Avalon Yuhas
Pronouns: she/her
Research Mentor(s): Anne Kort
Research Mentor School/College/Department: Earth and Environmental Sciences / LSA
Program:
Authors: Avalon Yuhas, Anne Kort
Session: Session 1: 9:00 am – 9:50 am
Poster: 33
Abstract
The bones in the body associated with locomotion, referred to as ‘postcrania’ (PTCR), give us a glimpse into how the associated creatures moved across their respective landscapes. The changes in how these bones are structured, whether that be in changes of the shapes/lengths of facets or the entire bone, can be telling of how the landscapes changed and how the animals adapted to this change over time. We looked at locomotor change over the Paleocene-Eocene Thermal Maximum (PETM), a period of rapid climate warming that occured 56 million years ago. We combed through the PTCR fossils of the University of Michigan Museum of Paleontology (UMMP) fossil mammal collections to see how mammalian locomotion may have changed over the PETM. We searched through the UMMP collections for PTCR from before and after the PETM, with the most prominent bones of interest being the humerus and the calcaneus. We looked through many boxes of miscellaneous bones, sorted out identifiable PTCR, and compiled a dataset of the identified fossils. Once a bone of interest was decided, the calcaneum, pictures were taken via imaging software (DigiCam Control) in the Research Museum, which were then virtually measured in Adobe Photoshop. We measured the calcaneal gear ratio (CGR), which is the ratio of two measurements: the measurement from the proximal to distal ends of the bone and the measurement from the sustentacular facet to the proximal end. This ratio correlates with the give-and-take between speed and strength in ankle motion of mammals. Currently, there is no clear trend that shows a major increase or decrease in CGR across the PETM. Further data is to be collected to gain more insight on the change in the locomotor properties of the calcaneum over time. The implications of this study entail the furthering of locomotor studies and the evolution of locomotion, alongside furthering a database of PCTR fossils for future use.
