Travels with my grant
By Christopher Mayerl, Clemson University
X-ray images of a walking turtle.Lateral (A) and ventral (B) views. Blue dotsindicate markers on the pelvis, red dots are marker locations on the femur, and green dots are markers located on the shell (carapace and plastron).Photo: Journal of Experimental Biology.
Christopher was a recent recipient of the SEB's Company of Biologist's travel grant. Christopher used the grant to travel to Brown University where he was able to collaborate with Prof. Beth Brainerd and use emerging X-ray reconstruction technology to test the pelvic rotation in different groups of turtles. The result of this research led to Christopher's work being published in the Journal of Experimental Biology! Read more about Christopher's travel grant experience below.
I used funds from my travel grant to go to Brown University, Rhode Island in order to collect data to determine whether turtles can move their pelvis inside the shell while they walk and swim. We did this using an emerging technology called X-Ray Reconstruction of Moving Morphology (XROMM) that coordinates CT scans of the skeleton with 3D X-ray video to allow precise measurements of the movements of internal structures in animals. The motivation behind the work began with a morphological difference in pelvic girdle structure between the two major groups of turtles: cryptodires and pleurodires. Cryptodires possess a pelvis that is similar to most other vertebrates, with the girdle attached to the vertebrae at a joint. However, pleurodires show a derived condition, in which the pelvis is fused to the shell. Because rotations of the pelvic girdle during locomotion enhance performance in most tetrapods, I wanted to investigate whether or not the difference in morphology between the groups corresponded with a difference in mobility in the two lineages. Does the pelvis rotate at all in any turtle, and are there differences between groups of turtles? What could such differences mean for their locomotor performance in different environments?
To see through the shell and test for movements of the pelvis we collaborated with Beth Brainerd, a professor at Brown who helped to develop XROMM. What we found was surprising! The pelvis of cryptodires moved just like it does in any other tetrapod, with rotations side to side up to 20 degrees! In contrast, the pleurodire pelvis didn’t move at all. The rotations of the pelvis in cryptodires enhanced their ability to protract their leg by over ten degrees, letting them take longer steps and move faster than they would otherwise be able to.
Traveling to Brown was an amazing experience. It was my first time in Rhode Island, and the campus was amazing. Even though it was in a pretty big city, you felt like you were in a small town, as Thayer street was just a block from the lab, with all sorts of local music and food to enjoy during lunches and dinners. Additionally, the faculty at Brown were all very welcoming, and made it an invigorating and inspiring environment.
See the full press release including video's of Christopher's research here.
Read the Journal of Experimental Biology published research article here.
Want to find out how you can get a travel grant? click here.
Author: Christopher Mayerl
Category: Animal Biology