ADDIS ABABA UNIVERSITY COLLEGE OF NATURAL SCIENCES School of Graduate Studies School of Earth Sciences “Evolution of Plio-Pleistocene Proboscidea from the Lower Omo Shungura Formation” By Tomas Getachew A thesis submitted to the school of Graduate Studies of Addis Ababa University in Partial fulfillment of the degree of Master of Science in Earth Sciences (Paleontology and Paleoenvironment). Advisors Balmual Atnafu (PhD) Jean-Renaud Boisserie (PhD) December, 2015 Addis Ababa Table of Contents Contents Page Approval Form ................................................................................................................................. i Acknowledgement ........................................................................................................................... ii List of tables ................................................................................................................................... iii List of figures ................................................................................................................................. iv Abstract ............................................................................................................................................ v 1. CHAPTER ONE: INTRODUCTION ...................................................................................... 1 1.1. Background ................................................................................................................ 1 1.2. Location of the study area .......................................................................................... 6 1.3. History of research in the Shungura Formation ......................................................... 7 1.4. Statement of the problem ......................................................................................... 10 1.5. Obj ectives of the study ........................................................................................... 12 1.5. Obj ectives of the study ........................................................................................... 12 1.5.1. General obj ective ................................................................................... 12 1.5.2. Specific objectives .................................................................................. 12 1.6. Significance of the study ......................................................................................... 12 1.7. Limitations of the study ........................................................................................... 13 1.8. Organization of the study ......................................................................................... 14 2. CHAPTER TWO:LITERATURE REVIEW ........................................................................... 15 2.1. Proboscidean evolution ........................................................................................... 15 2.2. Geology of the area ................................................................................................. 23 2.3. Fossil faunal assemblage at the Shungura Formation ............................................. 26 26 2.4. Previous works at the Shungura Formation. 26 30 3. CHAPTER THREE: MATERIALS AND METHODS 3.1. Materials .................................................................................................................. 30 3.1.1. The comparative materials ...................................................................... 32 3.2. Methods ................................................................................................................... 32 3.2.1. Field work ................................................................................................ 32 3.2.1. Laboratory work ...................................................................................... 33 3.3. Some of elephant tooth characters used for the study ............................................. 40 3.4. Terms and measurement procedure ......................................................................... 43 3.5. Methods of data analysis ......................................................................................... 45 4. CHAPTER FOUR: RESULTS ................................................................................................. 47 4.1. Morphological description of some new elephantid remains from the Shungura Formation .......................................................................................................................... 47 4.1.1. Systematic paleontology .......................................................................... 47 4.1.2. Description and comparison .................................................................... 49 4.2. The evolution of hypsodonty index within the five taxonomic groups ................... 54 4.3. The evolution of hypsodonty through the members of the Shungura Formation.56 4.4. The evolution of enamel thickness within the five taxonomic groups of Elephas recki 60 4.5. The evolution of lamellar frequency within the five taxonomic groups of Elephas recki 65 4.6. Comparison of enamel thickness versus hypsodonty index, and laminar frequency ............................................................................................................................ 68 4.7. Tooth wear-based dietary analysis for the five taxonomic groups of Elephas recki ............................................................................................................................. 70 5. CHAPTER FIVE: DISCUSSION............................................................................................. 74 5.1. Discussion on the comparative description of specimens of Elephas recki from the Shungura Formation.......................................................................................................... 74 5.2. Evolution of hypsodonty index through the Shungura Formation ........................... 75 5.3. Evolution of enamel thickness through the Shungura Formation ............................ 77 5.4. Evolution of lamellar frequency of the five taxonomic groups of Elephas recki lineage from the Shungura Formation ........................................................................................... 78 5.5. Paleoenvironments and dietary adaptations of Elephas recki ................................. 82 6. CHAPTER SIX: CONCLUSION AND RECOMMENDATIONS.......................................... 86 6.1. Conclusion ............................................................................................................... 86 6.2. Recommendations ................................................................................................... 88 REFERENCES ............................................................................................................................... 90 APPENDIX ................................................................................................................................ 100 Appendix 1: Biometric characteristics of the five taxonomic groups of Elephas recki ............. 101 Appendix 2: Measured mesowear angle of the five taxonomic groups of Elephas recki .......... 107 ADDIS ABABA UNIVERSITY COLLEGE OF NATURAL SCIENCES School of Graduate Studies School of Earth Sciences “Evolution of Plio-Pleistocene Proboscidea from the Lower Omo Shungura Formation” By Tomas Getachew A thesis submitted to the school of Graduate Studies of Addis Ababa University in Partial fulfillment of the degree of Master of Science in Earth Sciences (Paleontology and Paleoenvironment). Approved by examining committee Dr. Balmual Atnafu (Advisor) ___ Dr. Jean-Renaud Boisserie (Co-Advisor) Dr. Mulugeta Fisseha (Examiner) _____ Dr. Solomon Yirga (Examiner) _______ Dr. Mulugeta Alene (Chairman) _______ i Acknowledgment My deepest gratitude goes to my advisors Dr. Jean-Renaud Boisserie and Dr Balmua Atnafu for their constructive advice and suggestion to accomplish the thesis work. I would like to specially thank Dr. Jean- Renaud Boisserie for accepting to be my advisor and for providing me some references. I thank the ARCCH for allowing me the access of collection and laboratory facilities. I also thank Omo Group Research Expedition for allowing me to access and study a recently finds. I thank AAU, School of Earth Sciences for funding for my study. I am also grateful to Dr. Zeresenay Alemseged for providing me some references. Furthermore, my gratitude extends to my family members who have always been on my side through the ups and downs, my friends working at the ARCCH for their relentless encouragement and support of my research work. ii List of Tables Page Table 3. 2 Number of samples selected 32 57 Table 3. 2 Abbreviations of measurements and terms used in this study 57 Table 4.1 Metric data for Elephas recki molars from the eastern Africa sites Table 4.4 Probability (p) and statistical summary for Hypsodonty Index values of the five taxonomic group of Elephas recki lineage from the Shungura Formation 58 Table 4.5 Mann-Whitney pair tests: for hypsodonty index values of the five taxonomic group of Elephas recki from the Shungura Formation 59 Table 4. 6 Probability (p) and statistical summary of enamel thickness values of subspecies of Elephas recki from the Shungura Formation 61 Table 4.7 Probability (p) and statistical summary of the Enamel Thickness values of subspecies of Elephas recki from members of the Shungura Formation 62 Table 4.8 Mann- Whitney pair tests: for enamel thickness values of the five taxonomic