[N] 2006 A new basal ceratopsian dinosaur, Yinlong downsi
Xing Xu, Catherine A. Forster, James M. Clark, and Jinyou Mo (in press). A basal ceratopsian with transitional features from the Late Jurassic of northwestern China. Proceedings of the Royal Society
A new basal ceratopsian dinosaur, _Yinlong downsi_ gen. et. sp. nov. from the Late Jurassic upper part of the Shishugou Formation of Xinjiang, China. This new ceratopsian displays a series of features transitional between more derived ceratopsians and other ornithischians, shares numerous derived similarities with both the heterodontosaurids and pachycephalosaurians and provides strong evidence supporting a monophyletic Marginocephalia and its close relationship to the Heterodontosauridae. Character distributions along the marginocephalian lineage reveal that, compared to the bipedal Pachycephalosauria, which retained a primitive post-cranial body-plan, the dominantly quadrupedal ceratopsians lost many marginocephalian features and evolved their own characters early in their evolution.