Morphological Study On A New Psittacosaurus Material

Psittacosaurs are primitive ceratopsian dinosaurs that are well known from the Early Cretaceous beds in East Asia, especially in North China, Mongolia, and Sibiria, It was named because of its parrot-like beak. However, the large number of fossils is found, genus and species s number of the family Psittacosauridae are on the rise. So far 17 species in three genera were named, but validity of some taxa has been questioned. In this study, osteology of psittacosaur is performed, based on four specimens from the Early Cretaceous Yixian Formation of western Liaoning. Comparison with other psittacosaur taxa indicates several unique characters on one of the four specimens (LPM-R00167-1).In addition, anatomical analysis of LPM-R00167-1 reveals several unique characters, such as a pointed tip of rostral buccal edge, high position of nostril, two frontal processes, and little value of forelimb versus hindlimb. Comparison with other psittacosaur taxa and basal neoceratopsians of the Early Cretaceous further supports the uniqueness of this individual (LPM-R00167-1). Finally, further discussion is undertaken about the significance of the paleobiology and stratigraphy of psittacosaur.Until now, interrelationships of Psittacosaurus are unresolved, mainly due to uncertainties concerning characters of the questioned species. Additional information from the new specimens more or less progress the understanding on the concerning characters of psittacosaurs. However, a further phylogenetic analysis will be the next step of the future study after dissolving the validity of the above questioned species.