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.