国立科博専報,(47): 97–144,2011年4月15日 Mem. Natl. Mus. Nat. Sci., Tokyo, (47): 97–144, April 15, 2011 A Review of Bathyal Shell-bearing Gastropods in Sagami Bay Kazunori Hasegawa1 and Takashi Okutani2 1 Showa Memorial Institute, National Museum of Nature and Science, 4 –1–1 Amakubo, Tsukuba-shi, Ibaraki 305–0005, Japan. E-mail:
[email protected] 2 Marine Biodiversity Research Program, Japan Agency for Marine-Earth Science and Technology, 2–15 Natsushima, Yokosuka-shi, Kanagawa 237–0061, Japan. Abstract. Shell-bearing gastropods occurring in Sagami Bay at bathyal depths from 400 to 1600 m were reviewed based on information in literature, voucher material of some previous studies, and newly acquired specimens. 110 species that have been recorded from this area in lit- erature, excluding those exclusively associated with chemosynthesis-based communities, were reclassified into 97 species. 23 species were newly added to the fauna, resulting in 120 species in total recorded from this area. Among them, 88 species were identified as named species, two were only referrable to similar species, and 30 were not identifiable as any species previously known, at least in the northwestern Pacific. Among the 88 named species, six were recorded for the first time in this area, including one recorded for the first time in Japanese waters. Based on these results, the characteristics of the gastropod fauna in the Sagami Bay and adjacent areas is discussed from the bathymetrical and geographical points of view. Key words: Gastropoda, Sagami, bathyal, fauna, biogeography. continental shelf of the bay has thus been well Introduction documented (see Hasegawa, 2006 for gastro- The Sagami-nada (the Japanese word “nada” pods).