Bayannurosaurus is a non-hadrosauriform ankylopollexianornithopod described in 2018 by Xu Xing. It lived during the early Aptian period, being found in the Bayin-Gobi Formation of China.[1] The genus includes the type species Bayannurosaurus perfectus. A phylogenetic analysis of Bayannurosaurus indicates that it is more derived than Hypselospinus, yet less derived than Ouranosaurus and just outside of the Hadrosauriformes. It was a large iguanodontian, measuring up to 9 metres (30 ft) in total body length.[1] The genus name Bayannurosaurus comes from Bayannur, the area where it was found, while the species name perfectus comes from the "perfect" preservation of the holotype specimen (IMMNH PV00001).[1]
