Liaodactylus primus (Zhou et al. 2017) was considered the earliest filter-feeding pterosaur. Here it nests with the Solnhofen specimen of Gnathosaurus. Distinctly, Liaodactylus has short premaxillary teeth and longer dentary teeth than maxillary teeth. The skull was small, only half the length of Gnathosaurus, but with similar proprotions. The jugal was not elevated and so did not shrink the orbit.
Zhou et al. did not provide
a specimen-based phylogenetic analysis. but used only one taxon for each genus and so missed out on the gradual accumulation of traits that nested Liaodactylus with Gnathosaurus. Instead they nested it with Ctenochasma.
Zhou et al. used the data matrix
of Andres, Clark and Xu 2004, which nested Kryptodrakon as the basalmost pterodactyloid. As we learned earlier, those authors reconstructed the few bits and pieces of Kryptodrakon as a small Pterodactylus-like pterosaur, when it should have been reconstructed as a larger, but very gracile Sericipterus, which was found in the same deposits, but would not have made so many headlines.
Andres B, Clark JM and Xu X 2010.A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs, Journal of Vertebrate Paleontology 30: (1) 163-187.
Andres B, Clark J and Xu X 2014. The Earliest Pterodactyloid and the Origin of the Group. Current Biology (advance online publication)
Zhou C-F, Gao K-Q, Yi H, Xue J, Li Q and Fox RC 201. Earliest filter-feeding pterosaur from the Jurassic of China and ecological evolution of Pterodactyloidea. R. Soc. open sci. 4: 160672. http://dx.doi.org/10.1098/rsos.160672