A systematic and ecomorphological investigation of the early amniotes from Mazon Creek, Francis Creek Shale, Illinois, USA. by Arjan Mann A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth Sciences Carleton University Ottawa, Ontario ©2020, Arjan Mann Abstract The late Carboniferous-aged (309-307 Ma) Mazon Creek lagerstätte produces some of the earliest tetrapod fossils, including those of major Paleozoic lineages such as the second oldest reptile. Despite this, the Mazon Creek lagerstätte has remained a difficult and unproductive vertebrate locality for researchers to utilize in tetrapod diversity studies due to the scarcity of fossils of this kind. Over the past decades, several new terrestrial tetrapod fossils collected from Mazon Creek have come to light. These include several new virtually-complete fossils of the earliest fossorially adapted recumbirostrans. Here I provide a revised systematic study of the Mazon Creek pan- amniote fauna, in an attempt to reassess the terrestrial ecosystem diversity present at the late Carboniferous lagerstätte. The results accumulate to systematic descriptions of four new and unique recumbirostran taxa (Diabloroter bolti, Infernovenator steenae, FMNH 1309, and MPM VP359229.2) and a re-description of the basal eureptile Cephalerpeton ventriarmatum leading to the anointment of the oldest parareptile Carbonodraco lundi (formerly Cephalerpeton aff. C. ventriarmatum from Linton, Ohio). Descriptions are aided by modern imaging techniques and updated phylogenetic analyses using Maximum parsimony and Bayesian methods where applicable. Across the newly described terrestrial fauna there is an unexpected ecomorphological diversity of bauplans present. These range from the short-bodied Diabloroter to the serpentine, long-bodied, and limb-reduced MPM VP359229.2. This diversity in combination with an array of unique cranial specializations present in the new taxa highlight the early experimentation with fossoriality in terrestrial vertebrate ecosystems. Exceptional preservation of soft tissues in FMNH 1309 even reveal integumentary adaptations to a fossorial lifestyle. Collectively, I am able to provide a revised taxonomic list for the Mazon Creek Tetrapoda that reveals the fauna is compositionally similar to that of most Permo-Carboniferous tetrapod localities. Given recent studies that suggest that recumbirostrans are crown-group reptiles, the results of this thesis imply a more rapid mid-Carboniferous diversification of amniotes into a variety of terrestrial niches and consequently an earlier establishment of terrestrial vertebrate ecosystems. ii Acknowledgements First and foremost, I thank my mother, Pam, who first introduced me to paleontology, science, and a love of the natural world. Her kindness and love are immeasurable to me. I also thank my father, Jas, and my sister, Selena, for their continued love and support throughout my journey. I also extend thanks to all of my family and friends who provided me with kindness and support, especially my grandmother, who recently passed away. Little did she know, the stuffed Triceratops toy she bought me as a baby would spark a life-long pursuit. To my best friend, Iain Ching, knowing you’ll always have my back has been a comfort that words cannot express. To my dear friend, Alissa Fraser, thank you for your kindness, and support, seeing your life unfold has been an honour. I also extend a warm thanks to all of my friends for making my life so loving and complete. Thank you to Jesse Lewis, Kayley Lenders, Michael MacKinnon, Carolyn Chen, Michael Thompson, and Ryan Paterson, you were the best roommates in the world, whose company without, my time in Ottawa would not have been bearable. I am deeply grateful to Braden Gregory, for joining me on my quest to become a master swordsman. To my fellow Avengers, Jason Pardo, and Bryan Gee, I am grateful for our found comradery and friendship. I feel I have found life-long collaborators in the two of you, and I look forward to our next meeting, as Doctors in Philosophy. I sincerely thank Ami Calthorpe, Emily McColville, Emily McDaniel, and Gabrielle Adams for giving me the chance to be a mentor and friend. I give a special thanks to Ami Calthorpe who provided me with support, motivation, and discussion in the final days of my thesis research. In the field of Vertebrate Paleontology there are far too many people to thank, and they are acknowledged at the end of each chapter. However, two names stand out, the first of whom is the Late Dr. John R. Bolt, which I had the fortune of meeting before he passed. Without Johns willingness to share his knowledge and resources nothing in the following thesis would have been possible. I recall a conversation between John and I, where he mentioned he had received an NSF grant to essentially do the same Mazon iii Creek project in the 80’s, however, it never took off. John concluded our conversation by telling me, that he thought I was going to do good job. I think about that reassurance often. The second individual to whom I am equally indebted, is Dr. Robert W. Hook. Bob graciously offered notes, and comparative material from the cannel coal localities of Linton and the Five Points, Ohio, that were originally discovered by himself and Dr. Donald Baird. Without Bobs willingness to share resources, and offer insightful discussion on the tetrapod material of the Carboniferous my thesis would not be where it is today. Bob also played host to me several times in Austin, Texas where he was a most gracious host. Our meetings are always a rush of research filled adrenaline, and I look forward to continuing working with him in the future Finally, I would like to thank my former Masters supervisors Marc Laflamme, David Evans, and David Rudkin for their continued support in my research endeavors, including allowing me to work at the Royal Ontario Museum and University of Toronto in the summers. Last but certainly not least, I would like to thank my doctoral supervisor Dr. Hillary C. Maddin for giving me this opportunity, having patience with me, and joining me on this learning experience. Created by Henry Sutherland Sharpe. © 2019 Henry Sutherland Sharpe. Used under license iv Dedication For my Grandmother, Persin Kaur Buadhwal (1925-2020). And for my rabbit, Maddy (2007-2020). v Table of Contents Abstract .........................................................................................................................ii Acknowledgements ...................................................................................................... iii Dedication ...................................................................................................................... v Table of Contents ......................................................................................................... vi List of Tables ................................................................................................................ ix List of Figures ................................................................................................................ x List of Appendices ...................................................................................................... xiv Chapter 1: Introduction ................................................................................................ 1 1.1 Thesis Rationale & Amniote Origins .......................................................................... 1 1.2 The Mazon Creek Lagerstätte & Thesis Structure ....................................................... 7 1.3 References ................................................................................................................ 15 Chapter 2: Diabloroter bolti gen. et sp. nov. a short-bodied recumbirostran ‘microsaur’ from the Francis Creek Shale, Mazon Creek, Illinois ........................... 25 2.1 Authors and Addresses ............................................................................................. 25 2.2 Preface ..................................................................................................................... 25 2.3 Abstract .................................................................................................................... 25 2.4 Introduction .............................................................................................................. 26 2.5 Institutional Abbreviations........................................................................................ 29 2.6 Anatomical Abbreviations ........................................................................................ 29 2.7 Materials and Methods ............................................................................................. 29 2.8 Systematic Paleontology ........................................................................................... 30 2.9 Description ............................................................................................................... 34 2.10 Phylogenetic Analysis .............................................................................................. 40 2.11 Discussion ................................................................................................................ 42 2.12 Conclusion ............................................................................................................... 47 2.13 Acknowledgements .................................................................................................