Paleoecology of the Freshwater Ampullariidae from the Late Oligocene Nsungwe Formation of Tanzania A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Master of Science Yuwan Ranjeev Epa April 2017 © 2017 Yuwan Ranjeev Epa. All Rights Reserved. 2 This thesis titled Paleoecology of the Freshwater Ampullariidae from the Late Oligocene Nsungwe Formation of Tanzania by YUWAN RANJEEV EPA has been approved for the Department of Geological Sciences and the College of Arts and Sciences by Alycia L. Stigall Professor of Geological Sciences Robert Frank Dean, College of Arts and Sciences 3 ABSTRACT EPA, YUWAN RANJEEV, M.S., April 2017, Geological Sciences Paleoecology of the Freshwater Ampullariidae from the Late Oligocene Nsungwe Formation of Tanzania Director of Thesis: Alycia L. Stigall This study examines morphological diversification of the late Oligocene ampullariid species from the Rukwa Rift Basin of Tanzania. Six new species of ampullariids are described, including five species of Lanistes and one species of Carnevalea. The high-spired Lanistes species described record the earliest appearance of this morphotype in the fossil record. Carnevalea santiapillai records the first appearance of this genus outside the Eocene of Oman. Paleoecological interpretations suggest a paludal to lacustrine ecology for C. santiapillai and a lacustrine ecology for L. nsungwensis. Lanistes songwensis and L. songweellipticus were interpreted as fluviate species whereas L. microovum and L. songweeovum were capable of inhabiting both lentic and lotic habitats. Morphological variations among paleoenvironments provide evidence for tectonically induced local radiation of Lanistes. Overall, this study provides valuable insight onto the taxonomy, evolution and the biogeographic affinities of the Paleogene freshwater gastropods of Afro-Arabia, and thus contributes significantly to closing the “African Gap.” 4 DEDICATION I dedicate this thesis to my wife, Nilmani, and my family for their constant support, encouragement and especially for always believing in me. 5 ACKNOWLEDGMENTS I would like to thank my advisor, Professor Alycia Stigall for her patience, guidance and constant encouragement. I would also like to thank my thesis committee: Professor Nancy Stevens, Dr. Daniel Hembree, Dr. Gregory Springer and the late Professor Elizabeth Gierlowski-Kordesch for their generous advice and guidance. My sincere gratitude to Dr. Jonathan Hendricks, Dr. Haley O’ Brien and Dr. Gregory Nadon for their kind and helpful suggestions. I thank Dr. Matthew Borths, Karie Whitman, Eric Lund and all members of the Rukwa Rift Basin Project for providing me with an excellent collection of fossils for this thesis. I also thank The Academy of Natural Sciences, Drexel University and The University of California Museum of Paleontology, Berkeley, for providing comparative specimens for this project. I extend my appreciation to The Paleontological Society and the Ohio University Geological Sciences Alumni Graduate Research Grant Committee for funding this research. Finally, I would like to thank all members of the Department of Geological Sciences, Ohio University and to the staff at the Department of Zoology, University of Peradeniya, Sri Lanka, for their encouragement, which helped me achieve my lifelong goal of becoming a Paleobiologist. 6 TABLE OF CONTENTS Page Abstract ............................................................................................................................... 3 Dedication ........................................................................................................................... 4 Acknowledgments............................................................................................................... 5 List of Tables ...................................................................................................................... 8 List of Figures ................................................................................................................... 10 Chapter 1: Introduction ..................................................................................................... 12 Objectives and the Scope of the Present Investigation .................................................. 12 Adaptive Radiations and the Fossil Record ................................................................... 12 Chapter 2: Evolutionary History and Morphological Variation within the Family Ampullariidae ................................................................................................................... 16 Morphological Variation within the Family Ampullariidae .......................................... 16 Evolutionary History of the Ampullariidae ................................................................... 17 Morphological Disparity within the Genus Lanistes ..................................................... 19 Fossil Record of Lanistes and Carnevalea .................................................................... 20 Chapter 3: Geologic Setting .............................................................................................. 26 The Rukwa Rift Basin .................................................................................................... 26 Sedimentology of the Nsungwe Formation ................................................................... 29 Chapter 4: Materials and Methods .................................................................................... 33 Material Examined ......................................................................................................... 33 Morphological Data Collection...................................................................................... 34 Data Analyses ................................................................................................................ 38 Interpreting the Paleoecology of Nsungwe Ampullariidae ............................................ 39 Chapter 5: Results of Morphometric Analyses ................................................................. 40 Morphometric Analyses of Modern Lanistes Species ................................................... 40 Implications ............................................................................................................... 44 Morphometric Analyses of Nsungwe Ampullariids ...................................................... 45 Implications ............................................................................................................... 50 Morphometric Analyses of Fossil Ampullariid Specimens ........................................... 50 Implications ............................................................................................................... 54 7 Combined Morphometric Analyses of Fossil and Modern Ampullariid Specimens ..... 54 Implications ............................................................................................................... 58 Taxonomic Composition of Nsungwe Ampullariids ..................................................... 62 Chapter 6: Systematic Paleontology ................................................................................. 63 Chapter 7. Discussion ..................................................................................................... 103 New Ampullariid Fauna from the Late Oligocene Nsungwe Formation ..................... 103 Paleoecology of Nsungwe Ampullariids ..................................................................... 104 Ecophenotypic Variation within the Nsungwe Ampullariids ...................................... 106 Paleoenvironment of the Late Oligocene Rukwa Rift Basin ....................................... 109 Evidence for Adaptive Radiation of Nsungwe Lanistes .............................................. 112 Closing the African Gap .............................................................................................. 113 Chapter 8: Conclusions ................................................................................................... 115 References ....................................................................................................................... 119 Appendix A: All Nsungwe Fossils Examined ................................................................ 135 Appendix B: Modern and Fossil Museum Specimens Examined .................................. 142 Appendix C: Fossil Specimens Included in Morphometric Analyses ............................ 146 Appendix D: Modern Specimens Included in Morphometric Analyses ......................... 150 Appendix E: Fossil Specimens Loaned from Natural History Museums Included in Morphometric Analyses .................................................................................................. 157 8 LIST OF TABLES Page Table 1: Morphometric analysis of modern Lanistes species: Percent variation explained by principle components .................................................................................................42 Table 2: Morphometric analysis of modern Lanistes species: Loadings for individual variables ..........................................................................................................................42 Table 3: Morphometric analysis of Nsungwe ampullariid species: Percent variation explained by principle components ................................................................................48 Table