PALEONEUROLOGY OF CARNOTAURUS SASTREI (THEROPODA: ABELISAURIDAE): A PRELIMINARY STUDY BASED ON CT SCANS

CERRONI, M.A.; PAULINA CARABAJAL, A.; NOVAS, F.

Santa Clara del Mar

Jornada; 31 Jornadas Argentinas de Paleontología de Vertebrados; 2017

Museo

The endocranial morphology of abelisaurids is only known for Aucasaurus garridoi Coria, Chiappe and Dingus, and Viavenator exxoni Filippi, Méndez, Juárez Valieri and Garrido from Argentina, Majungasaurus crennatissimus Depéret from Madagascar, and a partial endocast of Indosaurus matleyi Huene and Matley from India. Here, we present the complete cranial endocast of Carnotaurus sastrei Bonaparte (MACN-CH 894) based on CT scans. Although the most delicate structures of the endocranial cavity are not clearly observed in the data set, the general morphology of the brain, plus some cranial nerves (i.e., CNs II, V, VI and XII) and some blood vessels (i.e., caudal middle cerebral brain and sphenoidal artery) are recognized. The shape and proportions of the endocranial cavity resemble those present in other Cretaceous abelisaurids, including well-marked cerebral hemispheres, robust and elongate olfactory tract and elongate, and slightly divergent olfactory bulbs. However, the olfactory tracts and bulbs of Carnotaurus are curved ventrally (therefore being aligned with the cerebral hemispheres), unlike the horizontally oriented structures described for other abelisaurids so far. Carnotaurus shares with the South American forms the presence of a low dorsal expansion (or pyramidal peak) and the angle between midbrain and hindbrain. Further studies will be focused on the particular olfactory region of the brain of Carnotaurus, which may respond to a sensorial capability different from that developed in Aucasaurus, Viavenator and probably Abelisaurus Bonaparte and Novas.