The first record of Leiosolenus simplex (Iredale, 1939) (Bivalvia: Mytilidae) boring into Plesiastrea versipora from Minamata Bay in Japan

In the family Mytilidae, six genera are known to include rock-boring species: Adula, Botula, Fungiacava, Gregariella, Leiosolenus and Lithophaga (Kleemann, 1990). Species of all except Fungiacava are distributed in Japan: Adula spp. are found north of the Boso Peninsula, Honshu and northward and bore into mudstone; Botula, Gregariella, Leiosolenus and Lithophaga spp. are found south of the Boso Peninsula and bore into dead corals, limestone or calcareous sandstone (Habe, 1977; Higo & Goto, 199 ; Kurozumi, 000). It is known that all Fungiacava species and some Leiosolenus species bore into living corals (Kleemann, 1990). In Japan, however, the distributions and habitats of these species are not yet clear. Leiosolenus simplex was collected from living Plesiastrea versipora (Anthozoa: Scleractinia) d is t r ibuted in Minamata Bay, Kumamoto Prefecture, Kyushu, and is recorded for the first time in Japan. In this paper, the shell morphology and habitat of this species are described, and the classification of Leiosolenus is discussed.