Though shallower, the nearly complete braincase of Arcovenator is otherwise similar in size to those of Majungasaurus and Carnotaurus, implying an animal about 5–6 metres (16–20 ft) long.[1] 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.[1] Less characteristically there is above the orbit a low fossa with a small fenestra bordered by the lacrimal, frontal and postorbital.[1] 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