Dorygnathus sp. R156 (Padian 2009) Early Jurassic ~190 mya ~13 cm skull length, was derived from a sister to the SMNS 55886 specimen of Dorygnathus and phylogenetically preceded Dorygnathus purdoni.

Distinct from SMNS 55886, the skull of R156 was wider and longer with a more inclined quadrate. The premaxillary teeth were oriented anteriorly and were larger than the maxillary teeth. The mandible was more robust.

Fingers I-III were enlarged.

Metatarsal I and II were subequal. The phalanges on digit IV were subequal. The pedal unguals were all enlarged. Pedal 5.1 extended to mid p4.2.

See the pterosaur family tree here.

Sericipterus wucaiwanensis (Andres, Clark and Xing 2012) IVPP V14725 Upper Jurassic, China, was one of the largest known Dorygnathids. Originally nested with Harpactognathus and Angustinaripterus, the present study nested Sericipterus closer to the Uppsala specimen (above) and Dorygnathus purdoni. The teeth were more widely spaced. The mandible was gracile.

Kryptodrakon progenitor (Andres, Clark and Xu 2014) is known from mere scraps that are virtually identical to those of the coeval Sericipterus, but were reconstructed as a much smaller pterosaur. See above. So it is not the earliest known pterodactyloid. Pterosaurs with complete pterodactyloid-grade traits evolved four times and two other clades evolved incomplete pterodactyloid-grade traits.

Andres B, Clark JM and Xing 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 JM and Xu X 2014. The earliest pterodactyloid and the origin of the group. Current Biology 24, 1–6, May 5, 2014

Padian K 2009. The Early Jurassic Pterosaur Dorygnathus banthenis (Theodori, 1830) and The Early Jurassic Pterosaur Campylognathoides Strand, 1928, Special Papers in Paleontology 80, Blackwell ISBN 9781405192248

wiki/Dorygnathus
wiki/Sericipterus
wiki/Kryptodrakon