The South American freshwater rays have 'teeth' very similar to the Atlatic. They are more small and round... with a slight point on some of the species. They lay flat on the jaw structure... so more like plates when you look at them. Usually the benthic rays are set up that way, while pelagic have the plates (I had to go back and do some research after that last thread came up.)
The pic posted of the cownose is actually skin. These are cownose teeth: