Can be commonly found in the carniverous caverns on Ragnarok. The easiest, wyvern accessible entrance is nearby pelagornis bay, up on the mountain. Be careful when inside, because there are normally two right at the entrance. Happy taming!
Can be found in Carno island cave, south west lava cave, south east cave near Stonehenge, Central cave near volcano, and possibly others. They are very rare spawns but if checked regularly you can encounter them if looking to tame.