Sereno ( 1999 ) used the name " Chaoyangsaurus " in an overview of ceratopsian taxonomy.
"Chaoyangsaurus " is recovered in a more basal position than Psittacosauridae, although Chinnery's original analysis finds it within Neoceratopsia.
These skeletons share a number of distinct features with a potential close relative, " Chaoyangsaurus ", discovered in the adjacent province of Liaoning, with the exception of several cranial formations.
In contrast to the previous analysis, You and Dodson find " Chaoyangsaurus " to be the most basal neoceratopsian, more derived than " Psittacosaurus ", while Leptoceratopsidae, not Protoceratopsidae, is recovered as the sister group of Ceratopsidae.
Under this definition, the most basal known ceratopsians are " Yinlong ", from the Late Jurassic Period, along with " Chaoyangsaurus " and the family Psittacosauridae, from the Early Cretaceous Period, all of which were discovered in northern China or Mongolia.
However, in December of that year, Cheng, Zhao, and Xu published an official description using the name " Chaoyangsaurus youngi ", and as the first name for this genus that is not a " nomen nudum ", it has official priority over all other spellings that have been used.
""'Chaoyangsaurus " "'( " Greek for " horned faces " ), a group of primarily herbivorous dinosaurs with parrot-like beaks which thrived in North America and Asia during the Cretaceous Period ( which ended 66 million years ago ) . " Chaoyangsaurus ", like all ceratopsians, was primarily a herbivore.
""'Chaoyangsaurus " "'( " Greek for " horned faces " ), a group of primarily herbivorous dinosaurs with parrot-like beaks which thrived in North America and Asia during the Cretaceous Period ( which ended 66 million years ago ) . " Chaoyangsaurus ", like all ceratopsians, was primarily a herbivore.