I was recently reading an article someone did about advertising of DAK before it opened, and the Discovery River Boats went by a spot where there was (or was supposed to be?) an AA Iguanodon. Is that what you are referring to? Or like something completely Jungle Cruise but with dinos?
Sadly there was also a cave with a "dragon" in it on that boat ride. Never saw the dragon, but I guess there was fire that came out of the cave when the boat passed by. I have been whining about this forever but seriously why not Beastly Kingdom