Phylogenetic history of <i>Auroraceratops rugosus</i> (Ceratopsia: Ornithischia) from the Lower Cretaceous of Gansu Province, China

Basal neoceratopsians are a relatively diverse group of small- to medium-sized herbivorous dinosaurs from the Early to Late Cretaceous of Asia and North America. Although known for over a century, this group has only relatively recently received intense independent study, tied to the rapid increase in known diversity since 1997. <i>Auroraceratops rugosus</i> is one of these recently discovered species and is one of the best-known basal neoceratopsians, being represented by over 80 specimens, and is also the most completely represented neoceratopsian from the Early Cretaceous. A phylogenetic analysis focusing on non-ceratopsid ceratopsians examines the phylogenetic context of <i>Auroraceratops</i>. The analysis is based on a new matrix of 41 taxa and 257 characters. The results recover an <i>Auroraceratops</i>-<i>Aquilops-</i>ZPAL MgD-I/156 clade within basal Neoceratopsia that is sister to a clade composed of <i>Asiaceratops</i>, <i>Yamaceratops</i>, <i>Mosaiceratops</i>, and the larger clades Leptoceratopsidae and Coronosauria. This phylogeny recovers a monophyletic Coronosauria, Leptoceratopsidae, and Protoceratopsidae. <i>Helioceratops</i> is recovered as sister to the rest of Leptoceratopsidae, <i>Ischioceratops</i> is recovered nested within Leptoceratopsidae, and the enigmatic genus <i>Mosaiceratops</i> is recovered as a basal neoceratopsian, sister to <i>Yamaceratops</i>. <i>Yinlong,</i> and <i>Hualianceratops</i> are recovered in an expanded Chaoyangsauridae, and the genus <i>Psittacosaurus</i> is recovered as the earliest diverging lineage in Ceratopsia. <i>Ajkaceratops</i>, the only European ceratopsian, is robustly recovered as sister to the rest of Ceratopsoidea. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Morschhauser, E. M., H. You, D. Li, and P. Dodson. 2019. Phylogenetic history of <i>Auroraceratops rugosus</i> (Ceratopsia: Ornithischia) from the Lower Cretaceous of Gansu Province, China; pp. 117–147 in Hailu You, Peter Dodson, and Eric Morschhauser (eds.), <i>Auroraceratops rugosus</i> (Ornithischia, Ceratopsia) from the Early Cretaceous of northwestern Gansu Province, China. Society of Vertebrate Paleontology Memoir 18. Journal of Vertebrate Paleontology 38(Supplement). DOI: 10.1080/02724634.2017.1509866.