The head drawing pattern can do very well
used to Epiplatys and relatives
of Aphyosemion and relatives
differentiate from each other.
Aphyosemion and Fundulopanchax show
three parallel oblique bands on the
Gill cover.
Epiplatys and “Roloffia” never have such a pattern. It is almost the same for them always a sideways "V".
When the preserved Episemion was the head drawing pattern unfortunately no longer to recognize. Also based on Episemion photos I couldn't quite tell how that Head drawing pattern looks like. Just like at Diapteron the pattern is indefinite. Two copies, illustrated by Seegers (1997) but show three parallel bands.