Intraspecific morphological variations in the Iranian endemic freshwater crab Potamon strouhali (Decapoda: Brachyura: Potamidae)

Potamon strouhali Pretzmann, 1976 is endemic to Iran, and distributed in a small heterogeneous region of the southern Persian plateau that includes two main drainage basins, the Khalij Fars-Oman and Markazi basins. Two subspecies of P. strouhali were previously recognized, but these, together with another species described that same year, P. eiseltiPretzmann, 1976, were all considered to be one species based on shared gonopod morphology. We examined individuals from the complete distributional range covering the type localities of all three taxa using morphological and morphometric-geometric data. The linear morphometric results using 21 characters and geometric-morphometric analysis of carapace shape were consistent. The results of the analysis indicated that P. strouhali has two main morphological populations and the subspecies are thus junior subjective synonyms of these two morphotypes. Potamon eiselti and P. s. shurium are attributed to morphotype 1 and P. s. strouhali to morphotype 2.