Many pterosaur species underwent a reduction in teeth as they evolved over time. This would be a good strategy for survival in species that were able to swallow food whole, as it would give a weight loss advantage to these flying animals.
Gallodactylus is one of the earliest pterosaurs to show a reduction in teeth. In this case, the anterior teeth have been retained at the tip of the jaw and the remainder of the jaw is toothless.
Dsungeripterus shows a different pattern of tooth reduction. Here, the anterior teeth are absent and the beak would have been covered in a horny sheath. The remaining teeth are solid crusher teeth suitable for opening the shells of cephalopods like small ammonites, and other shellfish.
Many of the larger pterosaurs like Nyctosaurus and also
Quetzalcoatlus, Azhdarcho and Pteranodon, show a complete loss
of teeth. These pterosaurs were prevalent in the Upper Cretaceous and
are found world wide.