ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES DEPARTMENT OF BIOLOGY Shearing Quotient based Ecomorphological Analysis of Cercopithecidae fossils from the Lower Omo Basin: Dietary Adaptation, Habitat Preference and Paleoenvironment Reconstruction By Mezgebu Ashagrie A Thesis Submitted to the School of Graduate Studies of the Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology (Dryland Biodiversity). Advisor: Solomon Yirga (D.Sc.) December 2008 Addis Ababa ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES Shearing Quotient based Ecomorphological Analysis of Cercopithecidae fossils from the Lower Omo Basin: Dietary Adaptation, Habitat Preference and Paleoenvironment Reconstruction BY Mezgebu Ashagrie A Thesis Submitted to the School of Graduate Studies of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology (Dryland Biodiversity) Approved by Examining Committee ___________________________ (Examiner) ______________________ _______________________ (Examiner) _______________________ ___________________________ (Advisor) _______________________ ___________________________ (Chairman) _______________________ DECLARATION I, hereby confirm that this thesis is my original work and has not been presented for a degree in any other University and that all resources of material used for this thesis have been duly acknowledged. Name Mezgebu Ashagrie Demissie Signature __________________ Date of submission _______________ This thesis has been submitted for examination with my approval as the research advisor. Name ________________________ Signature ____________________ Date _________________________ ACKNOWLEDGEMENT This research project would not have been achievable without the support of many people, all of whom I am indebted to. Especially, I am grateful to my research advisor Dr. Solomon Yirga for his valuable advices, comments, criticisms, insights and suggestions as well as for his tireless editing, encouragement, material and financial support that contributed much for the substance of this thesis. I thank Dr. Birhane Asfaw for his help in easy access to the study materials and emotional support. I also thank Addisu Mekonen, Antone, Dr. Brenda Benefit, Chalachew Mesfin, Dr. Dele Every, Dr. Jarono, Minasie, and Vola Bence for their help in one way or another. I thank Woizero Mamitu Yilma (Director of the National Museum of Ethiopia), all members of the Omo Research expedition for all their hard work in the collection and preparation of the cercopithecid specimens used in this study, Alemu Ademassu, Menkir Bitew and Bizuayehu Tegegn in the Paleoanthropology lab of the NME, Ketema Amberbir and Tibebe Dejene of the Zoological Natural History Museum, AAU, and Milite Berhe in Zoology lab of AAU for all of their kind help and cooperation to study the specimens in their care. Finally, I thank Woizero Tsehay Tegegn who helped me in many ways throughout my study duration that made my study far better than it would have been. My appreciation also goes to Fikirte Gebresenbet and Shetie Gatew for their kind cooperation in editing pictures and continuous moral support in different aspects. Above all, I would like to express my deepest gratitude to my family for all their care, moral and financial supports which contribute much to my academic achievements. TABLE OF CONTENTS ACKNOWLEDGEMENT........ ...................................................................................................I LIST OF TABLES.....................................................................................................................II LIST OF FIGURES...................................................................................................................III LIST OF APPENDICES............................................................................................................IV ABSTRUCT.............................................................................................................................1 1. INTRODUCTION.........................................................................................................2 1.1. Statement of the problem.........................................................................................4 1.2. Objectives of the study............................................................................................9 1.2.1. General objectives of the study.....................................................................9 1.2.2. Specific objectives of the study.....................................................................9 1.3. Research Questions..................................................................................................9 1.4. Significance of the Study.......................................................................................10 2. LITRATURE REVIEW...............................................................................................11 2.1. paleodietary Adaptation and Evolutionary Success of the Cercopithecoids.........11 2.2. Dental Evidence for Dietary Adaptation...............................................................14 2.3. Phylogenetic Relationship of Cercopithecidae......................................................18 3. MATERIALS AND METHODS.................................................................................20 3.1. Materials................................................................................................................20 3.2. Methods.................................................................................................................24 3.2.1. Statistical Analyses...................................................................................28 4. RESULT AND DISCUSSION....................................................................................29 4.1. Results...................................................................................................................29 4.1.1. Reconstruction of Dietary Adaptations.......................................................29 4.2. Discussion..............................................................................................................34 4.2.1. Reconstruction of Dietary Adaptation.........................................................34 4.2.2. Habitat preferences and Paleoenvironmental Reconstruction.....................43 5. CONCLUSIONS.........................................................................................................49 REFERENCES...........................................................................................................51 APPENDICES............................................................................................................59 LIST OF TABLES Table 1. distribution summary of cercopithecids across stratigrafic members of the Shhhungura formation or geological time intervals...........................................................21 Table 2. Descriptive statistics summary of logarismic transformed values of Shearing crest and mesiodistal length of Extant frugivore cercopithecidae.....................................26 Table 3. Statistical significance test summary of cercopithecine and colobine shearing quotients.............................................................................................................................29 Table 4. The shearing quotient descriptive statistics of the lower Omo fossil and extant cercopithecidae..................................................................................................................31 LIST OF FIGURES Figure 1. Shungura Formation stratigraphy showing Members A–L with magnetostratigraphic and radiometric dates......................................................................22 Figure 2. Measurement of shearing crest lengths (solid line) (1-8) and mesiodistal occlusal table length (broken line) on a Theropithecus molar...........................................25 Figure 3. Regression plot of summed shearing crest lengths (mm) versus second lower molar mesiodistal length (mm) of extant frugivore cercoipthecine...................................27 Figure 4. The shearing quotient values that indicate the length of shear crest..................30 Figure 5. A comparison of the shearing crest development (quotient) of the second lower molars of colobines and cercopithecines...........................................................................32 Figure 6. The relative proportion of different dietary adaptation groups in the Shungura sequences...........................................................................................................................45 LIST OF APPENDICES Appendix 1. List of fossil cercopithecids that are used in the study as a study materials.............................................................................................................................59 Appendix 2. List of extant frugivorous cercopithecines that are used in allometric scaling of shearing quotient of fossil cercopitheciids....................................................................62 ABSTRACT This study was undertaken to reconstruct the Shungura cercopithecid assemblages’ dietary adaptation, habitat preference and environmental changes. Their dietary adaptations were reconstructed through shearing quotient based ecomorphological analysis. Each species’ trophic adaptation was compared to their locomotor adaptations and associated environmental evidences