Matt, I think it would be very safe to say there are more than 4 locations of Panaque Armbrusteri. Check this link out and prepare yourself
http://silurus.acnatsci.org/ACSI/field/Pipe_Expedition/Loricariidae.html
Have a read about the full expedition, it is amazing. Also look at the location map and collection points. It shows how vast an area they are dealing with, As for human exploaration of the underwater parts of the Amazon....we have barely dipped our toes in the order.
Thats a great link to explore, thanks Alan. Something new to me after reading some, is that the areas they were collecting were the headwaters of the Xingu, Tapajos, Araguaia, so presumably these rivers are connected at least in some way. And then the Araguaia joins the Tocantins near Maraba (I think).
I've emailed Nathan Lujan, one of the guys who described P. armbrusteri and was on that PIPE expedition, to see if he can help a little.
On another note, getting this little panaque for you when I did was one of the if not the rarest fish I've ever sourced. He is so cute.
At the time I was a bit relieved you didn't get the 5 you expected, I wasn't much looking forward to the bill :whistle: But now I wouldn't have minded so much.