Meeting Abstract

1.3  Wednesday, Jan. 4  Biomechanical Modeling and In Vivo Bite Force in the Zebra Moray Eel, Gymnomuraena zebra (Muraenidae) SHARICK, Jeffrey/T*; MEHTA, Rita/S; LAPPIN, A./K; Univ. of California, Santa Cruz; Univ. of California, Santa Cruz; California State Polytechnic University, Pomona

Bite force in vertebrates is often used as a proxy for various performance traits (e.g. food processing, male-male combat, anti-predator strategies). In the context of feeding, studies have shown that biting ability is linked to the biomechanical challenge the prey presents for the predator. In this study, we contribute to the growing comparative work on vertebrate bite force by studying cranial design and how it relates to biting in the zebra moray, Gymnomuraena zebra. Within muraenid fishes, zebra morays are thought to be the hallmark of durophagy with their diet consisting mainly of hard shelled prey such as xanthid crabs and reef urchins. Physiological Cross-Sectional Area (PCSA) and Mandiblever 3.3 were used to estimate bite force performance. While Mandiblever uses effective mechanical advantage to estimate bite force, PCSA uses mechanical advantage, possibly resulting in an inflated estimate of bite force. We then compared model output to in vivo bite force measures (N = 4) to validate model estimates. Model calculations estimated posterior maximal bite force to be 57.1 N and 59.3 N while posterior maximum in-vivo bite force was 159.2 N. Although the estimates of the two models are not significantly different from each other, measures from the in vivo bite trials are three times stronger than predicted by the models. We used the geometric mean of head dimensions (length, width, depth) to account for size variation among individuals and found a strong positive relationship between in vivo bite force and head size (r2 = 0.95). We compare the bite performance of G. zebra to that of other durophagous vertebrates for which bite force has been measured empirically.