The Aquiry civilization (that this paper is about) actually ceased (either due to collapse or people changing their mind about that way of life, who knows) between 850 and 1000 CE.

And WDYM "anyone"? Obviously plenty of people met them and plenty of civilizations derived from them. By the time Europeans got there, the Amazon Basin was home to 5-10 million people (some models push it up to 20 million). I'm sure traces of that culture and history still mark those indigenous cultures today

I mean people from the old world.