Meeting Abstract

P3.176  Monday, Jan. 6 15:30  Jaw Muscle Activation in Freshwater Stingrays KHURSIGARA, A.J.*; BRODEUR, L.K.; GERRY, S.P.; Fairfield University ; Fairfield University ; Fairfield University akhursigara@student.fairfield.edu

Batoids (skates and rays) have specialized jaws that can function independently due to their cartilaginous skeleton, a lack of a ligamentous connection between the jaws and skull, and the presence of a highly flexible symphysis at the center of the upper and lower jaws. Bilateral implantation of the jaw muscles has lead to a greater understanding of the activity occurring on the left and right sides of the jaw during feeding events. A previous study has shown that skates activate their jaw muscles unilaterally without any activation of the contralateral side when processing complex prey. Therefore, the goal of our study was to investigate pairwise activation of the jaw muscles of a freshwater stingray Potamotrygon motoro when feeding on several prey types in order to determine if unilateral activation is a characteristic of batoid feeding mechanisms. We hypothesized that these rays would use synchronous activation when feeding on simple prey and unilateral activation to process complex prey. Electrodes were implanted bilaterally into three of the jaw adductors when the rays were fed three prey items of varying complexity. Two asynchrony indices were used to quantify the duration of muscle activation and the lag, or degree by which muscles are activated out of phase. Contrary to our hypothesis, data from two rays show that muscle pairs are activated synchronously for all prey types: there is no difference in duration or lag indices (P > 0.05). However, unilateral was sometimes observed when feeding on more complex prey. Further studies are needed to compare the variation observed in the feeding mechanisms of these two groups of batoids.