Amazonia is the lowland forest basin drained by the Amazon and its tributaries, across what are now Brazil, Peru, Colombia, Ecuador and Venezuela. It carries hundreds of languages belonging to unrelated families, and the atlas holds it as a region in its own right rather than folding it into South America or into The Andes.
The reason is practical rather than tidy. Andean religion is built around mountains as persons, around the ancestral dead kept and fed, and around a state tradition of terraced agriculture and centralised ceremony. Lowland Amazonian cosmologies are built around a different set of problems: the relation between human beings and animals, the transformation of one into the other, and the traffic between a specialist and the beings who own the game. Filing an Amazonian practice under an Andean heading produces a page that looks researched and is wrong, which is worse than leaving it unfiled.
What recurs across the basin, in societies otherwise very different, is a specialist who negotiates with non-human persons on the group's behalf, an understanding that appearance is unstable and that what looks like an animal may not be one, and the use of plant preparations as the means of seeing the arrangement as it really is. Peter Roe's comparative study of basin cosmology is a standard attempt to state what is shared without flattening what is not.
Colonial and missionary pressure, rubber-era violence and displacement have reshaped every one of these traditions, and none of them is a survival from before contact.