Here’s another specimen from Padian (2009) and a pair of slightly different interpretations, one based on visual examination and the other (below) based on photographic interpretation and DGS (digital graphic segregation), both of which are constantly evolving and perfecting as databases and experience grow.

Figure 1. Dorygnathus SMNS 55886 in situ. Note the dentary tip, distinct from the rest of the mandible.

Figure 2. Dorygnathus SMNS 55886 traced by Padian (2009). All images flipped left to right. No pterosaur has such a wide ascending process of the premaxilla. Padian doesn’t delineate the pmx/mx suture. No other pterosaur has such a deep squamosal descending process, beyond the height of the rising quadratojugal.

Figure 3. Dorygnathus SMNS 55886 with colors applied to bones. . The yellow bone below the jugal appears to be a hyoid that continues beyond the articular. The brown bone inside the naris appears to be a dislocated premaxillary palate shelf. As in other dorygnathids, like D. purdoni, the nasals extend further forward dorsal to the naris. The dislocated anterior jugal extends to below the naris.
It is worthwhile to check out Dorygnathus purdoni (formerly Parapsicephalus, fig. 4) in which most of the skull is preserved in 3D.

Figure 4. Dorygnathus purdoni, formerly Parapsicephalus, is instructive when dealing with crushed and cracked dorygnathids.
References
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