MCBRAYER, L.D.; Stephen F. Austin State University: The relationship between skull morphology, biting performance and foraging mode in Kalahari lacertid lizards

Lizards are a diverse clade in which one radiation of species consists entirely of sit-and-wait foragers and another consists of wide foragers. Lizards utilizing these two foraging modes are known differ in diet, but little is known about how feeding morphology and biomechanics are related to diet and/or foraging mode. This study tested the hypothesis that feeding morphology and performance are related to these dietary preferences and consequently co-evolve with foraging mode. Four species of lizards (Lacertidae) were used as a model system because they vary in foraging mode, their phylogenetic relationships are known, and they are well studied ecologically. Using an �ecomorphological� approach, feeding morphology and biting performance were quantified and mapped onto the phylogeny for the species. The results indicate that sit-and-wait species have shorter and wider skulls than the wide foraging species and that all are significantly different in overall head shape. The sit-and-wait species had similar values to one another for biting performance; however, clear phylogenetic patterns of covariation were not present between sit-and-wait and wide foraging species for either biting performance or skull morphology. Thus, this study suggests feeding morphology and performance have little influence on diet and foraging mode. Instead it is likely that other factors like seasonal prey availability and/or life history strategy shape foraging mode decisions.