The evolutionary journey of freshwater crabs of the genus Potamon (Decapoda: Brachyura: Potamidae).

AIM: Freshwater ecosystems host a rich biodiversity, including freshwater crabs. The family Potamidae is a diverse group of freshwater crabs with a Palearctic and Oriental distribution. Specifically, the genus Potamon is found in the Middle East, Southern Europe, and Northern Africa. Potamon species are considered true freshwater crabs due to their total independence from the marine environment, which makes them idea organisms to study historical freshwater connectivity dynamics. In this study we aim to elucidate the phylogenetic relationships of the genus Potamon and discuss the historical freshwater connectivity in the Mediterranean region. METHODS: Here we use up to eleven genetic markers to reconstruct a robust phylogenetic tree of the group and use Bayesian methods to time-calibrate the tree. We further use historical biogeography methods implemented in a Bayesian framework to assess the ancestral distribution ranges of the group. RESULTS: In this study we generate the most complete dataset for the group, covering practically the whole distribution range of the genus. We obtained a robust phylogenetic hypothesis and evaluated the times of divergence of the group. The result of the historical biogeography shows the evolution of historical distribution ranges of species of Potamon. MAIN CONCLUSIONS: The Mediterranean Sea is placed in a key intersection for the exchange of fauna and flora. Here we present evidence for the potential of freshwater fauna exchange, through the Mediterranean Sea after a period of desiccation and the loss of contact with the ocean. The origin of Potamon genus is found to be in Western Asia, probably Eastern Iran.

Barcoding and species delimitation of Iranian freshwater crabs of the Potamidae family (Decapoda: Brachyura).

Freshwater ecosystems are under multiple threats in modern times such as water extraction for human consumption, industries and agricultural activities, water contamination and habitat destruction for example. At the same time the biodiversity of these ecosystems are often poorly studied, especially in arid countries such as Iran. In this work, we study one of the ecologically important members of Iranian freshwater fauna, freshwater crab species of the genus Potamon. Here, we barcoded the different populations occurring in the country and delimited the species to allow for a better understanding of their distribution and taxonomy. In this study, we evaluated the taxonomical statues of Potamon species in Iran using genetic data. In addition, we created the first barcoding reference for Iranian freshwater crabs, which is an important resource for future environmental and conservation studies.