(I don't know if there's a post similar to this, so I'm deeply sorry if this suggestion has already been suggested!)
Howdy! Goldy 'ere.
I believe there isn't a prehistoric map in-game, and that's why I'm here, writing this very post! I'd like to suggest a unique prehistoric map, with of course, a bunch of prehistoric prey! Since there's a T-Rex in-game, why not move it in with some other dinosaurs? (I'm a big fan of dinos, so ye, mweheh. :3)
'Tis all from me! Thank you. :3