Morphometric analysis of the gull Larus (Aves:Laridae) with implications for small theropod diversity in the Late Cretaceous by Michel Haché A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Master of Science in Earth Science Carleton University Ottawa, Ontario © 2016, Michel Haché Abstract This project analyzed morphological diversity in the modern gull (Aves: Charadriiformes) genus Larus. Measurements of the post-cranial skeletons were made on specimens from six species of Larus and analyzed using Principal Component Analysis (PCA). Similar analyses were conducted on a series of theropod taxa. Landmark-based geometric morphometric analysis was also conducted on select skulls of gulls and analyzed using PCA. The results show that most of the gull species are very similar for the morphological parameters analyzed, only differing in overall body size, and, thus cannot be easily distinguished based on their skeletal morphology. These results were used as a modern analogue for inferring species diversity in the theropod fossil record. The implications of this study suggest that skeletal morphology, without the addition of soft tissue and behavior data available for modern birds, may not be able to distinguish closely related species of interbreeding, non-avian theropods in the fossil record. This suggests that the species diversity of extinct non-avian theropods was likely higher than can be of determined from their skeletal remains. 1 Acknowledgements I would like to thank my supervisors, Dr. Michael Ryan and Dr. Tim Patterson for their support over the past two years. I would like to thank Elizabeth Anderson for her patience and for helping me with writing this thesis. I would also like to thank Michel Goselin and the staff of the Canadian Museum of Nature for helping me with my data collection and allowing me access to the museum‘s collection. I would like to thank Mark Peck for helping me with the data collection of the specimens at the Royal Ontario Museum. I also want to thank Dr. Phil Currie for providing me with his database of theropod measurements. I want to thank everyone in the Patterson Research Group for their help and support. A special thank you to all my friends and family for all the support they‘ve given in the past three years. This research was, in part, supported by a NSERC Discovery Grant to Tim Patterson. 2 Table of Contents Abstract ............................................................................................................................ 1 Acknowledgements ....................................................................................................... 2 Table of Contents ........................................................................................................... 3 List of Tables ..................................................................................................................... 5 List of figures ..................................................................................................................... 6 Chapter 1: Introduction ................................................................................................ 7 1.1 Introduction .......................................................................................................................... 8 1.2 Project goals ..................................................................................................................... 13 1.3 Gulls.................................................................................................................................... 14 1.4 Avian evolution ................................................................................................................. 16 1.5 Laridae taxonomy ............................................................................................................. 20 1.6 Previous morphometric analyses of dinosaurs ............................................................ 24 1.7 Theropod taxonomy ......................................................................................................... 31 Chapter 2: Materials and Methods .................................................................. 39 2.1 Gull species analyzed ...................................................................................................... 39 2.2 Theropod taxa analyzed .................................................................................................. 43 2.3 Data collection .................................................................................................................. 49 2.4 Analysis .............................................................................................................................. 57 3.1 Gull postcranial morphometric analysis ........................................................................ 59 3.2 Intraspecific morphological variation ............................................................................. 66 3.3 Gull cranial morphometric analysis ............................................................................... 76 3.4 Theropod morphometrics analysis ................................................................................ 87 3 Chapter 4: Discussion .............................................................................................. 103 Conclusions................................................................................................................. 113 Appendices .................................................................................................................. 116 Appendix A Averaged measurements for the gull specimens ....................................... 116 Appendix B Standardized gull measurements ................................................................. 119 Appendix C Measurements of Theropod Specimens ...................................................... 121 Appendix D Loading of PC 1 and 2 of each analysis ...................................................... 125 Appendix E Landmarks digitized on Larus skulls ............................................................ 126 Appendix F Landmark location ........................................................................................... 127 References ................................................................................................................... 128 4 List of Tables Table 1: ........................................................................................................................43 Table 2 ..........................................................................................................................61 Table 3: .........................................................................................................................61 Table 4: .........................................................................................................................68 Table 5: .........................................................................................................................68 Table 6: .........................................................................................................................73 Table 7: .........................................................................................................................73 Table 8: .........................................................................................................................76 Table 9 ..........................................................................................................................76 Table 10 ........................................................................................................................77 Table 11 ........................................................................................................................83 Table 12 ........................................................................................................................90 Table 13 ........................................................................................................................90 Table 14 ........................................................................................................................95 Table 15 ........................................................................................................................95 Table 16 ........................................................................................................................98 Table 17 ........................................................................................................................98 5 List of figures Figure 1 ............................................................................................................................. 18 Figure 2 ............................................................................................................................. 19 Figure 3 ............................................................................................................................. 20 Figure 4 ............................................................................................................................. 27 Figure 5 ............................................................................................................................. 28 Figure 6 ............................................................................................................................