Braincase anatomy of the basal theropod Sinosaurus, from the lower Jurassic of China

XING, L.; PAULINA CARABAJAL, A.; CURRIE, P. J.; XU, X.; ZHANG, J. ; WANG, T.; DONG, Z.; BURNS, M.

ACTA GEOLOGICA SINICA-ENGLISH EDITION

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 88 p. 1653 - 1664

1000-9515

The neuroanatomy of the mid-sized theropod Sinosaurus from the Lufeng Basin in Yunnan Province, China was studied using X-ray computed tomography. The braincase is characterized by a large supraoccipital knob capped by a posterior projection of the parietal and two external foramina for the caudal middle cerebral vein which is completely enclosed by the supraoccipital. The basicranium has well defined, short basipterygoid processes that project ventral to the basal tubera. The basisphenoid is expanded, projects posteroventrally, and is pierced by four pneumatic recesses. The endocranial morphology resembles that observed in other basal theropods ? in particular some allosauroids, and has a strongly marked pontine flexure and a large dorsal expansion. The inner ear morphology is also similar to that observed in other basal theropods, with slender semicircular canals. The anterior semicircular canal 20% larger than the posterior semicircular canal, and the angle formed between them is less than 90° in dorsal view.