Two new species of "Psittacosaurus" were described by Canadian Dale Russell and Zhao in 1996. The first was named "P. neimongoliensis", after the Mandarin Chinese name for Inner Mongolia. It is based on a nearly complete fossil skeleton, including most of the skull, found in the Early Cretaceous Ejinhoro Formation with seven other individuals. Russell and Zhao also named "P. ordosensis" in 1996, after the Ordos prefecture of the Inner Mongolia Autonomous Region. The type specimen is a nearly complete skeleton, including part of the skull. However, only the skull, lower jaw, and foot have been described. Three other specimens were referred to this species but remain undescribed. Like "P. neimongoliensis", this species was discovered in the Eijnhoro Formation. Sereno (2010) found the species as described to be indistinguishable from "P. sinensis", another small species, but suggested that additional study of "P. ordosensis" might reveal diagnostic features. He provisionally designated "P. ordosensis" a "nomen dubium".