A CT scan of a titanosauriform skull (Dinosauria: Sauropoda) from the central Patagonia, Argentina.

MARTÍNEZ, RUBÉN D.; VITA, JAVIER; LAMANNA, MATTHEW C.; IBIRICU, LUCIO M.

Ottawa; Canada

Congreso; SVP; Reunión anual de Paleontología; 2006

Society of Vertebrate Paleontology (SVP)

We preliminarily report the results of a computed tomographic study of a titanosauriform skull from the Bajo Barreal Formation (Cenomanian-Turonian, early Late Cretaceous) of southern Chubut Province (central Patagonia, Argentina). For the study, we made a series of helical computed tomographies with a Multiple Slice System (MXTwin Multislice). Of the 281 images, 22 are three-dimensional reconstructions, 21 are sagittal, and 238 coronal. The slice thickness was two mm. The CT images allow the recognition of the olfactory bulb (CN I), the optic (CN II), trigeminal (CN V), and hypoglossal nerves (CN XII), the three subequal semicircular canals, middle and posterior cerebral veins, metotic fissure, and pituitary fossa. The latter is comparable in size to that in the endocranial mold of Camarasaurus grandis, although more rostrally oriented in the Chubut form. The exit points of the cranial nerves IX and X are tentatively identified. In the premaxillae, maxillae, and mandibles, the replacement teeth, adductor fossae and Meckelian grooves are visible. The latter are open medially as in Brachiosaurus and other forms. Other structures are more difficult to identify and will be the object of future studies. It is expected that the analysis of these images, and their comparison with related forms such as Brachiosaurus and more derived titanosauriforms, will allow to establish, in addition to the total encephalic volume of this dinosaur, characters and encephalic topographical features common to this sauropod lineage.