Original Articles
Discovery of the striped bonnet, Phalium flammiferum (Röding, 1798) (Gastropoda: Cassidae), on the beach of Kaminokuni-cho, southwestern Hokkaido, Japan
Takafumi ENYA and Akihiko SUZUKI
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Summary The drifted shells of the striped bonnet, Phalium flammiferum (Röding, 1798) on the sandy beach of Kaminokuni-cho, Matsumae Peninsula, the Japan Sea side of southwestern Hokkaido were examined. The Phalium shells were washed ashore due to severe storms. They were associated with some warm-water molluscan species such as Glycymeris albolineata (Lischke, 1872) and Olivella japonica Pilsbry, 1895. The discovery of P. flammiferum in the coast of Kaminokuni-cho is presumed to have occurred under the high temperature of surface sea water of the northern Japan Sea from the 2010 summer. Warming of the sea surface in the Japan Sea is considered to be accelerating the northward migration of warm-water molluscs in cool regions. |
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Key words: distributional expansion, global warming, Japan Sea |
Morphological variation and molecular phylogeny of Euhadra scaevola group (Gastropoda: Camaenidae)
Motohiro KAWASE, Kazuhisa NISHIO, Akihiko MORIYAMA, Takashi ICHIHARA and Eiichi SAKURAI
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Summary A molecular phylogeny based on sequence data from mitochondrial COI gene showed that Euhadra scaevola (Martens, 1877) s.l. consists of two lineages, each of which likely corresponds to E. s. scaevola and E. s. interioris Pilsbry, 1928, respectively. The dimensions of shell length and diameter are significantly different between two clades, suggesting that the two groups can be distinguished by shell morphology. On the other hand, E. s. interioris and E. s. mikawa Amano, 1939 could not be distinguished by COI sequences. However, one population of E. s. mikawa from Toyohashi-shi, Aichi Prefecture may be phylogenetically different from E. s. mikawa and E. s. interioris from other regions. |
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Key words: Euhadra scaevola scaevola, Euhadra scaevola interioris, Euhadra scaevola mikawa, geographical variation, cytochrome oxidase subunit I, molecular phylogeny |
Discovery of Gastrocopta theeli (Westerlund, 1877) (Gastropoda: Vertiginidae) from Heda, Numazu-shi, Shizuoka Prefecture, Japan
Takahiro HIRANO
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Summary Recently, a live population of Gastrocopta theeli (Westerlund, 1877) (= G. coreana Pilsbry, 1916) was found from Mihama beach, Heda, Numazu-shi, Shizuoka Prefecture. This is the first record of the species in Shizuoka Prefecture. The previous records of this species in Japan were reported mainly in the inland habitats and the records from the coastal ones have been very few. This is the third occurrence record of live individuals of the species in the coastal habitat, following Shirahama-cho, Nishimuro-gun, Wakayama Prefecture and Setojima Island, Mangokuura, Ishinomaki-shi, Miyagi Prefecture. |
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Key words: Gastrocopta coreana, denticle, coastal area |
Discovery of live individuals of Chelyconus fulmen (Reeve, 1843) (Gastropoda: Caenogastropoda: Conidae) in the Kujûkushima Islands, Nagasaki Prefecture, southwestern Japan, with emphasis on imposex and conservation significance of the species
Hiroki NAKASHIMA, Akihiro KAWAKUBO and Hiroshi FUKUDA
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Summary During 20112013, three live individuals of Chelyconus fulmen (Reeve, 1843) were collected from the Kujûkushima Islands, Sasebo-shi, Nagasaki Prefecture, northwestern Kyushu (around the border of the northeastern East China Sea and the southwestern Japan Sea) by fishermen. These individuals were kept alive in an aquarium. Although the present species was commonly found in temperate Japan before 1970s, it was assumed to have suffered from imposex by tributyltin (TBT) contamination and drastically decreased in recent 40 years. In Nagasaki Prefecture, the present three individuals are the first reliable record of the live specimens of the species after 1980s, but all of them are females with small penes, showing imposex development. This species should be listed as threatened in the Red Data Books. |
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Key words: cone shells, Neogastropoda, threatened species, biodiversity conservation, niku-nuki, East China Sea, Japan Sea, Kyushu |
Current status on the occurrence of the freshwater bivalve Anemina arcaeformis (Heude, 1877) (Bivalvia: Unionoida) in Hyogo Prefecture, western Japan
Yoshihiro B. AKIYAMA, Toshikazu KIZUKA and Shuji MATSUMOTO
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Summary This paper reviews the current status of the distribution of an endangered freshwater unionid bivalve Anemina arcaeformis (Heude, 1877) in Hyogo Prefecture, western Japan. Seven individuals of the species were collected by local citizens from a drainage ditch in the Kakogawa River basin in 2013 by chance. After about a year from this discovery, additional five individuals were collected from the study site. Some results of field researches and verbal evidence imply that the species rarely occurs in the study site. Activities to conserve A. arcaeformis are needed in Hyogo Prefecture. |
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Key words: new locality, Kakogawa River system, drainage, freshwater bivalve, Unionidae |
Faunal change of benthic animals around the outer area of the Isahaya reclamation dike after the temporary opening of the water gates: special notes on the occurrence of Devonia semperi (Ohshima, 1930) (Bivalvia: Veneroida: Galeommatoidea) from the outer area of the northern water gate
Ayaka YAMAMOTO, Shin'ichi SATO and Mikio AZUMA
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Summary Faunal change of benthic animals was examined around the outer area of the reclamation dike in Isahaya Bay. The water gates were temporarily opened during April and May 2002, and sea water flowed into the adjustment pond. Mean individual densities of bivalves and gammarids were most abundant in May 2002, and then decreased from 2004 and 2005. More than 10 individuals of a rare galeommatoid Devonia semperi (Ohshima, 1930) were collected from the outer area of the northern water gate in March 2002, August 2004, June 2012, and June 2013. This species is very rare around the inner part of Ariake Bay, and there are a few records to collect this species from the Seto Inland Sea, Amakusa, Yatsushiro Bay and Hakata Bay. The present study reports the distribution pattern of this species around the outer area of the reclamation dike in Isahaya Bay, identification of synaptid species as a host of this species, and sampling records of this species around the Japanese coasts. |
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Key words: Ariake Bay, bivalves, gammarids, synaptid holothurians, reducing environment |
Three rare gastropod molluscs collected from the upper parts of supratidal zones on cobble beaches of Narugashima Island and the Kitan Straits, Hyogo Prefecture, central Japan
Taichi WADA, Chihiro KAWABUCHI and Tomoyasu TAMEGO
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Summary Three rare gastropod molluscs, an assimineid Cavernacmella yamamotonis (Minato, 1973), two vertiginids Vertigo hirasei Pilsbry, 1901 and Gastrocopta (Sinalbinula) theeli (Westerlund, 1877), were collected from the upper part of supratidal zone on a cobble beach of Narugashima Island, Sumoto City, Hyogo Prefecture, central Japan in March and April, 2014. C. yamamotonis and G. (S.) theeli were recorded in Hyogo Prefecture for the first time. Our subsequent surveys in pebble beaches along the Kitan Straits confirmed that C. yamamotonis is widely distributed in this region and the species was recorded in Osaka Prefecture for the first time. The suitable habitat of C. yamamotonis is usually found on wet black mud bottoms at gloomy places in supratidal zones on pebble beaches facing semi-open seacoasts with running fresh seawater. The nomenclatural problems of the species are also discussed. Furthermore, identification keys for Vertigo hirasei and V. japonica Pilsbry & Hirase, 1904 are pointed out herein, because these two species have long been confused. |
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Key words: new locality, habitat, conservation, nomenclature, Tomogashima Islands, Awaji Island, Assimineidae, Vertiginidae, Cavernacmella yamamotonis, Vertigo hirasei, Vertigo japonica, Gastrocopta (Sinalbinula) theeli |
New localities of an endangered species Gyraulus soritai Habe, 1976 (Gastropoda: Planorbidae) in Miyagi Prefecture after the Great East Japan Earthquake
Takumi SAITO
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Summary Gyraulus soritai Habe, 1976, an endangered planorbid gastropod, has been discovered at three localities in Miyagi Prefecture. They are new distribution records for this species in the Prefecture. Also, these are the only known surviving populations in the Prefecture at present, because all the populations previously known were damaged by the impacts of the tsunami in the Tohoku District in 2011. Although the tsunami affected one of these three localities, the present discovery of G. soritai suggests a rapid recovery of the freshwater habitats. Further detailed surveys are required to clarify the distribution patterns of freshwater molluscan species including G. soritai. |
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Key words: freshwater snail, tsunami, conservation |