Meeting Abstract

S7.7  Tuesday, Jan. 5  Phylogeography, larval dispersal and recent history of Antarctic continental shelf fauna HALANYCH, KM; Auburn University ken@auburn.edu

Separation of the Antarctic and South American continental plates formed the Drake Passage roughly 30-35 MYA. This event lead to the establishment of the Antarctic Circumpolar Current (ACC) and the Antarctic Polar Front (APF) which have been repeatedly invoked to explain biogeographic patterns such as high endemism and circumpolar species in Antarctica. Genetic tools, in particular mitochondrial DNA sequence data, are being employed to test whether recent gene flow into and out of the Southern Ocean has been possible. To date, we have been able to examine nine continental shelf species that are found in Antarctic waters. Results indicate that isolation has occurred in the past between the South American and the Antarctic continental shelves, but much more recently than dogma contends. Additionally, mtDNA sequence data reveal cryptic speciation in several species, implying that 1) connectivity of ancestral populations that spanned the ACC and APF taxa was intermittent, and 2) Southern Ocean biodiversity is vastly underestimated. These recent findings will be compared and contrasted to information from other Antarctic habitats and organismal groups.