Chapter 1 - Introduction

Chapter 1 - Introduction

EURASIAN MIDDLE AND LATE MIOCENE HOMINOID PALEOBIOGEOGRAPHY AND THE GEOGRAPHIC ORIGINS OF THE HOMININAE by Mariam C. Nargolwalla A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Anthropology University of Toronto © Copyright by M. Nargolwalla (2009) Eurasian Middle and Late Miocene Hominoid Paleobiogeography and the Geographic Origins of the Homininae Mariam C. Nargolwalla Doctor of Philosophy Department of Anthropology University of Toronto 2009 Abstract The origin and diversification of great apes and humans is among the most researched and debated series of events in the evolutionary history of the Primates. A fundamental part of understanding these events involves reconstructing paleoenvironmental and paleogeographic patterns in the Eurasian Miocene; a time period and geographic expanse rich in evidence of lineage origins and dispersals of numerous mammalian lineages, including apes. Traditionally, the geographic origin of the African ape and human lineage is considered to have occurred in Africa, however, an alternative hypothesis favouring a Eurasian origin has been proposed. This hypothesis suggests that that after an initial dispersal from Africa to Eurasia at ~17Ma and subsequent radiation from Spain to China, fossil apes disperse back to Africa at least once and found the African ape and human lineage in the late Miocene. The purpose of this study is to test the Eurasian origin hypothesis through the analysis of spatial and temporal patterns of distribution, in situ evolution, interprovincial and intercontinental dispersals of Eurasian terrestrial mammals in response to environmental factors. Using the NOW and Paleobiology databases, together with data collected through survey and excavation of middle and late Miocene vertebrate localities in Hungary and Romania, taphonomic bias and sampling completeness of Eurasian faunas are assessed. Previous bioprovincial zonations of Europe and Western Asia are evaluated and modified based on statistical analysis of Eurasian faunas and consideration of geophysical, climatic and eustatic events. Within these bioprovinces, occurrences of in situ evolution and directionality of dispersals of land mammals are used as a framework to address and evaluate these same processes in Eurasian apes. The results of this analysis support previous hypotheses regarding first occurrences and phyletic relations among Eurasian apes and propose new ideas regarding the relations of these taxa to previously known and newly discovered late Miocene African apes. Together with analysis of environmental data, Eurasian mammals support the hypothesis that the descendant of a Eurasian ape dispersed to Africa in the early late Miocene (top of MN7/8 or base of MN9), however the question of whether this taxon founded the African ape and human lineage remains equivocal. ii Acknowledgements I have been so incredibly fortunate during the course of my graduate studies to be surrounded by some of the most brilliant, helpful and supportive colleagues and friends at the University of Toronto and in the field. First and foremost, I am indebted to my doctoral advisor, David Begun, who has patiently answered ten years of endless questions and who has always provided me with every opportunity to progress in the field of Paleoanthropology. I honestly could not have asked for a better advisor. I am grateful to my doctoral committee members, Shawn Lehman, Michael Schillaci and Martin Evison for their very helpful comments and suggestions for improving my dissertation. I am extremely lucky to have had John Fleagle as the external examiner extraordinaire, whose extensive comments will undoubtedly improve the quality of the publications derived from this project. In addition to my committee, I thank Matthew Betts, Dave Bovee, Maia Bukhsianidze, Terry “Captain Handsome” Clark, Andrew “has the Eagle landed?” Deane, János Hír, Laszlo Kordos, Gerald Romme, Matthew Tocheri and Márton Venczel. Each and every one of these individuals has contributed data, verified data, or discussed the methods used in my dissertation. I am also very lucky to have friends who are experts at picking me up when I’m down, brushing me off and sending me back on my way (everyone above and Jennifer Campbell, Emily Court, Lesley Howse, Karen Ryan and Alexandra Sumner). I thank Cleo and Charlie for keeping me company at all hours of the day and night and for their insightful comments on my dissertation. I thank Stephen Spensieri for pointing out that my potential as a play companion could not be reached until my dissertation was completed … and then for taking enough naps to let me finish writing. I thank my parents for their enthusiasm. Finally, I thank Carlo Spensieri, who has supported me since day one and has bent over backwards to help me accomplish everything that I have done. My research was supported by General Motors Women in Science and Mathematics, the Ontario Graduate Scholarship and University of Toronto Fellowship. Many years ago, a very wise woman told me to take an introductory course in Anthropology. She told me that it was a fascinating subject and although I didn’t really believe her at the time, it turns out that she was right. I dedicate this dissertation to her memory. iii Table of Contents Chapter 1 - Introduction .......................................................................................................1 Chronological overview........................................................................................................ 5 Paleoenvironmental overview............................................................................................... 7 Overview of study............................................................................................................... 11 Chapter 2 – Data Quality.................................................................................................... 14 Introduction......................................................................................................................... 14 Loss of Biological Information in the Fossil Record...................................................... 14 Materials and Methods........................................................................................................ 16 Spatio-temporal Distribution of Faunas.......................................................................... 16 Method of Analysis......................................................................................................... 17 Results................................................................................................................................. 19 Relationship between duration of temporal intervals & number of localities/number of localities & CI................................................................................................................. 19 Large Mammal Completeness ........................................................................................ 24 Small Mammal Completeness ........................................................................................ 29 Identification of “Marker Taxa” ..................................................................................... 33 Discussion........................................................................................................................... 38 Overall Completeness and Data Quality......................................................................... 38 Ecology of “Marker Taxa” ............................................................................................. 40 Distribution of sample localities..................................................................................... 40 Chapter Summary & Conclusions ...................................................................................... 44 Chapter 3 – Provinciality, paleoenvironments, in situ evolution and dispersal ................. 45 Introduction......................................................................................................................... 45 Zoogeographic Provinces and Purpose of Study ............................................................ 45 Barriers to dispersal & paleoenvironmental events in the Miocene of Eurasia.............. 46 Previous method and study of provinciality ................................................................... 53 Materials & Methods .......................................................................................................... 57 Materials ......................................................................................................................... 57 Analysis .......................................................................................................................... 58 Results................................................................................................................................. 69 Algorithms ...................................................................................................................... 69 Patterns of locality clustering ......................................................................................... 70 Discussion......................................................................................................................... 148 Resolution of analysis................................................................................................... 148 Faunal provinces in comparison to previous studies

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