You are what you eat: an analysis of morphological specializations to diet in Iguanid lizards.

HERREL A; VANHOOYDONCK B; CRUZ F

Salt Lake City, Utah, USA

Encuentro; SICB Annual Meeting 2011; 2011

The society for integrative and comparative biology

Small lizards are typically considered opportunistic foragers on invertebrate prey showing little or no dietary specialization. However, recent studies have demonstrated that many small-bodied lizards show dietary specializations including carnivory, herbivory, myrmecophagy in addition to the more common insectivorous or omnivorous diets. Given that small body size may constrain these animals in their ability to rely on postcranial food reduction mechanisms, we predict distinct adaptations to the cranial system in lizards that specialize on different food resources. Specifically, we predict a greater investment in jaw adductors in herbivorous species allowing them to maximize bite force for a given head size. Additionally, we predict that the relative proportions of the different jaw adductor groups will be different for carnivores versus herbivores to allow maximal bite force generation at large and small gape angles. Finally we predict low bite forces, a decrease in jaw adductor mass and a greater development of the hyolingual musculature in myrmecophagous specialists that swallow prey whole. Our results based on dissections of the cranial musculature in over 30 species of small-bodied iguanian lizards largely support our a priori predictions and show that small-bodied iguanian lizards show distinct specializations of the cranial muscle system allowing them to specialize of distinct food resources.