Doctoral Dissertation Improvement: Functional Morphology of Mammalian Sacra and Caudal Vertebrae: Implications for tail loss and positional behaviors in extinct primates

University Of Texas At Austin, Austin TX

Investigators

Abstract

Doctoral candidate Gabrielle Russo (University of Texas, Austin), under guidance of Dr. Liza Shapiro, will investigate evolutionarily significant aspects of primate functional morphology. The focus will be on features related to taillessness and upright posture, features which are important in understanding ape origins, evolutionary relationships and locomotion. Despite extensive study of the ape postcranial skeleton, researchers continue to face difficulty identifying taillessness and trunk posture from fossil material, in part because appropriate living primate analogs for comparison are lacking. This has compromised testing functional hypotheses focused on the evolution of such features as they are represented in the fossil record. This study will 1) identify anatomical correlates of tail length, posture and locomotion from the external and internal bony morphology of sacra and caudal vertebrae in a taxonomically and morphologically diverse mammalian sample, and then 2) apply the identified anatomical correlates to a reconstruction of tail length, posture, and locomotion in extinct hominoids and other primates. The project will generate an extensive dataset and test explicit hypotheses about tail length, posture and locomotion. External morphometric data will be collected from more than 73 species belonging to five mammalian orders. Using high resolution X-ray computed tomography, sacra representative of 18 living primate species will be scanned in order to analyze trabecular and cortical bone parameters. This study will produce the largest known CT scan sample of mammalian sacra, which will be made freely accessible to biological anthropologists, comparative mammalogists, and clinicians. This project also provides educational and research opportunities to undergraduate students by soliciting interns though a University of Texas at Austin program that targets first-generation and minority students.