[D] Archaeoceratops yujingziensis
You, Tanque & Dodson 2010
Cretaceous Early ?Aptian Albian
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Archaeoceratopidae
Xinminpu Group, (= Xinminbao Group), Yujingzi Basin, Mazongshan area, nortwestern China
Archaeoceratops oshimai (Dong & Azuma, 1997) > Archaeoceratops yujingziensis (You, Tanque & Dodson 2010)
Abstract: A new species of basal neoceratopsian dinosaur Archaeoceratops is described. The specimen was collected from the Lower Cretaceous Xinminpu Group of the Yujingzi Basin in the Mazongshan area of northwestern China, and is represented by a partial skull, right mandible, and partial postcranial skeleton. Archaeoceratops yujingziensis differs from the type species A. oshimai, in having laterally deflected rostral en dof the maxilla, striations on the enameled premaxillary teeth; absence of a primary ridge on the maxillary teeth, and a horizontal shelf on the dentary teeth. The discovery A. yujingziensis extends the geographic distribution of the genus 100 km southeast, and is compatible with the Early Cretaceous age designation for the dinosaurbearing beds of the Yujingzi Basin in the Mazongshan area.
Type specimen: Chines Academy of Geological Sciences-Institute of Gelolgy: CAGS-IG-VD-003. The material includes a partial skull extending from the right premaxilla to jugal and manibular process of the pterygoid, the distal part of the right quadrate, complete right mandible, a dorsal neural arch, a sacracentrum, three proximal caudals, a partial right scapula, both femora, two matatarsals, and three pedal phalanges.
Etymology: \\\"Yujingzi\\\" (Chinese) name of the basin where the specimen was discovered.
Diagnosis: A. yujingziensis posseses four autopomorphies that do not exist in A. oshimai: a laterally deflected rostral end of the maxilla, causing a spoon-shaped pemaxillary beak with the premaxillary teeth placed lateral to the line of the maxillary teeth; striations on the enameled premaxillary teeth, perhaps combined with their ventrolateral orientation; lack of a primary ridge on the maxillary teeth; and a horizontal shelf on the dentary teeth.
Locality and horizon: Yujingzi Basin, Mazongshan area, nortwestern China. Xinminpu (= Xinminbao) Group, Early Cretaceous,m ?Aptian-Albian (tang et al 2001)
The speciman was not discovered in the field but came to light during preperation of an iguanodontian dinosaur in the laboratory. Fusion of the cranial sutures is suggestive of maturity, but the unfused sacral centra and unfused neural arches are immature characters.