Changzuiornis ahgmi was named by Huang et al. (2018) [The placement of Changzuiornis ahgmi within the clade Ornithurae is supported by seven unambiguously optimized synapomorphies (listed in the Phylogenetic Analysis section below). It diagnosed by a combination of morphologies not seen in other described ornithurines: The rostrum is elongate, comprising greater than 60% of the total skull length. Most of this elongate rostrum is made up of maxilla, a characteristic not present in the avian crown clade in which most of the rostrum and nearly the entire facial margin is made up by premaxilla. The only other avialans known to exhibit an elongate rostrum with the facial margin comprised primarily of maxilla are Xinghaiornis, Juehuaornis and Dingavis and derived Late Cretaceous ornithurines previously placed phylogenetically as among the closest outgroups to the avian crown clade (i.e., Ichthyornis, hesperornithine taxa). It differentiated from Xinghaiornis by its much smaller size, many tiny teeth on the lower jaw, U-shaped furcula, metacarpal III sub-equal to metacarpal II in distal extent, a carpometacarpus with both proximal and distal fusion, and a tarsometatarsus that is completely fused. The skull is about 15% longer in Changzuiornis and Juehuaornis compared to Dingavis (Table S1). In addition, the scapula is proportionally longer in Changzuiornis, Juehuaornis and Dingavis have a manual phalanx II:2 shorter than manual phalanx II:1 while in Changzuiornis this phalanx is longer (Table S1). The new species is differentiated from Hesperornithes and Ichthyornis by significantly smaller teeth with less recurved crowns, the presence of a distinct dorsal process or “forking” of the posterior dentary, and the presence of a pubic symphysis. It is additionally differentiated from Ichthyornis by robust and more abbreviate furcular rami, a narrower sternal margin of the coracoid, and a significantly more elongate scapular acromion. While if new data shows that Xinghaiornis, Juehuaornis and Dingavis form a clade that constitutes the same genus, the genus name Juehuaornis would have priority for Dingavis longimaxilla and Changzuiornis ahgmi]. Its type specimen is AGB5840, a skeleton (A nearly-complete skeleton with feather impressions ), and it is a 3D body fossil. Its type locality is Sihedang, Lingyuan, which is in an Aptian lacustrine mudstone/shale in the Jiufotang Formation of China. It is the type species of Changzuiornis.