Published Paper Details:

Dental micro-wear consists of microscopic damage features on the occlusal surfaces of tooth enamel and reflects physical properties of the diet, as well as enamel structure and post-mortem history of the tooth. Micro-wear analysis has been used to infer the diets of extinct mammals through comparison of features on fossil teeth with those on teeth of living mammals with known diets. A method for documenting micro-wear of large mammals using a light microscope was developed as an alternative to approaches based on scanning electron microscopy. We adapted this method for investigating micro-wear features on squirrel teeth. Both modern and fossil squirrels occur in diverse terrestrial habitats and eat a range of herbivorous to omnivorous diets. We compared micro-wear features from upper molars of several modern species of frugivorous tree squirrels and omnivorous ground squirrels. We also examined fossil sciurid from the Miocene Siwalik sequence of India the central plains of the United States. We found significant differences in micro-wear features among modern squirrels of different diets and habitats, suggesting that micro-wear features can be used to infer the diets or preferred habitats of extinct species. Micro-wear features were preserved on some of the fossil specimens. A comparison of Pliocene Spermophilus rexroadensis to modern Spermophilus suggests a diet similar to that of the modern species examined. Micro-wear of Miocene Eutamias differed from the pattern in any of the living squirrels examined. The approach presented here holds strong potential for illuminating the trophic geomorphology of small-mammal fossils.