Title: The Evolutionary and Morphological Diversification of the Subtribe Papionina

Abstract:

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 the Papionina is consistent with genetic drift and/or selection. The study sample consists of six extant genera of Papionin, represented by 619 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.

 

Acknowledgements:

I want to thank my advisor, Dr. James M. Cheverud, whose brilliance is unsurpassed. The theory he has taught me is itself more than I ever thought I could possibly learn. Dr. Daniela Rossoni’s scholarship primarily through the data analysis portion of this project has added invaluable sophistication and depth to my conclusions. Their help through this process has allowed for a thesis of which I am forever proud. Thank you to my committee members, Dr. Thomas Sanger and Dr. Anne Grauer, for your guidance and thoughtfulness.

In addition, I would like to thank Dr. Michelle Singleton for allowing me to use her cranial landmark data from 238 specimens referenced in her 2002 paper titled “Patterns of cranial shape variation in the Papionini (Primates: Cercopithecinae).” I also want to thank Dr. Stephen Frost for allowing me to use his cranial landmark data of 452 specimens detailed in his 2003 paper, “Cranial Allometry, Phylogeography, and Systematics of Large-Bodied Papionins (Primates: Cercopithecinae) Inferred from Geometric Morphometric Analysis of Landmark Data.” This dataset represents specimens from 17 different institutions located across 3 continents. Dr. Singleton and Dr. Frost have my deepest gratitude for their trust and for the gift of an extraordinary dataset and sample size.

Lastly, I am forever grateful to my parents for their unconditional and unending support. I only strive to make them proud. Thank you also goes to my husband, Ben, for his encouragement, humor, and positivity. He is the best partner I could ever expect in this life.

 

Vita:

Sophie LaBelle grew up spending summers “Up North” in Michigan and school years in Arizona. Prior to attending graduate school at Loyola University Chicago, she received her Bachelor of Science in Biological Anthropology from the George Washington University in the nation’s capital. While an undergraduate, she served as secretary of the GW Roots & Shoots chapter and mentored children with the D.C. Reads nonprofit organization. After graduating, she volunteered at the Lincoln Park Zoo.

During her time at Loyola, Sophie was elected Vice President of the Biology Graduate Student Association, worked as a mammal preparator at Chicago’s Field Museum, and completed an animal care internship at the Cosley Zoo. She is currently enjoying life with her husband, two poodles, and newborn daughter, Lucy.

Research Mentor:

Dr. James M. Cheverud

Committee Members:

Dr. Anne L. Grauer

Dr. Thomas Sanger