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.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/17807 |
| Date | 25 September 2009 |
| Creators | Nargolwalla, Mariam C. |
| Contributors | Begun, David |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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