Ph.D. student Dexter Zirkle unraveling the mysteries of anterior inferior iliac spine!

Greetings! My name is Dexter Zirkle and I am a graduate student in the School of Biomedical Sciences/Physical Anthropology program at Kent State University (KSU). My primary goal this summer has been the completion of a manuscript that is an extension of my master's thesis topic. Seeking my first publication, it seemed natural to build off my previous work and incorporate new sources and ask new questions. In short, I am studying the growth and development of the anterior inferior iliac spine (AIIS of the pelvis) in hominids and comparing it to an analogous region (rectus femoris tubercle [RFT]) in non-human primates. In both hominids and non-human primates the AIIS/RFT region serves as the origin of the rectus femoris muscle which is involved in locomotion. It appears that the AIIS is a hominid autapomorphy, distinct in our lineage.

In order to expand my original work, I needed to establish partnerships with various individuals and institutions that had a piece to the puzzle I was working on. First off, I needed to increase the sample size of chimpanzee and gorilla pelves for quantitative analysis. My research request for access to skeletal material at the Cleveland Museum of Natural History (CMNH) was kindly accepted by Curator and Head of Physical Anthropology, Dr. Yohannes Haile-Selassie and Collections Manager, Lyman Jellema. I then needed to expand my human sample size as well as fossil hominid casts housed in the Department of Anthropology at KSU. I also collaborated with Chris Kegelman of The University of Virginia as our research interests, although varied, intersected by work on the human pelvis and the exploration of bony eminences.

This project involved a qualitative exploration of morphology and development, a quantitative study of comparative metrics, as well as radiological analysis. In addition to MRI scans of the human pelvis (Kegelman) and radiographs of the human and gorilla pelvis, I also needed access to radiographs of various lemur species because they show a unique prominence of the RFT. I worked with Dr. Erin Ehmke, Research Manager at the Duke Lemur Center to obtain a large number of lemur radiographs for analysis (thank you to Technician Jennifer Justen!). Relying on my previous work experience, lectures from Dr. Marcus Julius (radiologist, NEOMED), as well as radiological text, I was able to evaluate these radiographs for the presence (or absence) of secondary centers of ossification and evaluate trabecular patterns. Throughout this process, I've been lucky to be able to trade ideas and get input from KSU's very own Dr. Owen Lovejoy, my advisor, as well establish communication with Dr. Phil Reno, Assistant Professor of the Dept. of Anthropology at Penn State University. I crossed paths with Dr. Reno by accident at the CMNH as we were both sharing lab table space on the same days. He and I share many research interests so I can envision that being a very beneficial partnership moving forward.


I completed my first draft this month and I'm excited to see this project through and hopefully eventually see my first publication as a result. It's been a summer of building friendships, collaborations, and networking (and a lot of thinking, reading, and writing). Thanks for checking out my blog and good luck building collaborations in your own research! "Learn not for school but for life" -Seneca, roughly translated.

If you would like more information, please email Dexter at