Distributional patterns of endemic southern South American freshwater aeglids (Crustacea: Decapoda: Anomura: Aeglidae)

Abstract

The biogeographical and phylogenetic patterns of Aegla Leach, 1820 were analysed integrating track and cladistic biogeographic methods. We obtained 73 individual tracks, 10 generalised tracks and three nodes. Two taxon-area cladograms were constructed based on previous phylogenetic trees published for Aegla and Brooks Parsimony 26 Analysis (BPA) was applied to the presence-absence matrices of generalised tracks (rows) vs components (columns). Four and three equally most parsimonious trees were obtained and two strict consensus cladograms, respectively. The consensus cladogram shown here has a basal separation among three areas: Argentinean-Chilean Patagonian areas, Cuyan ecoregion in central-western Argentina, and the remaining areas in Argentina, Uruguay, Bolivia and Brazil. Within the latter, north-western Argentina, south-western Bolivian and Uruguay ecoregions were nested within several southern Brazilian areas. Our results support a close relationship between the Parana dominion of the Neotropical region and the Subantarctic subregion of the Andean region, which might be related to a temperate climate prevailing in southern South America before being disrupted by cooling and aridification conditions and to geo-climatic events that occurred since the Mesozoic. The Yungas biogeographic province was also supported by the distribution of Aegla. Nodes were all located in southern Brazil, coinciding with the hydrological processes of headwaters and drainages that occurred due to the Serra do Mar uplift. Some species of Aegla previously classified as a single species might constitute species complexes.