Date of Award


Degree Type


Degree Name

Master of Science (MS)




Analysis of variation is critical in understanding evolutionary processes. The subtribe Papionina, defined commonly as baboons and their closest relatives, is a highly morphologically diverse group of primates that is useful for the examination of the relationship between variation and evolution. The subtribe is also a valuable behavioral, ecological, and morphological analogy for hominins. This study uses landmark-based cranial geometric morphometric data and multivariate analysis to test whether the pattern of morphological diversification present in Papionina is consistent with genetic drift and/or selection. The study sample consists of six extant genera of Papionin, represented by ~500 individuals collected by Michelle Singleton and Stephen R. Frost from predominantly wild populations. Multivariate analysis was performed on 17 linear measurements obtained by following principles of morphological integration. The proportionality of variance/covariance matrix structure within and between populations was compared in order to identify the mode of morphological diversification present in the subtribe. Our results indicate that the mechanism driving diversification is unlikely to be drift alone and requires selection. The facial prognathism distinguishing baboons and mandrills from the rest of the subtribe is primarily the result of selection having acted on an immediate common ancestor.

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Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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