The type skull of "P. lujiatunensis" measures 19 cm (7.5 in) in length, while the largest-known skull is 20.5 centimetres (8 in) long, so this species was similar in size to "P. mongoliensis" and "P. sibiricus". There is a fossa in front of the eye, as in "P. mongoliensis". The jugal bones flare outwards widely, making the skull wider than it is long, as seen in "P. sinensis". Widely flared jugals are also found in "P. sibiricus". Overall, this species is thought to exhibit several primitive characteristics compared to other species of "Psittacosaurus", which is consistent with its greater geological age. "P. gobiensis" was small-bodied ( long) and differs from other species of "Psittacosaurus" by "significant, but structurally minor, details." These include the presence of a pyramidal horn on the postorbital, a depression on the postorbital-jugal contact, and enamel thickness. "P. mongoliensis" was a contemporary.