Bayannurosaurus is a non-hadrosauriform ankylopollexianornithopod described in 2018 by Xuet al from the early Aptian (Early Cretaceous) found in the Bayin-Gobi Formation of China.[1] The genus includes a new species Bayannurosaurus perfectus. A phylogenetic analysis of Bayannurosaurus indicates that it is more derived than Hypselospinus but less derived than Ouranosaurus just outside of Hadrosauriformes. It had a skull length of 80 cm, making it a mid-sized iguanodont.[1] By comparison Ouranosaurus had a 67 cm skull, and a length of 7 to 8.3 meters (23 to 27 feet). Though inexact, if this is used as a comparison to scale to, Bayannurosaurus would be 8.3 to 10 meters (27 to 33 feet) long. 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. [1]
