The goal of this project is to fill important gaps in our understanding of the role of the Magellanic region in the faunal exchanges and macroevolutionary process of the Southern Ocean. Sea stars (Asteroidea, Echinodermata) will be used as a model taxa because of their important taxonomical and ecological diversities in the area. They are also abundant, particularly easy to collect and have been the model organism of the BIOMAR Lab for decades. We aim to provide basic scientific knowledge needed for the creation of a diversity baseline of Magellanic sea stars. We also aim at disentangling the role of this pivotal region, at the crossroad of three oceans in the general phylogeographical context of the Southern Ocean. This project will involve several natural sciences disciplines (zoology, taxonomy, genetics) and is also multidisciplinary as it implies different methodologies: in situ sampling, morphological analyses, and the use molecular tools. The BIOMAR team has an extensive expertise in all aspects of the project and an ongoing collaboration with the local partner in southern Chile (Punta Arenas). This secures the feasibility of the project and the capacity to kickstart efficienciently.