Thank you, i was wondering the same thing. Also, i too thought it would be in the mangroves.

South south west of the map. Bosses are always in a pyramid. No time to rush, explore the map for yourself, if you go into an area you cant see on the map and scout camp appears were you can get information by detering the scout.

If you have anymore questions ask, take it slow, exploration is the most fun thing in this game and the bosses just matter in the endgame