The present study consolidates knowledge of Antarctic marine Rhodophyta, incorporating new observations from the Antarctic Peninsula. Descriptions of four new genera and five new species are included: Rhodokrambe laingioides (Delesseriaceae), Leniea lubrica, Austropugetia crassa, Varimenia macropustulosa R.L. Moe gens. et spp. nov., and Nereoginkgo populifolia R.L. Moe sp. nov. (Kallymeniaceae). The new combination Trematocarpus antarcticus (Hariot) Fredericq et R.L. Moe is proposed for Kallymenia antarctica Hariot (Sarcodiaceae). Phylogenetic relationships are suggested based primarily on unpublished molecular analyses of rbcL sequences provided by S.-M. Lin, S. Fredericq, P.W. Gabrielson, D.W. Freshwater and M. Volovsek. Habitat and environmental conditions are incorporated from the field studies of R.L. Moe and C.D. Amsler. A preliminary assessment is made of the biogeographic relationships between Antarctic red algae and those found in related temperate regions based on a summary of tectonic and climatic reconstructions of the Cenozoic Southern Ocean and the unpublished phylogenetic studies of Hommersand and his associates. © 2009 by Walter de Gruyter.