GEOLGY 307 Lecture Notes - Lecture 1: Mesozoic, Paleontology, Protoceratops
Document Summary
A dinosaur is a reptile-like or bird-like animal with an upright posture that spent most (perhaps all) of its life on land. Dinosaurs ancestors were reptiles and birds are descended from dinosaurs. Facultative bipedal: walk part time on hind limbs. Faculative quadrupedal: walk part time on all four limbs. Dinosaurs are defined by their special ankles ( we call it the am ankle) If it does not have an am ankle then it is not a dinosaur. A plyosaur lived at the same time as the dinosaur but lived exclusively in the oceans, not on land, and lacked the am ankle so it is not a dinosaur. Pterosaur lived the same time as the dinosaur but lived on land, flew in the air, and lacked lacked the am ankle so not a dinosaur. Dimetrodon usually put in toy collections because it is mislabeled as a dinosaur.
