paleobiogeographic history of European abelisaurids

Abstract

The upper Campanian–lower Maastrichtian site of Poyos (Guadalajara, Spain) has yielded an abundant fossil record of reptiles, including several cranial and postcranial elements of theropod dinosaurs. Here we present a study, based on statistical and cladistic analyses as well as on detailed description, of a sample of isolated theropod teeth collected from this site. The sample comprises twenty relatively complete and well-preserved tooth crowns, belonging to mesial and lateral teeth. The combination of morphological and morphometric features is consistent with the identification of these specimens as belonging to a medium-sized abelisaurid theropod. These specimens resemble the teeth associated with the holotype of Arcovenator escotae (upper Campanian of France) and some isolated teeth assigned to Arcovenator sp. from different temporal correlative localities of Spain. These similarities suggest the presence of an abelisaurid closely related to Arcovenator in Poyos, expanding the fossil record of this lineage of abelisaurids to the upper Campanian-lower Maastrichtian in the Iberian Peninsula. The currently known fossil record shows that abelisaurids were one of the most abundant groups of non-coelurosaurian theropods in the Upper Cretaceous of Europe and possibly the only medium-to large-size carnivorous dinosaurs in the Ibero-Armorican realm from the upper Cenomanian to the upper Maastrichtian. The increasing abundance of abelisaurids during the Late Cretaceous and the vanishing of other large theropods that dominated the Early Cretaceous faunas of Ibero-Armorica seem to be part of a faunistic turnover that can be related to a climate change to semi-arid conditions.