The fish were not exactly cooperative, but I managed to get these two overheads and composite them together so you can compare.
The fat bodied fish on the left is a female and the slimmer right hand one is the male. This is the first time I've done a side by side comparison. It's obvious from the specimens we've all seen that there appear to be two sub-species of this fish. Like Gold Nugget Plecostomus, there are small spot and large spot individuals, plus they have different fin colouring and markings.

So we bounced around ideas about regionally seperated species populations, etc. I've always kind of settled on that idea and not actively compared my fish. There's 5 or 6 mixed ones, so not a huge sample to compare. I looked at the overhead shot above. Although these fish both have large spots, the fins are of the two different types. I looked closer....the nose shape is different, plus the pectoral and pelvic fins are different shapes. The pelvics particularly are much larger in proportion to the pectorals in the right-hand fish.
So, in trying to illustrate sexual differences, I think I may have discovered that these might actually be different species. They both share the red nasal nares that we've always associated as a G. punctulatus trait. Recently, of course we've accepted that this fish is actually G. ctenocephalus.....but which one? Or are these two just sub-species where population isolation has led to different traits other than fin markings?
The thick plottens......

Martin.