Abstract: Psittacosaurids, with a confined distribution during the Early Cretaceous in East Asia, have an important bearing on understanding the origin and evolution of ceratopsian dinosaurs. Recent discovery of abundant psittacosaur fossils from the Lower Cretaceous fossil beds in western Liaoning of China provides the material for detailed study of the osteology and paleobiology of psittacosaurs. This paper furnishes a review of recent advances in the study of psittacosaurs, with comments and discussion on the taxonomic diversity, temporal and geographical distributions, and the phylogenetic relationships of psittacosaurids. This study shows that the validity of the taxon name of Hongshanosaurus houi is highly questionable, as the naming of the genus and species is based on a juvenile and distorted specimen that cannot be clearly distinguished from other specimens of the genus Psittacosaurus; further investigation is needed to clarify its taxonomic status. Low-Resolution X-ray CT scan of a well-preserved psittacosaur skull is performed, and three-dimensional reconstruction of the skull image is achieved for the first time of a psittacosaur. LRXCT scan reveals important palatal structures of the psittacosaur specimen, and hence, provides new information on understanding the anatomy and paleobiology of psittacosaurs.

Key words: Early Cretaceous, psittacosaurs, temporal and geographical distribution, CT scan

摘要： 鹦鹉嘴龙作为亚洲东部地区早白垩世时期中所特有的原始角龙类群，对研究角龙类的起源和演化有着重要意义。近年来在辽宁西部地区发现大量鹦鹉嘴龙化石，大大推进了该类恐龙的骨骼解剖学和古生物学研究。结合最新研究进展，对鹦鹉嘴龙科内的属种分异度进行了剖析，并对该科的地史地理分布特征和演化历史进行了讨论。此外，本项研究应用医学CT扫描和计算机辅助三维图像重建技术，对辽西新发现的一件完整的鹦鹉嘴龙头骨进行了CT扫描和三维图像的复原。这一手段的应用揭示了该头骨腭面的形态结构，为鹦鹉嘴龙类的解剖和生物学研究提供了新的特征信息。

关键词: 早白垩世, 鹦鹉嘴龙, 地史与地理分布, CT扫描