A dark shell hiding great variability: a molecular insight into the evolution and conservation of melanic D aphnia populations in the A lps

Zooplanktonic microcrustaceans of the D aphnia pulex group appear highly differentiated at high altitudes as a result of alternative colonizations and quick local adaptation to harsh environments. In particular, the occurrence of deeply differentiated mountain lineages of E uropean D aphnia pulicaria ( EuPC ) is highly related to glacial advances and retreats during the P leistocene. Nowadays, one single ancient EuPC lineage survives in the P yrenees, with another inhabiting the H igh T atra M ountains. Much less is known about populations inhabiting the A lps, where EuPC populations are extremely rare. Recently, four new melanic populations have been discovered in lakes in the W estern I talian A lps, offering the opportunity to study their origin and adaptations. We inferred phylogenetic relationships of melanic high‐mountain populations in order to disentangle their history and clarify the colonization patterns of alpine populations. Molecular data suggest that dark populations originated from at least two ancestors, one genetically close to boreal haplotypes, the other apparently related to refugial populations that survived in southern E urope. Therefore, dark pigmentation and obligate parthenogenesis evolved independently within both lineages inhabiting the studied lakes as extreme local adaptations to the alpine environment. Finally, since impacts of human‐related activities and climate changes on mountain species are known to be dramatic, we pose strong issues for the conservation of these extremely localized endemisms. © 2014 The Linnean Society of London