I remember learning this in high school – the so-called tongue map that claimed that each of the 4 fundamental tastes were “picked up” on different parts of the tongue: bitter in the back, sweet in the front, sour on the sides toward the back, and salt on the sides near the front. This was shown to be false long ago–all areas of the tongue are sensitive to all the tastes.
And yes, there are now believed to be more than 4 basic tastes. A fifth, savory or umami is widely accepted, and some researhers argue for a sixth, piquance.