POPULATION GENETIC STRUCTURE OF THE FRESHWATER ANOMURAN AEGLA URUGUAYANA SCHMITT, 1942 (DECAPODA, AEGLIDAE) IN THE CENTRAL REGION OF ARGENTINA

Aeglidae is the only freshwater family in the infraorder Anomura. Aegla uruguayana Schmitt, 1942 is one of the most widely distributed species in southern South America and is found in different environments, which makes it an interesting object for population genetic studies. The main objective of this work was to analyse the genetic population structure of A. uruguayana along a sea distance gradient for four populations that were studied in the La Plata Basin with an 1100-km range in relation to an east-west transect. The populations studied were the Rio Tercero Reservoir, the Setubal Lagoon, the Doll Stream and the Urquiza Stream. Aeglid DNA was extracted using a commercial kit that was amplified with ISSR markers. Of the 10 primers tested, we selected four that showed the best resolution and reproducible results. Our studies revealed a H-e of 0.3479 +/- 0.1383 (mean +/- SD) and a global Fs(T) of 0.3583 (p<0.0001), demonstrating genetic differentiation among populations with low gene flow. The Urquiza Stream population showed a genetic structure clearly different from that of the other populations. However, the Rio Tercero, Setubal and Doll populations were well grouped with one effective connection among them. The geomorphologic history of the basin provides evidence for the isolation hypothesis. These data demonstrate the importance of geoclimatic history in the study region and the importance of using complete population distribution data where the species live. These data permit us to interpret that different populations have independent histories that are delineated by the geomorphological events that occurred on earth.