PHYLOGENY, DIVERSITY, AND ECOLOGY OF THE AMMONOID SUPERFAMILY ACANTHOCERATOIDEA THROUGH THE CENOMANIAN AND TURONIAN DAVID A.A. MERTZ A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2017 Committee: Margaret Yacobucci, Advisor Andrew Gregory Keith Mann © 2017 David Mertz All Rights Reserved iii ABSTRACT Margaret Yacobucci Both increased extinction and decreased origination, caused by rising oceanic anoxia and decreased provincialism, respectively, have been proposed as the cause of the Cenomanian Turonian (C/T) extinction event for ammonoids. Conflicting evidence exists for whether diversity actually dropped across the C/T. This study used the ammonoid superfamily Acanthoceratoidea as a proxy for ammonoids as a whole, particularly focusing on genera found in the Western Interior Seaway (WIS) of North America, including Texas. Ultimately, this study set out to determine 1) whether standing diversity decreased across the C/T boundary in the WIS, 2) whether decreased speciation or increased extinction in ammonoids led to a drop in diversity in the C/T extinction event, 3) how ecology of acanthoceratoid genera changed in relation to the C/T extinction event, and 4) whether these ecological changes indicate rising anoxia as the cause of the extinction. In answering these questions, three phylogenetic analyses were run that recovered the families Acanthoceratidae, Collignoniceratidae, and Vascoceratidae. Pseudotissotiidae was not recovered at all, while Coilopoceratidae was recovered but reclassified as a subfamily of Vascoceratidae. Seven genera were reclassified into new families and one genus into a new subfamily. After calibrating the trees with stratigraphy, I was able to determine that standing diversity dropped modestly across the C/T boundary and the Early/Middle Turonian boundary. I also found an increase in the percentage of genera becoming extinct in the Late Cenomanian, not a decrease in origination. Finally, I used Westermann morphospace to relate shell shape to ecology and mode of life. I found no decrease in morphospace occupation across the C/T boundary. More mobile modes of life expanded at this time. Morphospace iv iv occupation iv did drop across the Early/Middle Turonian boundary. All changes in morphospace occupation were driven by the family Vascoceratidae, suggesting this family was uniquely able to shift into novel modes of life in response to environmental change. v ACKNOWLEDGMENTS I would like to thank Ann Molineux and the Non-vertebrate Paleontology Lab at the University of Texas and Austin as well as Kathy Hollis and the National Museum of Natural History for providing me access to fossil specimens in their care. I would also like to thank my committee, Margaret Yacobucci (Bowling Green State University), Andrew Gregory (Bowling Green State University), and Keith Mann (Ohio Wesleyan University). Additionally, I would like to thank the Department of Geology at Bowling Green State University for their support and Bill Butcher for help with various computer programs. Funding for this project was provided by BGSU’s Richard D. Hoare Research Scholarship and the Geological Society of America Graduate Student Research Grant Program. vi TABLE OF CONTENTS Page INTRODUCTION………………………………………………………………………..... 1 Ammonoids During the C-T……………………… .................................................. 3 METHODS……………………………………………………… ........................................ 8 Phylogenetic Analysis…………………………………………. ............................... 15 Standing Diversity ..................................................................................................... 18 Origination and Extinctions ....................................................................................... 19 Westermann Morphospace ......................................................................................... 19 RESULTS………………………. ......................................................................................... 22 Phylogenetic Analysis……………………………………………………………….. 22 Proposed Reclasification……………………………. ................................... 40 Standing Diversity……………………………………………………. .................... 43 Origination and Extinction………………………………………………….. ........... 43 Westermann Morphospace ......................................................................................... 48 Familiy-Level Patterns ................................................................................... 48 Ecological Changes Through Time ............................................................... 53 DISCUSSION……………………………. ........................................................................... 56 Phylogenetic Analysis……………………………………………………………….. 56 Pseudotissotiidae ............................................................................................ 57 Micromorphs……………………………………………………. ................. 57 Standing Diversity ..................................................................................................... 58 Origination and Extinction ......................................................................................... 58 vii Westermann Morphospace ......................................................................................... 59 Future Work ............................................................................................................ 60 CONCLUSIONS…………………………………………………………… ........................ 62 REFERENCES……………………………………………………………………………… 64 APPENDIX A. CHARACTER LIST …………………………………………………… ... 69 APPENDIX B. DATA MATRIX FOR PHYLOGENETIC ANALYSIS……………… .... 93 APPENDIX C. OTHER PHYLOGENETIC ANALYSES ................................................... 94 APPENDIX D. RAW MEASUREMENTS ........................................................................... 97 APPENDIX E. STANDING DIVERSITY RAW VALUES ................................................. 98 APPENDIX F. ORIGINATION AND EXTINCTION PERCENTAGES ............................ 99 APPENDIX G. NORMALIZED WESTERMANN MORPHOSPACE VALUES ............... 100 APPENDIX H. TUBERCLE AND SUTURE TERMS ......................................................... 105 APPENDIX I. REFERENCES FOR TAXONOMIC DESCRIPTIONS ............................... 106 viii LIST OF FIGURES Figure Page 1 Acanthoceratoid Stratigraphic Ranges ....................................................................... 4 2 Westermann Morphospace ......................................................................................... 6 3 Dunveganoceras albertense ....................................................................................... 9 4 Western Interior Seaway ............................................................................................ 10 5 Superfamily Composition .......................................................................................... 11 6 Westermann Morphospace Measurements ................................................................ 21 7 Consensus Tree 1 ....................................................................................................... 24 8 Bootstrap and Jackknife Analysis 1 ........................................................................... 26 9 Calibrated Tree 1 ........................................................................................................ 29 10 Consensus Tree 2 ....................................................................................................... 31 11 Bootstrap and Jackknife Analysis 2 ........................................................................... 33 12 Calibrated Tree 2 ........................................................................................................ 35 13 Consensus Tree 3 ....................................................................................................... 36 14 Bootstrap and Jackknife Analysis 3 ........................................................................... 38 15 Calibrated Tree 3 ........................................................................................................ 41 16 Standing Diversity ..................................................................................................... 45 17 Origination and Extinction ......................................................................................... 46 18 Westermann Morphospace for All Taxa .................................................................... 49 19 Westermann Morphospace for Acanthoceratidae ...................................................... 50 20 Westermann Morphospace for Collignoniceratidae .................................................. 51 21 Westermann Morphospace for Vascoceratidae ......................................................... 52 ix 22 Westermann Morphospae Occupation Through Time ............................................... 54 x LIST OF TABLES Table Page 1 Acanthoceratoid Genera in the WIS .......................................................................... 13 1 INTRODUCTION At the Cenomanian-Turonian (C/T) boundary (93.9 Ma), there was a major extinction event which has been cited as one of the ten largest mass extinctions of the Phanerozoic (Raup and Sepkoski, 1986). Elder (1989) reported that extinction among the ammonoids and inoceramid bivalves were the primary drivers of extinction patterns. Within ammonoids of the Western Interior Seaway (WIS) of North America, up to 93% species level extinction has been reported (Harries and Little,