Tsushima Island Research Articles

Comparative phylogeography of the endemic Japanese weasel (Mustela itatsi) and the continental Siberian weasel (Mustela sibirica) revealed by complete mitochondrial genome sequences

We analyzed the complete mitochondrial genome for 26 individuals of the endemic Japanese weasel (Mustela itatsi) and 20 individuals of its continental sister species, the Siberian weasel (Mustela sibirica). These species diverged an estimated 1.19 Mya, in the Early Pleistocene. Mustela itatsi comprised two haplotype clades that diverged an estimated 0.93 Mya, in the Middle Pleistocene: a northern (Honshu) clade comprising geographically distinct basal, northern, and eastern subclades, and a western paraphyletic group, as well as a southern clade comprising geographically distinct subclades on Kyushu, Shikoku, and adjacent small islands. Our results indicate a single migration of an ancestral population from the Korean Peninsula to southern Japan across an Early Pleistocene land bridge, followed by allopatric speciation of M. itatsi in Japan. The southern lineage appears to have remained in place, whereas the range of the northern lineage expanded stepwise from south-western to northern Honshu between 0.31 and 0.11 Mya. Mustela sibirica also comprised two main clades that diverged an estimated 0.67 Mya; one containing haplotypes from continental Russia and Tsushima Island (Japan), and the other containing haplotypes from Korea, China, and Taiwan. The M. sibirica population on Tsushima Island is likely a relict from the continental Russian population.

They Fear Us, yet Cling to Us: Russian Negotiations with Tsushima Domain Officials during the 1861 Tsushima Incident

ABSTRACTOver six months in 1861, Commander Birilëv of the Russian Navy constructed a base on the island of Tsushima and attempted to negotiate with local domain officials to turn the island into a Russian protectorate. While official Japanese documents, including Tsushima reports to the Tokugawa government in Edo, claim they vigorously resisted these most unwelcome Russian efforts, Birilëv records the Tsushima officials themselves as the ones who first requested Russian patronage. How can we reconcile these two dramatically different versions of the same event? Due to the relatively isolated position of Tsushima, separated from mainland Japan by the sea, the Russians incorrectly believed they were dealing with a borderland that could be detached from the Tokugawa polity, or even with an independent state, tied to Japan merely by flimsy ‘feudal’ bonds. At the same time, Tsushima officials, afraid of antagonizing the volatile Birilëv, resorted to various stratagems that were misinterpreted by him as signals of desire to switch feudal overlords. The resultant negotiations reveal much about international diplomacy across different political cultures in mid-19th century Asia, the influence of Russia on the development of the Japanese polity, and the conduct of gunboat diplomacy at the apogee of European imperialism.

The frontal system at the boundary of the East China Sea: Its variability and response to large-scale atmospheric forcing

High-resolution satellite sea surface temperature measurements (PATHFINDER dataset) indicate that the fronts at the boundary of the East China Sea (Taiwan front, Kuroshio frontal zone, and South Korean coastal front) appear as a unified dominating frontal structure when climatological averaging is applied. This structure is about 1200 km in length, spreads over the continental shelf from Taiwan to the Tsushima Islands, and separates productive seawaters from the oligotrophic oceanic waters. The Kuroshio frontal zone, incorporated into this structure, reveals interannual variability with periods consistent with El Nino–Southern Oscillation (4–5 years).

Description of a new species of the genus Hyalessa China (Hemiptera: Cicadidae: Sonatini) from Yunnan, China, with a key to the species of Hyalessa and a calling song analysis for two Hyalessa species.

A new species, Hyalessa scutata sp. nov., is described from Yunnan, China. This species is similar to Hyalessa fuscata (Distant, 1905) but is distinguished by the larger male opercula and the evenly narrow uncal lobe. Hyalessa ella (Lei & Chou, 1997) syn. nov. is synonymized with Hyalessa stratoria (Distant, 1905). A detailed sound analysis of the calling songs of Hyalessa fuscata (Distant, 1905) and Hyalessa maculaticollis (De Motschulsky, 1866) is provided. A key to the species of Hyalessa China, 1925 is also provided. A discussion is conducted for the first time about the presence of potential hybrids between H.maculaticollis and H. fuscata within Tsushima Island situated in the Korea Strait.

GIS-Based Integration of Subjective and Objective Weighting Methods for Regional Landslides Susceptibility Mapping

The development of landslide susceptibility maps is of great importance due to rapid urbanization. The purpose of this study is to present a method to integrate the subjective weight with objective weight for regional landslide susceptibility mapping on the geographical information system (GIS) platform. The analytical hierarchy process (AHP), which is subjective, was employed to weight predictive factors’ contribution to landslide occurrence. The frequency ratio (FR) method, which is objective, was used to derive subclasses’ frequency ratio with respect to landslides that indicate the relative importance of a subclass within each predictive factor. A case study was carried out at Tsushima Island, Japan, using a historical inventory of 534 landslides and seven predictive factors: elevation, slope, aspect, terrain roughness index (TRI), lithology, land cover and mean annual precipitation (MAP). The landslide susceptibility index (LSI) was calculated using the weighted linear combination of factors’ weights and subclasses’ weights. The study area was classified into five susceptibility zones according to the LSI. In addition, the produced susceptibility map was compared with maps generated using the conventional FR and AHP method and validated using the relative landslide index (RLI). The validation result showed that the proposed method performed better than the conventional application of the FR method and AHP method. The obtained landslide susceptibility maps could serve as a scientific basis for urban planning and landslide hazard management.

Hydraulic properties measurement of tight sandstone for CO2 geological storage

Permeability is one of the important rock properties in oil and gas exploration as essential input data of reservoir characterization and production simulation. As production of unconventional resources such as tight gas/oil, shale gas and coal bed methane increases, there is a growing need to measure the permeability of tight formation rocks. Direct measurement by conventional steady-state flow methods, however, is limited due the length of time needed for pressure equilibration. In this study the pressure pulse-decay method is applied to measure low permeability (lower than 9.87E-18m2) rocks. This method is based on the analysis of unsteady-state gas flow. The dissipation rates of dimensionless differential pressure (ΔPD) with time indicates permeability of various core samples. The low permeability measured by using the pressure pulse-decay method, is compared with the permeability recovered from the steady-state method for validation. These low permeability measurements are conducted to six tight sandstones from the Gyeongsang and Janggi basins, South Korea and Tsushima Island, Japan. The apparent permeability measured by the pressure pulse-decay method was approximately twice higher than permeability measured by steady-state method. By comparing the relationship between permeability and mean pressure, this may result from gas slippage effects.

Distribution and Phylogeography of <i>Caryopteris incana</i> (Lamiaceae) Based on Chloroplast DNA Sequences in West Kyushu, Japan

Caryopteris incana is a continental plant, transferred to Japan from continental Asia via a land bridge between the Korean Peninsula and Tsushima Islands during a glacial period. It currently grows wild in West Kyushu, Japan. In a previous study, we investigated the distribution of C. incana in the Tsushima Islands and confirmed the genetic structure of populations by using chloroplast DNA sequence analysis, suggesting that different haplotypes were distributed in the same area. Thus, it seemed that populations of C. incana throughout the Tsushima Islands colonized at different times; each haplotype had remained within its population without mixing. In this study, we conducted fieldwork to construct a detailed distribution map in West Kyushu excluding the Tsushima Islands. Additionally, we confirmed genetic structure of the C. incana population in these areas by using chloroplast DNA sequence analysis to study the intraspecific phylogenetic relationship of C. incana in Japan. We confirmed 37 natural populations in 257 locations throughout West Kyushu excluding the 72 natural populations in the Tsushima Islands. We also confirmed a recent decreasing trend in the number of natural populations in the Nagasaki Mainland. Using the leaves of individuals cultivated from seeds collected from each natural population, we analyzed the chloroplast DNA sequence variations. Among the investigated populations, sequence variations were confirmed in six regions of chloroplast DNA, and those haplotypes were mainly classified into two groups distributed in different areas on the phylogenetic tree. This finding revealed that the common ancestor of C. incana in Japan diverged early into two groups, followed by a fragmentation in population distribution for each area. The haplotype network almost reflected the geographical distribution on haplotypes. However, several haplotypes that were distributed in other areas were confirmed in the Nagasaki Mainland, suggesting a complicated distribution formation in the past.

Performing Alterity: Postcolonial Genesis of Borderland Identity in Japan

Marginalized borderlanders on Tsushima Island now celebrate histories that have been long silenced by Japanese nationalist discourse. Although the emerging alternative past appears to embody regional postcolonial defiance, this ethnographic investigation reveals the complicated, multilayered meanings of an annual festival situated at the crossroads of three interrelated cultural spaces: Japan’s postcolonial global modernity, Tsushima islanders’ racialized border identity, and dislocated emigrants’ creative imagining of the homeland. The paper will investigate this festival’s cultural performance as a touchstone for ideological diversity and social agency. I argue that the cultural performance simultaneously engenders local ideological unrest and new cultural possibilities, and in turn ignites the genesis of new border identities.

Occurrence and genetics of black‐eyed migratory locusts, Locusta migratoria (Orthoptera: Acrididae)

AbstractBlack‐eyed Locusta migratoria appeared in albino locusts as a result of crossing between a short‐winged strain originating from Tsushima Island, Japan, and an albino strain originating from Okinawa Island. The black eye trait was recessive to the white eye trait because the crosses between black‐ and white‐eyed albino locusts produced only individuals with white eyes in the F1 generation. In the F2 generation, black‐ and white‐eyed individuals appeared in a ratio of 1:3, indicating that the black eye trait was controlled by a simple Mendelian unit. The black eye trait showed no genetic association with other traits including wing morph, adult body dimensions and classical morphometric ratios such as hind femur length / head width and forewing length / hind femur length.

Two new species of Calanthe (Orchidaceae: Epidendroideae) from Korea

Two new species, Calanthe insularis S.H.Oh, H.J.Suh & C.-W.Park and Calanthe rubra S.H.Oh, H.J.Suh & C.-W.Park, are described, illustrated, and compared with closely related species. Calanthe insularis, distributed in the southwestern region of Korea and Tsushima Island in Japan, is morphologically similar to C. aristulifera and C. striata, but it is distinguished from the last two species in its creamy yellow and pale orange-yellow flowers, arcuate spur as long as the lip, pale orange-yellow pedicels, and green ovary with pale green ridges. Calanthe rubra, from Gageodo Island, Korea, is similar to C. striata and C. insularis, but differs from them in its much smaller flowers with purplish red sepals and petals and the white spur.

Saturnia jonasii Butler, 1877 on Jejudo Island, a new saturnid moth of South Korea with DNA data and morphology (Lepidoptera: Saturniidae).

Saturnia (Rinaca) jonasii Butler, 1877 is distributed in Japan, including Tsushima Island and Taiwan, whereas S. boisduvalii Eversmann, 1846 is distributed in northern areas, such as China, Russia, and South Korea. In the present study we found that the specimens from Mt. Hallasan on Jejudo, a southern remote offshore island, were S. jonasii, rather than S. boisduvalii based on morphology, DNA barcode, and nuclear elongation factor 1 alpha (EF-1α) sequences. The major morphological differences between the two species included the shape of wing pattern elements of fore- and hindwings and male and female genitalia. A DNA barcode analysis of the sequences of the Jejudo specimens and S. boisduvalii, along with those of Saturnia species obtained from a public database showed a minimum sequence divergence of 4.26% (28 bp). A phylogenetic analysis also showed clustering of the Jejudo specimens with S. jonasii, separating S. boisduvalii (Bayesian posterior probability = 0.99). The EF-1α-based sequence and phylogenetic analyses of the two species from Jejudo Island and the Korean mainland showed the uniqueness of the Jejudo specimens from S. boisduvalii collected on the Korean mainland, indicating distribution of S. jonasii on Jejudo Island in South Korea, instead of S. boisduvalii.

Polyploidy in Lilium lancifolium: Evidence of autotriploidy and no niche divergence between diploid and triploid cytotypes in their native ranges

Lilium lancifolium, the tiger lily, constitutes a polyploid complex with both diploids (reproduced by seeds and bulbils) and triploids (propagated exclusively via bulbils). An autopolyploid origin for the triploid forms has been previously suggested based on classical cytogenetics, chromosome mapping techniques, ecological data, and geographic distribution in their native range (Korea and the Japanese Tsushima Island). Using 13 allozyme loci, we comparatively assessed clonal structure and levels of genetic diversity in four diploid and 11 triploid populations in South Korea to test the autopolyploid origin of the triploid cytotype and to infer which seedling recruitment strategy is operating within the diploid populations. We also employed ecological niche modeling and multivariate analysis to determine whether triploids of L. lancifolium occupy different and broader niches to those of diploids in Korea and Tsushima Island. The diploids harbored higher levels of within-population genetic diversity than triploids, and allele profiles found in triploids were exactly subsets of those in diploids. Repeated seedling recruitment was inferred for the diploids, whereas all the studied triploid populations were monoclonal since there is no seedling (sexual) recruitment. Although we found no niche divergence between cytotypes of L. lancifolium, the triploids have a broader niche breadth. Genetic data further confirm the autotriploid origin of L. lancifolium, and the lack of a clear, strong evidence for niche divergence between cytotypes of L. lancifolium supports the view that ecological differentiation is not a pre-requisite for the establishment of new polyploid lineages.

Intraspecific Phylogenetic Relationships of Caryopteris incana in the Tsushima Islands, Japan, Using DNA Sequence Analysis

Caryopteris incana is a perennial shrub distributed in the temperate zone of the East Asia. It is found in West Kyushu in Japan, where it is designated as an endangered species. Tsushima, Nagasaki, which experienced repeated connection and fragmentation between the Korean Peninsula and Japan, is an island on the route along which C. incana moved to Japan from continental Asia. We conducted field work and confirmed the genetic structure of populations using DNA sequence analysis to construct a detailed distribution map and clarify the intraspecific phylogenetic relationships of C. incana in Tsushima Island. We confirmed 72 populations in Tsushima. Using the leaves of individuals cultivated from seeds collected from each natural population, we analyzed the chloroplast and nuclear DNA sequence variations. Among the populations, sequence variations were confirmed in six regions of chloroplast DNA, and six haplotypes, including base substitutions, were distinguished. Two haplotypes were mainly divided at the border of the northern part of the southern island in Tsushima. One population in the northwestern part of the north island showed a haplotype derived from the southern part. This finding revealed that the distribution of C. incana had been artificially influenced. Several haplotypes were confirmed by sequence variations in the northern populations, but only one haplotype in the southern populations, suggesting that C. incana on the north island had separated early from the south island in Tsushima.

Bon-odori in Are and Tsushima Island

Bon-odori in Are and Tsushima Island

Comparison of the male and female genitalia and DNA barcoding between Japanese subspecies of Graphium doson (C. Felder & R. Felder) (Lepidoptera, Papilionidae), with determination of the subspecies of the Okinawa-jima and Tsushima Island populations

Comparison of the male and female genitalia and DNA barcoding between Japanese subspecies of Graphium doson (C. Felder & R. Felder) (Lepidoptera, Papilionidae), with determination of the subspecies of the Okinawa-jima and Tsushima Island populations

Origin of a White-tailed Eagle Wintering on Tsushima Island, Japan, Established by Mitochondrial and Nuclear DNA Analyses

The White-tailed Eagle breeds and winters on Hokkaido, the northern island of Japan. It is not known whether wintering eagles occasionally observed in southern Japan migrate there from the Hokkaido population or arrive from an Asian continental population. To further our understanding of their migration, we examined a nucleotide sequence of mitochondrial DNA and a multilocus genotype from the nuclear DNA of an eagle found wintering on Tsushima Island, southern Japan. Our results revealed that the eagle had originated from a continental population.

Taxonomic relationship between two Gammarus species, G. nipponensis and G. sobaegensis (Amphipoda: Gammaridae), with description of a new species.

To assess the taxonomic relationship between G. nipponensis and G. sobaegensis, morphological features and molecular phylogenetic relationships using the nuclear 28S rRNA and the mitochondrial COI genes were examined. Detailed morphological observations revealed that G. nipponensis and G. sobaegensis were clearly distinguishable. In addition to the morphological differences, these two species were genetically diverged. In the course of this study, an undescribed species was found from Tsushima and Iki Islands and described here as G. mukudai. In the molecular phylogenetic analyses, monophyletic relationships of G. nipponensis, G. sobaegensis, and G. mukudai were shown but relationships among three species were unclear due to low statistical supports. Phylogeography of G. nipponensis, G. sobaegensis, and G. mukudai were discussed.

Description of a new brown frog from Tsushima Island, Japan (Anura: Ranidae: Rana).

Because all available evidence from allozymes, mtDNA sequences, and artificial hybridization suggests presence of high genetic differentiation between populations of East Asian brown frogs currently assigned to Rana dybowskii Günther, 1876, I compared morphological characters between specimens from Tsushima Island of Japan and Maritime territory of Russia. The population from Tsushima is slightly, but significantly different from R. dybowskii from Russia, including the holotype. I therefore consider the Tsushima population to be specifically distinct, and describe it as a new species R. uenoi. The new species also occurs in the Korean Peninsula and adjacent islands, but the distributional relationships with R. dybowskii are unclear, as detailed distribution in northern Korea is lacking.

Age of the Taishu Group, southwestern Japan, and implications for the origin and evolution of the Japan Sea

AbstractThe Taishu Group, a marine formation with a thickness of >5400 m, crops out on Tsushima Island, located in the southwestern Japan Sea. The group, which is generally regarded as early Eocene to early Miocene in age, provides important information about the tectonic setting of the Japan Sea. In this study, we present new SHRIMP U–Pb dates for igneous zircons from the Kunehama Tuff, which is in the basal part of the Taishu Group, and the Oobaura Tuff, which is in the uppermost part of the group. Results show that the Taishu Group was deposited rapidly, during the short interval of 17.9–15.9 Ma (early–middle Miocene), and is equivalent to other early–middle Miocene strata found in the Japan Sea region. Our results provide new constraints on the geological history of the Japan Sea and its islands.

Description of a new species of Sternomoera (Crustacea: Amphipoda: Pontogeneiidae) from Japan, with an analysis of the phylogenetic relationships among the Japanese species based on the 28S rRNA gene.

A new species of amphipod, Sternomoera morinoi Tomikawa and Ishimaru, is described from subterranean aquatic habitats in Shiga Prefecture, Japan. In addition, Relictomoera tsushimana (Uéno, 1971) from a well on the island of Tsushima in Japan is transferred to Sternomoera and redescribed based on the holotype. Sternomoera morinoi sp. nov. is most similar to S. tsushimana (Uéno, 1971) comb, nov., but is distinguished by having many fine setae on the body, a shorter antenna 1, fewer C-setae on mandibular palp article 3, a shorter mandibular palp article 3, sparsely setose anterior margins of coxae 1-4, a different armature of the palmar margins of gnathopods 1 and 2, and no long setae on the posterior margin of the basis in gnathopod 2 and pereopods 3 and 4. The phylogenetic relationships among the Japanese species of Sternomoera are also estimated, based on partial DNA sequences of the nuclear 28S rRNA gene.