Meeting Abstract

67.1  Tuesday, Jan. 6  Biomechanical modeling of bite-force generation in the America alligator (Alligator mississippiensis) throughout ontogeny GIGNAC, P. M.*; ERICKSON, G. M.; Florida State University; Florida State University pgignac@bio.fsu.edu

The American alligator, Alligator mississippiensis, shows up to 5000-fold increases in mass during development. A substantial resource shift to increasingly larger and more durable prey items accompanies this change. To capture and subjugate these food resources this taxon utilizes absolutely high bite forces that have recently been shown to increase with positive allometry during development. Allometry of the cranial skeleton and jaw adductor musculature has been posited as the cause of such patterning. Nevertheless, the links between anatomical form and force generation have not been empirically tested. To address the cause of positively allometric bite forces in this taxon, we dissected a growth series of wild-caught A. mississippiensis and developed a mathematical model of bite-force generation based on ontogenetic changes to its feeding functional morphology. Muscle length, mass, pennation angle, and origin-insertion points for all six jaw adductors were considered. The model was tested against experimentally measured bite forces for an additional growth series of wild A. mississippiensis. The results show that bite force can be accurately predicted across the full size range of A. mississippiensis and that both mass increases and average attachment distance from the jaw joint of several of the jaw adductor muscles together contribute to the positive allometry of bite force in this taxon.