It is immediately apparent when looking at Malaysian and Indonesian oxycephalum that there is a distinct difference between the two when it comes to head shape. It is also fun to compare the oxycephalum to the Jampea (black) and Sulawesi jansenii.
I’ll post photos of each below, but keep in mind that there are always variations. For example, you’ll notice that on the silver jansenii photo the prefrontal scale is single whereas on the others it is split. This is not consistent. Some of my jansenii from the very same clutch exhibit both split and single prefrontal scales.
What does seem to be consistent is that the head shape of the Malaysian oxycephalum is distinctively elongated and more “elegant”.