of the ischium and absence of an obturator foramen were not characteristics seen in other pachycephalosaurs. Galton concluded Stenopelix to be ceratopian. However, exact cladistic analyses by Paul Sereno have resulted in a position in the Pachycephalosauria. But paleontologists Richard J. Butler and Robert M. Sullivan nonetheless view the species as being Marginocephalia incertae sedis, rejecting the presumed synapomorphies with the Pachycephalosauria as incorrect identifications or lacking cogency because of a possible presence in ceratopsian groups. In 2011, a cladistic analysis performed by Butler et al. showed that Stenopelix is a basal member of the Ceratopsia, and its sister taxon is Yinlong. In 2020, Yu et al. classified Stenopelix as a chaoyangsaurid with Yinlong, Chaoyangsaurus, Xuanhuaceratops, Hualianceratops. See also Timeline of ceratopsian research References External links Article about Stenopelix on DinosaurusBlog (in Czech) Ceratopsians Marginocephalians Berriasian life Early Cretaceous dinosaurs of Europe Cretaceous Germany Fossils of Germany Fossil taxa described in 1857 Taxa named by Christian Erich Hermann von Meyer Ornithischian genera