The major goal of the study was to reconstruct the divergence history of L. fluviatilis and L. planeri using RAD-sequencing data. The objectives were (i) to compare alternative models of demographic divergence history, (ii) estimate the proportion of the genome experiencing reduced gene flow, (iii) identify genomic markers showing particularly high differentiation between ecotypes under the most likely divergence demographic model and (iv) evaluate the extent of parallelism among replicate pairs of ecotypes.