Marshall University Marshall Digital Scholar Theses, Dissertations and Capstones 1-1-2011 Plesiosaur Body Shape and its Impact on Hydrodynamic Properties Courtney D. Richards [email protected] Follow this and additional works at: http://mds.marshall.edu/etd Part of the Animal Sciences Commons, and the Terrestrial and Aquatic Ecology Commons Recommended Citation Richards, Courtney D., "Plesiosaur Body Shape and its Impact on Hydrodynamic Properties" (2011). Theses, Dissertations and Capstones. Paper 274. This Thesis is brought to you for free and open access by Marshall Digital Scholar. It has been accepted for inclusion in Theses, Dissertations and Capstones by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected]. PLESIOSAUR BODY SHAPE AND ITS IMPACT ON HYDRODYNAMIC PROPERTIES A thesis submitted to the Graduate College of Marshall University In partial fulfillment of the requirements for the degree of Master of Science in Biological Sciences by Courtney D. Richards Approved by Dr. F. Robin O’Keefe, Committee Chairperson Dr. Brian L. Antonsen Dr. Suzanne G. Strait Marshall University May 2011 Acknowledgments I would like to extend my gratitude to my advisor, Dr. F. R. O’Keefe, and my committee members, Dr. B. Antonsen and Dr. S. Strait, for all of their guidance throughout this project. I am also grateful to Dr. D. Henderson for his work on the modeling portion of this study. Thanks to H. Zhu for her work on the Tatenectes reconstruction. I would also like to thank my fellow lab members, W. Holloway, B. Wilhelm, and N. Gardner. Thanks to the Natural History Museum, London, for allowing me access to their collections. This research was made possible by a MURC student travel grant. This thesis would not have been possible without the encouragement and support that has been provided by all of my family and friends throughout the course of my graduate studies. I would particularly like to thank my parents, Wes and Jeanie; my siblings, Nathaniel, Chelsea, and Seth; and my good friends, John and Kate. ii Table of Contents Acknowledgments ............................................................................................................. ii List of Figures and Tables .................................................................................................v Abstract ............................................................................................................................ vii Chapter 1-Introduction .....................................................................................................1 Background on Plesiosauria .....................................................................................1 Study Taxa ...............................................................................................................3 Hydrostatic Buoyancy ..............................................................................................6 Modeling Extinct Taxa ..........................................................................................11 Research Objective ................................................................................................19 Chapter 2-Plesiosaur Reconstructions ...........................................................................21 Introduction ............................................................................................................21 Materials and Methods ...........................................................................................21 Materials ....................................................................................................21 Photographs................................................................................................22 Vertebrae and Girdle Articulation .............................................................23 Centrum Angles .........................................................................................24 Rib Orientation...........................................................................................27 Transverse Cross Section ...........................................................................28 Results ....................................................................................................................29 Discussion ..............................................................................................................44 Chapter 3-Plesiosaur Buoyancy and Stability ...............................................................46 Introduction ............................................................................................................46 iii Materials and Methods ...........................................................................................47 Materials ....................................................................................................47 Methods......................................................................................................47 Tests ...........................................................................................................52 Results ....................................................................................................................54 Models........................................................................................................54 Tests ...........................................................................................................55 Discussion ..............................................................................................................60 Comparison ................................................................................................60 Habitat Implications ...................................................................................63 Possible Sources of Error ...........................................................................64 Future Work ...............................................................................................64 Conclusion .............................................................................................................65 Literature Cited ...............................................................................................................66 iv List of Figures and Tables Figure 1.1. Pliosauromorph and plesiosauromorph body shapes ....................................... 2 Figure 1.2. Plesiosaur phylogeny .........................................................................................4 Figure 1.3. Cryptocleidoidea relationships ..........................................................................6 Figure 1.4. Pachyostosis in Tatenectes ................................................................................7 Figure 1.5. Body shape approximation ..............................................................................12 Figure 1.6. Tyrannosaurus rex outline ...............................................................................14 Figure 1.7. Tyrannosaurus rex 3-D mesh ..........................................................................16 Figure 2.1. Cryptoclidus rib orientation .............................................................................28 Figure 2.2. Tatenectes reconstruction ................................................................................32 Figure 2.3. Cryptoclidus reconstruction.............................................................................33 Figure 2.4. Muraenosaurus reconstruction ........................................................................34 Figure 2.5. Transverse cross-sections ................................................................................35 Table 2.1. Tatenectes centra angle .....................................................................................36 Table 2.2. Cryptoclidus centra angles ................................................................................37 Table 2.3. Muraenosaurus centra angles ...........................................................................39 Table 2.4. Tatenectes wedging angles ...............................................................................39 Table 2.5. Tatenectes anteroposterior wedging angles ......................................................40 Table 2.6. Cryptoclidus wedging angles ............................................................................41 Table 2.7. Cryptoclidus anteroposterior wedging angles...................................................42 Table 2.8. Muraenosaurus wedging angles .......................................................................43 Table 2.9. Muraenosaurus anteroposterior wedging angles ..............................................44 Figure 3.1. 3D slicing method............................................................................................48 v Figure 3.2. Lung position ...................................................................................................50 Figure 3.3. Models at equilibrium......................................................................................57 Figure 3.4. Buoyant recovery.............................................................................................58 Table 3.1. The effects of lung deflation on body mean density and buoyancy .................59 Figure 3.5. Lateral roll recovery ........................................................................................61 vi Abstract Plesiosaur body shape and its impact on hydrodynamic properties