LOUIE, Kristina D.; JACOBS, David K.; Univ. of California, Los Angeles; Univ. of California, Los Angeles: Microevolution in the sea: Genetic structure in the Eastern Pacific eelgrass limpet Tectura depicta (Lottidae: Patellogastropoda)

We examined the population structure of the Eastern Pacific eelgrass limpet (Tectura depicta) from Monterey Bay, CA to San Quintin Bay, Baja CA, Mexico and its relation to shell polymorphism (oval, narrow, and intermediate forms). We obtained a 351 bp from the mitochondrial DNA cytochrome b gene and found seven haplotypes. Despite a week-long pelagic larval phase, a major genetic break (φ-ct = 0.953) was detected between northern (Monterey and Channel Islands in CA) and southern populations (from Alamitos Bay, CA to San Quintin Bay, Baja CA) that corresponded to shell morphology and proposed biogeographic breaks in other marine taxa. The northern group was monomorphic for the oval shell morphology and the southern group included both narrow and intermediate forms. The lower morphological and genetic diversity in the north and relationship among haplotypes may indicate a recent range expansion from southern locations.