And that's what I get not reading full articles lol!
There are no CONFIRMED cases of cannibalism in the Amazon. However there are in New Guinea as you said.
The Ache of Paraguay practiced cannibalism until 1990. But they live in a region which is known as Chaco (outside the Amazon). Cannibalism was practised by the Tupi of Eastern Brazil (outside Amazonia) until the 18th century, when most of the Tupian tribes were exterminated. Amazonian Tupi never practiced cannibalism.
Out of the 2,000 nations (around 10,000 to 15,000 tribes) which populated South America before the European contact, only some 200 have survived to this date (~1,000 tribes). Most of the survivors are heavily assimilated.
Only some 70 tribes are uncontacted (completely isolated). There are no reports of any cannibalism among them. Most of these tribes number less than 20 individuals and live in pockets of forest surrounded by ranches. I have studied some two dozen of these tribes as a part of my project work. I found that the population is declining in 80% of the cases, while 20% of the tribes (mostly in the Javari) showed stable population.
There are another 70 or 80 tribes, such as the Yanomami and Xavante who have preserved their traditions. But they have also abandoned cannibalism.
