Meeting Abstract
33.5 Wednesday, Jan. 5 The ontogeny of dental form and tooth pressures in the American alligator (Alligator mississippiensis) GIGNAC, P. M.*; ERICKSON, G. M.; Stony Brook University; Florida State University paul.gignac@stonybrook.edu
In addition to its size, the American alligator, Alligator mississippiensis, utilizes absolutely high bite forces to capture and subjugate increasingly durable prey throughout development. Moreover, the application of these forces is mediated through its pseudoheterodont dentition. The mesial caniniform teeth are long, semi-sharp, and used for seizing prey; whereas, the distal molariform teeth are blunter and used for crushing durable prey tissues. Both reside in alveoli at the apex of the upper jaw convexities, and thus act in isolation to initiate contact with the prey during feeding. Their biomechanical performance can be directly linked to morphology and dietary ecology; however, the role of the teeth during feeding has not been quantified throughout ontogeny in A. mississippiensis, or in any other crocodilian for that matter. As a result, it remains unclear how changes in dentition contribute to developmental niche shifts in this taxon. To address this issue, an analysis of tooth pressures throughout ontogeny was undertaken at the most prominent caniniform and molariform tooth positions. Results showed that dental form changes substantially during growth and facilitates the pressures needed to mechanically fail durable prey tissues, such as bone, relatively early in development, indicating that access to new prey resources can be partially accounted for by ontogenetic changes to the dentition. Pairing these findings with recently collected data on the ontogeny of maximum bite force, rostral form, and jaw adductor muscle physiology that underpin the capabilities of this feeding system, it is now clear that the acquisition of new biomechanical capacities is mediated by accelerated changes in the feeding anatomy early in ontogeny which slow before the onset of sexual maturity.
