University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2016 Nesting and Egg Incubation in Dinosaurs: Morphological and Statistical Investigations into the Study of Eggs, Eggshells, and Nests Tanaka, Kohei Tanaka, K. (2016). Nesting and Egg Incubation in Dinosaurs: Morphological and Statistical Investigations into the Study of Eggs, Eggshells, and Nests (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/27073 http://hdl.handle.net/11023/3505 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Nesting and Egg Incubation in Dinosaurs: Morphological and Statistical Investigations into the Study of Eggs, Eggshells, and Nests by Kohei Tanaka A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN GEOLOGY AND GEOPHYSICS CALGARY, ALBERTA DECEMBER, 2016 © Kohei Tanaka 2016 i Abstract Archosaurs (e.g., crocodylians, dinosaurs, and birds) are the most diverse and successful terrestrial vertebrates. An understanding of the nesting strategies in both extinct (e.g., non-avian dinosaurs) and extant archosaurs (i.e., crocodylians and birds) is crucial for advancement of our knowledge on the evolution and diversification of this group. However, nesting methods and behaviors of non-avian dinosaurs are still poorly understood due to the limitations of the fossil record. In this dissertation, certain features of eggs and nests in dinosaurs (e.g., clutch size, egg mass, substrates of nests, water vapor conductance of eggs, and eggshell porosity) are compared with those of their closest living relatives (i.e., birds and crocodylians) and aspects of dinosaur nesting (i.e., nest type, incubation behavior, incubation heat source, and incubation period) are inferred and reconstructed. Findings in this dissertation suggest that nests and nesting styles among non-avian dinosaurs were diverse, and that bird-like traits were acquired throughout their evolution. Analyses of eggs and eggshell porosity indicate that more basal dinosaurs (i.e., ornithischians, sauropodomorphs, Lourinhanosaurus) completely covered their eggs with nest materials during incubation, although more derived forms (e.g., oviraptorosaurs, troodontids) used open nests, like modern birds, in which the eggs were not fully buried. The lithologies of the clutches of basal dinosaurs reveal their nests were probably incubated with external heat sources (e.g., microbial respiration, solar radiation), like those of modern crocodylians and megapode birds. Distribution and lithologies of some ornithischian and some sauropodomorph clutches show that heat from microbial respiration, in particular, was used for incubation, whereas other sauropodomorphs may have used inorganic heat sources, such as solar radiation. More derived dinosaurs (i.e., maniraptorans) had eggshell porosities and clutch lithologies that indicate their nests were partially open, indicating that these taxa brooded their eggs. Regardless of the type of nest, heat source, or incubation behavior, incubation period of most non-avian dinosaurs examined was relatively short, more comparable to that of birds than crocodylians. Major dinosaur (and archosaur) clades show diversity in their nesting and incubation, and also reveal a transition to more bird-like nesting features through evolution. ii Acknowledgements I would like to thank a number of people who helped and supported my Ph.D. program. Firstly, I am significantly indebted to my supervisor, Dr. Darla Zelenitsky, who guided and encouraged me throughout the program. My Ph.D. research was further improved by her endless support and patience. Along with Dr. Zelenitsky, I would like to thank my supervisory committee, Drs. François Therrien and Jason Anderson for their significant input and direction. I am also grateful to the rest of my examiners, Drs. Jessica Theodor, Don Brinkman, Alex Dutchak, and Dan Georgescu for their significant feedback. My special thanks go to Dr. Yoshitsugu Kobayashi, who gave me endless supports and invaluable advice. I would like to thank Drs. Donald Hoyt (California State Polytechnic University, Pomona, California), Roger Seymour (University of Adelaide, Adelaide, Australia), Chris Ruff (Johns Hopkins University, Baltimore, Maryland), and Chris DeBuhr (University of Calgary) for their significant input. I am also grateful to Drs. Lars Schmitz (Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California), Jessica Theodor, Anthony Russell (University of Calgary), Nick Campione (Uppsala University, Uppsala, Sweden), Theodor Garland Jr. (University of California Riverside, Riverside, California), and David Varricchio (Montana State University, Bozeman, Montana) for their technical support. I am deeply indebted to Gregory Watkins-Colwell (Yale Peabody Museum of Natural History, New Haven, Connecticut), Kristof Zyskowski (Yale Peabody Museum of Natural History), Peter Brazaitis (Yale Peabody Museum of Natural History), Mark Peck (Royal Ontario Museum, Toronto, Canada), Kevin Torregrosa (St. Augustine Alligator Farm Zoological Park, St. Augustine, Florida), José Rosado (Museum of Comparative Zoology, Cambridge, Massachusetts), Tsuyoshi Takahashi (Museum of Comparative Zoology), B. J. Gill (Auckland War Memorial Museum, Auckland, New Zealand), Daisuke Suzuki (Sapporo Medical University, Sapporo, Japan), Hiroki Echizenya (Hokkaido University Museum), Dawna MacLeod (Royal Tyrrell Museum of Palaeontology, Drumheller, Canada), Brandon Strilisky (Royal Tyrrell Museum of Palaeontology), Kenneth Krysko (Florida Museum of Natural History, Gainesville, Florida), and Kent Vilet (University of Florida, Gainesville, Florida) for specimen access. Some eggshell materials, which are now registered and housed at the Yale Peabody Museum and the Hokkaido University Museum, were kindly iii provided by the Connecticut's Beardsley Zoo (Bridgeport, Connecticut), Hamamatsu City Zoo (Hamamatsu, Japan), Jacksonville Zoo and Gardens (Jacksonville, Florida), Kobe City Oji Zoo (Kobe, Japan), Philadelphia Zoo (Philadelphia, Pennsylvania), Sapporo City Maruyama Zoo (Sapporo, Japan), and St. Augustine Alligator Farm Zoological Park. I am also grateful to Annie Quinney, Junchang Lü, Yuong-Nam Lee, Sean Modesto, Frank Hadfield, Kirstin Brink, Caleb Brown, Matthew Ceasar, Kentaro Chiba, Julius Csotonyi, Robin Cuthbertson, Jordan Mallon, Amanda McGee, Haruo Saegusa, Tadahiro Ikeda, Huali Chang, Shaohui Fan, Songhai Jia, Hua Li, Hanyong Pu, Zhanfu Shao, Li Xu, Laiping Yi, Hui Zhong, Eamon Drysdale, Rachel Nottrodt, Jared Voris, and colleagues at Anderson’s, Russell’s, and Theodor’s labs at the University of Calgary as well as colleagues and volunteers at Kobayashi's lab at Hokkaido University for their encouragement and scientific discussion. Finally, many thanks go to Takahiko and Makiko Tanaka, my two sisters, my niece Tsumugi, Sachiko Ohnishi, Hana, Adam, Kathy, and KJ Jansen with Chixdiggit, Vicky, Gary, Cloé, Françoise, and Jason Lawrence, Kyle Zelenitsky Therrien, Kei Nakano, Jun-Ichi Washio, and Toshikazu Toyama. My Ph.D. projects were supported by grants from the Japan Student Services Organization (JASSO), the Yoshida Scholarship Foundation, the Department of Geoscience (University of Calgary), Dinosaur Research Institute, the Society of Vertebrate Paleontology, as well as through a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant awarded to my supervisor (Darla Zelenitsky). iv Dedication For Sachiko Ohnishi v Table of Contents Abstract ............................................................................................................................... ii Acknowledgements ............................................................................................................ iii Dedication ............................................................................................................................v Table of Contents ............................................................................................................... vi List of Tables ..................................................................................................................... ix List of Figures .................................................................................................................... xi List of Abbreviations ....................................................................................................... xiii CHAPTER 1: GENERAL INTRODUCTION ..............................................................1 1.1 INTRODUCTORY STATEMENT ...............................................................................1 1.2 NESTING METHODS AND BEHAVIORS IN EXTANT ARCHOSAURS ..............2 1.3 DINOSAUR EGGS AND EGGSHELLS IN THE FOSSIL RECORD ........................2 1.4 PREVIOUS WORK ON EGG WATER VAPOR CONDUCTANCE AND NEST TYPE IN DINOSAURS .............................................................................................3 1.5 PREVIOUS WORK ON INCUBATION IN DINOSAURS .........................................4