Open Paleo

Archaeoceratops

Dong & Azuma, 1997 AHR-kee-o-SER-a-tops

From Greek 'archaios' meaning 'ancient', 'keras' meaning 'horn', and 'ops' meaning 'face', translating to 'ancient horned face'.

113.2–100.5 million years ago Albian, Early Cretaceous
Early Cretaceous stages

Archaeoceratops, meaning "ancient horned face", is a genus of basal neoceratopsian dinosaur from the Early Cretaceous (Aptian stage) of north central China. It appears to have been bipedal and quite small, reaching 0.9 m (3.0 ft) in length and 10 kg (22 lb) in body mass. It had a comparatively large head but no horns, possessing only a small bony frill projecting from the back of its head.

Diagnosis

  1. Modest bumpy ornamentation covering much of the lateral surface of the jugal, resembling that seen on the jugals of pachycephalosaurs.
  2. Excavation on the lateral surface of the ischiadic peduncle of the ilium.
  3. Shaft and proximal end of metatarsal I strongly reduced, though the distal condyle remains well formed.

Species (2)

Archaeoceratops oshimai Dong & Azuma, 1997

Type species

Named for Mr. Oshima, director of the Chunichi-Shinbun of Japan, who supported the Sino-Japan Silk Road Dinosaur Expedition.

Holotype
IVPP V11114 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Well-preserved, nearly complete skull and jaws; an articulated partial vertebral column of one cervical, twelve dorsal, and six sacral vertebrae; and a partial pelvis including both ilia, both pubes, and a partial ischium.
Horizon
Zhonggou Formation, Albian, Early Cretaceous , 113.2–100.5 million years ago
Locality
Gongpoquan Basin, Gansu, China Suarez and colleagues (2018) measured no sections in the Gongpoquan Basin, and You and colleagues (2018) find the Mazongshan and Jiuquan beds cannot be easily correlated, so the unit is a working hypothesis.

Archaeoceratops yujingziensis You et al., 2010

Named for the Yujingzi Basin, where the holotype was discovered.

Holotype
CAGS-IG-VD-003 , Institute of Geology, Chinese Academy of Geological Sciences
Material
Partial skull (right premaxilla to jugal), right mandible, dorsal neural arch, sacral centrum, three proximal caudals, partial right scapula, both femora, two metatarsals, three pedal phalanges.
Horizon
upper Xiagou Formation, Aptian, Early Cretaceous , 121.4–113.2 million years ago
Locality
Yujingzi Basin, Mazongshan area, Gansu, China
Diagnosis
  1. Laterally deflected rostral end of the maxilla, producing a spoon-shaped premaxillary beak with premaxillary teeth lateral to the maxillary tooth row
  2. Striations on the enameled premaxillary teeth, combined with their ventrolateral orientation
  3. Primary ridge absent on the maxillary teeth
  4. Horizontal shelf on the dentary teeth

References

  1. Dong, Z.; Azuma, Y. (1997). On a primitive neoceratopsian from the Early Cretaceous of China. Sino-Japanese Silk Road Dinosaur Expedition 68-89. China Ocean Press, Beijing. dong1997c
  2. You, H.; Dodson, P. (2003). Redescription of neoceratopsian dinosaur Archaeoceratops and early evolution of Neoceratopsia. Acta Palaeontologica Polonica 48(2): 261-272.

    Detailed redescription of the holotype and paratype of Archaeoceratops oshimai; recovers the genus as the sister group to all Late Cretaceous Neoceratopsia.

    you2003d
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the appearance features.

    jones2026a
  4. You, H. L.; Tanoue, K.; Dodson, P. (2010). A new species of Archaeoceratops (Dinosauria: Neoceratopsia) from the Early Cretaceous of the Mazongshan area, northwestern China. New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium (Ryan, M. J.; Chinnery-Allgeier, B. J.; Eberth, D. A., eds.) 59-67. Indiana University Press, Bloomington. you2010a
  5. Suarez, M. B.; Milder, T.; Peng, N.; Suarez, C. A.; You, H.; Li, D.; Dodson, P. (2018). Chemostratigraphy of the Lower Cretaceous dinosaur-bearing Xiagou and Zhonggou formations, Yujingzi Basin, northwest China. Journal of Vertebrate Paleontology 38(sup1): 12-21. doi:10.1080/02724634.2018.1510412 suarez2018a
  6. You, H.; Morschhauser, E. M.; Li, D.; Dodson, P. (2018). Introducing the Mazongshan Dinosaur Fauna. Journal of Vertebrate Paleontology 38(sup1): 1-11. Taylor and Francis. doi:10.1080/02724634.2017.1396995

    Places A. yujingziensis in the gray-variegated beds of the Yujingzi Basin, which its working hypothesis assigns to the upper Xiagou Formation and an Aptian age.

    you2018a