The role of the Antarctic for the origin and global distribution of sea spiders (Pycnogonida) with a focus on the family Colossendeidae

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The goal of this project is to study the evolutionary and biogeographic history of sea spiders (Pycnogonida) of the family Colossendeidae, especially the Southern Ocean species. This marine benthic animal group shows an especially high proportion of endemic Antarctic species. The "longitarsal" group within the Colossendeidae is distributed mostly in the Southern Ocean, but some species within it occur in other regions. Therefore, this group could be an Antarctic radiation, in which a strong evolutionary diversification took place after colonization of the Antarctic. To answer these questions, several hundreds of genetic loci shall be sequenced for about 40 representatives of the relevant species. By comparing the already sequenced pycnogonid genomes, conserved regions will be identified and probes will be designed based on them. The DNA of Antarctic and non-Antarctic colossendeids shall be hybridized with these probes and the genome regions obtained by this will be sequenced by next-generation methods. From these results, phylogenetic trees will be reconstructed and different scenarios on the distribution history of the group will be tested. Besides, tests for diverging patterns of selection under different environmental conditions will be conducted.