ASSESSMENT OF CHARACTER VARIATION IN THE CRANIA AND TEETH OF MODERN ARTIODACTYLS FOR BETTER SPECIES DIAGNOSIS IN THE FOSSIL RECORD by MEAGHAN MARIE EMERY A DISSERTATION Presented to the Department of Geological Sciences and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy September 2016 DISSERTATION APPROVAL PAGE Student: Meaghan Marie Emery Title: Assessment of Character Variation in the Crania and Teeth of Modern Artiodactyls for Better Species Diagnosis in the Fossil Record This dissertation has been accepted and approved in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Geological Sciences by: Edward Davis Chair Samantha Hopkins Core Member Josh Roering Core Member Douglas Warrick Core Member Stephen Frost Institutional Representative and Scott Pratt Dean of the Graduate School Original approval signatures are on file with the University of Oregon Graduate School. Degree awarded September 2016 ii © 2016 Meaghan Marie Emery This work is copyrighted under a Creative Commons Attribution license iii DISSERTATION ABSTRACT Meaghan Marie Emery Doctor of Philosophy Department of Geological Sciences September 2016 Title: Assessment of Character Variation in the Crania and Teeth of Modern Artiodactyls for Better Species Diagnosis in the Fossil Record Accurately distinguishing species in the fossil record is difficult when the extent of osteological variation in many modern animals is unknown. Research into intraspecific variation has been conducted in a number of groups, but has not been conducted for systematics use in most modern artiodactyls. In this dissertation I quantify intraspecific variation of teeth in 14 species of modern artiodactyl, then test how accurately cranial characters diagnose modern, sympatric species of duikers, and use this information to reassess the artiodactyl diversity of a fossil group: the superfamily Merycoidodontoidea in the John Day Fossil Beds. Ultimately, variation is not constant between orders or different size classes, is influenced by morphology, size, and dimorphism, and this variation should be incorporated into fossil diagnoses to avoid both overconfidence of diagnosis and under-recognition of possible intraspecific variation. This dissertation includes previously unpublished co-authored material, as Chapters II and III were coauthored with Dr. Edward Byrd Davis. iv This dissertation contains additional supplemental files, including excel formatted versions of Appendix F, Appendix I, and the data for Chapter III. There is also a nexus file of data for Chapter IV. v CURRICULUM VITAE NAME OF AUTHOR: Meaghan Marie Emery GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED University of Oregon, Eugene, Oregon, USA Chiayi University, Chiayi City, Taiwan Oregon State University, Corvallis, Oregon, USA Portland State University, Portland, Oregon, USA Lethbridge University, Lethbridge, Alberta, Canada DEGREES AWARDED Doctor of Philosophy, Geological Sciences, 2016, University of Oregon Bachelors of Science, Biology, 2008 Oregon State University AREAS OF SPECIAL INTEREST Paleobiology of artiodactyls PROFESSIONAL EXPERIENCE Graduate Assistant, University of Oregon (2012-2016) Geologist/Paleontologist, John Day Fossil Beds National Monument (2014) Biologist, Merlin Biological (2011-2015) Instructor, Oregon Museum of Science and Industry (2009-2011) English Teacher, Lincoln American School (2008-2009) Apprentice Instructor, Oregon Museum of Science and Industry (2001-2008) Learning Strategist and Tutor, Oregon State University (2007-2008) vi GRANTS, AWARDS AND HONORS: Graduate Teaching Fellowship, University of Oregon, 2012-2016 Science Slam 1st Place, University of Oregon, 2016 Johnson Award for Research, University of Oregon, 2016 Doris O. and Samuel P. Welles Research Fund, University of California at Berkeley, 2015 Thomas Condon Fellowship, University of Oregon, 2015 Outstanding Editorial Achievement, American Federation of Teachers, 2015 Outstanding Student Employee, University of Oregon, 2015 Field Museum of Natural History Research Grant, FMNH Chicago, 2014 Ernst Mayr Travel Fellowship, Harvard University, 2014 Geocorps Travel Grant, Geological Society of America, 2014 Student Travel Award, Geological Society of America, 2014 Thomas Condon Fellowship, University of Oregon, 2014 Theodore Roosevelt Memorial Fund Award, American Museum of Natural History, 2013 Smith Scholarship, University of Oregon, 2013 People’s Choice Award, Three Minute Thesis Competition; University of Oregon, 2013 Best Poster Award, Graduate Student Research Forum, University of Oregon, 2013 vii PUBLICATIONS: Emery-Wetherell, M., McHorse, B., and Davis, E. "Spatially-explicit analysis sheds new light on the Pleistocene Megafaunal Extinction in North America." Paleobiology. (In Review) Emery, M., Davis, E., and Hopkins, S. 2016. "Reassessment of the agriochoerid oreodont from the Hancock Mammal Quarry, Clarno (Eocene: Duchesnean), Oregon." Journal of Vertebrate Paleontology 36(2): e1041970. viii ACKNOWLEDGMENTS Brianna McHorse (Harvard) took additional Hylochoerus pictures when I lost mine. Mark Fonstad (UO) introduced me to Photoscan after Josh Roering (UO) suggested it. Access to collections was given by Judy Chupasko (MCZ), Rebecca Banasiak (FMNH), Eileen Westwig (AMNH), Chris Sagabiel (VPL), and Chris Conroy (MVZ). Reviews and guidance for this project were given by Edward Davis (UO), Steve Frost (UO), Douglas Warrick (OSU), Samantha Hopkins (UO), and Josh Roering (UO). Brianna McHorse, Iain Burke, Madison Ball, Kristen Burns, Todd and Marvis Sorenson, and David, Becky, Leo and Isaac Houts provided much-needed housing during museum trips. Bob and Ellen Hunt provided excellent stratigraphic and taxonomic advice for Chapter IV. Theodore Fremd and Pat Holroyd hunted down the locality information for obscure specimens and sites. Bruce Lander provided invaluable taxonomic advice and clarification. This work was funded by the Field Museum Research Grant from the Field Museum of Natural History in Chicago, the Theodore Roosevelt Grant from the American Museum of Natural History, the Ernst Mayer Grant from Harvard University and the Thomas Condon Scholarship and Smith Scholarship from the University of Oregon. Nessie and Eleanor Wakefield for emotional support and excellent writing company. ix DEDICATION To my mother, who always encouraged me to grow up to be a nerd, and to my husband Logan and my best friend Amy, who worked together to keep me sane. x TABLE OF CONTENTS Chapter Page I. INTRODUCTION .................................................................................................................... 1 II. DENTAL VARIATION DOES NOT DIAGNOSE MODERN ARTIODACTYLS: IMPLICATIONS FOR THE SYSTEMATICS OF MERYCOIDODONTOIDEA ................. 7 Abstract ..................................................................................................................................... 7 Keywords .................................................................................................................................. 8 Introduction ............................................................................................................................... 8 Abbreviations .......................................................................................................................... 11 Museums ............................................................................................................................... 11 Terminology .......................................................................................................................... 12 Species .................................................................................................................................. 12 Materials and Methods ............................................................................................................ 12 Measurements ....................................................................................................................... 12 Discriminant Function Analysis ........................................................................................... 13 Variation Tests ...................................................................................................................... 13 Coefficient of Variation ........................................................................................................ 16 Significance Tests ................................................................................................................. 17 Results and Discussion .......................................................................................................... 17 Model Uncertainty and Methodology ................................................................................... 17 Discriminant Function Analysis ........................................................................................... 19 Pattern of Variation ............................................................................................................... 21 Influence of Age-Related Wear on Dental Variation ........................................................... 24 xi Chapter Page Sexual Dimorphism .............................................................................................................. 26 Coefficients of Variation....................................................................................................... 28 t-Tests