Abstract: Reconstructing the diet of extinct species is a fundamental goal in vertebrate paleobiology. Dental calculus is the calcium phosphate deposits on teeth, which captures a large number of food particles and contains the food information of ancient animal. It is possible to explore ancient animal dietary and investigate the environmental information from dental calculus. A large number of starch granules were found in dental calculus of Dicros gansuensisexcavated from the earliest Late Miocene Guonigou fauna of the Linxia Basin, Gansu Province. It is the first time that starch granules from Late Miocene were found. We classified the ancient starch granules by its morphological characteristics and also analyzed the starch granules of leaves of modern plants around the living environment of D. gansuensis to find modern starch granules and compare them with ancient ones. The results indicate that D. gansuensismay eat not only shrubs leaves, such as the plant from Caprifoliaceae, but also some tree leaves from Juglandaceae (walnut), and maybe some herbs from Ranunculaceae and Polygonaceae. It is consistent with the results of previous morphological studies, and it also provides more information. Our study extends the range of time and object for dental calculus research, and offers more possibilities for research on feeding habits of ancient mammals. 

摘要： 古动物食性研究是动物系统演化过程研究中的重要问题。牙结石中的微体植物化石如淀粉和植硅体等是揭示古代动物食性的重要依据。本研究分析了中国甘肃晚中新世最早期郭泥沟动物群发现的甘肃黑犀(Dicros gansuensis)牙结石中淀粉粒的形态及组合特征，并结合现生植物嫩叶淀粉粒形态对比，探讨了黑犀的食性及其环境意义。结果显示，晚中新世甘肃黑犀以进食灌木枝叶(如忍冬科的繁果忍冬和猥实)和一些乔木类嫩叶(如胡桃科的胡桃)为主，同时可能会涉及一些草本植物(如蓼科酸模和毛莨科耧斗菜), 这一结论与之前形态学研究结果相一致，并有所补充。本次研究首次将淀粉粒的形态数据前推至距今11.6 Ma的晚中新世，扩展了牙结石研究的对象和时间范围，为有关哺乳动物食性的研究打开了新视野。