ZOO 2090 Lecture Notes - Lecture 13: Sauropsida, Triceratops, Cervical Vertebrae

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Jinzhong Fu

Document Summary

Smaller stem groups and the archosaurs, ( ruling reptiles) a very large group. Archosaurs include crocodilians, dinosaurs, birds, and related groups. They were dominant in the jurassic-cretaceous individual pocket where each tooth sits. Trend toward bipedal locomotion likely evolved multiple times (cid:198) more efficient body support and locomotion the forelimbs become regressed, and the pelvic joint changes over this development. First vertebrate group to evolve powered flight (late triassic, birds and bats evolved later) using membranous wings supported by an elongated forelimb. Early forms had long tails and teeth (e. g. , ramphorhynchus) teeth are lost in birds. Later forms lost the tail and teeth, and possessed a projecting crest at the back of the head (e. g. , pteranodon) Major radiation begins in the late triassic following decline of basal archosauromorphs and thecodonts. Saurischia and ornithischia are distinguised by the structure of the pelvic girdle. Main groups: (5) sauropodomorphs mostly herbivorous (e. g. , apatosaurus,