Phylogenomic and morphological limits of radiation in subterranean beetle tribe Leptodirini

Adaptive radiation represents one of the astonishing processes generating biodiversity, characterized by a rapid increase in number of species originating from a common ancestor, and accompanied with ecological and morphological diversification. Adaptive radiations were thoroughly studied in epigean taxa, including the renown anoles, cichlids or Darwin’s finches, whereas its contribution to subterranean biodiversity was not considered as relevant. Subterranean ecosystems were traditionally considered as extreme environments, while the inhabiting fauna was thought to represent evolutionary dead-ends. This view changed in the last decades, when it was shown that subterranean species can descend from subterranean ancestors and specialize to micro-habitats. Moreover, a recent study pointed out that adaptive radiation unfolded in subterranean freshwaters, questioning our knowledge on the origin of European fauna. Considering high species richness in some terrestrial subterranean taxa, it can be expected that freshwater amphipods do not represent an isolated case of subterranean adaptive radiation in Europe. With more than 900 species described, exhibiting immense morphological variability and inhabiting a wide variety of habitats throughout Southern Europe and adjacent areas, Leptodirini present one of the species richest groups in subterranean environments. Considered as terrestrial paralogues of amphipods, they represent a perfect study system to question generality of adaptive radiations in European subterranean environments. By applying comparative phylogenetic methods, we will test whether continental radiation of Leptodirini unfolded under predictable pattern of adaptive radiation and what were the potential triggers causing it. We will test whether diversification patterns met in Leptodirini repeat within different subclades, and can they be mirrored to different Southern European mountain ranges exhibiting high species richness? Finnally, we will test whether a simple Brownian model best explains body shape diversification, or did Leptodirini evolve under a more complicated model characterized by distinct adaptive optima? To answer these questions, we will infer a large, robust molecular phylogeny (>350 species), based on phylogenomic and Sanger sequencing data. Molecular data will be accompanied with morphological and occurrence data, gathered for a wide range of Leptodirini representatives distributed throughout the clade’s range. Comparative phylogenetic methods will be used to disentangle the geographic origin of the clade, reconstruct the common ancestor and test the tempo, mode and ecological disparification in Leptodirini. A three-year project will be organized in nine working packages, comprising developmental, exploratory, analytical and dissemination packages. An attractive and species rich group of subterranean beetles will be used to study one of the most intriguing topics in evolutionary biology. Results are expected to link micro and macro evolutionary mechanisms with the patterns of Leptodirini continental radiation. By resolving the mode and tempo of Leptodirini mega-diversification, we expect to change the view on subterranean fauna and its contribution to biodiversity in Europe. By combining phylogenomic and morphological analyses within the framework of adaptive radiation, we will introduce a novel system into eco-evolutionary research. Finally, we expect to show that subterrranean environments, despite their simplicity and remoteness, can provide exciting systems for studies of most relevant evolutionary questions.