The Ulansuhai Formation () is a geological formation in Inner Mongolia, north China. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. .
The Ulansuhai Formation has traditionally been considered to date to the Aptian-Albian stages of the Lower Cretaceous, due to similarities between the Ulansuhai fauna and known Aptian formations. However, radiometric dating done on underlying formations has shown this to be incorrect. Due to the age of underlying rocks, the Ulansuhai Formation cannot be older than the Turonian stage of the Late Cretaceous, about 92 Ma.Kobayashi, Y., and Lu, J.-C. (2003). "A new ornithomimid dinosaurian with gregarious habits from the Late Cretaceous of China." Acta Palaeontol. Pol., 48: 235–259.Benson, R.B.J. and Xu, X. (2008). "The anatomy and systematic position of the theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the Early Cretaceous of Alanshan, People's Republic of China." Geol. Mag., 145: 778–789. Evans et al. (2021) suggested that the formation is likely dated to the Santonian-Campanian ages or older, but younger than .
Fossil content
Dinosaurs
Ornithischians Ornithischians of the Ulansuhai Formation Genus Species Location Stratigraphic position Material Notes Images Iguanodontia indet. Indeterminate An indeterminate iguanodontian. Sinocephale S. bexelli Skull fragments. A pachycephalosaurine pachycephalosaurid
Theropods Theropods of the Ulansuhai Formation Genus Species Location Stratigraphic position Material Notes Images ChilantaisaurusBenson, R.B.J. and Xu, X. (2008). "The anatomy and systematic position of the theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the Early Cretaceous of Alanshan, People's Republic of China." Geol. Mag., 145: 778–789. "Table 4.1," in Weishampel, et al. (2004). Page 73. C. tashuikouensis Fragmentary postcranial skeleton. A tetanuran theropod Sinornithomimus"Table 5.1," in Weishampel, et al. (2004). Page 138. S. dongi "[Fourteen] skeletons, juvenile to adult". A ornithomimid ornithomimosaur
Turtles Turtles of the Ulansuhai Formation Genus Species Location Stratigraphic position Material Notes Images KuhnemysS.-Y. Hu. 1964. [Carnosaurian remains from Alashan, Inner Mongolia]. Vertebrata PalAsiatica. 8(1):42-63 K. maortuensis A pan-trionychid turtle
Crustaceans Crustaceans of the Ulansuhai Formation Genus Species Location Stratigraphic position Material Notes Images cf. Cyprididae Indet. Indeterminate A cypridid ostracod
See also List of dinosaur-bearing rock formations
References