Abstract
Dental morphology reflects an organism’s diet. Functional dental theory predicts that tooth shape corresponds to the mechanical properties of food. Most studies of mammalian teeth have focused on qualitative measures of dental anatomy and have not formally tested how the functional components of teeth adapt in response to diet. Here, murine rodents (Old World rats and mice) are used to quantify the relationship between diet and tooth shape and further, to identify a suite of functional dental characters that best distinguish amongst diets. Phylogenetic relationships are also taken into consideration. Biomechanically based size and shape predictions were also developed. Eighty-eight dental characters were extracted from images of the incisors and upper and lower tooth rows for 98 species. Results show that species with plant-dominated diets typically have deep incisors, a longer M3, longer molar crests, blunt posteriorly angled cusps, and more expanded laterally oriented occlusal cusps than species with animal dominated diets. Measures of incisor depth, crest length, cusp angle and sharpness, occlusal cusp orientation, M3/m3 length, most effectively separate amongst diets. Results suggest that these specific aspects of dental morphology can be used to accurately infer diet for both extinct and extant murine species. After performing a phylogentically independent analysis, my results suggest that phylogenetic history does not constrain dental morphology and convergent dental adaptations arise in response to diet.
|
