|Mounted skeleton of Coelophysis bauri, Cleveland Museum of Natural History|
Theropods first appear in the earliest part of the Upper Triassic about 230 million years ago. They were the sole large terrestrial carnivores from the Lower Jurassic until the close of the Cretaceous, about 65 million years ago.
The earliest and most primitive of the theropod dinosaurs were:
- Holtz, Thomas R., Jr. (2012). Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix.
- Zanno L.E; Gillette D.D; Albright L.B. and Titus A.L. 2009. A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution. Proceedings of the Royal Society B, Published online before print July 15, 2009, doi: 10.1098/rspb.2009.1029.