Braincase Anatomy of the Basal Theropod Sinosaurus from the Early Jurassic of China

• 作 者: XING Lida Ariana PAULINA-CARABAJAL Philip J.CURRIE XU Xing ZHANG Jianping WANG Tao Michael E.BURNS DONG Zhiming
• 机 构: School of the Earth Sciences and Resources, China University of Geosciences,Museo Carmen Funes, Cons
• 出 处: Acta Geologica Sinica(English Edition)
• 发表日期: 2014年06期
• 关键词: Jurassic dorsal canal basal caudal projection slender sized preserved ventral

The neuroanatomy of the mid-sized theropod Sinosaurus triassicus from the Lower Jurassic Lufeng Formation, Lufeng Basin in Yunnan Province, China was studied using X-ray computed tomography. The braincase is characterized by a large supraoccipital knob that is 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 is 20% larger than the posterior semicircular canal, and the angle formed between them is less than 90° when seen in dorsal view.

The neuroanatomy of the mid-sized theropod Sinosaurus triassicus from the Lower Jurassic Lufeng Formation, Lufeng Basin in Yunnan Province, China was studied using X-ray computed tomography. The braincase is characterized by a large supraoccipital knob that is 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 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 is 20% larger than the posterior se micircular canal, and the angle formed between them is less than 90 ° when seen in dorsal view.