Meeting Abstract

P2.217  Saturday, Jan. 5  Phylogeography of Leptasterias aequalis Near Terrestrial Runoff Sources in the San Francisco Bay Area SMITH, R. J.*; COHEN, S; San Francisco State University ; San Francisco State University rjoysmith24@yahoo.com

Small six-rayed seastars, Leptasterias spp., form a cryptic species complex commonly found in the rocky intertidal zone from Alaska to southern California. In 2008, L. aequalis were sub-divided into four finer scale clades (Flowers & Foltz, 2008). In 2009, an additional clade were detected in Central California, resulting in an unresolved taxonomic status (Coleman & Cohen, 2009). While many sea star species have a planktonic larval stage, Leptasterias spp. brood their larvae and after direct development, the young crawl away. This limited dispersal potential may lead to establishment of semi-isolated populations where local differentiation and adaptation to local conditions may occur. To gain insight into patterns of local distribution of Leptasterias spp., we compare population genetic diversity to population density and local environmental features, specifically terrestrial runoff into the ocean. We hypothesize that local populations at sites either separated by freshwater flow or impacted by urban runoff will show local differences in clade compositions. At sites with nearby outlets in Sonoma, Marin, San Francisco and San Mateo counties, we have categorized oceanic and anthropogenic habitat variation in comparison to genetic composition. We are comparing a 300 nt. fragment of the mitochondrial control region in 215 Leptasterias spp. samples to estimate patterns of clade distribution related to geographic features. The results will allow us to map the cryptic species complex of Leptasterias spp. in order to determine if their distribution is affected by local sources of terrestrial runoff, a possible indication of local environmental conditions within their diverse range.