Oh dear lord. Hahaha.
Very, VERY interesting thread, and one that does seem to ring true in my tanks as well. I've got 3 supposed SAE, all of which love munching on java moss (not to the point of eating it all, but certainly taking care of a lot of its brushiness unfortunately). Alas, no dark patch on their abdomen. I'm pretty sure they have barbels, but I'll have to take a closer look later - they're sleeping/hiding right now.