The skull of the SMNS 51827 specimen of Dorygnathus is preserved palate side up (Figs. 1-6). Even so, enough is shown that we can put a pretty decent skull reconstruction together. Specimen images are from Padian (2009).
This specimen was discovered in 1981 and is among the best for this genus.
Padian reported the fused symphysis of the mandible to be edentulous, but basal pterosaurs have a history of anteriorly projecting teeth there. To Padian’s point, the jaw tips of Campylognathoides and Eudimorphodon are edentulous, but distinct in texture from the rest of the mandible. The tip in Eudimorphodon is not sharp. In Campylognathoides and Dorygnathus it is sharp. So despite demarcation that probably marked the boundary of a keratinous extension, the jaws tips in Dorygnathus are edentulous.
Different species of Dorygnathus may be identified by the relative length of the antorbital fenestra, whether or not the naris is above the antorbital fenestra or not, and the relative depth of the mandible, among many other traits.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
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