角龙类是恐龙当中化石最丰富和最受关注的植食性类群之一。其早期成员体型小、两足行走、牙齿简单、无复杂头饰，晚期成员体型变大，四足行走，有恐龙当中最为复杂的齿系和头饰结构（角和颈盾），有关这一转化是如何完成的一直是角龙类演化研究的重要问题，也一直存在争议，其中一个主要原因是有关早期角龙类的研究不够深入，尤其是早期角龙的系统发育存在诸多争议。中国有着丰富的早期角龙化石材料，特别是准噶尔盆地上侏罗统石树沟组的角龙类代表已知最早的角龙类，其深入研究对于解决以上问题具有重要意义。本项目拟在前期研究基础上，开展深入的形态学研究，尤其是采用CT技术，对其齿系形态和脑颅形态展开深入研究，探讨早期角龙类的食性和行走姿态。同时，依据丰富的材料，开展骨组织学研究，探讨早期角龙类的发育和生长模式，并根据形态学资料，复原早期角龙类的个体发育过程。结合中国和其他地区的早期角龙化石，进一步恢复可靠的角龙类系统发育树。

Ceratopsia represents one of the most abundant and best known dinosaurian group. The early members are small, bipedal dinosaurs with simple tooth shape and skull frill, whereas the later members are large, quadrupedal with complicated tooth structure and skull frill. How these features and behaviors transferred in ceratopsians is an important issue but is still controversial. In recent decades, abundant early ceratopsians have been found in China. The ceratopsians (Yinlong and Hualianceratops) from the Upper Jurassic Shishugou Formation of Junggar basin represent the earliest taxa. A detailed study of these materials is significant to solve these issues. Our project will do a new comprehensive study on morphology, especially on tooth structure and endocranial cavity reconstruction based on CT Scans, in order to discuss their diets and walking position. Additionally, we will do bone histological analysis based on their abundant materials, which could provide accurate information on development and growth pattern. Ontogenetic variation will be accurately recovered based on morphology and bone histological information. Combining other ceratopsians from China, we could recover a new reliable phylogenetic analysis of early ceratopsians, and clarify growth pattern, walking position, the complication of tooth structure during the evolution of early ceratopsians.