This article is within the scope of WikiProject Dinosaurs, a collaborative effort to improve the coverage of dinosaurs and dinosaur-related topics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.DinosaursWikipedia:WikiProject DinosaursTemplate:WikiProject Dinosaursdinosaurs articles
This article is within the scope of WikiProject Palaeontology, a collaborative effort to improve the coverage of palaeontology-related topics and create a standardized, informative, comprehensive and easy-to-use resource on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PalaeontologyWikipedia:WikiProject PalaeontologyTemplate:WikiProject PalaeontologyPalaeontology articles
Sullivan (2006) concludes that Stenopelix cannot be shown to a pachycephalosaur and assigns it to Ornithischia incertae sedis. My best guess is that Stenopelix, as well as another putative pachycephalosaur, Ferganocephale, may be basal marginocephalians ancestral to the pachycephalosaur-ceratopsian split. The discovery of Yinlong from the Middle Jurassic of China may show that in the upper stages of the Middle Jurassic, ceratopsians and pachycephalosaurs split from thier common ancestor.
Sullivan, R.M., 2006. A taxonomic review of the Pqachycephalosauridae (Dinosauria: Ornithischia). New Mexico Museum of Natural History and Science Bulletin 35: 347-365.