Durham E-Theses The extent of homoplasy in the trunk and forelimb of the hominoidea Worthington, Steven How to cite: Worthington, Steven (2002) The extent of homoplasy in the trunk and forelimb of the hominoidea, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/4095/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk The Extent of HomopBasy in the Trunk and Forelimb of the Hominoidea A Thesis presented by Steven Worth engton to The Graduate School For the Degree of Master of Science in Biological Anthropology 2 9 JAN 2003 Department of Anthropology University of Durham June 2002 The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. Declaration This thesis is the result of my own work, and no part of it has previously been submitted for a degree at any university. Material from the published or unpublished work of others, which is referred to in the thesis, is credited to the source in the text. Statement of Copyright The copyright of this thesis rests with the author. No quotation from it should be published without their prior written consent and information derived from it should be acknowledged. ii Abstract of the Thesis The Extent of Homoplasy in the Trunk and Forelimb of the Hominoidea by Steven Worthington M.Sc. Thesis Biological Anthropology Department of Anthropology University of Durham June 2002 For the last century, palaeoprimatologists have questioned whether extant hominoids acquired their trunk and forelimb adaptations (previously interpreted as correlated with forelimb suspension) from a common ancestor, or developed them independently. Various workers have proposed that (1) the adaptations are hominoid synapomorphies; (2) hylobatids acquired these traits independently of hominids; (3) pongines and hylobatids evolved these features independently of each other and the African apes/humans; (4) the adaptations are independently derived in all hominoid genera. To test between these alternatives, nine characters from the trunk and forelimb are used to determine the evolution of character states in extant and Miocene hominoids. Metric traits from ten extant anthropoid and nine fossil catarrhine genera are used in computer based analyses to reconstruct the ancestral conditions of these traits for a given cladogram. Ancestral morphotypes are compared with conditions exhibited in terminal taxa to identify synapomorphy/homoplasy. Results suggest that five of the nine characters examined are hominoid synapomorphies. Of the remaining traits, one is shared derived for hominids, one is a synapomorphy of the African ape/human clade, one is not diagnostic for apes at all, and one reflects absolute differences in body size between taxa. Four traits exhibit homoplasy, in the form of convergence or reversal. None of these traits, however, show homoplasy between two or more hominoid taxa. Therefore, it is unlikely that hylobatids, pongines or African apes/humans evolved these traits independently of each other. Three main conclusions can be drawn from this study: (1) some of the characteristics previously interpreted as synapomorphies for extant and stem hominoids are not in fact shared derived for this clade; (2) there is no homoplasy between extant hominoid genera in the features examined; and, (3) the association of these traits with forelimb suspensory locomotion is unlikely. iii A©kBi©wli£c!c|©irt!©irets My sincere thanks go to Dr. Todd C. Rae for his supervision, encouragement, enthusiasm and, on occasions, patience during the research and writing of this thesis. I would also like to thank the administrative staff at the Department of Anthropology, University of Durham, and in particular Pat Barber, for the help I have received. I thank those individuals who allowed me access to the collections of primates in their care, and who provided assistance during my visits: Bob Randal, at the American Museum of Natural History, New York; and, Linda Gordon and Richard Thorington, at the National Museum of Natural History, Washington D.C. I would like to thank my fellow postgraduate students, and in particular Kate Read and Louise Blundel, for their encouragement, informative discussions and alcoholism. My thanks are also extended to my family and friends, who, over the course of this project have supported me emotionally and financially, despite having to put up with my erratic moods, unsociable work habits and seemingly bizarre interests. Finally, I thank Hilary for her consistently good selection of wines and beverages. iv Abbreviations The following abbreviations are used in the text. Measurements BTH Breadth LTH Length Dimensions Ant Anterior Post Posterior Prox Proximal Dist Distal Med Medial Lat Lateral Sup Superior Inf Inferior AP Anteroposterior ML Mediolateral PD Proximodistal CC Craniocaudal MID-S Mid-shaft Cladogram Statistics CI Consistency Index v Museum Accession Prefixes AMNH American Museum of Natural History CGM Cairo Geological Museum CP Can Ponsic DPC Duke Primate Centre IGF Instituto di Geologia Firenze IPMC Institut de Paleontologia Miquel Crusafont " -CL1 Can Llobateres 1 KNM Kenya National Museum " -MB Maboko Island " -RU Rusinga Island " -TH Tugen Hills MNHB Museum of Natural History, Basel MUZM Makerere University Zoology Museum NMNH National Museum of Natural History RUD Rudabanya UMP Ugandan Museum of Palaeontology YPM Yale Paleological Museum Others GFA Glenoid Fossa Angle HSC Homogeneous Subset Coding LCA Last Common Ancestor LTK Lateral Trochlear Keel Mya Million years ago USP Ulnar Styloid Process vi To my family. vii TABLE OF CONTENTS TABLE OF FIGURES xii CHAPTERS 1. INTRODUCTION 1 Aims and Objectives 1 Homology and Homoplasy 3 Systematics and Taxonomy 5 Extant Primate Systematics and Taxonomy 5 Fossil Primate Systematics and Taxonomy 7 Previous Phylogenetic Hypotheses 8 Introduction 8 Hominoid Trunk and Forelimb Synapomorphy 9 Hylobatid Trunk and Forelimb Homoplasy 13 Pongine and Hylobatid Trunk and Forelimb Homoplasy 15 Trunk and Forelimb Homoplasy in all Hominoid Genera 21 Summary 23 Hypotheses to Test 24 Thesis Outline 25 2. EXTANT ANTHROPOID TRUNK AND FORELIMB MORPHOLOGY AND LOCOMOTOR PATTERNS 26 Introduction 26 Hominoidea 28 Note on the Term 'Brachiation' 28 Trunk and Forelimb Morphology and Locomotion 29 Pan 33 Gorilla 36 Pongo 38 Hylobates 41 viii Summary 47 Cercopithecoidea 48 Chlorocebus 50 Colobus 51 Ceboidea 53 Ateles 56 Lagothrix 59 Alouatta 60 Saimiri 61 Summary 62 3. FOSSIL CATARRHINE TRUNK AND FORELIMB MORPHOLOGY AND LOCOMOTOR PATTERNS 64 Reconstructing Fossil Primate Locomotion 64 Trunk and Forelimb Morphology and Locomotor Patterns of an Oligocene Stem Catarrhine 66 Introduction 66 Aegyptopithecus 67 Trunk and Forelimb Morphology and Locomotor Patterns of some Miocene Stem Hominoids 69 Introduction 69 Early Miocene Stem Hominoids 71 Proconsul 71 Dendropithecus 75 Morotopithecus 76 Nyanzapithecus • 77 Middle and Late Miocene Stem Hominoids 79 Equatorius 79 Kenyapithecus 81 Dryopithecus 83 Sivapithecus 88 Oreopithecus 90 Summary 95 ix 4. CHARACTER ANALYSIS OF NEONTOLOGICAL ANTHROPOID TRUNK AND FORELIMB MORPHOLOGY 97 Introduction 97 Materials 97 Taxa 97 Characters 99 1: Manubrium Breadth 99 2: Glenoid Fossa Angle 100 3: Humeral Head Size 101 4: Humeral Head Shape 107 5: Humeral Head Torsion Angle 108 6: Humeral Medial and Lateral Trochlear Keel Development 108 7: Ulnar Olecranon Process Length 109 8: Ulnar Styloid Process Length 110 9: Lunate Breadth Ill Methods 111 Cladistics Ill Parsimony 115 Synapomorphy and Homoplasy 116 Polarity 117 Coding 119 Computer Program 121 Results 122 Character 1: Manubrium Breadth 122 Character 2: Glenoid Fossa Angle 123 Character 3: Humeral Head Size 123 Character 4: Humeral Head Shape 124 Character 5: Humeral Head Torsion Angle 144 Character 6: Humeral Medial and Lateral Tochlear Keel Development.... 144 Character 7: Ulnar Olecranon Process Length 145 Character 8: Ulnar Styloid Process Length 146 Character 9: Lunate Breadth 146 Summary of Results for Extant Anthropoid Analysis 147 x 5. CHARACTER ANALYSIS OF PALAEONTOLOGICAL CATARRHINE TRUNK AND FORELIMB MORPHOLOGY 148 Introduction 148 Materials 148 Taxa 148 Characters 149 Specimens 149 Methods 156 Results 157 Character 4: Humeral Head Shape 157 Character 6: Medial and Lateral Trochlear Keel Development 170 Summary of Results for Fossil Catarrhine Analysis 172 6. DISCUSSION AND CONCLUSIONS 173 Introduction 173 Hominoid Phylogeny 174 Extant Hominoid Synapomorphies 174 Fossil Hominoid Systematics 175 Hominoid Adaptations 176 Ancestral Hominoid Adaptations 176 Ancestral Hominid Adaptations 181 Ancestral African Ape Adaptations 182 Functional Significance of Hominoid Trunk and Forelimb Traits ... 183 Further Research 184 Summary and Conclusions 184 APPENDIX