Jianchangnathus is an extinct genus of basal pterosaur from the Middle Jurassic Tiaojishan Formation of northeastern China.[1]
Jianchangnathus was first described and named by Cheng Xin, Wang Xiaolin, Jiang Shunxing and Alexander W.A. Kellner in 2012 and the type species is Jianchangnathus robustus. The generic name combines a reference to Jianchang County with a Greek γνάθος, gnathos, "jaw". The specific name means "robust" in Latin.[1]
Jianchangnathus was initially described based on a single fossil skeleton, holotype IVPP V16866, recovered near Linglongta, in Jianchang County. The second specimen, PMOL-AP00028, consisting of a partially articulated skull and fragments of postcranial skeleton of a subadult individual, was described in 2014.[2]
Autapomorphies of Jiangchangnathus include: a convex top margin of the lower jaw; a large front branch of the jugal; and the first three pairs of teeth of the lower jaws pointing strongly forwards. Its describers found it to share several features with Scaphognathus, including a high front end of the lower jaws, a pear-shaped lower temporal fenestra with the broad end below and teeth in the maxilla of the upper jaw that have a space equal to that of three toothsockets between them.[1] Additionally, undescribed fossils of a pterosaur referred to Jianchangnathus suggest that the color of its pycnofibers was brown.[3]
Jianchangnathus was assigned by the describers to the Scaphognathidae by the describing authors,[1] which was corroborated by later phylogenetic analyses which included this taxon.[4]