Roger in the Flip, Flap, and Fly Thread:
Pheh, the people giving the press release don't even know what Petrie is. What does that tell you? Pterodactyl may be a well-known name, but its still wrong. You'd think they'd at least know what dinosaurs are in the film.
Actually that is something nobody eber seemed to be really certain about.
There are quite a few land before time books which name Petrie a Pterodactylus. His size too would indicate that origin.
His uncle of course bears a strong resemblance to a Pteranodon. His mother is difficult to identify with certainty. That crest on Petrie's and his mother's head (note that unless Petrie's crest is going to develope, gender can't be the point to make a difference) doesn't make them look too much like Pteranodons. We only ever see distinctly older relatives (sibilings I guess) of Petrie in the first movie (there are some of his size and age while there are some distinctly taler than him, but smaller than his mother), none of them bears a clear resemblance to Pterano or Pteranodons in general.
Crests have caused confusion in Ducky's case already. The same problem that applies to her applies to Petrie (those crests didn't usually grow from the middle of the occiput but were rather extensions of the nose- (or should I say beak-) -bridge).
Also not even Pterano's size doesn't match that of a fully grown Pteranodon. In my opinion all claims about Petrie's species have to be accepted with a certain reservation.