I'm doubtful the OP is even serious.
I don't think there's any chance we'll see countries DLCs at any point. (Okay we got Australia, but they could have easily named it Oceania).
Countries are too specific and it would undoubtedly make many people unhappy, as an extremely absurd number of countries would be left behind. Hell, I even doubt we'll see biome-based DLCs at this point, given that we're still in the continent-DLCs route. Europe, North America, arguably Asia and Africa + possible DLCs for aquatic animals and birds. And most likely only ~8 DLCs left.
Other than that, if they revisit South American fauna (which I hope they will), I'd much rather expect tropical/rainforest animals, mainly. The mara, puma and maned wolf are the only ones I see them being added, and the latter two are actually widely spread and more abundant in other American countries.