Fig. 3

Maximum likelihood mtDNA gene tree of the B. alpinus species group COI unique haplotypes. The color of the sample label indicates the B. alpinus cryptic lineages and B. melanonyx as identified based on nuclear microsatellites (A: Blue; B: Green; B. melanonyx: Orange). B. alpinus, from Genbank and unpublished B. melanonyx and B. nubecularis sequences were included (in black). Additional information on the published or provided sequences, including the geographic origin of the samples, mountain massif and respective GenBank accession number, is provided in Additional file 1: Table S3. Baetis rhodani was used as an outgroup. Filled colored circles indicate nuclear subgroup membership for B. alpinus lineages A and B (see Fig. 6). Numbers at nodes represent branch support based on 500 bootstrap replicates, and are shown for support values >80 %. The scale bar indicates the estimated number of nucleotide substitutions per site