Fossil strata containing Aerodactyl are unusual in that they contain no Ivysaur or Kabutops or any other evolved pokemon. Modern experiments with revived Aerodactyl have recently confirmed what has long been theorized based on these findings: Aerodactyl possess a strange, prehistoric power which can stop evolution in its tracks.
In and of itself, however, this ability would be meaningless, an interesting curiosity. Pokemon evolution in real life does not occur in mid-battle like in card games, the range of this power is not infinite (although many feared it would be and protested the first revivals from amber) and Aerodactyl lack the ability to devolve an already evolved pokemon. Therefore, although Aerodactyl can keep an area unevolved and weak, they can not keep it that way alone, for evolved pokemon from nearby areas would invade, taking habitats over from the weak basic pokemon which would populate such a territory. And yet, as the fossil record shows, they did no such thing.
There must be something which is not understood, some missing link which explains why Aerodactyl's strange power became a meaningful adaptation, perhaps a pokemon not yet discovered with the power to devolve others. Some have speculated based on readings of a few old legends that this Pokemon was Mew. Most scientists, however, dismiss these claims with the rebuttal that there is no such thing as Mew.