I googled tectonic shift animation and discovered that at one point N & S America were separate. TBH it is fantasy so my (very rough) map is moot. Thinking about your replies I think I’ll sink SA (sorry Brazil 
) and make it a mix of large and small islands dominated by a central larger island nation, similar to the Minoan Culture during the Classical period. It’s a great excuse to have deep ones all over the place along with communities worshipping Straasha and/or Grome for the Elric novels.