Dorygnathus (undescribed, the Donau specimen) Middle Jurassic ~175mya, ~26 cm snout-to-vent length. Encased in stone, data from this specimen was obtained by X-rays. Derived from a sister to Sordes, the much larger Donau specimen of Dorygnathus phylogenetically preceded the SMNS 51827 specimen of Dorygnathus.

Distinct from Sordes, the skull of the Donau specimen reduced the antorbital fenestra by expanding the ascending process of the maxilla. The ventral orbit was reduced by a posterior migration of the lacrimal process of the jugal and by slightly increasing the depth of the jugal.

The cervicals were relatively longer. The torso was longer. Fewer sacrals were present. The caudals were attenuated distally.

The small triangular sternal complex developed an expanded posterior (or lost its posterior corners). The manus was slightly larger. The fingers were more disparate in length with m3.2 greatly increasing in length.

The ischicum had a straight posterior rim. The prepubis was greatly enlarged. Metatarsals I and III were subequal to mt II.

The Dorygnathia is a clade that went unrecognized due to taxon exclusion in all prior studies. No one bothered to check to see if every specimen labeled Dorygnathus was distinct enough to add to a cladistic analysis. Many are. Rather than being an oddball pterosaur, best mentioned as a sidelight, Dorygnathus turns out to be the key taxon with regard to the division of the former 'Pterodactyloidea' into four separate clades. Two were derived from Dorygnathus. Another two were derived from Scaphognathus, itself a descendant of Dorygnathus via Pterorhynchus.

The Dorygnathia is defined as Dorygnathus, Pterodaustro, their last common ancestor and all of its descendants.

The two pterodactyloid-grade clades that evolved from Dorygnathus include the Ctenochasmatidae and the Azhdarchidae.

Click to Enlarge. The immediate descendants of Sordes, demonstrating the variety in the genus Dorygnathus.

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