The cranial osteology of Concavenator corcovatus (Theropoda; Carcharodontosauria) from the Lower Cretaceous of Spain

Concavenator corcovatus is a carcharodontosaurid dinosaur represented by an almost complete and articulated skeleton from the 'Las Hoyas' fossil site (Lower Cretaceous, Spain). The skull of Concavenator is almost complete, missing only the anteriormost and posteriormost regions. Here, a review of the cranial anatomy of Concavenator has been carried out to test its phylogenetic relationships. This description provides a detailed revision of the cranial anatomy of carcharodontosaurids, which is relevant to their general phylogenetic relationships. The results show that the skull of Concavenator has several carcharodontosaurid synapomorphies such as: (1) a lacrimal-postorbital contact, (2) a well-developed postorbital boss, (3) anteroventrally oriented postorbital ventral process, (4) an intraorbital process in the postorbital, (5) rostrally projected roughness in the dorsal surface of the postorbital, (6) a notch in the ascending ramus of the maxilla, (7) a sulcus on the anterior margin of the lacrimal ventral ramus, (8) curved dorsal surface of the lacrimal, and (9) fused frontal-parietal contact. Finally, Concavenator has three cranial autapomorphies: (1) connection between the different recesses on the lateral surface of the nasal, (2) elongated and acuminate posterior narial fossa, and (3) a rounded morphology of the ventral surface of the postorbital boss. In addition, anatomical comparison has enabled to create a complete 3D reconstruction of the skull of Concavenator.