Pterosaurs were winged reptiles that ruled the skies during the time of the dinosaurs.  They first appear in the fossil record near the Carnian-Norian boundary, soon after the dinosaurs made their debut, and they went extinct during the same catastrophe that the dinosaurs did.  They were also closely related to dinosaurs. 

     Rapid evolution best describes the origins of the pterosaurs.  According to Haines and Chambers,

 

In particular, pterosaurs suddenly appear in the fossil record as highly specialized fliers with no clear intermediates before them.[1] 

 

They go from no representation in the fossil record to suddenly very adequate representation in the Norian, and quickly radiate into several new species to fill various ecological niches.  The earliest among them is Eudimorphodon, which is found in various rocks of early Norian age, such as the Fleming Fjord formation.[2]  Moreover, one pterosaur feature that was at one time considered advanced, namely the head crests of the later pterodactyls, is now known from a fossil of Norian age,[3] thus demonstrating that the pterosaurs achieved advanced features at the very beginning of their history. 

     The fundamental features of the pterosaur body plan remained constant from their earliest beginnings to their ultimate demise.  They had small bodies, lightweight bones, sharp teeth, long mouths, and long arms.  At the end of their arms, they possessed four fingers.  The first three fingers terminated in three short claws, which stuck out at the front of the wing and could be used for crawling on the ground when not in flight.  The fourth finger was extremely long by comparison, often extending several feet away from the body.  The bulk of the wing was supported on this fourth finger.  The wing was a lightweight flap stretching from the fourth finger to the back leg.  This body plan continued unchanged for all of their 160 million year tenure. 

     The most plausible ancestor the fossil record can provide is Scleromochlus of the Lossiemouth Formation.  If Scleromochlus is the ancestor of the pterosaurs, it would mean that pterosaurs accomplished a tremendous amount of evolution very quickly across the Carnian-Norian boundary.  Scleromochlus did not have even the beginnings of wings.  The fourth finger, so greatly elongated in pterosaurs to support the wings, in Scleromochlus is no more elongated than the other fingers.  Scleromochlus also had short arms and long legs, the opposite of pterosaurs.  Benton even concluded that Scleromochlus was no more related to pterosaurs than to dinosaurs, but had split from both of them shortly before their most recent common ancestor.[4]  Hence, the morphological differences between Scleromochlus and the earliest pterosaurs are great, and require that a tremendous amount of evolution must have occurred in a short time for them to have had been ancestor and descendent. 

     Then, there is the problem of whether Scleromochlus really predates their supposed descendents, the pterosaurs.  There is some question as to whether the allegedly late Carnian strata of Scotland's Lossiemouth Sandstone is really Carnian or whether it is actually early Norian.[5]  If Norian, the supposed ancestor is a contemporary of the pterosaurs, and therefore unlikely to be an ancestor.  To add fuel to the fire, there is also some question over whether the pterosaurs first appear in the Norian or in the late Carnian.  A pterosaur jawbone has been reported from the Dockum Group of Texas, hence plausibly putting the first pterosaurs in the Carnian.[6]  If this is correct, then it makes the pterosaurs at least contemporary with, if not before, their supposed ancestor Scleromochlus.  In any case, Scleromochlus cannot support the idea that pterosaurs evolved gradually, because it did not arrive in the fossil record substantially beforehand. 

     Thus, the search for a pterosaur ancestor is elusive at best, both for morphological reasons and for stratigraphical reasons.  The most that can be said is that they arose suddenly, without intermediaries, and that the closest thing to their ancestor is essentially their contemporary.  Hence, pterosaur origins point to an instance of rapid evolution, whereby evolutionary change happened so fast that no fossil intermediaries were preserved.

     The evidence does not, however, point to the spontaneous creation of the pterosaurs by God.  It is highly unlikely God created them perfectly, for the earliest among them were lacking shorter tails and toothless mouths – two features that are proved advantageous adaptations to an aerial lifestyle, both in pterosaurs and in birds, and the former in bats as well.  If God is perfect, it stands to reason that he creates new forms perfectly, but pterosaur tails and teeth were far from perfect when they first took to the skies. 

It took 40 million years to shorten the tail of pterosaurs such that by the latter Jurassic they evolved into the very short-tailed pterodactyls.  Yet strangely it only took a fraction of this time for pterosaurs to get wings with full-powered flight.      Their primal point of origin, their morph into a new and completely different body structure at the base of their lineage, is shrouded in mystery, and seems to have happened so rapidly that it did not leave a trace in the fossil record.  Hence, pterosaur evolution represents a two step process – rapid evolution of a new form, followed by small improvements to that form over time.