Analysis of endemicity and regionalisation of the freshwater ichthyofauna of Middle America

The first step towards understanding the spatial and temporal patterns of diversity amongs freshwater fishes is through the delimitation of areas of endemism. In this work, we used two of the most popular methodologies for recognising areas of endemism, Parsimony Analysis of Endemicity (PAE) and Endemicity Analysis (EA) to describe and compare the number of endemic regions of freshwater fishes in Middle America using both grid cells (0.5° and 1° resolution). Besides, we built a regionalisation scheme to compare PAE and cluster analysis using different natural basins as study units. The number of areas of endemism recovered varied widely depending on the method used, PAE being a better approach than EA. PAE identified six provinces and 38 sub-provinces for the ichthyofauna of Middle America, most of which were similar to those described previously. We describe an ichthyological province not previously listed and recovered both ocean slopes from southern Mexico to Panamá as a single province instead of two as previously suggested. We used Parsimony Analysis of Endemicity (PAE) and Endemicity Analysis (EA) to assess the patterns of endemicity amongst the freshwater fishes of Middle America; PAE regionalisation recovered a total of eight provinces and 26 sub-provinces; Most of the provinces recovered by PAE were congruent with earlier approaches, allowing the support of a general purpose regionalisation scheme.