Areas of Endemism: To overlap or not overlap ? That is the question

CLAUDIA A. SZUMIK; VERÓNICA V. PEREYRA; M. DOLORES CASAGRANDA

Buenos Aires

Congreso; XXXV Internacional Meeting of the Willi Hennig Society; 2016

Willi Hennig Society/Museo Argentino de Ciencias Naturales

The criteria applied by VNDM to identify areas of endemism search for spatial concordance between diverse groups of taxa. The method considers that the spatial patterns are caused by ?common? historical and/or ecological factors. Whether a given region is affected by a causal factor, some taxa are affectedand some others not affected at all. Then, those taxa with similar response to a common factor should have similar distribution. Following the idea of response or not response to several factors, there will be patterns partially overlapping and perfectly nested as well. In contrast, many biogeographers believe thatthe criteria applied by VNDM fail because they can identify overlapped patterns, regardless of whether the evidence indicates the existence of such patterns. In the literature on historical biogeography there is quite a common statement: areas of endemism do not overlap, ever. Apparently, the nonoverlap conditionis predicated on the idea that the only factor that can produce areas of endemism are vicariant events. So, any two areas of endemism overlapped are a kind of homoplasy or hypothesis ad hoc. In this manner, it is always assumed that any two areas must be sister areas, containing sister taxa, or parts of supersets that in turn are sisters to each other. Surprisingly, the statement that areas can not overlap because areas can only be sister to each other has never been seriously discussed, much less evaluated empirically. This studyuses a data set of almost 700 species from the 11 orders of Mammals present in North America (including Mexico), to specifically focus on the problem of overlapped areas.