Arcovenator

Arcovenator ("Arc hunter") is an extinct genus of abelisaurid theropod dinosaurs hailing from the Late Cretaceous of France. The type and only described species is Arcovenator escotae. Though shallower, the nearly complete braincase of Arcovenator is otherwise similar in size to those of Majungasaurus and Carnotaurus; it was thus initially estimated as being about long, but it was estimated in 2016 as being in length. The skull roof exhibits as a unique diagnostic character a midline foramen, possibly housing the pineal gland, situated on the posterior surface of a slight dome formed by frontal bones as moderately thick as in Aucasaurus, thus less so than for Rajasaurus, though more than those of Rugops. Less characteristically, above the orbit is a low fossa with a small fenestra bordered by the lacrimal, frontal, and postorbital. The parietal bordering the supratemporal fenestrae forms ridges medially on the latter's respective anteromedial margins which, as they approach the parietal eminence, fuse into a sagittal crest. The postorbital is intermediate between the plesiomorphic T-shaped condition of Eoabelisaurus and the derived inverted L-shaped one of Carnotaurus due to the unique feature of having a sheet of bone linking its ventral and posterior processes. It has, in a similar autapomorphic fashion, a thick, rough-surfaced process dorsal to the eye socket that extends to the lacrimal, forming a bony brow ridge, and in a less notable way, a lateral rugose tuberosity on the extremity of its ventral process. The paroccipital processes have remarkable accessory dorsal and ventral bony bars, that thus bound depressions lateral to the foramen magnum. The ear region closely resembles that of Majungasaurus, though differing most substantially on a laterally directed basipterygoid process, with the shorter crista prootica and the smaller extent of a groove anterior to the 2nd and 3rd cranial nerve foramina being minor deviances from Majungasaurinae's type. The squamosal is similar to that of the latter except for a less prominent parietal process.