Meeting Abstract
11.3 Sunday, Jan. 4 Contrasting phylogeographic patterns among three Antarctic brittle star species HUNTER, Rebecca L*; HALANYCH, Kenneth M; Auburn University; Auburn University belchrl@auburn.edu
Antarctica and its surrounding waters are isolated environments typically characterized as stable over ecological time scales, but physically and geologically dynamic over evolutionary time scales. This region has been isolated for approximately 40 million years, due largely to the Antarctic Circumpolar Current (ACC) and Antarctic Polar Front (APF) that flow uninterrupted around the continent. The structure of marine populations inhabiting the Antarctic continental shelf has been influenced by the ACC and APF as well as smaller gyres and eddies. Additionally, Pleistocene glacial cycles likely played a significant role in shaping marine populations, especially of marine invertebrates. Many Antarctic marine invertebrates have circumpolar distributions, however, levels of connectivity between circumpolar populations are largely unknown for most groups. Another factor contributing to population structure is mode of development, which for marine invertebrates includes brooding, where a dispersive larval stage is lacking, lecithotrophy, which involves a non-feeding larval stage, and planktotrophy, where a feeding larvae is present. In an attempt to evaluate the relative contributions of oceanographic features, Pleistocene glacial cycles and life history constraints on resulting population structure of Antarctic marine invertebrates, three species of brittle stars with contrasting life histories were compared. Mitochondrial sequence data was used to determine levels of genetic connectivity throughout a portion of the Antarctic benthos where the ranges of these three species overlap, the Antarctic Peninsula. Preliminary data analyzed using statistical parsimony suggest that life history mode may not predict population structure among some brittle star species. Further analyses will attempt to elucidate which factors have been most influential in shaping the Antarctic benthos.
