The beetle tribe Leptodirini (Leiodidae: Cholevinae) represent one of the largest evolutionary radiations in the subterranean environment. Despite being subjected to many studies, the systematics and phylogeny of the group is not sufficiently understood. In this study we evaluated phylogenetic relationships within the group and tested the validity of the current supra-generic systematics We performed molecular phylogenetic analyses of 147 new samples of Leptodirini beetles supplemented by published DNA sequences of additional 44 taxa. The studied samples covered 116 genera from the Western Palearctic region. Using standard methods, we PCR-amplified six gene sequences. We reconstructed phylogenetic relationship applying Bayes inference and the Maximum likelihood. All analysed genera of Leptodirini beetles formed a monophyletic group, consisting mostly of geographically defined clades. All analyses placed the genus Adelopsella from the central part of the Western Balkans in a sister relation to the rest of the genera, suggesting that the evolution of this group started within the area that now constitutes the Balkan Peninsula. Soon thereafter, ancestors of other lineages spread across Europe at a relatively fast rate to independently colonize disjunct areas of subterranean habitats. Within isolated karstic massifs, evolutionary radiations lead to morphologically distinct yet genetically related groups of species. These radiations took place within the following geographical clades: Stara Planina, South Carpathian, Rhodopean, East Alpine, North Dinaric and South Dinaric. Clade support was not sufficient for a precise delimitation of the East European and a few West European clades. Within the Dinaric Karst several clades coexist and have partly overlapping ranges. Exclusively Dinaric are the genera of the North Dinaric and South Dinaric clades. These two clades are not in a sister relation, and represent two independent evolutional radiations. We found that the current subtribe classification of the Leptodirini does not reflect phylogenetic relations and that the presently accepted systematic groups (subtribes) above the genus level are not monophyletic. The currently used diagnostic morphological characters are mainly homoplastic.
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