This is the forelimb fossil of Psittacosaurus, which is very complete and has very clear bone lines. This one includes Humerus, Radius and Ulna. Matrix: 17*10*4 cm and forelimb: 14 cm. Psittacosaurus is a very early ceratopsaurus dinosaur. They have developed many characteristics on their own, and they also have many of the same physiological and structural features as the later ceratops, such as protoceratops and elephant-sized triceratops.