Areas of endemism: to overlap or not to overlap, that is the question

Abstract

The concept of "areas of endemism", and the assumption that these patterns are always a consequence of vicariant events, arereviewed. This assumption is related to the idea that areas of endemism have well-defined limits and never share any surfacewith other areas of endemism because they must represent sister areas supported by sister taxa. Based on this idea, overlappingareas have been considered rarely, or ignored completely. Using a data set of mammals of North America, we test here whetherthe overlapping areas are indeed sister areas supported by sister taxa, thus evaluating whether vicariant events are commonlythe factor producing areas of endemism.