Unformatted text preview: Pachycephalosaurs with large bone-filled heads Stegosaurs (e.g., Stegosaurus ) with large dorsal spines of disputed use in thermoregulation Ankylosaurs heavily armored and abundant in late Cretaceous The only living relatives of Dinosaurs are Birds. From the names of the two groups one might expect that the birds descended from the Ornithischians. This is not the case. Birds are related to Therapod dinosaurs . The living sister taxon to birds are Crocodylians; how do they fit in? You probably think of Pterosaurs as dinosaurs, too, but they are not. Below is a simplified cladogram of relationships....
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- Fall '10
- Biology, Sauropods, Major Groups