I get to geek out on dinosaurs this week in my prep work for my 4e game, because the players time jumped into the past at the end of last session. As far as I am concerned, if your PCs time travel into the past, there better be some dinosaurs on the other side. Conveniently I just bought myself a cool book on dinosaurs which I am going to spend the evening looking through, but first I did some internet searches on pterosaurs.
Often Google image searches of real life monsters like pterosaurs or deep sea critters yield some incredible results. Feast your eyes on this awesomeness (image lifted from this website about pterosaur flight). It is a dimorphodon.
I ended up sketching the dimorphodon picture in my game notes, along with a Quetzalcoatlus (the largest pterosaur ever discovered, with a wingspan that may have stretched greater than 30'). Then my wife got home from work and colored my pen and ink sketches, so I figured I should upload the end result.
Fire Breathing Pterosaur
I added a bit of a Pelican like pouch to the beak, because this is the ancestor of the dragons of my world. A colony of chemosynthetic, heat-resistant bacteria live in and coat the inside of the beak, digesting minerals that the Quetzalcoatlus scoops into the beak-pouch and emitting a flammable gas as a by-product which is stored in special sacks along the neck. The heat-resistant bacteria also coat the gizzard, and the fire-breathing pterosaur swallows live embers and keeps them in the gizzard until blowing them out mixed with the gas to form a fiery blast.
Killer Toothed Pterosaur
My wife thinks her version is colored "much more realistically" than the original artist's. She does have a lot of experience handling raptors so maybe I will believe her.