STL Science Center

STL Science Center

28 June 2017

The Face of Chaoyangsaurus

©Jamie A Headden
Creative Commons Attribution 3.0 Unported
The type material of Chaoyangsaurus consists mainly of dorsal cranial material including the mandible. There are are also some shoulder girdle materials and cervical vertebrae. The skull elements, particularly the maxilla and the mandible, contain the characteristics that associate the small dinosaur with its descendants, the ceratopsians. The teeth possessed similar wear patterns to those seen in definitive early ceratopsians and psittacosaurs like Psittacosaurus. The snout of Chaoyangsaurus and its jugals are also similar to those in ceratopsians. The jugal bones are a set of bones in the "cheek" of ceratopsian dinosaurs that give the larger dinosaurs their characteristically pointy jowls. Phylogenetic analyses taking these and many other characteristics into consideration in the original paper placed Chaoyangsaurus into a polytomy with Psittacosaurus and the base of the ceratopsian family tree proper.

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