Ecological diversification, recent evolution and speciation of Amphipoda in the polar regions: the case study of Eusirus genus

Because of their long history, the polar regions and especially Antarctica are natural laboratories for evolutionary research. The diverse and specialized polar fauna has evolved during millions of years, and has survived past environmental changes including the glaciations. Given that certain parts of the polar regions are among the fastest warming regions on this planet, knowledge on how these organisms managed to survive climate changes in the past can help us to extrapolate to the future. Here, Eusirus amphipods (crustaceans) are chosen as model organisms because they occur on both poles, are very diverse and live in different habitats. Our knowledge on their ecology and biogeography is still very limited although they are an important component of the marine fauna. From the same amphipod specimens, genetic data, morphological data and ecological data (general ecology, trophic ecology) will be acquired. The evolutionary history of Eusirus amphipods will be reconstructed through time with phylogenetic and population genetic methods, and the obtained phylogenies will be used to map morphological and ecological diversity. This will ultimately reveal which evolutionary processes led to the current diversity of Eusirus amphipods, and if speciation events were constant through time or occurred in bursts. This kind of analyses will also test if there has been convergent evolution of Eusirus amphipods in the two polar regions