A new pterosaur specimen from the Lower Cretaceous Yixian Formation of Liaoning Province, China: The oldest fossil record of Nurhachius

The Istiodactylidae is one of three ornithocheiroid pterosaur lineages, characterised by a large nasoantorbital fenestrae and labiolingually compressed teeth. Their remains have been reported from Early Cretaceous rocks of northeastern China and Western Europe. A new istiodactylid pterosaur from the upper part of the Yixian Formation (Jingangshan Member) of the Jehol Group, distributed in western Liaoning Province and neighbouring areas, is described on the basis of an incomplete specimen including the partial skull, forelimb and hindlimb bones, and pelvis. This individual, here designated as a referred specimen of Nurhachius (Nurhachius sp.) is a skeletally almost mature pterosaur with an estimated wingspan of 1.6 m. This specimen is not only the geologically oldest known occurrence of Nurhachius, but also a new component of the pterosaur assemblage of the Jingangshan Member, and provides new information on the pelvis and hindlimb of istiodactylids and the palaeobiology of this clade. Considering previous reports of the istiodactylid remains and the geological ages of the strata that yielded them, it is suggested that different istiodactylids existed in Europe and China during the late Barremian.