Earth Sciences 2266F/G Lecture Notes - Lecture 22: Articular Processes, Mosasaur, Lepidosauria
26 Jul 2016
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Document Summary
Giant marine reptiles are not dinosaurs, not even archosaurs; they belong to leptosaurs. Ichthyosaurs are the most advanced in terms of adaptation in living in aquatic environments. No lateral mandibular fenestrae, no antorbital fenestrae (just nostrils in front of eye sockets) Behind the eye, for all diapsids, they have 2 holes; this group is still diapsids, but there is only an indentation of the lower hole now. Teeth: in cross-section it"s fairly rounded, but in archosaurs the teeth should be laterally compressed like a blade. In terms of evolution, this is a simplified chart; from this we can review the ecological adaptations. Within archosaurs, there are major adaptations towards living on land; e. g. dinosaurs specialize on terrestrial land. Flying animals evolved twice in archosaurs: pterosaurs and aves (one flies with membrane, one flies with feathers) Within lepidosaurs, these are the true marine mode of life.
