Cranial anatomy of the basal neoceratopsian Auroraceratops rugosus (Ornithischia: Ceratopsia) from the Yujingzi Basin, Gansu Province, China

The basal neoceratopsian dinosaur Auroraceratops rugosus was described based on a single skull from the Gongpoquan Basin in northwestern Gansu Province, China. The genus is now known from over 80 specimens, including many from the neighboring Yujingzi Basin. Auroraceratops is one of the best-known basal neoceratopsians. Auroraceratops can be diagnosed by the following autapomorphies: inflated premaxillary teeth; a fungiform expansion of the lacrimal; large tuber caudodorsally on the dentary near the contact with the surangular; and tubercle on the lateral face of the dentary at about the middle of the mandible. Auroraceratops also has a combination of plesiomorphic and derived characters. It possesses characters plesiomorphic to Neoceratopsia, such as broad nasals (seen in basal ceratopsians, such as Yinlong), the absence of a lateral ridge on the surangular, a relatively high number of premaxillary teeth (three), and rugosity on the dentary, jugal, surangular, and sometimes the postorbital, which is in detail similar to that seen in chaoyangsaurids. At the same time, Auroraceratops possesses derived characters not seen in Liaoceratops, the earliest diverging member of Neoceratopsia. These features include an epijugal and a surangular wall lateral to the mandibular glenoid fossa. The cranial anatomy of the early horned dinosaur Auroraceratops rugosus is described. Citation for this article: Morschhauser, E. M., D. Li, H. You, and P. Dodson. 2019. Cranial anatomy of the basal neoceratopsian Auroraceratops rugosus (Ornithischia: Ceratopsia) from the Yujingzi Basin, Gansu Province, China; pp. 36-68 in Hailu You, Peter Dodson, and Eric Morschhauser (eds.), Auroraceratops rugosus (Ornithischia, Ceratopsia) from the Early Cretaceous of northwestern Gansu Province, China. Society of Vertebrate Paleontology Memoir 18. Journal of Vertebrate Paleontology 38(Supplement). DOI: 10.1080/02724634.2017.1399136.