Phylogeography of an intertidal direct-developing gastropod Batillaria cumingi around the Japanese Islands

Abstract

The phylogeography of the direct-developing intertidal gastropod Batillaria cumingi was examined by comparing the nucleotide sequences of part of the mitochondrial gene for cytochrome c oxidase subunit I (COI) from 507 individuals, obtained from 24 sites that cover the distribution area of this species along the Japanese coasts, and from 2 sites on the Korean Peninsula. The individuals could be divided into 2 groups. Individuals in the first group mainly inhabit coasts along the Kuroshio Current, as well as Ariake Bay in western Kyushu, while the second group inhabits coasts along the Tsushima Current and its branches. Individuals in the 2 groups coexisted at only 3 sites, which correspond to the boundaries between the distributions of the 2 groups. The level of the genetic structure of B. cumingi is higher than those of the lecithotrophic gastropod species Turbo (Batillus) cornutus and the planktotrophic congeneric species B. multiformis.