Sea star (Asteroidea, Echinodermata) diversity in the Magellanic region (South-Chile) and their affinities within the Southern Ocean

• Main Author: Vantomme, L.
• Format: Master Thesis
• Language: English
• Published: 2022
• Subjects: Cycethra frigida; Southern Ocean
• Online Access: https://www.vliz.be/imisdocs/publications/385128.pdf

Sea stars are a diverse and important component of the Southern Ocean benthos. However, only scarce information is available regarding their diversity and evolution, and taxonomic revisions are required. The Magellanic region (south of Chile) remains under-sampled despite its pivotal location for species distribution being adjacent to three ocean basins. Therefore we assessed sea star biodiversity in this region and evaluated its role in sea star biogeography. An integrative approach combining morphological identification with DNA barcoding has been implemented to highlight taxonomic discrepancies such as synonymous species and cryptic species. We identified 12 species from theMagellanic region and reported Cycethra frigida there the first time in the Magellanic region. Furthermore we propose to synonymise two species pairs within the Anasterias and Odontaster genera. Four geographical patterns are observed covering narrow (endemic to the Magellanic region) to broad (circumpolar to bipolar or possible cosmopolitan) distribution ranges. Although developmental mode has been suggested as important in shaping biogeographical patterns, relying on this alone is insufficient and other life history traits, physiological constraints, competition, bathymetrical range, and the possibility of passively rafting on kelp are suggested to be at least equally important.