Black and white tegus are the largest of the tegus. They are mainly from Argentina, but some are also found in Uruguay and Brazil. Someone who is now not with us any more used to raise tegus and other large lizards at a compound in Alabama, where he raised them outdoors. So, it's no surprise that they are thriving in Florida.
Here is a photo of a full grown b/w tegu with a ranger to show you how big they are:
