Anderson, Jason SPardo, Jason Daniel2014-10-072014-11-172014-10-072014http://hdl.handle.net/11023/1914Lysorophia is a poorly-understood group of fossil tetrapods known from the Late Carboniferous and Early Permian of North America. Some prior workers have noted similarities between lysorophians and modern amphibians, suggesting that lissamphibians may have evolved from lysorophian-like ancestors. I used high resolution x-ray micro-computed tomography (HR-XCT) to study skulls of the lysorophian Brachydectes newberryi from the Early Permian of Kansas and Nebraska, USA. I present a detailed description of the skeletal morphology of these skulls, including fine structure of the braincase. With reference to the skeletal morphology described here, I present a list of new, phylogenetically-informative characters from the braincase and incorporate these into phylogenetic analysis of early tetrapods. Lysorophians are found to be microsaurs, a diverse group of early tetrapods. The data presented here suggest that lysorophians and microsaurs may be early reptiles and thus not relevant to the discussion of lissamphibian origins.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.PaleontologyPaleontologyPhylogenetic AnalysisLissamphibiaLepospondyliCarboniferousPermianmaster thesis10.11575/PRISM/27009