Jianchangnathus robustus (Cheng et al. 2012) Middle Jurassic, China ~14 cm skull length (IVPP V 16866) was originally compared to Scaphognathus from the Late Jurassic. It was also compared to Fenghuangopterus, a basal dorygnathid from the same deposits at Jianchangnathus.
Here Jianchangnathus nested at the base of the Scaphognathia, essentially the second half of the Pterosauria. So it is a key taxon. Jianchangnathus was derived from a sister to the Donau specimen of Dorygnathus, itself at the very base of the Dorygnathia and not far from Sordes, the outgroup taxon. Pterorhynchus and the wukongopterids (= darwinopterids) were sister taxa.
The upturned premaxilla and anteriorly-oriented teeth are traits of Dorygnathus, but that taxon was not mentioned in comparison. The relatively large skull is trait shared with Pterorhynchus and the wukongopterids. The manual and pedal element proportions are common to all sister taxa.
Cheng et al. (2012) looked at the non-fusion of the scapula and coracoid and mistakenly considered Jianchangnathus immature. In this case fusion or a lack thereof is a matter of phylogeny, not ontogeny, because pterosaurs are lizards that do not follow archosaur growth patterns as reported earlier. Jianchangnathus is the size of its sister taxa.
The second specimen skull (PMOL-AP00028, above) attributed to Jianchangnathus (Zhou 2014) appears to be close, but not a match to the holotype. The orbit overhanging the antorbital fenestra has a closer match in Scaphognathus.