Divergence time estimations and contrasting patterns of genetic diversity between Antarctic and southern South America benthic invertebrates

Abstract

Diversity, abundance and composition of taxonomic groups in the Southern Ocean differ from elsewhere in the planet, since the biogeography in this region reflects the complex interactions of tectonics, oceanography, climate and biological elements since the Eocene. Several groups of marine benthic organisms exhibit high levels of genetic divergence among provinces in this region, supporting the existence of a vicariance process through plate tectonics, while other groups with high dispersive capacity exhibit recent divergence processes. Moreover, the discovery of non- Antarctic decapod larvae in Antarctic Peninsula suggests that some groups can travel across the Antarctic Circumpolar Current. Here we analyzed levels of genetic divergence in congeneric species of three Southern Ocean's benthic invertebrate groups with dispersive potential. For this purpose we included in the analyses COI sequences of an echinoid (Sterechinus), a gastropod (Nacella), and a bivalve (Yoldia). Considering t