Contrasting genetic structure of sympatric congeneric gastropods: do differences in habitat preference, abundance, and distribution matter?

Aim: The relationship of population genetics with the ecology and biogeography of species may be explored by comparing phenotypically similar but ecologically different congeners with overlapping ranges. We compared genetic differentiation between two congeneric rocky intertidal gastropods across a major portion of their sympatric range. We hypothesized that the habitat generalist with high abundance and continuous distribution would exhibit comparatively less genetic differentiation than the habitat specialist with low abundance and a fragmented distribution. Location: Northeast Atlantic from the northwest Iberian Peninsula to southern British coastline. Taxon: Gastropoda, Trochidae, Steromphala (formerly Gibbula) Methods: Field surveys were conducted to assess presence/absence and abundance of Steromphala umbilicalis (generalist) and S. pennanti (specialist) at 23 localities along ~1800 km coastline. We isolated polymorphic microsatellite markers for both species (seven loci ...