Abstract
The depths of the North Atlantic Ocean host a species-rich fauna providing heterogeneous habitats from thermal vent fields to cold-water coral reefs. With the increasing threat of destruction of deep-sea habitats due to human impacts, such as demersal fishing and the beginning of deep-sea mining, an analysis of the diversity and distribution of species is crucial for conservation efforts. Brittle stars occur in high biomasses, contributing to the biodiversity of the seafloor. We collected specimens during several scientific expeditions to gain a more detailed insight into the brittle star diversity in the North Atlantic Ocean. The integrative approach to identify the species with DNA barcoding (mtCOI) in combination with morphological studies revealed 24 species. Most species are previously known from the North Atlantic, but sequences for 13 species are newly added to public repositories. Additionally, we successfully applied the MALDI-TOF-MS proteomic analysis for 196 specimens with known COI barcodes. This results in a congruent species delimitation demonstrating the functionality of proteomics for identification of brittle stars. This dataset significantly expands our understanding of the taxonomic and genetic diversity and contributes to publicly available data. It emphasizes the importance of considering habitat heterogeneity for large scale patterns of biodiversity.