Testing the morphology- and intuition-based taxonomic hypotheses using integrative approach: unexpected discovery of triplet of sibling species within a widespread Eurasian butterfly, Hyponephele lycaon.

In well-studied groups of organisms, the taxonomic landscape can be very complex, with several alternative classifications describing diversity within the same set of populations. For example, three hypotheses have previously been proposed to describe the taxonomy of the common and widespread Eurasian Dusky Meadow Brown butterfly, Hyponephele lycaon, and its close relatives. The morphology-based hypothesis (1) is explicitly based on genital differences between two putative species. The other two hypotheses, the hypothesis of multiple allopatric species (2) and the hypothesis of two sympatric species (3) within the H. lycaon complex, are based on scientific intuition rather than on rigorous data and analyses. Here, using an integrative taxonomic approach, we cannot confirm any of the previous classifications, although elements of each can be found in the suggested new system. As a result, we show that Dusky Meadow Brown butterfly is a triplet of sibling species. Two of them, H. collina (Turkey, Levant, Iran) and H. lycaon (Europe, temperate Asia), are allopatric. The third species, H. libanotica, is widely sympatric with H. collina in Turkey, Israel and Iran. We argue that past taxonomic hypotheses, including those based on implicit evidence, are useful priors for planning sampling strategies and more detailed modern taxonomic analyses.