ZOO 2090 Lecture Notes - Lecture 14: Synapsid, Pelycosaur, Osteoderm

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Jinzhong Fu

Document Summary

Arose in late carboniferous and radiated in the early permian to become the dominant terrestrial carnivores. Displayed a single temporal opening and a relatively posterior position of the orbit. Moderate size (0. 5 3 m), they still had a sprawling posture and some had a broad sail" along the back made of extended neural spines and skin. The sail might have been used in intra-specific communication or as a solar collector. Herbivorous forms had blunt teeth organized as a crushing plate and a laterally expanded rib cage suggesting a large gut used in fermentation of plant material. Early groups evolved in the early permian and radiated in the late. They were dominant throughout the world until the end of the triassic. Some groups re-radiated after the end permian mass extinction event (the boundary between paleozoic and mesozoic faunas) Earliest therapsids known (biarmosuchia) displayed enlarged temporal fenestrae and reduction of palatal teeth.