I definitely see the Pterodactyl influences, but not sure as much about the bat. He does like to wrap his wings around his torso though, and bats do that sometimes right?
It might not help much but here's the image of him from the Other M art gallery in case it helps us out:
His head on the left there makes me definitely think of a bird, I just can't think of which type specifically I'm thinking of when I see it.
Anyway, I don't know if there is any direct correlation between one creature and Ridley. To me he's definitely a mix of a few different types and for me I most often think of Pterodactyls and Dragons when I think of him.
Outside of the knuckles on the feet and the number of fingers (plus the obviously dragon parts) that's a very VERY human structure. It even has the male chest muscular build.
Looking at the art (never did on my save) that Ridley is fucking bad ass.
This is the original concept art for ridley. I see a creature that is more alien than dragon. He has become more dragon/earthlike as the series has aged, but he was always supposed to be very un-earthlike.