18. p. 397Avemetatarsalia and the Origin of Dinosauria
- F. Harvey Pough, F. Harvey PoughProfessor Emeritus, Rochester Institute of Technology
- William E. Bemis, William E. BemisProfessor of Ecology and Evolutionary Biology and Faculty Curator of Ichthyology, Cornell University
- Betty McguireBetty McguireSenior Lecturer, Cornell University
- , and Christine M. JanisChristine M. JanisProfessor Emerita of Biology, Brown University, USA, Honorary Professor of Earth Sciences, University of Bristol, UK
Abstract
This chapter looks into early avemetatarsalians and the origin of Dinosauria. From the period of late Triassic and Mesozoic, Avemetatarsalia is a large and diverse clade including many familiar extinct vertebrates, such as pterosaurs and non-avian dinosaurs like birds. Moreover, Avemetatarsalians decoupled the functions of the fore and hindlimbs, which then allowed the subsequent evolution of bipedalism and flight. The chapter also looks into the biology, characteristics, and evolution of pterosaurs, ornithischians, and sauropodomorphs. It mentions how the origin and diversification of birds coincided with an increase in the body size of pterosaurs, which suggested that birds may have outcompeted pterosaurs at small body sizes.
