Unless the spells 'Magic Fangs' and 'Greater Magic Fangs' have changed, they are useless to clerics with the Reptilian domain, for they can only be cast on animal companions -something clerics don't get.

I think I've mentioned this before, but it seems that the Spell Changes post didn't get updated (should be updated now):

Magic Fang and Greater Magic Fang, when used by clerics with the Reptilian domain, will affect summoned creatures.