It's no wonder it's confusing. When you read the article, the experts themselves disagreed or were confused until stalsbergi was officially classified. Meanwhile, books and articles were calling different fish the true rivulatus. I was very interested when staslbergi were officially named, but after arguing on a forum where someone thought I was saying white edge rivulatus were stalsbergi-- I wasn't-- I wanted to find a good reference article (there was a PFK article, but it was confusing, using it as a reference led to the argument).
I was already familiar with the Alf Stalsbergi Andinoacara page, one of my favorites, and had an older Wayne Leibel article that was good but without as much history, I was actually looking for that one when I found the 2010 article, best I've seen for getting it all straight.
I guess if you want to split hairs on the order the fish came into the hobby, according to the article white edged rivulatus came first, soon after was gold edged rivulatus, then a third fish appeared in photos (1973) that we now know as stalsbergi, of which some were collected in 1975. But, as I understand the article, the fish that made the biggest splash, the fish some people were so anxious to breed but found so crazy aggressive, giving them the "terror" name, was the gold edged fish.
None of which matters that much now imo, except that the gold saums that are so common that we don't think that much about them were once so expensive and difficult that for a little while they were sort of a holy grail fish.