A GENETIC ANALYSIS OF SYMPATRIC SUBPOPULATIONS OF THE SIBLING SPECIES LITTORINA SAXATILIS (OLIVI) AND LITTORINA ARCANA HANNAFORD ELLIS

A detailed analysis of shell characteristics (four parameters)and allozyme allele frequencies (eight to nine polymorphic loci)of sympatric Littorina saxatilis and Littorina arcana subpopulationsfrom Filey Brigg on the east coast of England supports theiridentification as closely related but separate species. Oneenzyme system, esterase-2, was nearly species diagnostic. Resultswere generally comparable with an earlier study of the two speciesfrom East Lothian, Scotland. Littorina saxatilis was again foundto be more variable than L. arcana. (Received 14 December 1983;