Ursprung, Speziation, Ausbreitung und intraspezifische Differenzierung arktischer und antarktischer Schlangensterne der Gattung Ophiocten: Hinweise aus vergleichenden Untersuchungen molekulargenetischer Signaturen

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Brittle stars (Echinodermata: Ophiuroidea) have been identified as key elements of benthic ecosystems in both Arctic and Antarctic seas. However, despite their general ecological significance, there is only scarce information for many species with respect to origin, speciation, taxonomic status and distribution range in relation to biological traits (life cycle and reproduction mode) and geological history (plate tectonics and climate oscillations). Therefore, we propose a case study on the abundant and widespread genus Ophiocten in order to reconcile patterns in phylogenetic relationship and recent biogeographic distribution of Arctic, Atlantic and Antarctic species with the course of drastic environmental changes at evolutionary time scales. Molecular methods will be applied to elucidate genetic similarity patterns at both (i) species and (ii) population level: The comparative analysis of various molecular genetic signatures will be used (i) to deduce the phylogenetic relationships between selected species in order to describe the course of speciation and colonization of polar seas and to solve the taxonomic status of closely related taxa, as well as (ii) to track the dispersal routes of meroplanktonic larvae and to identify genetically distinct populations.