著者

竹之内 孝一

出版者

日本貝類学会

雑誌

貝類学雑誌Venus : the Japanese journal of malacology (ISSN:00423580)

巻号頁・発行日

vol.44, no.2, pp.110-122, 1985-06-10

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An account was given of the variations of shell color and the patterns of sculpture of an intertidal common gastropod, Monodonta labio (Linne) from the Japanese Islands. Four color forms were recognized. Darkgreen shell color with red or white dots (Form A) and yellow shell color with dark-red dots (Form B) were common, while light green shell color with red dots (Form C) and yellow shell color with green or red dots (Form D) were rare. Forms A, C and D had smaller number of granules on body whorl and smaller numbers of cords, as compared with Form B of the same size. These differences between Forms A and B were significant at the co-occurring areas, except in Amami Ohshima. They occurred sympatrically in southern coast of Honshu, Shikoku, Kyushu, Okinawa islands and in Hong Kong, southern coast of China. But the difference in habitat was observed between the two forms : Form A occurred mainly on the wave-exposed shore, while Form B on the sheltered shore or the reef-barriered shore. Monodonta labio has been considered, by some workers, to consist of two subspecies, Monodonta labio labio and Monodonta labio confusa. Considering shell characters of these forms, Forms A, C, D and Form B were referred to M. labio confusa and M. labio labio, respectively. But from this study, it is evident that these forms are neither allopatric subspecies nor two extreme variations.