Emma Gilmore
Pronouns: she/her
Research Mentor(s): Lindsey Dehaan
Research Mentor School/College/Department: Earth and Environmental Sciences / LSA
Program:
Authors:
Session: Session 5: 2:40 pm – 3:30 pm
Poster: 61
Abstract
Feeding biomechanics of fishes are highly complex and diverse across the fish tree of life as some fish capture prey with speed and fast closing jaws while others feed with crushing force. The adductor mandibulae is the muscle responsible for closing the jaw and it is composed of varying segments that are located behind the skull and it also protrudes into the lower jaw. A previous study found no correlation between the mass of the adductor mandibulae and the force at which the jaw closes. However, the morphology of the adductor mandibulae and the length at which the muscle protrudes into the lower jaw is highly variable. Using Carangaria (Billfishes, Jacks and Flatfishes), a group of fish that is widely diverse in their eating habits, we examined the relationship among body size, the length of which the muscle protrudes into the lower jaw, and the mechanical advantage, a proxy used to estimate jaw closing force, to answer two questions. (1) How morphologically diverse is the adductor mandibulae in Carangaria? And (2) Does the length at which the adductor mandibulae protrude into the lower jaw correlate with the force in which the jaw closes? We collected data from 40 species using X rays taken at the University of Michigan Museum of Zoology (UMMZ) and used phylogenetic corrected linear regression to test for correlations among the traits. We found a negative correlation between mechanical advantage and length of the muscle in the lower jaw, and mechanical advantage and average body size. These results demonstrate that the longer the muscle is in the lower jaw, the lower the mechanical advantage (a less forceful bite) and the shorter the muscle in the jaw, the higher the mechanical advantage (a more forceful bite). But despite these findings, there was a lot of variation between species as outliers were present. This correlation and the morphological diversity of Carangaria are important to consider when furthering studies on the diverse feeding biomechanics of fishes.
