Earth Sciences 1083F/G Lecture Notes - Lecture 25: Dinos, Mesozoic, Mosasaur
12 Sep 2016
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Document Summary
The advantage of being a furball: diversification of mammals. Among the earliest of the mammal-like reptiles were the pelycosaurs (evolved from anapsids by early permian) Suggested that some of them may have had hair or even whiskers. Succeeding the pelycosaurs were the therapsids or mammal-like reptiles. Got off to a pretty good start, diversified in the mid-to-late permian: things went downhill from there. Therapsids themselves hard-hit by end-permian mass extinction, then again by the end- Triassic extinction, and totally wiped out by early cretaceous. The skull is distinctly more mammal like: can be seen in the teeth. May have been the dominant reptile at the time. Dinosaurs would have become the dominant reptile when these ones were almost wiped out during the end permian. Primitive mammal-like reptiles had decidedly reptilian characteristics. More advanced mammal-like reptiles have sprawling stance, but very mammal-like in many other skeletal features: pits in skulls of some forms even suggest whiskers.
