INTEGBI N33 Lecture Notes - Lecture 18: Iguanodontia, Hadrosaurid, Hypsilophodont
31 Mar 2018
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Document Summary
3rd major group of ornithischians, evolved towards advanced food processing. Long narrow bone in front of pubis for locomotor muscle attachment. Helps to support weight for large euornithopods. Hands could go on ground for grazing. Duck billed dinosaur large diverse group of ornithopods characterized by lost joint in 3rd digit and some having thumb spike. Have front digits modified into hooves for weight-bearing. Teeth packed closely together and aligned to form a solid battery for grinding plant matter. Thought toes had webbed feet and maybe they were swamp dwelling but turns out, it was fluid-filled cushions at base of toes to help support weight. Stiff ossified tale would could not have swayed side to side for swimming. Dental battery for chewing tough land plants not mushy swamp plants. Were ambulatory/graviportal, body definitely evolved to bear weight not swim. Many had crests, which were likely used for display since adults have more pronounced crests and they exhibit sexual dimorphism.
