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.

The base of the Scaphognathia. Sordes, Pterorhynchus, Kunpengopterus, Darwinopterus and Scaphognathus in phylogenetic order. The darwinopterids were originally considered transitional taxa between primitive long-tailed pterosaurs and later short-tailed pterosaurs (Lü et al. 2010). Here darwinopterids were derived from Pterorhynchus, which also lost the external naris.

Cheng et al. (2012) reported fusion between the premaxilla and maxilla. Here (Fig. 3) the suture is between the 4th and 5th tooth as in sister taxa. The first fang was the first maxillary tooth, as in the SMNS 55886 specimen of Dorygnathus. The dentary did not extend to the quadrate but extended posteriorly beneath posterior jugal as in sister taxa. The nasal (pink anteriorly, purple posteriorly) extended to mid orbit as in sister taxa. The jugal extended to the pmx/mx suture as in sister taxa. The prefrontals were longer than originally reported. The vomers, ectopalatine and pterygoid were rod-like elements as in sister taxa. The tip of the mandible is a double-tooth morphology.

Cheng X, Wang X-L, Jiang S-X and Kellner AWA 2012. A new scaphognathid pterosaur from western Liaoning, China. Historical Biology iFirst article available online 29 Nov 2011, 1-11. doi:10.1080/08912963.2011.635423

Zhou C-F 2014. Cranial morphology of a Scaphognathus-like pterosaur, Jianchangnathus robustus, based on a new fossil from the Tiaojishan Formation of western Liaoning, China. Journal of Vertebrate Paleontology 34(3):597-605.

wiki/Jianchangnathus