3 ms·
After some quick research online: Plesiosaurs and pterosaurs are not dinosaurs mainly due to the configuration of their skeletons. It seems that dinosaurs have
by nier 4y ago
After some quick research online: Plesiosaurs and pterosaurs are not dinosaurs mainly due to the configuration of their skeletons. It seems that dinosaurs have their limbs under the body while plesiosaurs and pterosaurs have their limbs stick out from the side like crocodiles and turtles.
- moloch-hai 4y agoTechnically, they are not dinosaurs because they are not descended from the common ancestor of all dinosaurs, which had limbs so configured. Some "allied" lineages had them, too, omitted from Dinosauria proper for technical reasons. Some isolates developed it independently, mammals notably among them. Probably some dinosaurs developed a sprawling gait "secondarily". Biology is a messy business.