My Giant Columbian Ramshorns. First one has an atypical shell - nearly jet black without any stripes - it is pretty unusual for this species to have a stripeless shell.
It also has a very white foot which isn’t the usual either - they’re often a very light colour but typically have some mottling. This one has no mottling on the underside.
I suspect this one is male but can’t be certain.
He’s dragging a dead stargrass leaf which makes it look like his foot is divided though it isn’t - presumably he’ll finish eating the leaf soon enough.
My other one just might be female - again, not certain of that. There is an obvious but slight outward flare to the growing edge of the shell which the other snail does not have. It seems to have a wider aperture too, characteristic of adult females compared to males.
In the P.canaliculata species a slight outward flare of the growing edge is seen in males - so it will be interesting to see if this is sexual dimorphism or not and whether I’ve got it right way round or backwards.
This one is very typical in appearance with very bold stripes and the foot is a dirty light beige with some mottling showing in the underside.