This project will analyze the evolutionary relationships of Otavipithecus namibiensis, the recently discovered Miocene hominoid species from Namibia. The Miocene hominoids, a diverse assemblage of fossil apes which occupied the Old World from roughly 22 to 5 million years before present, gave rise both to humans and our closest living relatives, the African apes. Consequently, understanding the evolutionary relationships of these early apes is crucial to the study of human origins. This study also will address a specific methodological problem in hominoid studies: the role of quantitative morphological characters in the reconstruction of hominoid evolutionary relationships. Current methods of coding quantitative characters into discrete character states for cladistic analysis and several statistically-based methods new to primate systematics will be applied to morphometric data taken from hominoid mandibles. The relative effectiveness of these methods will be compared. The study sample will comprise fossil and extant hominoid mandibles housed in collections in the U.S., Europe, and Africa, with an emphasis on constructing valid biological samples and maximizing sample sizes. Evolutionary analysis will be performed using current computer-assisted methods of phylogeny reconstruction, and previously stated hypotheses concerning the evolutionary relationships of Otavipithecus namibiensis will be examined in the light of these results. In addition to being a detailed investigation of the evolutionary affinities of Otavipithecus, this study will provide the first rigorous examination of the role of quantitative character coding in primate phylogeny reconstruction, the results of which ultimately may be generalized to additional anatomical regions in hominoids, as well as to studies of other primate groups.
