EARTH 7 Lecture Notes - Lecture 13: Tetanurae, Herrerasaurus, Coelophysis
Document Summary
Predominantly meat eaters: herbivory evolved convergently. Lighter for more efficient running (and later flight) Lost in living birds, but present in early birds: hollow bones. Herrerasaurus: ~230 ma (mid triassic), argentina, one of the earliest known dinosaurs, small and bipedal. Coelophysis: ~216 ma, late triassic, small, bipedal, and fast. Herrerasaurus and coelophysis probably look quite similar to the ancestor of all dinosaurs: many important changes throughout theropod evolution, but many later theropods (cid:373)ai(cid:374)tai(cid:374) this (cid:862)typi(cid:272)al(cid:863) for(cid:373) Stiff tails: tetanus = stiff, uro = tail, straight helps with efficient running. Complex branching air sacs: bones have pockets and air spaces similar to what birds have. We think this was used for more efficient breathing: goes into the air sacs and the lungs when bird breathes out, when bird breathes out, the oxygen in the air sacs is being pumped into the lungs. Even when breathing out, the lungs are still getting oxygen. Present (but highly reduced), very short: 3-digit hands.
