Meeting Abstract

62.2  Saturday, Jan. 5  To brood or not to brood: the role of reproductive mode in the dispersal of Antarctic benthic invertebrates MAHON, A.R.*; HALANYCH, K.M.; Auburn University; Auburn University armahon@gmail.com

Antarctica is a region of extreme isolation and its fauna include a high number of endemic organisms, many of which are described as circumpolar. Previous work has shown that invertebrates in Antarctic waters exhibit many different developmental modes, including a high number of brooding organisms. With developmental mode significantly affecting hypothetical limits of dispersal in marine organisms, those species that have a planktotrophic life history stage should have an increased ability to maintain genetic continuity over greater distances. The aim of this work was to describe the life history and genetic connectivity of two species of Antarctic organisms with different modes of reproduction, both reported to have a circumpolar distribution in the Southern Ocean: the sea spider Nymphon australe (Pycnogonida; brooder) and the proboscis worm Parborlasia corrugatus (Nemertea; planktotrophic reproduction). Using mitochondrial COI and 16S sequence data, we find that both N. australe and P. corrugatus exhibit genetic connectivity across large distances around the continent of Antarctica, with neither species displaying genetic breaks across the range for which they were sampled. Results of this work show that a brooding organism in Antarctica does not necessarily conform to previous hypotheses of limited dispersal capabilities and that gene flow can occur across large distances in the Southern Ocean. Future work should investigate both the limits of this connectivity around the entire continent of Antarctica and the mechanisms by which organisms are dispersed.