Evolution of the Antarctic marine fauna: what can DNA and fossils tell us?

Abstract

The opening of the Drake Passage, establishment of the Polar Front and the onset of cooling around the Eocene-Oligocene boundary have been recognised as the most significant events in shaping the recent Antarctic marine fauna. Glacial cycles leading to loss of shelf habitat during glaciations may have been integral in determining extant biodiversity, including the establishment of regional isolation and diversification. Adaptive radiation of major clades, notably icefish, molluscs and crustaceans, occurred in isolation from the rest of the world. Cooler periods may have been associated with extinction of cold-intolerant species but rapid evolution of cold-tolerant groups. These groups have radiated and there is evidence that some have invaded other parts of the world. Modern techniques utilising DNA, fossil and biogeographical evidence can be used to give robust estimates to determine the dates of divergence and molecular rate. This sheds light onto the evolutionary history of the Antarctic marine fauna