A new turbinid species, Lunella ogasawarana n. sp., is described. This species from the Ogasawara Islands was previously identified as Lunella cinerea. However, both morphological and preliminary molecular studies have revealed that the new species is distinct from L. cinerea. Lunella ogasawarana n. sp. occurs only in the Ogasawara Islands and much of its habitat has been destroyed over the last few decades, so that it is in danger of extinction.
A new Japanese species of the family Ovulidae is described from the Sumisu Bank near Hachijo-jima Island in the Izu Islands, from Tatsumi-dashi in the Ogasawara Islands, from off Kagoshima Prefecture, and from Okinawa Island. Primovula luna n. sp. most closely resembles Primovula shikamai (Cate, 1973) in overall morphology, but it can be distinguished by a different color pattern on the dorsum, its callous thickened columella, larger, triangular funiculum, narrower aperture, wider and flatter labrum, widely developed columellar peristome and fossula, and non-twisted anterior terminal ridge. Two possible polymorphic forms are also recognized in the present new species.
In the third in a series of papers, a further nine valid species of the fasciolariid genus Fusinus occurring in Japanese waters are examined: F. akitai Kuroda & Habe, 1961, F. colus (Linnaeus, 1758), F. crassiplicatus Kira, 1959, F. gemmuliferus Kira, 1959, F. nodosoplicatus (Dunker, 1867), F. penioniformis Habe, 1970, F. tuberosus (Reeve, 1847), F. nigrirostratus E. A. Smith, 1879 and F. nicobaricus (Roding, 1798). Fusinus grabaui Kuroda & Habe, 1952 is placed in the synonymy of F. nodosoplicatus Dunker, 1867, and F. sagamiensis Kuroda & Habe, 1971 in that of F. nigrirostratus. Lectotypes are selected for F. brenchleyi Baird, 1873 (= F. nicobaricus), F, colus, F. crassiplicatus, F. gemmuliferus, F. nicobaricus, F. nodosoplicatus, F. tuberosus and F. nigrirostratus. The type locality of F. colus is restricted to Cebu, Philippines. F. colus is shown to be represented in Japanese waters by two forms that intergrade in certain places.
A new mytilid mussel found colonizing a whale skeleton at a depth of 4020 m on the Torishima Seamount in the Northwest Pacific is described. It is the third named species in the genus Benthomodiolus Dell, 1987. Only minor superficial characters separate it from the two other known species; these are a lack of both periostracal hairs and radial lines and the fact that this new taxon is the only species in the genus living attached to whale bones. In addition, however, the morphology of the byssal muscles in this species is different from the other two.
A new deep-sea mussel, Bathymodiolus manusensis n. sp., is described from hydrothermal vents in the Manus Basin, Papua New Guinea. This new species is characterized by having subterminal umbones, round anterior and posterior margins, separated inner mantle folds, two diverging posterior retractor, and a very short valvular siphonal membrane. B. manusensis n. sp. resembles B. septemdierum, B. elongatus and B. brevior from the Pacific Ocean, B. marisindicus from the Indian Ocean, and B. puteoserpentis from the Atlantic Ocean. However, it is distinguishable from these species by the height/length and width/length ratios, the thickness of the shell, the position of the umbones, the length and strength of the ligament, the position of the anterior bundle scar of the posterior byssus retractor, the length of the foot, and the shape of the intestine.
Two new species of unionid mussels are described as Pronodularia seomjinensis and Inversiunio verrucosus from the Seomjin River, Jeollabuk-do, Korea. P. seomjinensis differs from related species in having a smooth surface, and I. verrucosus in having a warty sculpture and coarse radial ribs on the posterior slope. I. verrucosus also resembles P. japanensis very closely, but they differ in the shape of the glochidium.
Pitar (Agriopoma) japonicum Kuroda & Kawamoto, 1956 has been accepted as the valid name for "Usu-hamaguri", or the Japanese Pitar Venus. However, it is preoccupied by Pitar japonica Ando, 1953, ex Kuroda MS from the Middle Pleistocene in Kobe, southwestern Japan. An examination of the cardinal properties shows P. japonica Ando, 1953 to not be conspecific with P. (A.) japonicum Kuroda & Kawamoto, 1956 but to be a distinct species belonging to Paphia (Protapes). Thus, Kuroda & Kawamoto's (1956) species is a primary junior homonym of Ando's (1953) species. Since Ando's (1953) name was used by Ando (1965), the reversal of precedence (ICZN Article 23.9) cannot be applied. Paphia (Protapes) japonica (Ando, 1953) comb. nov. is proposed and a redescription is presented. In addition, Pitar (Pitarina) kurodai nom. nov. is proposed for P. (Agriopoma) japonicum Kuroda & Kawamoto, 1956.
Population density and size composition of the limpet Patelloida heroldi were investigated over a 6-year period on a boulder shore at Amakusa, western Kyushu. The vertical distribution range extended from the low to the mid intertidal zone. The density on the shore showed an increasing trend over the 6-year period, with a clear seasonal fluctuation: high in spring-summer and low in fall-winter. The size frequency histogram of each sampling occasion had 1-3 peaks. The maximum shell length was 17.80 mm. By following the temporal changes of the size frequency histograms, the recruitment and growth of cohorts were estimated. Recruitment of new cohorts (3-5 mm in shell length) occurred mainly in winter. They grew up to 10 mm within 8 months. Longevity of cohorts was variable, but always less than one and half years. Previous ecological studies on this genus are reviewed in relation to recent taxonomic work.
Nipponacmea fuscoviridis (Teramachi, 1949) is enormously abundant in the intertidal zone throughout the temperate area of the Japanese islands (southern Hokkaido and southward: Sasaki & Okutani, 1993). It also occurs in part of the Ryukyu Islands, but known subtropical localities are extremely few in number. In the literature, reliable records exist only from four of the Nansei Islands, viz. Amami-Oshima Island, Kakeroma Island, Tokashiki Island and Kunigami, Okinawa Island (Sasaki & Okutani, 1993; Kubo & Kurozumi, 1995). In 2004 one of us (T. S.) surveyed the molluscan fauna of Iriomote Island, Okinawa (Sasaki et al, 2006) and unexpectedly collected specimens of the genus Nipponacmea, which is mainly distributed in temperate areas. As a result of morphological examinations they were identified as N. fuscoviridis based on shell characters, animal pigmentation and radular sac configuration. In addition, molecular phylogenetic analysis confirmed that the material is genetically conspecific with temperate population of N. fuscoviridis. We report this interesting range extension in this paper.