To be entirely honest, I don't know exactly what it means, but it is used when people are unsure of the species (like Necturus c.f. beyeri). Another member came up with the name. Though I believe it means 'calling for now' or something to that affect. Not sure exactly what subspecies they are, but know of at least one individual that has almost entirely completed metamorphosis (it's at a friend's house, will ask for pics soon).
cf. stands for Latin confer. It means derived or consult. In nomenclature cf. means similar to but not certainly identified. It means it looks like it is something but I'm not 100% certain it is.