The specimen, holotypeIVPP V 11821, was excavated in the Xiaguan Formation dating to the Turonian-Campanian stages. It consists of a partial skeleton lacking the skull. Eight posterior dorsal vertebrae, a sacrum of six vertebrae and a tail of thirty-six vertebrae have been preserved, together with a partial ischium, a forelimb and a hindlimb. The describers considered Nanyangosaurus to be of Albian age because of its primitiveness, but the type horizon is now believed to be Turonian-Campanian in age based on plant and invertebrate fossils.[2]
Nanyangosaurus was a rather small euornithpod with an estimated length of four to five metres. The length of the femur is 517 millimetres. The forelimbs were relatively long with a long hand. The first digit of the hand was completely absent including the first metacarpal; according to the describers this was not an accident of preservation but the actual condition of the living animal. The species would then not have possessed the thumb spike typical of its relatives.
^X. Xu, X.-J. Zhao, J.-C., W.-B. Huang, Z.-Y. Li and Z.-M. Dong, 2000, "A new iguanodontian from Sangping Formation of Neixiang, Henan and its stratigraphical implication", Vertebrata PalAsiatica38(3): 176-191
^Wang, D. et al., 2013. Discovery of invertebrate zoolite in the Xiaguan Formation of Xiaguan-Gaoqiu Basin, Henan, China, and its importance for stratigraphic subdivision comparison. Acta Geologica Sinica 87: 1049–1058.