Meeting Abstract

19.4  Thursday, Jan. 3  Genetic connectivity in Sterechinus (Echinodermata: Echinoidea) from South American and Antarctic waters COX, L.N.*; HALANYCH, K.M.; Clemson University; Auburn University lncox@clemson.edu

The genus Sterechinus Koehler, 1901 represents the only regular urchins found in Antarctic waters. In particular, S. neumayeri, S. antarcticus, and S. agassizi are morphologically similar species found in the Antarctic peninsular region and/or in South America with the potential to disperse across the Drake Passage via larval transport. These species have a planktotrophic larval stage that can last as long as three months in the water column during the austral summer. There have been numerous larval and ecological studies of S. neumayeri and S. antarcticus, but the biogeographic distributions and relationships among populations of these species are poorly known. Antarctic benthic fauna has been proposed to be isolated geographically for about 25-41 Ma due to the formation of the Drake Passage in the Early Oligocene when South America and Antarctica separated leading to the development of the Antarctic Circumpolar Current. However, an estimated 40% of non-endemic invertebrate species suggests gene flow across this proposed barrier to dispersal. Using the 16S and COI mitochondrial genes, we measure the level of genetic differentiation between South American and Antarctic populations of Sterechinus and infer interspecific relationships among the three species.