Studies on the Biology and Ecology of the Intertidal Animals of Chichijima Island in the Ogasawara (Bonin) Islands III : Description, Form and Habitat of the Trochid Snail, Monodonta perplexa boninensis n. subsp. in Comparison with those in Monodonta perplexa perplexa (Pilsbry)

Abstract

Monodonta perplexa boninensis n. subsp. is described and its form and habitat are observed. This new subspecies is endemic to the Ogasawara Island and has a flatter shell with less constricted sutures and lighter greencolor surface than M. perplexa perplexa from Japanese temperate region. Its habitat is a lower intertidal zone in boulder beaches, although M. perplexa perplexa inhabits a middle intertidal zone.