Species identification from archived snail shells via genetic analysis: a method for DNA extraction from empty shells

During the summer of 2009, apple snails (Mollusca: Ampullariidae) of the genus Pomacea were found to have established a self-sustaining population for the first time in Europe (Ebro Delta, Catalonia, Spain). This group is known for its genetic diversity and at least two distinct species are represented in a clade typified by Pomacea canaliculata. Various citations refer to egg size and color, and clutch size, in addition to shell morphology, for distinction between species. However, due to overlapping characters and phenotypic plasticity, genetic analyses are becoming more widely used methods for this group. Herein, we present a method for DNA extraction to identify species with sufficient precision from empty shells recovered from the field. This technique may be of use more widely for analyses of shells archived in museum collections for phylogenetic and taxonomic studies.