Baryonyx is perfect for the lower south cave! They are slim, so any that creates a small and slim space ii will fit (just have to ride it through those parts or struggle coaxing it out). Also it can swim pretty fast. Think of it as a spino for the lower south cave. It can swim fast, run fast, can kill fast, can stun in water, and can jump. It also can breathe underwater (unlike spino)! It has saved me from having to go into the cave again due to megarabies (I'm on PS4 that's why).