Meeting Abstract

P2.132  Saturday, Jan. 5  Does the unique desmognathine jaw morphology enhance bite force? RICHARDSON, J.R.*; LARGHI, N.P.; DEBAN, S.M.; Univ. of South Florida, Tampa; Univ. of South Florida, Tampa; Univ. of South Florida, Tampa jcricha3@mail.usf.edu

Analysis of bite force in vertebrates provides insight into the performance of functions such as anti-predator defenses and prey capture and processing. Desmognathine salamanders have been observed consuming crustaceans and other salamanders, prey items which require powerful jaws for subduing and crushing. The robust jaw and skull morphology and unique jaw mechanics of desmognathines, in which the cranium is pulled ventrally while the mandible is locked in place, have led investigators to hypothesize that these salamanders can produce higher bite forces than comparatively sized salamanders. Desmognathus quadramaculatus is an ideal species in which to test this hypothesis because of its large size (70-120 mm SVL) and willingness to bite. In vivo voluntary bite force was measured during feeding bites using a custom-built piezoelectric bite meter, in both D. quadramaculatus and in the comparably sized Pseudotriton ruber, another salamander-feeder with a more generalized jaw morphology. D. quadramaculatus was found to generate static forces over ten times greater than Pseudotriton ruber (8.49 vs 0.59 N on average). Comparison to published bite forces suggests that neither D. quadramaculatus nor Pseudotriton ruber exerts bite forces that are significantly different than other comparably sized vertebrates. The divergent jaw mechanics of Desmognathus may enable bite force to be maintained with reduced levator muscle mass, rather than increasing bite force, per se.