That is not true at all.
Kuelap alone had 40k to 80k. Whatever source you have is pretty bad then.
There are tons of city names for many civs in the Andes. I could name at least 15, and there are even more with Spanish names after them.
Also there are oral traditions and records of UAs, Wars, etc. And not mysterious at all. They stablished a confederation which have documented trade from all within the Americas. Jade, Amazonian goods, etc. were all traded through Chachapoyan alnds at high rates to neighboring civs. They became rich. ANd this is according to Incan sources along with Spanish sources.
And for example everyone knows about Tiwanaku and the Chachapoya being among the most important in shaping religion. Kuelap for example has bodies that were buried there after having traveled miles from all accross South America to have been buried at the important relgious site.
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Again, I think you are just ignorant on this subject. I mean if you are going to say something as ridiculous about a civ that existed for 700-850 years as that they had a population of only 40k kinda of shows you only did a quick wiki search.
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Edit perhaps you saw the city "Chachapoyas" which had a pop of about 40k at one time. (Never the main city of the Chachapoya so perhaps thats where confusion lies).
Well, I asked you for sources, and yet you have provided none so far.
I can show where I got the info.
"Garcilaso added that “[the province] then had more than forty thousand
inhabitants, and is extremely inaccessible.” Calancha claimed that more than “twenty
thousand tribute-paying Indians” resided in Chachapoyas. Yet, we will never know the
size of the Chachapoya population on the eve of the Inka conquest in the mid-fifteenth century, despite the abundance of ruined settlements." (
http://museoleymebamba.org/chachaarki.website.pdf)
This one says it may have reached 100,000.
"On the eve of the Spanish invasion, the population may have numbered 100,000 individuals, assuming a ratio of one taxpayer for each family of five within two hunus." (
http://columbusstate.academia.edu/WarrenChurch/Papers/275692/Chachapoyas_Cultural_Development_at_an_Andean_Cloud_Forest_Crossroads)
Even if it was a bit over that, it still pales in comparison to the Tupi, who were over 1 million and covered a wider area.
Like I said, there isn't enough info to create many cities for them. To put cities of the Andes under their rule just for the sake of it is inventing history. That, along with UA, UB, UU, etc.
And then you go "everyone knows about the Chachapoya being...". Dude, wake up. No one knows these people even existed. I'm talking about 99,9999% of the world's population in the least. Not even in South America people know about them. I'm sorry, you may call me ignorant on Chachapoyas, and I truly am, but it's not mine or anyone's fault that you fell in love with them and now over-estimates their importance.
The truth is that there are dozens of other tribes who lived for centuries but eventually disappeared. The Chachapoyas are just one of them. Any attempt to put them as a Civ would be silly at best, since it wouldn't be truly representative of anyone in South America, especially when the Incas took their place and were much, much more important.