How to sex Cercophonius spp.
Look for chelal apophyses
As juveniles, sexing Cercophonius spp is probably near, if not impossible. There is one distinct sexual dimorphism present in members of this genus as adults and that is the presence of a lump or series of lumps on the inner surface of the chela. The male has these protuberances to more than likely increase his grip during the promenade. They are quite distinct.....take a look.