Found mine in the rocky mountains near red obelisk. I think that's the most common place. Dont try to chase it with a dragon, you'll waste your time. Wait until it despawns and build a trap. These tame are not practical but are flipping awesome! The fact that they are so rare makes it better in my opinion. Dont give up.
It usually spawns near the red obolisk or the sand dunes or the Rocky mountains behind the red obolisk. 80% of the times it's their 15% of the time it's near the silicon pearl loop in the middle of the map 5% of the time near the corners of the map. Happy hunting.