Development and characterization of a microsatellite library for the freshwater crab Potamonautes danielsi Peer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 (Brachyura: Potamonautidae) and its transferability across three congeneric species

The need for highly-variable, nuclear microsatellite markers to accurately determine population genetic structure and infer patterns of gene flow and dispersal in true freshwater crabs of the genus Potamonautes MacLeay, 1838 (Potamonautidae) was raised more than a decade ago. The present study uses a shotgun genomic approach, next-generation sequencing and a bioinformatics pipeline designed for isolating microsatellites from Illumina sequence read data to isolate di- and tetra-nucleotide repeat microsatellites for Potamonautes danielsi Peer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 from data produced by a fraction of a MiSeq run. Twelve loci were initially identified, with reproducible amplification of eight loci in the target species. Compiled in two multiplex reactions, all eight loci were polymorphic with between three and 15 alleles. Evaluated according to PIC, three loci were considered to be highly informative and four as reasonably informative. Cross-amplification success was evaluated by screening loci for three species (P. lividus Gouws, Stewart & Reavell, 2001, P. principe Cumberlidge, Clark & Baillie, 2002 and P. sidneyi (Rathbun, 1904)) representing varying degrees of phylogenetic relatedness to P. danielsi. Cross-amplification attenuated along with relatedness, with seven loci being successfully amplified P. lividus and P. sidneyi, and four in P. principe. The number of polymorphic loci was further reduced and, for P. sidneyi at least, individual amplification success was low. Nonetheless, the present study does present a microsatellite panel that can be applied to population genetic studies of the widespread P. danielsi and has some potential for closely-related species. This is only the third microsatellite panel to be developed for the true freshwater crabs.