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Satoshi Chiba

Section

Center for Northeast Asian Studies

Job title

Professor

Degree

理学博士（東京大学）
理学修士（東京大学）

researchmap

https://researchmap.jp/read0191572

J-GLOBAL ID

200901099098503778

Professional Memberships 3

American Society of Nauralist
Society for the study of evolution
日本生態学会

Research Interests 6

Behaviour
Diversity
evolution
Mollusca
speciation
Ogasawara

Research Areas 5

Environmental science/Agricultural science / Social-ecological systems / Conservation biology
Life sciences / Evolutionary biology /
Life sciences / Biodiversity and systematics /
Life sciences / Genetics / Population Genetics
Life sciences / Ecology and environmental science /

Awards 4

日本進化学会学会賞
毎日出版文化賞
日本古生物学会学術賞
日本古生物学会論文賞

Papers 180

Chromosome-Level Genome Assembly of the Asian Tramp Snail Bradybaena similaris (Stylommatophora: Camaenidae). International-journal Peer-reviewed

Yasuto Ishii, Atsushi Toyoda, Alec Lewis, Angus Davison, Osamu Miura, Kazuki Kimura, Satoshi Chiba

Genome biology and evolution　17　(5)　2025/04/30

DOI： 10.1093/gbe/evaf070 　

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While terrestrial land snails have long been used for evolutionary research, a lack of high-quality genomic resources has impeded recent progress. Bradybaena snails in particular have numerous intriguing traits that make them a good model for studying evolution, including shell pattern polymorphism and convergent evolution. They are also introduced and invasive across the world. In this study, we present a chromosome-level genome assembly of the Asian tramp snail Bradybaena similaris, utilizing 88-fold Illumina short-read sequences, 125-fold Nanopore long-read sequences, 63-fold PacBio HiFi sequences, and 47-fold Hi-C sequences. The assembled genome of 2.18 Gb is anchored to 28 chromosomes and exhibits high completeness (single copy, 91.7%; duplicates, 7.1%) and contiguity (N50 of 75.6 Mb). Additionally, we also obtained a high-quality transcriptome for annotation. This resource represents the first chromosome-level assembly for snails in the superfamily Helicoidea, which includes more than 5,000 species of terrestrial snails, and will facilitate genomic study in Bradybaena and, more broadly, in the superfamily Helicoidea.
Investigation of introgressive hybridization in endangered Sinohyriopsis mussels (Mollusca: Unionidae) using genome-wide data in Japan International-journal Peer-reviewed

Yasuto Ishii, Youdai Kawamoto, Akihisa Shirai, Takumi Saito, Daishi Yamazaki, Bin Ye, Shun Ito, Takaki Kondo, Takahiro Hirano, Satoshi Chiba, Isao Sano

Conservation Genetics　2024/11/23
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s10592-024-01657-z 　

ISSN： 1566-0621

eISSN： 1572-9737

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Abstract Anthropogenic hybridization is a global phenomenon and a major concern in conservation biology. Sinohyriopsis schlegelii (Mollusca: Bivalvia: Unionidae), native to Lake Biwa in Japan, is considered endangered because of its hybridization with an introduced Chinese species, S. cumingii. Although previous research suggested hybridization among Sinohyriopsis mussels, the research has failed to (1) evaluate the prevalence of hybrids, (2) predict the genetic consequences for populations containing hybrids, and (3) genetically assess a population devoid of hybrids. This study aimed to fill the knowledge gaps. We collected samples from all persistent populations in Lake Biwa, Lake Kasumigaura, and Lake Anenuma (the latter two populations were introduced from Lake Biwa) and analyzed genome-wide single nucleotide polymorphisms (SNPs) data. Our findings demonstrate that hybrids are prevalent in Lake Biwa and Lake Kasumigaura but absent in Lake Anenuma. The proportion of S. cumingii ancestry increased over the past 20 years, indicating that the genetic material of S. schlegelii may diminish further in the future. Moreover, the S. schlegelii population in Lake Anenuma shared genetic similarities with the pre-hybridization population of Lake Biwa. Although the Lake Anenuma population exhibited lower genetic diversity, no signs of inbreeding were observed. Overall, the Lake Anenuma population remains the only genetically pure S. schlegelii population, but its low genetic diversity indicates a reduced adaptive potential to environmental changes. This study provides valuable insights into the current genetic status of S. schlegelii, ultimately informing conservation efforts for this critically endangered species.
The population structure and demography of an intertidal gastropod Lunella correensis around the Japanese Archipelago affected by past environmental change International-journal Peer-reviewed

Osamu Kagawa, Shun K. Hirota, Takahiro Hirano, Kazuki Kimura, Genki Kobayashi, Yoshihisa Suyama, Satoshi Chiba, Daishi Yamazaki

Marine Biology　171　(9)　2024/08/13
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s00227-024-04497-0 　

ISSN： 0025-3162

eISSN： 1432-1793
Hidden invasiveness of non-native Schlegel's Japanese gecko (Reptilia: Squamata: Gekkonidae) and three-way competition among natives and non-natives in Japan. International-journal Peer-reviewed

Minoru Chiba, Satoshi Chiba

Molecular Ecology　e17420　2024/06/04

DOI： 10.1111/mec.17420 　

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In this study, we investigated the invasiveness of Gekko japonicus, a prevalent gecko species in Japan and an ancient non-native species, focusing on its competition with both the undescribed endemic Gekko species (referred to as Nishiyamori in Japanese) and G. hokouensis. These species are co-distributed with G. japonicus, leading us to hypothesize that G. japonicus was invasive upon its initial introduction. We employed niche analysis and population genetics through ddRAD-seq to assess the historical invasiveness of G. japonicus by comparing regions with and without interspecies competition. Our niche analysis across the Goto Islands, Hiradojima Island (colonized by G. japonicus) and the Koshikishima Islands (not colonized by G. japonicus) indicated that endemic Gekko sp. alter their microhabitat usage in response to invasions by other gecko species, despite having similar suitable habitats and microhabitat preferences. Population genetic analysis revealed significant population declines in Gekko sp. within areas of introduced competition, in contrast to stable populations in areas without such competition. These findings suggest a tripartite competitive relationship among the gecko species, with G. japonicus and G. hokouensis invasions restricting the distribution of the endemic Gekko sp. Consequently, G. japonicus may have historically acted as an invasive species. Acknowledging the historical dynamics of current biodiversity is crucial for addressing complex ecological issues and making informed conservation decisions.
Southernmost record of an epibiotic alga Pseudocladophora conchopheria (Sakai) Boedeker & Leliaert (Cladophorales, Ulvophyceae) with insights into the geographical dispersal and host utilization Peer-reviewed

Osamu Kagawa, Do Van Tu, Takeaki Hanyuda, Satoshi Chiba, Daishi Yamazaki

Marine Biodiversity　54　(3)　2024/06

DOI： 10.1007/s12526-024-01437-5 　

ISSN： 1867-1616

eISSN： 1867-1624
Secondary contact of two cryptic Hokou gecko groups in the Izu Islands, Japan Peer-reviewed

Minoru Chiba, Daishi Yamazaki, Shun Ito, Osamu Kagawa, Satoshi Chiba

Mitochondrial DNA Part A　2024/01/30

DOI： 10.1080/24701394.2024.2310278 　
Phylogenetic analysis of Chinese Enidae: Inference from genome-wide analyses and morphological studies on three selected genera Peer-reviewed

Bin Ye, Takahiro Hirano, Jun-Feng Xia, Yuta Morii, Min Wu, Satoshi Chiba

Zoological Research: Diversity and Conservation　1　(4)　247-261　2024
Publisher: Zoological Research
DOI： 10.24272/j.issn.2097-3772.2024.007 　

ISSN： 2097-3772

eISSN： 1005-0388
Host preference of a symbiotic flatworm and its response to conspecific and host mucus Peer-reviewed

Wakana Sakata, Masanori Tatani, Satoshi Chiba, Osamu Kagawa

Journal of Ethology　42　(1)　53-59　2023/12/23
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s10164-023-00802-4 　

ISSN： 0289-0771

eISSN： 1439-5444
Overcoming the congenitally disadvantageous mutation through adaptation to environmental UV exposure in land snails Peer-reviewed

Shun Ito, Satoshi Chiba, Junji Konuma

Biology Letters　19　(11)　2023/11/22
Publisher: The Royal Society
DOI： 10.1098/rsbl.2023.0356 　

eISSN： 1744-957X

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Congenital fitness-disadvantageous mutations are not maintained in the population; they are purged from the population through processes such as purifying selection. However, these mutations could persist in the population as polymorphisms when it is advantageous for the individuals carrying them in adapting to a specific external environment. We tested this hypothesis using the dimorphic land snail Euhadra peliomphala simodae in Japan; these snails have dark or bright coloured shells. The survival rate of dark snails at hatching was lower than that of the bright ones, as observed in the F1 progenies produced through crossing. Dark snails have a congenital fitness-disadvantageous mutation; however, they also have protection against ultraviolet radiation. They have a higher survival rate than the bright snails in a UV environment, as observed using the UV exposure experiments and UV transmittance measurements. This is a good example of a congenitally disadvantageous mutation that is advantageous for adapting to the external environment. These results explain the maintenance of polymorphism and highlight the genotypic and phenotypic diversity in the wild population.
Community composition and diversity of land snails along an elevation gradient in the World Natural Heritage Site, Yakushima Island. Peer-reviewed

Osamu Kagawa, Yasuto Ishii, Koji Fujimoto, Kazuki Kimura, Satoshi Chiba, Shun Ito

Global Ecology and Conservation　e02746-e02746　2023/11
Publisher: Elsevier BV
DOI： 10.1016/j.gecco.2023.e02746 　

ISSN： 2351-9894
Host-Shift Speciation Proceeded with Gene Flow in Algae Covering Shells Peer-reviewed

Osamu Kagawa, Shun K. Hirota, Takumi Saito, Shota Uchida, Hiroaki Watanabe, Ryusuke Miyazoe, Takanobu Yamaguchi, Taiki Matsuno, Kouta Araki, Hinata Wakasugi, Sayaka Suzuki, Genki Kobayashi, Hikaru Miyazaki, Yoshihisa Suyama, Takeaki Hanyuda, Satoshi Chiba

The American Naturalist　202　(5)　721-732　2023/11/01
Publisher: University of Chicago Press
DOI： 10.1086/726221 　

ISSN： 0003-0147

eISSN： 1537-5323
Did Captain Beechey see a living Mandarina luhuana, an extinct land snail species? Peer-reviewed

Satoshi Chiba

Journal of Molluscan Studies　89　(4)　2023/10/03
Publisher: Oxford University Press (OUP)
DOI： 10.1093/mollus/eyad018 　

ISSN： 0260-1230

eISSN： 1464-3766

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ABSTRACT Knowledge about prehuman biotas and the impact of early human contact, particularly on land snails inhabiting oceanic islands, is still poor. One specific example of interest is Mandarina luhuana, which was first collected from the Chichijima Islands of the Ogasawara Archipelago in 1827 during Captain Frederick William Beechey's expedition. The initial description of M. luhuana included an image of a shell with dark brown pigmentation, which contrasts with current understanding, with all known specimens being considered to lack dark colouration. Traditionally, it is believed that M. luhuana represents a fossil species that became extinct on the island before human arrival. However, I propose that the specimen collected for the original description was either recently dead or still alive at the time of collection. Furthermore, I hypothesize that M. luhuana faced extinction after human arrival on Ogasawara, which began during the 17th century. To test this hypothesis, I used accelerator mass spectrometry dating to determine the extinction dates of subfossil samples of M. luhuana. The results of this study suggest that M. luhuana became extinct after the 17th century, with the species having possibly survived until the early 19th century. It is likely that the extinction of M. luhuana occurred shortly after human arrival in the islands. These findings underscore the need for further research to understand the impact of human arrival on island ecosystems and to uncover the original diversity of land snail faunas on islands.
What makes the diverse flight of birds possible? Phylogenetic comparative analysis of avian alula morphology Peer-reviewed

Masanori Tatani, Takeshi Yamasaki, Hiroto Tanaka, Toshiyuki Nakata, Satoshi Chiba

Biological Journal of the Linnean Society　2023/09/13
Publisher: Oxford University Press (OUP)
DOI： 10.1093/biolinnean/blad085 　

ISSN： 0024-4066

eISSN： 1095-8312

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Abstract Studies on the evolution of avian flight have failed to clarify why wing shape is weakly correlated with flight styles and phylogenetically constrained. Birds seem to have achieved their diverse flight styles owing to changes in the shapes of localized parts of the wing, despite a highly conserved wing outline. The alula, which stems from the first digit of the wing, is a part of the wing that might have enabled various flight styles to develop. To test this hypothesis, we measured alula length and width using museum specimens of 187 species from 21 orders of birds and used a phylogenetic comparative method to investigate the relationship between alula morphology and flight style, body mass, habitat and migratory distance. We found that: (1) phylogenetic signals were weak for the alula width and aspect ratio but moderate for length; (2) alula morphology exhibited an allometric relationship with body mass; and (3) fewer flapping birds had large alulae. Alula morphology might have evolved in response to changes in body mass and flight styles. Variations in the shape of localized wing parts, such as the alula, which modifies airflow around a wing, might be key to the evolution of the diverse flight styles of birds.
First Records of Introduced Planorbella duryi (Wetherby, 1879) (Gastropoda: Hygrophila: Planorbidae) in Japan Peer-reviewed

Takumi Saito, Shota Uchida, Satoshi Chiba

American Malacological Bulletin　40　(1)　2023/08/17
Publisher: American Malacological Society
DOI： 10.4003/006.040.0101 　

ISSN： 0740-2783
Reconsidering invasion history of common land snails in Japan through genome-wide analyses Peer-reviewed

Takahiro Hirano, Daishi Yamazaki, Shun Ito, Mitsuhiko P. Sato, Ayumi Matsuo, Takumi Saito, Hirotaka Nishi, Bin Ye, Zhengzhong Dong, Do Van Tu, Aileen Tan Shau-Hwai, Yoshihisa Suyama, Satoshi Chiba

Biological Invasions　2023/08/03
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s10530-023-03123-2 　

ISSN： 1387-3547

eISSN： 1573-1464
Direct evidence for intercontinental dispersal of a snail via a bird Peer-reviewed

Takumi Saito, Masanori Tatani, Yoshiya Odaya, Satoshi Chiba

Ecography　2023/07/10
Publisher: Wiley
DOI： 10.1111/ecog.06771 　

ISSN： 0906-7590

eISSN： 1600-0587
Evolutionary history of inshore oceanic island land snails diversified in shell colour Peer-reviewed

Shun Ito, Satoshi Chiba, Junji Konuma

Journal of Biogeography　2023/03/28
Publisher: Wiley
DOI： 10.1111/jbi.14601 　

ISSN： 0305-0270

eISSN： 1365-2699
Phylogenomic analyses reveal incongruences between divergence times and fossil records of freshwater snails in East Asia Peer-reviewed

Takahiro Hirano, Takumi Saito, Shun Ito, Bin Ye, T. Mason Linscott, Do Van Tu, Zhengzhong Dong, Satoshi Chiba

Molecular Phylogenetics and Evolution　107728-107728　2023/02
Publisher: Elsevier BV
DOI： 10.1016/j.ympev.2023.107728 　

ISSN： 1055-7903
Taxonomic insights and evolutionary history in East Asian terrestrial slugs of the genus Meghimatium Peer-reviewed

Shun Ito, Daishi Yamazaki, Yuichi Kameda, Osamu Kagawa, Bin Ye, Takumi Saito, Kazuki Kimura, Van Tu Do, Satoshi Chiba, Takahiro Hirano

Molecular Phylogenetics and Evolution　182　107730-107730　2023/02
Publisher: Elsevier BV
DOI： 10.1016/j.ympev.2023.107730 　

ISSN： 1055-7903
Molecular investigation on diversity of the land snail genus Aegista (Gastropoda, Camaenidae) in South Korea Peer-reviewed

Kazuki Kimura, Satoshi Chiba, Jae-Hong Pak

Biodiversity Data Journal　11　2023/01/31
Publisher: Pensoft Publishers
DOI： 10.3897/bdj.11.e96800 　

ISSN： 1314-2836

eISSN： 1314-2828

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Aegista Albers, 1850 is a large genus of the land snail family Camaenidae Pilsbry, 1895 and distributed in south, southeast and east Asian countries (from India and Nepal to Korea and Japan). Fourteen species and subspecies of Aegista are known from South Korea. They were described, based only on shell morphology during 1887–1943 and our knowledge on diversity of Korean Aegista has seldom been updated since then. In this study, we provide the report on the first molecular investigation of diversity of Aegista in South Korea, which unmasked some of overlooked diversity of this group.
The mutual history of Schlegel’s Japanese gecko (Reptilia: Squamata: Gekkonidae) and humans inscribed in genes and ancient literature Peer-reviewed

Minoru Chiba, Takahiro Hirano, Daishi Yamazaki, Bin Ye, Shun Ito, Osamu Kagawa, Komei Endo, Shu Nishida, Seiji Hara, Kenichiro Aratake, Satoshi Chiba

PNAS Nexus　1　(5)　2022/11/01
Publisher: Oxford University Press (OUP)
DOI： 10.1093/pnasnexus/pgac245 　

eISSN： 2752-6542

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Abstract Knowing how the present distribution of organisms was formed is an essential issue in evolutionary ecology. Recently, the distribution of organisms on Earth has been significantly changed by human-mediated dispersal due to globalization. Therefore, significant attention has been paid to such processes. However, although humankind has taken considerable time to achieve modernization, the impact of ancient human activity on ecosystems has not yet been thoroughly studied. We hypothesized that ancient urban development and transitions had a non-negligible effect on species distribution. Inferring the impact of past human activity on ecosystems from ancient literature and verifying that impact by genetic analysis and human history is an effective means of tackling this problem. As geckos, a popular neighbor of human dwellings, are good material for this model, we performed this combination approach using Schlegel’s Japanese gecko, Gekko japonicus. We show that G. japonicus migrated from China to the western Japanese archipelago before Christ. The gecko species dispersed itself from western to eastern the archipelago on a time scale of thousands of years. There are many synchronizations between the dispersal history of G. japonicus and the historical development of human society. It is suggested by such synchronizations that humans have influenced the distribution of G. japonicus many times throughout its dispersal history.
Even short‐distance dispersal over a barrier can affect genetic differentiation in Gyraulus , an island freshwater snail Peer-reviewed

Takumi Saito, Tetsuro Sasaki, Yoshihiro Tsunamoto, Shota Uchida, Kiyoshi Satake, Yoshihisa Suyama, Satoshi Chiba

Freshwater Biology　67　(11)　1971-1983　2022/11
Publisher: Wiley
DOI： 10.1111/fwb.13990 　

ISSN： 0046-5070

eISSN： 1365-2427
Genetic variation of Littorina horikawai; endemic to the western coast and the adjacent islands around Kyushu, Japan inferred by mtDNA analyses Peer-reviewed

Daishi Yamazaki, Tomoki Seo, Takahiro Hirano, Takumi Saito, Yuichi Kameda, Hiroshi Fukuda, Satoshi Chiba

Plankton and Benthos Research　17　(3)　271-276　2022/08/30
Publisher: The Plankton Society of Japan/The Japanese Association of Benthology
DOI： 10.3800/pbr.17.271 　

ISSN： 1880-8247

eISSN： 1882-627X
Characterization of polymorphic microsatellite markers for the Japanese endangered land snail Mandarina. International-journal Peer-reviewed

Shu Nishida, Kotaro Mimura, Hideaki Mori, Satoshi Chiba

BMC research notes　15　(1)　255-255　2022/07/16

DOI： 10.1186/s13104-022-06147-4 　

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OBJECTIVE: Mandarina is an endangered land snail genus of the oceanic Ogasawara archipelago. On Chichijima Island, the largest inhabited island in Ogasawara, this genus is almost extinct in the wild due to predation by invasive species. Although ex situ conservation programs started in 2010, genetic diversity and population structure remain unclear due to a lack of genetic markers with sufficient genetic variation. In this study, we designed polymorphic microsatellite markers of Mandarina to enable genetic analysis and to develop appropriate conservation plans. RESULTS: Twenty-three polymorphic microsatellite markers were identified from the genomic DNA of wild samples of Mandarina mandarina. We assessed the genetic diversity of each marker. In 16 markers, neither linkage disequilibrium nor deviation from Hardy-Weinberg equilibrium was detected. These 16 markers were tested for multiplex PCR using low-density DNA extracted non-lethally from captive samples of M. mandarina, M. chichijimana and M. suenoae. Of the 16 markers, 15, 12 and 9 were usable for multiplex PCR, respectively. Genetic analysis using these microsatellite loci will be an important resource for the conservation of Mandarina.
Resolving species-level diversity of Beringiana and Sinanodonta mussels (Bivalvia: Unionidae) in the Japanese archipelago using genome-wide data. International-journal Peer-reviewed

Isao Sano, Takumi Saito, Shun Ito, Bin Ye, Takeru Uechi, Tomoki Seo, Van Tu Do, Kazuki Kimura, Takahiro Hirano, Daishi Yamazaki, Akihisa Shirai, Takaki Kondo, Osamu Miura, Jun-Ichi Miyazaki, Satoshi Chiba

Molecular phylogenetics and evolution　107563-107563　2022/07/06

DOI： 10.1016/j.ympev.2022.107563 　

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Accurate species identification is of primary importance in ecology and evolutionary biology. For a long time, the unionid mussels Beringiana and Sinanodonta have puzzled researchers trying to unravel their diversity because of their poorly discernible morphologies. A recent study conducted species delineation of unionid mussels based on mitochondrial DNA variation, opening up a new avenue to grasp species diversity of the mussels. However, mtDNA-based classification may not align with species boundaries because mtDNA is prone to introgression and incomplete lineage sorting that cause discordance between species affiliation and gene phylogeny. In this study, we evaluated the validity of the mtDNA-based classification of unionid mussels Beringiana and Sinanodonta in Japan using mitochondrial sequence data, double digest restriction site-associated DNA library (ddRAD) sequencing, and morphological data. We found significant inconsistencies in the mitochondrial and nuclear DNA phylogenies, casting doubt on the reliability of the mtDNA-based classification in this group. In addition, nuclear DNA phylogeny revealed that there are at least two unionid lineages hidden in the mtDNA phylogeny. Although molecular dating technique indicates that Beringiana and Sinanodonta diverged more than 35 million years ago, their shell morphologies are often indistinguishable. Specifically, morphological analyses exhibited the parallel appearance of nearly identical ball-like shell forms in the two genera in Lake Biwa, which further complicates species identification and the morphological evolution of unionid mussels. Our study adds to a growing body of literature that accurate species identification of unionid mussels is difficult when using morphological characters alone. Although mtDNA-based classification is a simple and convenient way to classify unionid mussels, considerable caution is warranted for its application in ecological and evolutionary studies.
Uncovering overlooked diversity using molecular phylogenetic approach: A case of Japanese sphaeriid clams (Bivalvia: Sphaeriidae). International-journal Peer-reviewed

Takumi Saito, Koji Fujimoto, Shota Uchida, Daishi Yamazaki, Takahiro Hirano, Isao Sano, Bin Ye, Osamu Kagawa, Mohammad Shovon Shariar, Van Tu Do, Yuta Morii, Larisa Prozorova, Satoshi Chiba

Molecular phylogenetics and evolution　173　107508-107508　2022/05/14

DOI： 10.1016/j.ympev.2022.107508 　

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Revealing the species and lineage diversity of a taxon is important for many biological studies of wildlife. In recent decades, DNA-based approaches have been widely utilised to elucidate the diversity of taxa, especially those that are difficult to distinguish based on morphological traits. This study focused on freshwater clams (Sphaeriidae) in Japan, a biodiversity hotspot of freshwater molluscs. Molecular phylogenetic approaches, including divergence time estimation, species delimitation, rarefaction, and biogeographic area estimation, were used to reveal the nature of the species diversity and its formation process, which are largely unknown. Our delimitation and rarefaction analyses suggest that Japanese sphaeriid clams consist of at least 18 delimitated lineages. This lineage diversity is relatively high compared to other Japanese freshwater molluscs, and in addition, the majority of the Japanese lineage appears to have high endemicity despite the possibility of long-distance dispersal in sphaeriid clams. Our biogeographical analyses suggest that this diversity may be due to the combination of colonisation, during the period when Japan was connected to the continent, and the relatively recent dispersal. Our results highlight the overlooked biodiversity of Japan and provide a basis for further Japanese sphaeriid research, including conservation perspectives.
Species identification of introduced veronicellid slugs in Japan. International-journal Peer-reviewed

Takahiro Hirano, Osamu Kagawa, Masanori Fujimoto, Takumi Saito, Shota Uchida, Daishi Yamazaki, Shun Ito, Shovon Mohammad Shariar, Takuo Sawahata, Satoshi Chiba

PeerJ　10　e13197　2022/04/22

DOI： 10.7717/peerj.13197 　

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Reliable identification of species is important for protecting native ecosystems against the invasion of non-native species. DNA barcoding using molecular markers, such as the mitochondrial cytochrome oxidase subunit 1 (COI) gene, helps researchers distinguish species. In this study, we focused on introduced veronicellid slugs in the Ryukyu Islands and some greenhouses on mainland Japan. Some veronicellids are medium-to-high risk pest species for humans. Identifying veronicellid species by their external morphology is difficult and unreliable because there is substantial overlap between intraspecific variation and interspecific differentiation. Therefore, internal morphologies such as male genitalia have been the primary traits used to distinguish veronicellids. To identify introduced veronicellid slugs in Japan to the species level, we used morphological assessment of male genitalia and DNA barcoding of the standard COI gene fragment. We also conducted species-delimitation analyses based on the genetic data. The results showed that five evolutionarily significant units, corresponding to four nominal species inhabit the Ryukyu Islands, of which two species were also found in the greenhouses of mainland Japan, including the first record of Sarasinula plebeia in Japan. The presence of non-native slug species could increase the transmission of parasites in Japan.
Long-distance dispersal from island to island: colonisation of an oceanic island in the vicinity of the Asian continent by the land snail genus Karaftohelix (Gastropoda: Camaenidae) Peer-reviewed

Kazuki Kimura, Satoshi Chiba, Larisa Prozorova, Jae Hong Pak

Molluscan Research　42　(2)　168-174　2022/04/03
Publisher: Informa UK Limited
DOI： 10.1080/13235818.2022.2066454 　

ISSN： 1323-5818

eISSN： 1448-6067
High-throughput SNPs dataset reveal restricted population connectivity of marine gastropod within the narrow distribution range of peripheral oceanic islands. International-journal Peer-reviewed

Daishi Yamazaki, Shun Ito, Osamu Miura, Tetsuro Sasaki, Satoshi Chiba

Scientific reports　12　(1)　2119-2119　2022/02/08

DOI： 10.1038/s41598-022-05026-z 　

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Molecular studies based on the high resolution genetic markers help us to grasp the factor shaping the genetic structure of marine organisms. Ecological factors linking to life history traits have often explained the process of genetic structuring in open and connectable oceanic environments. Besides, population genetic divergence can be affected by fragmented habitat, oceanic current, and past geographical events. In the present study, we demonstrated the genetic differentiation of marine gastropod Monodonta sp. within a narrow range of peripheral oceanic islands, the Ogasawara Islands. Genetic analyses were performed not only with a mitochondrial DNA marker but also with a high-throughput SNPs dataset obtained by ddRAD-seq. The results of the mtDNA analyses did not show genetic divergence among populations, while the SNPs dataset detected population genetic differentiation. Population demographic analyses and gene flow estimation suggested that the genetic structure was formed by sea level fluctuation associated with the past climatic change and regulated by temporal oceanographic conditions. These findings provide important insights into population genetic patterns in open and connectable environments.
Sexual inactivation induced by the mucus that covers love-darts of a land snail: Sexual selection and evolution of allohormones in hermaphrodites. International-journal Peer-reviewed

Kaito Shibuya, Satoshi Chiba, Kazuki Kimura

The Journal of experimental biology　2022/02/03

DOI： 10.1242/jeb.238782 　

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The transfer of male accessory gland secretions is a well-investigated reproductive strategy for winning in sexual selection. An example of such a strategy is the conspicuous mating behaviour of simultaneously hermaphroditic land snails, the so-called shooting of love-darts, whereby a snail drives love-dart(s) into the body of its mating partner. It has been shown that a specific mucus, which coats the love-dart, is transferred into the partner's hemolymph and that it suppresses subsequent matings in the darted individual in Euhadra quaesita. However, how the mucus of the love-dart suppresses rematings remains unclear. In the present study, we tested the hypothesis that by injection of the dart mucus, love-dart shooters manipulate the physiology of a dart recipient and make the individual sexually inactive. In an experiment in which snails were provided opportunities to encounter a potential mating partner, we found that the latency period to achieve sexual arousal was longer in snails injected with the dart mucus than in snails of the control treatments. This finding indicates that the dart mucus delays sexual arousal in injected snails. This delay in arousal is a novel example of the effects of the mucus in simultaneously hermaphroditic land snails. The remating suppression effect of the dart mucus is likely to occur through sexual inactivation.
Patterns of diversification of the operculate land snail genus Cyclophorus (Caenogastropoda: Cyclophoridae) on the Ryukyu Islands, Japan. International-journal Peer-reviewed

Takahiro Hirano, Takumi Saito, Parm Viktor von Oheimb, Katharina C M von Oheimb, Tu Van Do, Daishi Yamazaki, Yuichi Kameda, Satoshi Chiba

Molecular phylogenetics and evolution　107407-107407　2022/01/11

DOI： 10.1016/j.ympev.2022.107407 　

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The Ryukyu Islands, an island chain in southwestern Japan, originated from land masses that separated from the Eurasian continent due to the formation of sea barriers about 1.55 million years ago. In this study, we investigated the phylogenetic relationships of the operculate land snail genus Cyclophorus (Caenogastropoda: Cyclophoridae) in the Ryukyu Archipelago and surrounding regions based on DNA sequence data. According to our results, all studied Cyclophorus specimens from Japan form a monophyletic group containing eight subclades. Six of these subclades were found only on the Ryukyu Islands. On most islands of the Ryukyu Archipelago, no more than one Cyclophorus subclade was recorded, which may be due to limited ecological niche space and competition. No subclade was found to occur on both sides of the Watase Line, a regional zoogeographical boundary. Divergence times were estimated based on a time-calibrated phylogeny. We found that multiple splits among the Japanese Cyclophorus subclades predate the emergence of major sea barriers in the Ryukyu Archipelago. Vicariance due to sea barrier formation, as assumed for many other taxa from the region, was thus likely not the main driver for subclade divergence in these snails. Instead, certain geographical features might have shaped the diversification of subclades prior to sea barrier formation. Given that Cyclophorus populations were also present on islands that have never been connected to other land masses, the snails must have colonized them via oversea dispersal. As not all nominal taxa corresponded to monophyletic groups, our molecular phylogenetic approach revealed that a taxonomic revision of the Japanese Cyclophorus fauna is necessary. The eight subclades may be regarded as potential species-level groups based on COI p-distances. A canonical discriminant analysis using shell morphological data revealed slight differences among the subclades.
Species identification and invasion pathways of an introduced snail Macrochlamys sp. in Japan Peer-reviewed

Kodai Kudo, Osamu Kagawa, Shun Ito, Shinichiro Wada, Hirotaka Nishi, Shovon Shariar, Daishi Yamazaki, Takahiro Hirano, Satoshi Chiba

BioInvasions Records　11　(4)　839-854　2022
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
DOI： 10.3391/bir.2022.11.4.03 　

eISSN： 2242-1300
Comparing the genetic diversity and population structure of sister marine snails having contrasting habitat specificity. International-journal Peer-reviewed

Daishi Yamazaki, Satoshi Chiba

Molecular biology reports　49　(1)　393-401　2022/01

DOI： 10.1007/s11033-021-06885-x 　

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BACKGROUND: To grasp the processes of spatial genetic structuring in open and connectable marine environments is the principal study goal in molecular biological studies. Comparative seascape genetics using multiple species are a powerful approach to understand the physical geographic and oceanographic effects on genetic variation. Besides, species-specific ecological traits such as dispersal abilities and habitat specificity are important factors for spatial genetic structuring. METHODS AND RESULTS: We focused on the sister marine snail species Tegula kusairo and T. xanthostigma around the Japanese mainland, which have contrasting habitat specificities for wave strength. Tegula kusairo only inhabits sheltered coastal environments, while T. xanthostigma is found mainly on wave-exposed rocky shores facing the open sea. We estimated their genetic diversity indices and levels of population differentiation based on mtDNA. We found that the genetic diversity of T. kusairo was lower than that of T. xanthostigma, while their level of population genetic differentiation was higher than that of T. xanthostigma. Namely, the species specific to weak wave environments had a higher level of population genetic differentiation than the species specific to strong wave action. CONCLUSION: Ecological traits linked not only to dispersal abilities but also to habitat specificity can influence genetic variation in a pair of closely related sister species distributed in the same seascape.
A comprehensive phylogeography of the widespread pond snail genus Radix revealed restricted colonization due to niche conservatism. International-journal Peer-reviewed

Takumi Saito, Takahiro Hirano, Bin Ye, Larisa Prozorova, Mohammad Shariar Shovon, Tu Van Do, Kazuki Kimura, Purevdorj Surenkhorloo, Yuichi Kameda, Yuta Morii, Hiroshi Fukuda, Satoshi Chiba

Ecology and evolution　11　(24)　18446-18459　2021/12

DOI： 10.1002/ece3.8434 　

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To clarify the effect of niche conservatism on evolutionary history, we focused on freshwater snails, which have different ecological and phylogenetic properties from previously tested taxa. We conducted a phylogenetic analysis using 750 lymnaeid individuals from 357 sites of eleven Radix species. Then, we estimated the ancestral distribution using the geographic coordinates and colonization routes. In addition, a statistical test of the colonization distances in the latitudinal and longitudinal directions was performed. We also conducted ecological niche modeling for two widely distributed species using climatic data. Ancestral geographic reconstruction estimated the origin of the genus to be around the Indian subcontinental region and showed that latitudinal immigration distances were shorter than longitudinal immigration distances in the diversification process. Ecological niche models suggested that the current distribution was restricted by climate, with annual mean temperature and precipitation of the driest month as particularly strong factors. Niche conservatism to the climate can affect the diversification of freshwater snails.
Shell colour diversification induced by ecological release: A shift in natural selection after a migration event. International-journal Peer-reviewed

Shun Ito, Takahiro Hirano, Satoshi Chiba, Junji Konuma

Ecology and evolution　11　(22)　15534-15544　2021/11

DOI： 10.1002/ece3.8080 　

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Ecological release is often attributed to the rapid adaptive diversification of phenotypic traits. However, it is not well understood how natural selection changes its strength and direction through the process of ecological release. Herein, we demonstrated how shell colour of the Japanese land snail Euhadra peliomphala simodae has diversified via a shift in natural selection due to ecological release after migration from the mainland to an island. This snail's shell colour diversified on the island due to disruptive selection after migration from the mainland. We used trail camera traps to identify the cause of natural selection on both the mainland and the island. We then conducted a mark-recapture experiment while collecting microhabitat use data. In total, we captured and marked around 1,700 snails on the mainland, some of which were preyed upon by an unknown predator. The trail camera traps showed that the predator is the large Japanese field mouse Apodemus speciosus, and the predatory frequency was higher on the mainland than on the island. However, this predation did not correlate with shell colour. Microhabitat use on the island was more extensive than on the mainland, with snails on the island using both ground and arboreal microhabitats. A Bayesian estimation showed that the stabilizing selection on shell colour came from factors other than predation. Our results suggest that the course of natural selection was modified due to ecological release after migration from the mainland, explaining one cause of the phenotypic diversification.
Molecular and morphological evidence for a unified, inclusive Sinotaia quadrata (Caenogastropoda: Viviparidae: Bellamyinae) Peer-reviewed

Bin Ye, Takahiro Hirano, Takumi Saito, Zheng zhong Dong, Van Tu Do, Satoshi Chiba

Journal of Molluscan Studies　87　(3)　2021/07/09
Publisher: Oxford University Press (OUP)
DOI： 10.1093/mollus/eyab013 　

ISSN： 0260-1230

eISSN： 1464-3766

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<title>ABSTRACT</title> The taxonomy of species in the caenogastropod genus Sinotaia (Viviparidae: Bellamyinae) has been a complex and controversial issue since the 19th century. Sinotaia quadrata, the type species of Sinotaia, comprises many named forms and transitions between them, and the taxonomic validity of some species similar to S. quadrata also requires clarification. To clarify relationships in this common and significant member of the freshwater benthos, we reconstructed a phylogeny for species related to S. quadrata based on the 16S rRNA and cytochrome c oxidase subunit I genes to test which classifications are robust using modern data and interpretation. We also compared the shell outline morphology of type material of most species in the genus Sinotaia from the original literature. The combination of phylogenetic and shape variance data suggests that seven currently recognized species of Sinotaia should be synonymized with S. quadrata. We used microsatellite markers and landmark-based geometric morphometric analysis to examine the genetic differentiation and shell shape variation of S. quadrata populations in both China and Japan. Genetic and shape variations were not congruent, suggesting that minor variations in shell shape do not indicate distinct Sinotaia species. Shell shape variation shows no clear separations and shows environmental plasticity. Using data on molecular phylogenetics, genetic diversity and shell morphology, we provide a more inclusive species concept for S. quadrata. This provides a basis to formally revise this taxon and the seven closely related nominal species that are widely distributed in China and East Asia.
Detection of Anolis carolinensis using drone images and a deep neural network: an effective tool for controlling invasive species Peer-reviewed

Tomoki Aota, Koh Ashizawa, Hideaki Mori, Mitsuhiko Toda, Satoshi Chiba

BIOLOGICAL INVASIONS　23　(5)　1321-1327　2021/03

DOI： 10.1007/s10530-020-02434-y 　

ISSN： 1387-3547

eISSN： 1573-1464
Hideaki Mori, Mayu Inada, Satoshi Chiba. Translocation of endangered Mandarina in the Ogasawara Islands. Invited

Hideaki Mori, Mayu Inada, Satoshi Chiba

Tentacle　29　36-37　2021/02
Comparative seascape genetics of co-distributed intertidal snails Monodonta spp. in the Japanese and Ryukyu archipelagoes Peer-reviewed

Daishi Yamazaki, Osamu Miura, Shota Uchida, Minoru Ikeda, Satoshi Chiba

MARINE ECOLOGY PROGRESS SERIES　657　135-146　2021/01

DOI： 10.3354/meps13553 　

ISSN： 0171-8630

eISSN： 1616-1599
Note on occurrence of the land slug family Rathouisiidae Heude, 1885 from South Korea and its DNA barcode Peer-reviewed

Kazuki Kimura, Takahiro Hirano, Satoshi Chiba, Jae-Hong Pak

Biodiversity Journal　11　(4)　1015-1019　2020/12/30
Publisher: Edizioni Danaus sas
DOI： 10.31396/biodiv.jour.2020.11.4.1015.1019 　

ISSN： 2039-0394

eISSN： 2039-0408
A new replacement name for Chlorostoma lischkei Pilsbry, 1889 (not of Tapparone-Canefri, 1874) (Vetigastropoda: Trochida: Tegulidae) Peer-reviewed

Daishi Yamazaki, Takahiro Hirano, Satoshi Chiba, Hiroshi Fukuda

Molluscan Research　40　(4)　1-18　2020/12/09
Publisher: Informa UK Limited
DOI： 10.1080/13235818.2020.1831716 　

ISSN： 1323-5818

eISSN： 1448-6067
Citizen science via social media revealed conditions of symbiosis between a marine gastropod and an epibiotic alga. International-journal Peer-reviewed

Osamu Kagawa, Shota Uchida, Daishi Yamazaki, Yumiko Osawa, Shun Ito, Satoshi Chiba

Scientific reports　10　(1)　19647-19647　2020/11/12

DOI： 10.1038/s41598-020-74946-5 　

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Environmental factors promote symbiosis, but its mechanism is not yet well understood. The alga Pseudocladophora conchopheria grows only on the shell of an intertidal gastropod Lunella correensis, and these species have a close symbiotic relationship which the alga reduces heat stress of the gastropod. In collaboration with general public, we investigated how environmental conditions alter the symbiotic interaction between the alga and the gastropod. Information about the habitats of each gastropod and images of shells was obtained from the Japanese and Korean coasts via social media. We constructed the hierarchical Bayesian model using the data. The results indicated that the proportion of shell area covered by P. conchopheria increased as the substrate size utilized by the gastropod increased. Meanwhile, temperature did not affect the proportion of P. conchopheria on the shell. These suggested that the alga provides no benefits for the gastropod on small substrates because gastropod can reduce the heat stress by diving into the small sediment. Further, the gastropod's cost incurred by growing the alga on the shell seems to be low as the algae can grow even in cooler places where no benefits of heat resistance for gastropods. Different environments can yield variable conditions in symbiosis.
First molecular examination of Vietnamese mudflat snails in the genus Naranjia Golding, Ponder & Byrne, 2007 (Gastropoda: Amphibolidae). International-journal Peer-reviewed

Takumi Saito, Larisa Prozorova, Ngo Xuan Quang, Satoshi Chiba

Scientific reports　10　(1)　18714-18714　2020/10/30

DOI： 10.1038/s41598-020-75200-8 　

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Maritime ecosystems in Vietnam such as mangroves and mud flats are characterized by high biodiversity. However, elements of its biodiversity remain unclear and highly threatened. In this context, the assessment of rare species is a starting point to develop effective strategies for the conservation of entire ecosystems. In this paper, we report upon cryptic amphibolid gastropods in Vietnamese mangrove forests from the Mekong Delta. The snail fauna in the mangrove forests was previously known from published literature and three museum specimens as three amphibolid species, 'Amphibola' burmana, A. quadrasi, Salinator fragilis and 'S.' quadrasi. We investigated the identities of such snails using molecular and morphological methods. The amphibolids found in this survey were identified to belong to the genus Naranjia, new for Vietnam fauna. In addition, our phylogenetic analyses suggested that the Vietnamese amphibolids were the same species as Naranjia sp. reported from Thailand, and the amphibolids have both genetic and morphological polymorphisms within the population. These findings add to the great biodiversity of Vietnamese mangrove forests and mudflats.
Ancient drainage networks mediated a large-scale genetic introgression in the East Asian freshwater snails Peer-reviewed

Osamu Miura, Misako Urabe, Hideaki Mori, Satoshi Chiba

Ecology and Evolution　10　(15)　8186-8196　2020/08/01

DOI： 10.1002/ece3.6523 　

eISSN： 2045-7758
The genetic structure of the marine flatwormStylochoplana pusilla(Rhabditophora: Polycladida) and its use of intertidal snails Peer-reviewed

Daishi Yamazaki, Tomoki Aota, Satoshi Chiba

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM　100　(5)　713-717　2020/08

DOI： 10.1017/S0025315420000570 　

ISSN： 0025-3154

eISSN： 1469-7769
Human-geographic effects on variations in the population genetics ofSinotaia quadrata(Gastropoda: Viviparidae) that historically migrated from continental East Asia to Japan Peer-reviewed

Bin Ye, Takumi Saito, Takahiro Hirano, Zhengzhong Dong, Van Tu Do, Satoshi Chiba

ECOLOGY AND EVOLUTION　10　(15)　8055-8072　2020/08

DOI： 10.1002/ece3.6456 　

ISSN： 2045-7758
Type materials of the species of the Planorbidae (Mollusca, Gastropoda, Hygrophila) described by Shuichi Mori Peer-reviewed

Takumi Saito, Satoshi Chiba, Hiroshi Fukuda

Molluscan Research　40　(2)　169-182　2020/04

DOI： 10.1080/13235818.2020.1724604 　

ISSN： 1323-5818
Conservation programmes for endemic land snails in the Ogasawara Islands: captive breeding and control of invasive species. Invited

Hideaki Mori, Mayu Inada, Satoshi Chiba

Tentacle　28　23-27　2020/02
Phylogenetic Position of the Japanese Land Slug Genus Granulilimax Minato, 1989 Based on Preliminary Analyses of Mitochondrial and Nuclear Genes Peer-reviewed

Kazuki Kimura, Isao Sano, Yuichi Kameda, Takumi Saito, Satoshi Chiba

American Malacological Bulletin　37　(2)　53-61　2020/01/23

DOI： 10.4003/006.037.0202 　

ISSN： 0740-2783
The first record of the introduced land snail Bradybaena similaris (Férussac, 1822) (Mollusca: Heterobranchia: Camaenidae) from Bangladesh Peer-reviewed

Takahiro Hirano, Takumi Saito, Shovon Mohammad Shariar, Rupamoy Tanchangya, Satoshi Chiba

BioInvasions Records　9　(4)　730-736　2020
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
DOI： 10.3391/bir.2020.9.4.07 　

eISSN： 2242-1300
Formin, an opinion Peer-reviewed

Angus Davison, Gary S. McDowell, Jennifer M. Holden, Harriet F. Johnson, Christopher M. Wade, Satoshi Chiba, Daniel J. Jackson, Michael Levin, Mark L. Blaxter

DEVELOPMENT　147　(1)　2020/01

DOI： 10.1242/dev.187427 　

ISSN： 0950-1991

eISSN： 1477-9129
Evolutionary history and diversity of unionoid mussels (Mollusca: Bivalvia) in the Japanese archipelago Peer-reviewed

Isao Sano, Takumi Saito, Jun Ichi Miyazaki, Akihisa Shirai, Takeru Uechi, Takaki Kondo, Satoshi Chiba

Plankton and Benthos Research　15　(2)　97-111　2020

DOI： 10.3800/pbr.15.97 　

ISSN： 1880-8247

eISSN： 1882-627X
Publisher Correction: Cretaceous amber fossils highlight the evolutionary history and morphological conservatism of land snails (Scientific Reports, (2019), 9, 1, (15886), 10.1038/s41598-019-51840-3)

Takahiro Hirano, Kaito Asato, Shûhei Yamamoto, Yui Takahashi, Satoshi Chiba

Scientific Reports　9　(1)　2019/12/01
Publisher: Nature Research
DOI： 10.1038/s41598-019-55311-7 　

ISSN： 2045-2322
Role of ancient lakes in genetic and phenotypic diversification of freshwater snails Peer-reviewed

Takahiro Hirano, Takumi Saito, Yoshihiro Tsunamoto, Joichiro Koseki, Larisa Prozorova, Van Tu Do, Keiji Matsuoka, Katsuki Nakai, Yoshihisa Suyama, Satoshi Chiba

Molecular Ecology　28　(23)　5032-5051　2019/12/01

DOI： 10.1111/mec.15272 　

ISSN： 0962-1083

eISSN： 1365-294X
Enigmatic incongruence between mtDNA and nDNA revealed by multi-locus phylogenomic analyses in freshwater snails Peer-reviewed

Takahiro Hirano, Takumi Saito, Yoshihiro Tsunamoto, Joichiro Koseki, Bin Ye, Van Tu Do, Osamu Miura, Yoshihisa Suyama, Satoshi Chiba

Scientific Reports　9　(1)　2019/12/01

DOI： 10.1038/s41598-019-42682-0 　

eISSN： 2045-2322
Prevalence and species richness of trematode parasites only partially recovers after the 2011 Tohoku, Japan, earthquake tsunami Peer-reviewed

Osamu Miura, Gen Kanaya, Shizuko Nakai, Hajime Itoh, Satoshi Chiba

INTERNATIONAL JOURNAL FOR PARASITOLOGY　49　(13-14)　1023-1028　2019/12

DOI： 10.1016/j.ijpara.2019.07.006 　

ISSN： 0020-7519

eISSN： 1879-0135
Cretaceous amber fossils highlight the evolutionary history and morphological conservatism of land snails. International-journal Peer-reviewed

Takahiro Hirano, Kaito Asato, Shûhei Yamamoto, Yui Takahashi, Satoshi Chiba

Scientific reports　9　(1)　15886-15886　2019/11/04

DOI： 10.1038/s41598-019-51840-3 　

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Other than hard bones and shells, it is rare for soft tissues to fossilize, but occasionally they are well-preserved in amber. Here, we focus on both modern and fossilized species of the land snail superfamily Cyclophoroidea. Phylogenetic relationships within the Cyclophoroidea were previously studied using extant species, but timing of divergence within the group remains unclear. In addition, it is difficult to observe morphological traits such as the chitinous operculum and periostracum of fossil snails due to their poor preservation potential. Here we describe nine species including a new genus and five new species of well-preserved fossil cyclophoroideans from the mid-Cretaceous Burmese amber. These fossils include not only the shell, but also the chitinous operculum and periostracum, soft body, and excrements. We present the first estimation of divergence time among cyclophoroidean families using fossil records and molecular data, suggesting extreme morphological conservatism of the Cyclophoroidea for nearly 100 million years.
Phenotypic divergence in viviparid snails in a recently converted freshwater lagoon Peer-reviewed

Kagawa O, Saito T, Uchida S, Chiba S

Plankton and Benthos Research　14　(3)　189-196　2019/08
Publisher: The Plankton Society of Japan/The Japanese Association of Benthology
DOI： 10.3800/pbr.14.189 　

ISSN： 1880-8247

eISSN： 1882-627X
Divergence before and after the isolation of islands: Phylogeography of the Bradybaena land snails on the Ryukyu Islands of Japan Peer-reviewed

Hirano T, Kameda Y, Saito T, Chiba S

Journal of Biogeography　46　(6)　1197-1213　2019/06

DOI： 10.1111/jbi.13575 　

ISSN： 0305-0270

eISSN： 1365-2699
Insights into the Evolution of Shells and Love Darts of Land Snails Revealed from Their Matrix Proteins. International-journal Peer-reviewed

Keisuke Shimizu, Kazuki Kimura, Yukinobu Isowa, Kenshiro Oshima, Makiko Ishikawa, Hiroyuki Kagi, Keiji Kito, Masahira Hattori, Satoshi Chiba, Kazuyoshi Endo

Genome biology and evolution　11　(2)　380-397　2019/02/01

DOI： 10.1093/gbe/evy242 　

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Over the past decade, many skeletal matrix proteins that are possibly related to calcification have been reported in various calcifying animals. Molluscs are among the most diverse calcifying animals and some gastropods have adapted to terrestrial ecological niches. Although many shell matrix proteins (SMPs) have already been reported in molluscs, most reports have focused on marine molluscs, and the SMPs of terrestrial snails remain unclear. In addition, some terrestrial stylommatophoran snails have evolved an additional unique calcified character, called a "love dart," used for mating behavior. We identified 54 SMPs in the terrestrial snail Euhadra quaesita, and found that they contain specific domains that are widely conserved in molluscan SMPs. However, our results also suggest that some of them possibly have evolved independently by domain shuffling, domain recruitment, or gene co-option. We then identified four dart matrix proteins, and found that two of them are the same proteins as those identified as SMPs. Our results suggest that some dart matrix proteins possibly have evolved by independent gene co-option from SMPs during dart evolution events. These results provide a new perspective on the evolution of SMPs and "love darts" in land snails.
First record of the land gastropod genus Otesiopsis from South Korea (Helicarionoidea Bourguignat, 1877). International-journal Peer-reviewed

Kazuki Kimura, Satoshi Chiba, Jae-Hong Pak

Biodiversity data journal　7　e46984　2019

DOI： 10.3897/BDJ.7.e46984 　

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Otesiopsis Habe, 1946 is a land snail genus, which is known so far from Japan and Taiwan. Individuals of this genus were collected from Gageodo Island, South Korea. This is the first record of the genus Otesiopsis from this country. The individuals from Gageodo Island appear to be a new species because of their unique shell morphologies, while the details of their anatomy are still lacking. Further studies are encouraged to investigate the taxonomic and conservation status of the genus Otesiopsis in South Korea.
Phenotypic determinism and contingency in the evolution of hypothetical tree-like organisms. International-journal Peer-reviewed

Tomonobu Nonoyama, Satoshi Chiba

PloS one　14　(10)　e0211671　2019

DOI： 10.1371/journal.pone.0211671 　

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Whether evolutionary history is mostly contingent or deterministic has been given much focus in the field of evolutionary biology. Studies addressing this issue have been conducted theoretically, based on models, and experimentally, based on microcosms. It has been argued that the shape of the adaptive landscape and mutation rate are major determinants of replicated phenotypic evolution. In the present study, to incorporate the effects of phenotypic plasticity, we constructed a model using tree-like organisms. In this model, the basic rules used to develop trees are genetically determined, but tree shape (described by the number and aspect ratio of the branches) is determined by both genetic components and plasticity. The results of the simulation show that the tree shapes become more deterministic under higher mutation rates. However, the tree shape became most contingent and diverse at the lower mutation rate. In this situation, the variances of the genetically determinant characters were low, but the variance of the tree shape is rather high, suggesting that phenotypic plasticity results in this contingency and diversity of tree shape. The present findings suggest that plasticity cannot be ignored as a factor that increases contingency and diversity of evolutionary outcomes.
An updated checklist of land and freshwater gastropod fauna on Ulleung Island, South Korea Peer-reviewed

Kimura K, Saito T, Chiba S, Pak JH

American Malacological Bulletin　37　(.)　35-39　2019
First record of the slug species Semperula wallacei (Gastropoda: Eupulmonata: Veronicellidae) in Japan. Peer-reviewed

Hirano, T, Yamazaki, D, Uchida, S, Saito, T, Chiba, S

BioInvasions Records　7　(2)　258-265　2019
Recent lake expansion triggered the adaptive radiation of freshwater snails in ancient Lake Biwa. Peer-reviewed

Miura, O, Urabe, M, Nishimura, T, Nakai, K, Chiba, S

Evolution Letters　2　2018/11

DOI： 10.1002/evl3.92 　
Snails wearing green heatproof suits: the benefits of algae growing on the shells of a intertidal gastropod. Peer-reviewed

Kagawa, O, Chiba, S

Journal of Zoology　306　(4)　256-263　2018/11
Publisher: Wiley
DOI： 10.1111/jzo.12641 　

ISSN： 0952-8369

eISSN： 1469-7998
Relationship between contrasting morphotypes and the phylogeny of the marine gastropoda genus Tegula in East Asia. Peer-reviewed

Yamazaki, D, Hirano, T, Uchida, S, Miura, O, Chiba, S

Journal of Molluscan Studies　84　2018/11

DOI： 10.1093/mollus/eyy055 　
Phylogeography of freshwater planorbid snails reveals diversification patterns in Eurasian continental islands. Peer-reviewed

Saito, T, Hirano, T, Prozorova, L. A, Do Van Tu, Sulikowska-Drozd, A, Sitnikova, T, Surenkhorloo, P, Yamazaki, D, Morii, Y, Kameda, Y, Fukuda, H, Chiba, S

BMC Evolutionary Biology　18　164　2018/10

DOI： 10.1186/s12862 　
Endangered freshwater limpets in Japan are actually alien invasive species Peer-reviewed

Takumi Saito, Van Tu Do, Larisa Prozorova, Takahiro Hirano, Hiroshi Fukuda, Satoshi Chiba

Conservation Genetics　19　1-12　2018/05/12
Publisher: Springer Netherlands
DOI： 10.1007/s10592-018-1068-5 　

ISSN： 1572-9737 1566-0621
Genetic and morphometric rediscovery of an extinct land snail on oceanic islands Peer-reviewed

Takahiro Hirano, Shinichiro Wada, Hideaki Mori, Shota Uchida, Takumi Saito, Satoshi Chiba

Journal of Molluscan Studies　84　(2)　148-156　2018/05/01
Publisher: Oxford University Press
DOI： 10.1093/mollus/eyy003 　

ISSN： 1464-3766 0260-1230
Molecular phylogeny of glacial relict species: a case of freshwater Valvatidae molluscs (Mollusca: Gastropoda) in North and East Asia. Peer-reviewed

Saito, T, Prozorova, L, Sitnikova, T, Surenkhorloo, P, Hirano, T, Morii,Y, Chiba, S

Hydrobiologia　818　105-118　2018/03
A phylogenetic overview of the genus Vertigo O. F. Müller, 1773 (Gastropoda: Pulmonata: Pupillidae: Vertigininae) Peer-reviewed

Nekola, J.C, Chiba, S, Coles, B.F, Drost, C.A, Proschwitz, T, Horsák, M

Malacologia　62　21-161　2018/01
Single-gene speciation: Mating and gene flow between mirror-image snails Peer-reviewed

Richards, P.M, Morii, Y, Kimura, K, Hirano, T, Chiba, S, Davison, A

Evolution Letters　1　(6)　282-291　2017/11
Publisher: Wiley
DOI： 10.1002/evl3.31 　

ISSN： 2056-3744
Genetic diversification of intertidal gastropoda in an archipelago: the effects of islands, oceanic currents, and ecology Peer-reviewed

Daishi Yamazaki, Osamu Miura, Minoru Ikeda, Akihiro Kijima, Do Van Tu, Tetsuro Sasaki, Satoshi Chiba

MARINE BIOLOGY　164　(9)　2017/09

DOI： 10.1007/s00227-017-3207-9 　

ISSN： 0025-3162

eISSN： 1432-1793
Declining soil Crustacea in a World Heritage Site caused by land nemertean Peer-reviewed

Shotaro Shinobe, Shota Uchida, Hideaki Mori, Isamu Okochi, Satoshi Chiba

SCIENTIFIC REPORTS　7　12400　2017/09

DOI： 10.1038/s41598-017-12653-4 　

ISSN： 2045-2322
Microsatellite records for volume 9, issue 1 Peer-reviewed

Ana Castillo-Paez, Axayacatl Rocha-Olivares, Celia Isabel Bisbal-Pardo, Dongfa Zhu, Dongmei Zhu, Hajime Itoh, Hiroaki Fukumori, Joichiro Koseki, John Carlos Garza, Jotaro Urabe, Yefeng Lv, Masayuki Maki, Miguel Angel del Rio-Portilla, Satoshi Chiba, Wataru Makino, Weimin Wang, Wen Song, Xuejun Chai, Yasunori Kano, Yuebin Wang, Zehui Hu

CONSERVATION GENETICS RESOURCES　9　(1)　165-171　2017/03

DOI： 10.1007/s12686-017-0689-1 　

ISSN： 1877-7252

eISSN： 1877-7260
Ecological and genetic impact of the 2011 Tohoku Earthquake Tsunami on intertidal mud snails Peer-reviewed

Osamu Miura, Gen Kanaya, Shizuko Nakai, Hajime Itoh, Satoshi Chiba, Wataru Makino, Tomohiro Nishimura, Shigeaki Kojima, Jotaro Urabe

SCIENTIFIC REPORTS　7　44375　2017/03

DOI： 10.1038/srep44375 　

ISSN： 2045-2322
Effects of an invasive ant on land snails in the Ogasawara Islands Peer-reviewed

Shota Uchida, Hideaki Mori, Tsubasa Kojima, Kayo Hayama, Yuko Sakairi, Satoshi Chiba

CONSERVATION BIOLOGY　30　(6)　1330-1337　2016/12

DOI： 10.1111/cobi.12724 　

ISSN： 0888-8892

eISSN： 1523-1739
Parallel evolution of passive and active defence in land snails Peer-reviewed

Yuta Morii, Larisa Prozorova, Satoshi Chiba

SCIENTIFIC REPORTS　6　35600　2016/11

DOI： 10.1038/srep35600 　

ISSN： 2045-2322
Dynamics of evolutionary radiation under ecological neutrality Peer-reviewed

Takanori Mizuno Suzuki, Satoshi Chiba

JOURNAL OF THEORETICAL BIOLOGY　406　1-7　2016/10

DOI： 10.1016/j.jtbi.2016.06.006 　

ISSN： 0022-5193

eISSN： 1095-8541
Effect of injection of love-dart mucus on physical vigour in land snails: can remating suppression be explained by physical damage? Peer-reviewed

K. Kimura, K. Shibuya, S. Chiba

ETHOLOGY ECOLOGY & EVOLUTION　28　(3)　284-294　2016/07

DOI： 10.1080/03949370.2015.1037359 　

ISSN： 0394-9370

eISSN： 1828-7131
Formin Is Associated with Left-Right Asymmetry in the Pond Snail and the Frog Peer-reviewed

Angus Davison, Gary S. McDowell, Jennifer M. Holden, Harriet F. Johnson, Georgios D. Koutsovoulos, M. Maureen Liu, Paco Hulpiau, Frans Van Roy, Christopher M. Wade, Ruby Banerjee, Fengtang Yang, Satoshi Chiba, John W. Davey, Daniel J. Jackson, Michael Levin, Mark L. Blaxter

CURRENT BIOLOGY　26　(5)　654-660　2016/03

DOI： 10.1016/j.cub.2015.12.071 　

ISSN： 0960-9822

eISSN： 1879-0445
Evolution and Extinction of Land Snails on Oceanic Islands Peer-reviewed

Satoshi Chiba, Robert H. Cowie

ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS, VOL 47　47　123-141　2016

DOI： 10.1146/annurev-ecolsys-112414-054331 　

ISSN： 1543-592X
Characterization of 22 polymorphic microsatellite loci for Cryptoblepharus nigropunctatus. Peer-reviewed

Koseki J, Makino W, Maki M, Urabe J, Chiba S

Conservation Genetics Resources　9　(1)　2016
Phylogeny of freshwater viviparid snails in Japan Peer-reviewed

Takahiro Hirano, Takumi Saito, Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　81　435-441　2015/11

DOI： 10.1093/mollus/eyv019 　

ISSN： 0260-1230

eISSN： 1464-3766
Assortative mating with respect to size in the simultaneously hermaphroditic land snail Bradybaena pellucida Peer-reviewed

Kazuki Kimura, Takahiro Hirano, Satoshi Chiba

ACTA ETHOLOGICA　18　(3)　265-268　2015/10

DOI： 10.1007/s10211-014-0211-7 　

ISSN： 0873-9749

eISSN： 1437-9546
Evidence of introgressive hybridization between the morphologically divergent land snails Ainohelix and Ezohelix Peer-reviewed

Yuta Morii, Jun Yokoyama, Masakado Kawata, Angus Davison, Satoshi Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　115　(1)　77-95　2015/05

DOI： 10.1111/bij.12466 　

ISSN： 0024-4066

eISSN： 1095-8312
Phytophagous Insects on Native and Non-Native Host Plants: Combining the Community Approach and the Biogeographical Approach Peer-reviewed

Kim Meijer, Hidde Zemel, Satoshi Chiba, Christian Smit, Leo W. Beukeboom, Menno Schilthuizen

PLOS ONE　10　(5)　2015/05

DOI： 10.1371/journal.pone.0125607 　

ISSN： 1932-6203
The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity Peer-reviewed

Kazuki Kimura, Satoshi Chiba

PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES　282　(1804)　2015/04

DOI： 10.1098/rspb.2014.3063 　

ISSN： 0962-8452

eISSN： 1471-2954
A new species of Aegista (Gastropoda: Eupulmonata: Camaenidae) from the Chugoku District, western Honshu, Japan Peer-reviewed

Takahiro Hirano, Yuichi Kameda, Satoshi Chiba

MOLLUSCAN RESEARCH　35　(2)　128-138　2015/04

DOI： 10.1080/13235818.2015.1023175 　

ISSN： 1323-5818

eISSN： 1448-6067
Divergence in the shell morphology of the land snail genus Aegista (Pulmonata: Bradybaenidae) under phylogenetic constraints Peer-reviewed

Takahiro Hirano, Yuichi Kameda, Kazuki Kimura, Satoshi Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　114　(1)　229-241　2015/01

DOI： 10.1111/bij.12407 　

ISSN： 0024-4066

eISSN： 1095-8312
A new Helicostyla species (Bradybaenidae: Helicostylinae) from Patnanungan Island, Philippines Peer-reviewed

Emmanuel Ryan C. de Chavez, Ian Kendrich C. Fontanilla, Gizelle A. Batomalaque, Satoshi Chiba

ASIA LIFE SCIENCES　24　(1)　37-49　2015/01

ISSN： 0117-3375
Phylogeny of the land snails Bradybaena and Phaeohelix (Pulmonata: Bradybaenidae) in Japan Peer-reviewed

Takahiro Hirano, Yuichi Kameda, Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　80　177-183　2014/05

DOI： 10.1093/mollus/eyu004 　

ISSN： 0260-1230

eISSN： 1464-3766
Common effect of the mucus transferred during mating in two dart-shooting snail species from different families Peer-reviewed

Kazuki Kimura, Satoshi Chiba, Joris M. Koene

JOURNAL OF EXPERIMENTAL BIOLOGY　217　(7)　1150-1153　2014/04

DOI： 10.1242/jeb.095935 　

ISSN： 0022-0949

eISSN： 1477-9145
Substantial incongruence among the morphology, taxonomy, and molecular phylogeny of the land snails Aegista, Landouria, Trishoplita, and Pseudobuliminus (Pulmonata: Bradybaenidae) occurring in East Asia Peer-reviewed

Takahiro Hirano, Yuichi Kameda, Kazuki Kimura, Satoshi Chiba

MOLECULAR PHYLOGENETICS AND EVOLUTION　70　171-181　2014/01

DOI： 10.1016/j.ympev.2013.09.020 　

ISSN： 1055-7903

eISSN： 1095-9513
Strategic ejaculation in simultaneously hermaphroditic land snails: more sperm into virgin mates Peer-reviewed

Kazuki Kimura, Satoshi Chiba

BMC EVOLUTIONARY BIOLOGY　13　264　2013/12

DOI： 10.1186/1471-2148-13-264 　

ISSN： 1471-2148
Long-term stasis and short-term divergence in the phenotypes of microsnails on oceanic islands Peer-reviewed

Shinichiro Wada, Yuichi Kameda, Satoshi Chiba

Molecular Ecology　22　(18)　4801-4810　2013/09

DOI： 10.1111/mec.12427 　

ISSN： 0962-1083 1365-294X
Delayed spermatophore removal in the land snail Euhadra peliomphala Peer-reviewed

Kazuki Kimura, Satoshi Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　108　(4)　806-811　2013/04

DOI： 10.1111/bij.12008 　

ISSN： 0024-4066
The mucus of a land snail love-dart suppresses subsequent matings in darted individuals Peer-reviewed

Kazuki Kimura, Kaito Shibuya, Satoshi Chiba

ANIMAL BEHAVIOUR　85　(3)　631-635　2013/03

DOI： 10.1016/j.anbehav.2012.12.026 　

ISSN： 0003-3472
ADAPTATION FROM RESTRICTED GEOMETRIES: THE SHELL INCLINATION OF TERRESTRIAL GASTROPODS Peer-reviewed

Ryoko Okajima, Satoshi Chiba

EVOLUTION　67　(2)　429-437　2013/02

DOI： 10.1111/j.1558-5646.2012.01772.x 　

ISSN： 0014-3820
Quantitative genetic analysis of subspecific differences in body shape in the snail-feeding carabid beetle Damaster blaptoides Peer-reviewed

J. Konuma, T. Sota, S. Chiba

HEREDITY　110　(1)　86-93　2013/01

DOI： 10.1038/hdy.2012.68 　

ISSN： 0018-067X
A maladaptive intermediate form: A strong trade-off revealed by hybrids between two forms of a snail-feeding beetle Peer-reviewed

Junji Konuma, Teiji Sota, Satoshi Chiba

Ecology　94　(11)　2638-2644　2013
Publisher: Ecological Society of America
DOI： 10.1890/12-2041.1 　

ISSN： 0012-9658
The Dual Protection of a Micro Land Snail against a Micro Predatory Snail Peer-reviewed

Shinichiro Wada, Satoshi Chiba

PLOS ONE　8　(1)　e54123　2013/01

DOI： 10.1371/journal.pone.0054123 　

ISSN： 1932-6203
Destruction of populations of Batillaria attramentaria (Caenogastropoda: Batillariidae) by tsunami waves of the 2011 Tohoku earthquake Peer-reviewed

Osamu Miura, Yoshiki Sasaki, Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　78　377-380　2012/11

DOI： 10.1093/mollus/eys025 　

ISSN： 0260-1230
Seabirds as adhesive seed dispersers of alien and native plants in the oceanic Ogasawara Islands, Japan Peer-reviewed

Yukiko Aoyama, Kazuto Kawakami, Satoshi Chiba

BIODIVERSITY AND CONSERVATION　21　(11)　2787-2801　2012/10

DOI： 10.1007/s10531-012-0336-9 　

ISSN： 0960-3115
Functional adaptation for unique habitats in the species of intertidal limpets Patelloida Peer-reviewed

Shizuko Nakai, Norio Wakayama, Satoshi Chiba

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM　92　(3)　547-552　2012/05

DOI： 10.1017/S0025315411001986 　

ISSN： 0025-3154
Ecological character displacement caused by reproductive interference(<Feature 2>Reproductive interference and ecological communities)

Konuma Junji, Chiba Satoshi

JAPANESE JOURNAL OF ECOLOGY　62　(2)　247-254　2012
Publisher: The Ecological Society of Japan
DOI： 10.18960/seitai.62.2_247 　

ISSN： 0021-5007
Symmetry and entropy of one-dimensional legal cellular automata Peer-reviewed

Yamasaki, K, Nanjo, K, Chiba, S

Complex Systems　19　351-361　2012
Snails can survive passage through a bird's digestive system Peer-reviewed

Shinichiro Wada, Kazuto Kawakami, Satoshi Chiba

JOURNAL OF BIOGEOGRAPHY　39　(1)　69-73　2012/01

DOI： 10.1111/j.1365-2699.2011.02559.x 　

ISSN： 0305-0270
Vertigo shimochii Kuroda & Amano 1960 synonymized with Gastrocopta servilis (Gould, 1843) based on conchological and DNA sequence data Peer-reviewed

Jeffrey C. Nekola, Alex Jones, Gabe Martinez, Sarah Martinez, Khayman Mondragon, Terrence Lebeck, John Slapcinsky, Satoshi Chiba

ZOOTAXA　(3161)　48-52　2012/01

ISSN： 1175-5326

eISSN： 1175-5334
How Does Life Adapt to a Gravitational Environment? The Outline of the Terrestrial Gastropod Shell Peer-reviewed

Ryoko Okajima, Satoshi Chiba

AMERICAN NATURALIST　178　(6)　801-809　2011/12

DOI： 10.1086/662674 　

ISSN： 0003-0147
Selectivity of terrestrial gastropod extinctions on an oceanic archipelago and insights into the anthropogenic extinction process Peer-reviewed

Satoshi Chiba, Kaustuv Roy

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA　108　(23)　9496-9501　2011/06

DOI： 10.1073/pnas.1100085108 　

ISSN： 0027-8424
Seashore in the mountain: limestone-associated land snail fauna on the oceanic Hahajima Island (Ogasawara Islands, Western Pacific) Peer-reviewed

Shinichiro Wada, Satoshi Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　102　(3)　686-693　2011/03

DOI： 10.1111/j.1095-8312.2010.01604.x 　

ISSN： 0024-4066
Symmetry and entropy of biological patterns: Discrete Walsh functions for 2D image analysis Peer-reviewed

Kazuhito Yamasaki, Kazuyoshi Z. Nanjo, Satoshi Chiba

BIOSYSTEMS　103　(1)　105-112　2011/01

DOI： 10.1016/j.biosystems.2010.10.010 　

ISSN： 0303-2647
The Age Structure of a Breeding Population of Hynobius lichenatus (Amphibia, Caudata) Peer-reviewed

Tomonori Yamamoto, Hiroshi Ota, Satoshi Chiba

Current Herpetology　30　(1)　7-14　2011

DOI： 10.5358/hsj.30.7 　

ISSN： 1345-5834 1881-1019
Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida) Peer-reviewed

Noriko Iwai, Shinji Sugiura, Satoshi Chiba

NATURWISSENSCHAFTEN　97　(11)　997-1002　2010/11

DOI： 10.1007/s00114-010-0717-4 　

ISSN： 0028-1042

eISSN： 1432-1904
Predation impacts of the invasive flatworm Platydemus manokwari on eggs and hatchlings of land snails Peer-reviewed

Noriko Iwai, Shinji Sugiura, Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　76　275-278　2010/08

DOI： 10.1093/mollus/eyq007 　

ISSN： 0260-1230
Invasive Non-Native Species' Provision of Refugia for Endangered Native Species Peer-reviewed

Satoshi Chiba

CONSERVATION BIOLOGY　24　(4)　1141-1147　2010/08

DOI： 10.1111/j.1523-1739.2010.01457.x 　

ISSN： 0888-8892
Interspecific interference competition alters habitat use patterns in two species of land snails Peer-reviewed

Kazuki Kimura, Satoshi Chiba

EVOLUTIONARY ECOLOGY　24　(4)　815-825　2010/07

DOI： 10.1007/s10682-009-9339-8 　

ISSN： 0269-7653
Invasive rats alter assemblage characteristics of land snails in the Ogasawara Islands Peer-reviewed

Satoshi Chiba

BIOLOGICAL CONSERVATION　143　(6)　1558-1563　2010/06

DOI： 10.1016/j.biocon.2010.03.040 　

ISSN： 0006-3207
CAUSE OF BIMODAL DISTRIBUTION IN THE SHAPE OF A TERRESTRIAL GASTROPOD Peer-reviewed

Ryoko Okajima, Satoshi Chiba

EVOLUTION　63　(11)　2877-2887　2009/11

DOI： 10.1111/j.1558-5646.2009.00780.x 　

ISSN： 0014-3820

eISSN： 1558-5646
Effects of habitat history and extinction selectivity on species-richness patterns of an island land snail fauna Peer-reviewed

Satoshi Chiba, Isamu Okochi, Takashi Ohbayashi, Daichi Miura, Hideaki Mori, Kazuki Kimura, Shinichiro Wada

JOURNAL OF BIOGEOGRAPHY　36　(10)　1913-1922　2009/10

DOI： 10.1111/j.1365-2699.2009.02115.x 　

ISSN： 0305-0270

eISSN： 1365-2699
Morphological divergence as a result of common adaptation to a shared environment in land snails of the genus Hirasea Peer-reviewed

Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　75　253-259　2009/08

DOI： 10.1093/mollus/eyp020 　

ISSN： 0260-1230
Associations between stable carbon isotope ratio and vegetation in modern and fossil land snails Mandarina chichijimana on Chichijima of the Ogasawara Islands Peer-reviewed

Satoshi Chiba, Angus Davison

PALEONTOLOGICAL RESEARCH　13　(2)　151-157　2009/06

DOI： 10.2517/1342-8144-13.2.151 　

ISSN： 1342-8144
Sociality improves larval growth in the stag beetle Figulus binodulus (Coleoptera: Lucanidae) Peer-reviewed

Hideaki Mori, Satoshi Chiba

EUROPEAN JOURNAL OF ENTOMOLOGY　106　(3)　379-383　2009

DOI： 10.14411/eje.2009.048 　

ISSN： 1210-5759

eISSN： 1802-8829
Preservation of the shell matrix protein dermatopontin in 1500 year old land snail fossils from the Bonin islands Peer-reviewed

Isao Sarashina, Yoshiki Kunitomo, Minoru Iijima, Satoshi Chiba, Kazuyoshi Endo

ORGANIC GEOCHEMISTRY　39　(12)　1742-1746　2008/12

DOI： 10.1016/j.orggeochem.2008.08.004 　

ISSN： 0146-6380
Possible dispersal of land snails by birds Peer-reviewed

Kawakami, K, Wada, S, Chiba, S

Ornithological Science　7　167-171　2008/12
ANATOMICAL AND MOLECULAR STUDIES REVEAL SEVERAL CRYPTIC SPECIES OF THE ENDEMIC GENUS MANDARINA (PULMONATA: HELICOIDEA) IN THE OGASAWARA ISLANDS Peer-reviewed

Satoshi Chiba, Angus Davison

JOURNAL OF MOLLUSCAN STUDIES　74　373-382　2008/11

DOI： 10.1093/mollus/eyn029 　

ISSN： 0260-1230
Contrasting response to Pleistocene climate change by ground-living and arboreal Mandarina snails from the oceanic Hahajima archipelago Invited Peer-reviewed

Angus Davison, Satoshi Chiba

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES　363　(1508)　3391-3400　2008/10

DOI： 10.1098/rstb.2008.0113 　

ISSN： 0962-8436
Molecular evidence of the evolutionary origin of a Bonin Islands endemic, Stenomelania boninensis Peer-reviewed

O. Miura, H. Mori, S. Nakai, K. Satake, T. Sasaki, S. Chiba

JOURNAL OF MOLLUSCAN STUDIES　74　199-202　2008/05

DOI： 10.1093/mollus/eyn003 　

ISSN： 0260-1230
Subfossil land snail fauna (mollusca) of central Chichijima, Ogasawara Islands, with description of a new species Peer-reviewed

Satoshi Chiba, Tetsuro Sasaki, Hajime Suzuki, Kazuo Horikoshi

PACIFIC SCIENCE　62　(1)　137-145　2008/01

DOI： 10.2984/1534-6188(2008)62[137:SLSFMO]2.0.CO;2 　

ISSN： 0030-8870
Taxonomic revision of the fossil land snail species of the genus Mandarina in the Ogasawara Islands Peer-reviewed

Satoshi Chiba

Paleontological Research　11　(4)　317-329　2007/12/30

DOI： 10.2517/1342-8144(2007)11[317:TROTFL]2.0.CO;2 　

ISSN： 1342-8144
Morphological and ecological shifts in a land snail caused by the impact of an introduced predator Invited Peer-reviewed

Satoshi Chiba

ECOLOGICAL RESEARCH　22　(6)　884-891　2007/11

DOI： 10.1007/s11284-006-0330-3 　

ISSN： 0912-3814
Rapid decline of endemic snails in the Ogasawara Islands, Western Pacific Ocean Invited Peer-reviewed

Takashi Ohbayashi, Isamu Okochi, Hiroki Sato, Tsuyoshi Ono, Satoshi Chiba

APPLIED ENTOMOLOGY AND ZOOLOGY　42　(3)　479-485　2007/08

DOI： 10.1303/aez.2007.479 　

ISSN： 0003-6862
Temperature-related diversity of shell colour in the intertidal gastropod Batillaria Peer-reviewed

Osamu Miura, Syuhei Nishi, Satoshi Chiba

JOURNAL OF MOLLUSCAN STUDIES　73　235-240　2007/08

DOI： 10.1093/mollus/eym019 　

ISSN： 0260-1230

eISSN： 1464-3766
Trade-offs between force and fit: Extreme morphologies associated with feeding behavior in carabid beetles Peer-reviewed

Junji Konuma, Satoshi Chiba

AMERICAN NATURALIST　170　(1)　90-100　2007/07

DOI： 10.1086/518182 　

ISSN： 0003-0147
Ecological character displacement caused by reproductive interference Peer-reviewed

Junji Konuma, Satoshi Chiba

JOURNAL OF THEORETICAL BIOLOGY　247　(2)　354-364　2007/07

DOI： 10.1016/j.jtbi.2007.03.013 　

ISSN： 0022-5193
Species richness patterns along environmental gradients in island land molluscan fauna Peer-reviewed

Satoshi Chiba

Ecology　88　(7)　1738-1746　2007/07

DOI： 10.1890/06-1735.1 　

ISSN： 0012-9658
Shell shape and habitat use in the North-west Pacific land snail Mandarina polita from Hahajima, Ogasawara: Current adaptation or ghost of species past? Peer-reviewed

Satoshi Chiba, Angus Davison

Biological Journal of the Linnean Society　91　(1)　149-159　2007/05

DOI： 10.1111/j.1095-8312.2007.00790.x 　

ISSN： 0024-4066 1095-8312
Endemic land snail fauna (Mollusca) on a remote Peninsula in the Ogasawara Archipelago, northwestern Pacific Peer-reviewed

Satoshi Chiba, Angus Davison, Hideaki Mori

PACIFIC SCIENCE　61　(2)　257-265　2007/04

DOI： 10.2984/1534-6188(2007)61[257:ELSFMO]2.0.CO;2 　

ISSN： 0030-8870

eISSN： 1534-6188
Effects of trematode double infection on the shell size and distribution of snail hosts Peer-reviewed

Osamu Miura, Satoshi Chiba

PARASITOLOGY INTERNATIONAL　56　(1)　19-22　2007/03

DOI： 10.1016/j.parint.2006.10.002 　

ISSN： 1383-5769
Introduced cryptic species of parasites exhibit different invasion pathways Peer-reviewed

Osamu Miura, Mark E. Torchin, Armand M. Kuris, Ryan F. Hechinger, Satoshi Chiba

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA　103　(52)　19818-19823　2006/12

DOI： 10.1073/pnas.0609603103 　

ISSN： 0027-8424
The recent history and population structure of five Mandarina snail species from subtropical Ogasawara (Bonin Islands, Japan) Peer-reviewed

Angus Davison, Satoshi Chiba

MOLECULAR ECOLOGY　15　(10)　2905-2919　2006/09

DOI： 10.1111/j.1365-294X.2006.02990.x 　

ISSN： 0962-1083
Labile ecotypes accompany rapid cladogenesis in an adaptive radiation of Mandarina (Bradybaenidae) land snails Peer-reviewed

Angus Davison, Satoshi Chiba

Biological Journal of the Linnean Society　88　(2)　269-282　2006/06

DOI： 10.1111/j.1095-8312.2006.00624.x 　

ISSN： 0024-4066 1095-8312
Morphological and habitat divergence in the intertidal limpet Patelloida pygmaea Peer-reviewed

Shizuko Nakai, Osamu Miura, Masayuki Maki, Satoshi Chiba

MARINE BIOLOGY　149　(3)　515-523　2006/06

DOI： 10.1007/s00227-005-0241-9 　

ISSN： 0025-3162
Parasites alter host phenotype and may create a new ecological niche for snail hosts Peer-reviewed

Osamu Miura, Armand M. Kuris, Mark E. Torchin, Ryan F. Hechinger, Satoshi Chiba

PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES　273　(1592)　1323-1328　2006/06

DOI： 10.1098/rspb.2005.3451 　

ISSN： 0962-8452
Molecular evolution and functionally important structures of molluscan Dermatopontin: Implications for the origins of molluscan shell matrix proteins Peer-reviewed

Sarashina, I, H Yamaguchi, T Haga, M Iijima, S Chiba, K Endo

JOURNAL OF MOLECULAR EVOLUTION　62　(3)　307-318　2006/03

DOI： 10.1007/s00239-005-0095-2 　

ISSN： 0022-2844
The way of the samurai snail Peer-reviewed

Joris M. Koene, Satoshi Chiba

American Naturalist　168　(4)　553-555　2006
Publisher: University of Chicago Press
DOI： 10.1086/508028 　

ISSN： 0003-0147
Sex and darts in slugs and snails (Mollusca : Gastropoda : Stylommatophora) Peer-reviewed

A Davison, CM Wade, PB Mordan, S Chiba

JOURNAL OF ZOOLOGY　267　329-338　2005/12

DOI： 10.1017/S0952836905007648 　

ISSN： 0952-8369
Speciation and gene flow between snails of opposite chirality Peer-reviewed

A Davison, S Chiba, NH Barton, B Clarke

PLOS BIOLOGY　3　(9)　1559-1571　2005/09

DOI： 10.1371/journal.pbio.0030282 　

ISSN： 1544-9173
Appearance of morphological novelty in a hybrid zone between two species of land snail Peer-reviewed

S Chiba

EVOLUTION　59　(8)　1712-1720　2005/08

ISSN： 0014-3820
Molecular-genetic analyses reveal cryptic species of trernatodes in the intertidal gastropod, Batillaria cumingi (Crosse) Peer-reviewed

O Miura, AM Kuris, ME Torchin, RF Hechinger, EJ Dunham, S Chiba

INTERNATIONAL JOURNAL FOR PARASITOLOGY　35　(7)　793-801　2005/06

DOI： 10.1016/j.ijpara.2005.02.014 　

ISSN： 0020-7519
Characterization of 17 microsatellite loci in the Japanese land snail genera Mandarina, Ainohelix, and Euhadra (Mollusca, Gastropoda, Pulmonata) Peer-reviewed

A Davison, S Chiba, M Kawata

MOLECULAR ECOLOGY NOTES　4　(3)　423-425　2004/09

DOI： 10.1111/j.1471-8286.2004.00680.x 　

ISSN： 1471-8278
Enhanced colour polymorphisms in island populations of the land snail Euhadra peliomphala Peer-reviewed

Morito Hayashi, Satoshi Chiba

Biological Journal of the Linnean Society　81　(3)　417-425　2004/03

DOI： 10.1111/j.1095-8312.2003.00292.x 　

ISSN： 0024-4066
Ecological and morphological patterns in communities of land snails of the genus Mandarina from the Bonin Islands Peer-reviewed

S Chiba

JOURNAL OF EVOLUTIONARY BIOLOGY　17　(1)　131-143　2004/01

DOI： 10.1046/j.1420-9101.2004.00639.x 　

ISSN： 1010-061X
Species-area curve for land snails on Kikai Island in geological time Peer-reviewed

Yasunari Marui, Satoshi Chiba, Jun'ichi Okuno, Kazuhito Yamasaki

Paleobiology　30　(2)　222-230　2004
Publisher: Paleontological Society
DOI： 10.1666/0094-8373(2004)030<0222:SCFLSO>2.0.CO;2 　

ISSN： 0094-8373
The evolution of extreme shell shape variation in the land snail Ainohelix editha: a phylogeny and hybrid zone analysis Peer-reviewed

H Teshima, A Davison, Y Kuwahara, J Yokoyama, S Chiba, T Fukuda, H Ogimura, M Kawata

MOLECULAR ECOLOGY　12　(7)　1869-1878　2003/07

DOI： 10.1046/j.1365-294X.2003.01862.x 　

ISSN： 0962-1083
Laboratory temperature variation is a previously unrecognized source of genotyping error during capillary electrophoresis Peer-reviewed

A Davison, S Chiba

MOLECULAR ECOLOGY NOTES　3　(2)　321-323　2003/06

DOI： 10.1046/j.1471-8286.2003.00418.x 　

ISSN： 1471-8278
Pacific island land snails: extinction and conservation of the endemic land snails of the Ogasawara Islands. Invited

Chiba S

Tentacle　11　13-14　2003/01
Species diversity and conservation of Mandarina, an endemic land snail of the Ogasawara Islands. Invited Peer-reviewed

Chiba S

Global Environmental Research　7　(1)　29-37　2003/01
Major adaptive radiation in neritopsine gastropods estimated from 28S rRNA sequences and fossil records Peer-reviewed

Y Kano, S Chiba, T Kase

PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES　269　(1508)　2457-2465　2002/12

DOI： 10.1098/rspb.2002.2178 　

ISSN： 0962-8452
Ecological diversity and speciation in land snails of the genus Mandarina from the Bonin Islands Invited Peer-reviewed

Satoshi Chiba

Population Ecology　44　(3)　179-187　2002/12

DOI： 10.1007/s101440200021 　

ISSN： 1438-3896
High within-population mitochondrial DNA variation due to microvicariance and population mixing in the land snail Euhadra quaesita (Pulmonata: Bradybaenidae) Peer-reviewed

Y. Watanabe, S. Chiba

Molecular Ecology　10　(11)　2635-2645　2001

DOI： 10.1046/j.0962-1083.2001.01388.x 　

ISSN： 0962-1083
Intraspecific diversity of mitochondrial DNA in the land snail Euhadra peliomphala (Bradybaenidae) Peer-reviewed

M Hayashi, S Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　70　(3)　391-401　2000/07

DOI： 10.1006/bijl.1999.0376 　

ISSN： 0024-4066
Anisotropic shape of islands and species richness of land snail fauna of the Ryukyus. Invited Peer-reviewed

Yamasaki, K, Chiba, S, Nagahama, H

Tropics　10　95-103　2000/07

DOI： 10.3759/tropics.10.93 　
Geometrical effect of island shape on the species richness Peer-reviewed

K Yamasaki, S Chiba, H Nagahama

FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY　7　(4)　353-357　1999/12

ISSN： 0218-348X

eISSN： 1793-6543
A new species of the land snail genus Mandarina (Gastropoda: Pulmonata) from Hahajima of the Bonin Islands, western Pacific: a species that became extinct after 2000 yr BP. Peer-reviewed

Chiba S

Bulletin of the National Science Museum　25　121-127　1999/10
Accelerated evolution of land smails Mandarina in the oceanic Bonin Islands. Peer-reviewed

Chiba S

Evolution　53　460-471　1999/10

DOI： 10.2307/2640782 　
Character displacement, frequency-dependent selection, and divergence of shell colour in land snails Mandarina (Pulmonata) Peer-reviewed

S Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　66　(4)　465-479　1999/04

DOI： 10.1006/bijl.1998.0281 　

ISSN： 0024-4066
Historical and ontogenetic changes in shell width and shape of land snails on the island of Kikai Peer-reviewed

E Hayakaze, S Chiba

AMERICAN MALACOLOGICAL BULLETIN　15　(1)　75-82　1999

ISSN： 0740-2783
A mathematical model for long-term patterns of evolution Peer-reviewed

Chiba S

Paleobiology　24　336-348　1998/10
Synchronized evolution in lineages of land snails in oceanic islands Peer-reviewed

Satoshi Chiba

Paleobiology　24　(1)　99-108　1998
Publisher: Paleontological Society
DOI： 10.1017/S0094837300019990 　

ISSN： 0094-8373
Genetic variation derived from natural gene flow between sympatric species in land snails (Mandarina) Peer-reviewed

Satoshi Chiba

Heredity　80　(5)　617-623　1998
Publisher: Nature Publishing Group
DOI： 10.1038/sj.hdy.6883300 　

ISSN： 0018-067X
Morphological stasis and phylogenetic relationships in tadpole shrimps, Triops (Crustacea: Notostraca) Peer-reviewed

N SunoUchi, F Sasaki, S Chiba, M Kawata

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　61　(4)　439-457　1997/08

DOI： 10.1006/bijl.1997.0138 　

ISSN： 0024-4066
Novel colour polymorphisms in a hybrid zone of Mandarina (Gastropoda: Pulmonata) Peer-reviewed

S Chiba

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY　61　(3)　369-384　1997/07

DOI： 10.1006/bijl.1996.0124 　

ISSN： 0024-4066
A new species of Mandarina from Anijima in the Bonin Islands. Peer-reviewed

Chiba S

Bulletin of the National Science Museum　22.　(3)　53-61　1996/12
Publisher: National Science Museum
ISSN： 0385-244X

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A new species of Mandarina PILSBRY, 1894 (Pulmonata, Camaenidae), Mandarina anijimana sp. nov., is described from Anijima in the Bonin Islands. Although this new species and Mandarina chichijimana CHIBA, 1989 have similar genital morphology, they can be discriminated by differences in color polymorphisms. Genetic and paleontological studies support the idea that these species have evolved independently on different islands. I suggest that their resemblance in genital morphology results from convergent or parallel evolution in the two lineages.
Ecological and morphological diversification within single species and character displacement in Mandarina, endemic land snails of the Bonin Islands Peer-reviewed

S Chiba

JOURNAL OF EVOLUTIONARY BIOLOGY　9　(3)　277-291　1996/05

ISSN： 1010-061X
A 40,000-year record of discontinuous evolution of island snails Peer-reviewed

Satoshi Chiba

Paleobiology　22　(2)　177-188　1996
Publisher: Paleontological Society
DOI： 10.1017/S009483730001616X 　

ISSN： 0094-8373
MODERN AND HISTORICAL EVIDENCE FOR NATURAL HYBRIDIZATION BETWEEN SYMPATRIC SPECIES IN MANDARINA (PULMONATA, CAMAENIDAE) Peer-reviewed

S CHIBA

EVOLUTION　47　(5)　1539-1556　1993/10

ISSN： 0014-3820
Taxonomy and morphologic diversity of Mandarina in the Bonin Islands. Peer-reviewed

Chiba S

Trans. Proc. Palaeont. Soc. Japan, N. S.　155　218-251　1989/09

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Books and Other Publications 14

ダーウィンの呪い

千葉, 聡

講談社　2023/11

ISBN: 9784065336915
进化吧蜗牛：蜗牛与进化论的故事

千叶聪(丁丁虫译)

人民邮电出版社　2023/05

ISBN: 9787115616319
招かれた天敵

千葉, 聡

みすず書房　2023/03

ISBN: 9784622095965
大陸と日本をつなぐ自然史 : 地質・生態系の総合研究最前線

鹿野, 秀一, 平野, 直人, 千葉, 聡

古今書院　2021/01

ISBN: 9784772253123
進化のからくり : 現代のダーウィンたちの物語

千葉, 聡

講談社　2020/02

ISBN: 9784065187210
歌うカタツムリ : 進化とらせんの物語

千葉, 聡

岩波書店　2017/06

ISBN: 9784000296625
生物多様性と生態学―遺伝子・種・生態系

宮下直, 井鷺裕司, 千葉聡

2012
外来生物―生物多様性と人間社会への影響

西川潮, 宮下直編

2011
シリーズ群集生態学２進化生物学からせまる

大串隆之, 近藤倫生, 吉田丈人編

2009/03
古生物の進化

速水格他

朝倉書店　2004/08
生態学入門

日本生態学会編

東京化学同人　2004/08
脱環境ホルモンの社会

吉村仁他

三学出版　2002/04
世界の知性科学を語る

日経サイエンス社編集部編

日経サイエンス社　1995/04
フィールドガイド小笠原の自然

小笠原自然環境研究会編

古今書院　1992/01

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Presentations 10

Adaptive and nonadaptive radiation in oceanic island snails Invited

Satoshi Chiba

International e-Conference & 8th Malacological Convention Philippines　2021/03/20
Evolution and conservation in island mollusca Invited

Satoshi Chiba

International Symposoum on "Island Plant" Evolution and Conservation　2020/10/13
形が不連続になる理由 Invited

千葉聡

日本分子生物学会　2019/12/05
Lessons from the ongoing mass extinction of land snails in Ogasawara: direct and indirect effects of multiple invasive species Invited

S Chiba

Molluscs 2018 International conference of MAU
Adaptive and non-adaptive radiation in island snails Invited

S Chiba

個体群生態学会　2017/10/14
Conservation in freshwater molluscs in Japan Invited

S Chiba

3rd International Symposium of Benthological Society of Asia　2016/08/28
Evolution and conservation in land snails in Ogasawara Invited

S Chiba

New Zealand Ecological Society　2014/11/14
Evolutionary impacts of nonnative specie Invited

S Chiba

World Congress of Malacology　2013/07/26
Adaptation in land snail shell shape Invited

Schilthuizen M, Chiba S

World Congree of Malacology　2013/07/22
スケールを変えて見た在来種の外来種への応答 Invited

千葉聡

日本生態学会

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Research Projects 41

東北アジア地域の生物地理学 Competitive

System: Grant-in-Aid for Scientific Research

2010/04 - Present
海洋生物の種多様性の空間的、時間的パターンの形成維持機構 Competitive

2004/04 - Present
海洋生物のホストーパラサイト系 Competitive

2004/04 - Present
外来種の侵入と定着機構の解明 Competitive

2004/04 - Present
Study on evolution of island biota Competitive

1999/04 - Present
Evolutionary Studies on land snails Competitive

1995/04 - Present
人新世進化の小世界：外来種が駆動する小笠原諸島固有陸貝の進化

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東北大学

2024/04/01 - 2027/03/31
絶滅に瀕する島嶼陸産貝類の保全に向けた貝食性外来種防除技術の開発

千葉聡

Offer Organization: 環境再生保全機構

System: 環境研究総合推進費

2024/04 - 2027/03
左右反転の謎を解く：キラルな陸貝をモデルとして

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業基盤研究(B)

Category: 基盤研究(B)

Institution: 東北大学

2021/04/01 - 2024/03/31

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陸産貝類のヒダリマキマイマイを対象として、体の左右の非対称性の進化を生じるプロセスと、その種分化との関係について明らかにするために、遺伝的、生態学的、生理学的な研究を行った。東北地方におけるヒダリマキマイマイ（左巻き）とその右巻きの個体であるアオモリマイマイについて、生殖的隔離の有無が地域ごとにどのように変わるかを調べるため、全域にわたって両者の分布と生息位置を調べ、右巻きと左巻き個体の、共存の状況を極めて細かい空間スケールで記録した。その結果、完全に共存している地域は少なく、多くは側所的な分布が見られた。 Rad-seq解析による遺伝子解析を行い、集団動態推定を行った。その結果、東北地方の一部の地域では、共存するヒダリマキマイマイとアオモリマイマイの間にほぼ完全な生殖的隔離が存在していたが、別の地域では、共存するこれら左巻きと右巻きの個体間で十分な遺伝的交流があり、任意交配からの有意なずれが認められない集団があった。それ以外の地域では、遺伝的交流のレベルは部分的であり、不完全な生殖的隔離が維持されていると考えられた。ヒダリマキマイマイとアオモリマイマイの交尾により、正常な受精が行われるかどうかを調べるため、その準備としてヒダリマキマイマイの正常な交尾によって起きる雌器官内での精苞の移動と分解の過程を調べるための実験系を確立した。そして交尾実験と解剖学的、生理学的にそのプロセスを明らかにした。また左巻き同士の恋矢による操作の機能により、死亡率がどのように高まるのかを明らかにした。これは右巻きのアオモリマイマイとの交尾ではこれらの機能が変化するという仮説を検証するための重要な基礎となる。
How does the past constrain the present: a model for Oceanic island snail communities

Chiba Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2018/04/01 - 2021/03/31

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The evolutionary history of the lineages of terrestrial molluscan communities distributed on islands and freshwater molluscan communities distributed in ancient lakes, mainly in East Asia including Japan, was comprehensively elucidated by molecular phylogeny. In addition to estimating the habitat use of the species in the modern community, fossil records were used to estimate past habitat use and compare it with phylogenetic relationships to infer trends in habitat shifts. The results showed that both terrestrial and freshwater molluscs from "Darwinian island" environments had characteristics that allow for flexible and rapid niche shifts, but significant levels of phylogenetic conservatism were detected as a whole. We conclude that these evolutionary constraints and niche conservatism have a significant influence on the distribution of ecological properties in the community.
Diversity created by threats: the evolutionary explosion of molluscan fauna in Russia and Vietnam

Chiba Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2017/04/01 - 2020/03/31

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Field survey and molecular phylogenetic analysis of terrestrial and freshwater molluscs in the Russian Far East, Vietnam and surrounding areas indicate that niche diversity potentially increase speciation rates and contribute to species diversity. On the other hand, in some cases, the abundance of resources (the amount of calcium carbonate required for shell formation) is likely to increase population density and thus, ecologically neutral processes can promote speciation and increase species diversity. The present results suggest that the predator-prey relationship increase phenotypic diversity and promote speciation and increase species diversity. These results indicate that ecological processes play an important role in the evolution of species diversity .
Preventing extinction by evaluation of adaptive traits

Chiba Satoshi, UCHIDA Shota, SHINOBE Shotaro, AKIYAMA Kao

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2016/04/01 - 2018/03/31

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Serious impacts of nonnative malacophagous flatworms on native land snails on the Ogasawara Island were detected, and medium size-large species have become mostly extinct on Chichijima. However, native micro snails were still survive and widely distributed on the island. Nonnative land snails Acusta and Satsuma were not affected by flatworms and extended their distributions. Mucus of native land snails attract flatworms, while mucus of nonnative species exhibited repellent action against flatworms. In addition, Acusta avoid attack of the flatworms by active defense behavior. These characteristics appear to be a result of adaptation against predation of flatworms on mainland, and are effective to mitigate impacts of the nonnative predators.
Process of species diversification in fossil records of land snails on remote islands

Chiba Satoshi, HIRANO Takahiro, MORII Yuuta, Prozorova Larisa, SUZUKI Takanori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2015/04 - 2018/03

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A rapid morphological and ecological divergence was documented in the fossil records ofland snails in the Pleistocene and Holocene deposits on the Ogasawara Islands. However, such rapid divergence is not found in the fossil snail sequences in the Ryukyu Islands (e.g. Kikai Island). Molecular phylogenetic analyses and ecological surveys showed consistent relationships among morphology, ecology and phylogeny were found in Ogasawara, Ryukyu, and mainland lineages, but rapid ecological and species divergence are limited to the snails of Ogasawara. These patterns are consistent with those detected in the fossil records. Divergence of habitat use promoted by competitive interaction appears to be a major process of speciation and radiation on oceanic islands, while speciation on mainland occurs by adaptation against predation as well as geographic isolation.
Conservation palaeontology: protecting future biodiversity by past information

CHIBA Satoshi, MAKINO Wataru

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2012/04/01 - 2015/03/31

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Temporal changes in environmental condition and its impacts on community were estimated by investigating fossil and modern land snail assemblages on the Ogasawara and Ryukyu Islands. The results of stable isotope analyses and morphological analyses suggest that habitat shift from wet to dry condition occurred at the end of the last ice age (ca. 10ka), and it caused sSerious extinction and rapid changes of species composition. On the Ogasawara Islands, extinction of land snails occurred due to large changes in vegetation after 300 years ago when first human immigration occurred. These suggest that habitat of these islands were formerly more moist than the present condition, and land snail species adapted to wet habitat were domminated in the community in the past. These information would be crucial for conservation plan for these snails.
Diversity, adaptation and coevolution in snail-feeding carabid beetles and land snails

SOTA Teiji, CHIBA Satoshi, TAKAMI Yasuoki, MORII Yuta, HAYASHI Masakazu, LIANG Hongbin, KARAGYAN Gayane, AKIYAMA Kazutoshi, KIM Jung-lark)

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Kyoto University

2011/04/01 - 2014/03/31

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To understand how the land snail fauna is related with the divergence of morphology related to snail feeding (macrocephalism vs. stenocephalism) in the subtribe Carabina, we conducted field studies in China, Korea, Armenia, and Morocco. In the inland region of China, especially, diverse snail-feeding Carabina species and land snails occur. Macrocephalic Carabina species occur in habitats harboring small-sized bradybaenid snails abundantly. In habitats where both macro- and stenocephalic Carabina species occur, the shell morphology of bradybaenid snails was markedly diversified, suggesting an adaptive radiation due to strong predation pressure from snail-feeding predators.
Detection of human mediated evolution by fossil records

CHIBA Satoshi, URABE Jotaro, TOYOFUKU Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2009 - 2011

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We investigated how ecosystem has responded to human activity on the basis of analyses of carbon stable isotope ratio of the fossil land snails. In addition, evolutionary changes caused by anthropogenic impacts was estimated by historical records. The results of these surveys showed that evolutionary changes in shell color and shape and habitat preference have occurred since human colonization. Some of these changes were caused by impacts of nonnative species. Evolutionary changes by human activity cannot be ignored in planning conservation programs for endangered species.
Multidisciplinary approach for the origin of biodiversity in the tropical Southeast Asian islands

KASE Tomoki, WATANABE Tsuyoshi, CHIBA Satoshi, KANO Yasunori, KURIHARA Yukito, TSUTSUI Makiko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: National Museum of Nature and Science, Tokyo

2006 - 2009

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This research project aims to clarify the origin of high marine biodiversity of the tropical Southeast Asian islands based on multidisciplinary studies of fossil and modern invertebrates from Philippines and Indonesia. The results include the discovery of previously unknown Cenozoic fossil assemblages, new age controls for the fossil assemblages based on microfossil analyses, segregation of marine biota between the east and west of Indonesian Seaway in Neogene times, the presence of a permanent El Nino event, etc.
MECHANISMS OF ADAPTIVE DIVERGENCES

CHIBA Satoshi, MAKINO Wataru, YAMAZAKI Kazuhito, TOYOFUKU Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2006 - 2008
Evolution in frontier environments

CHIBA Satoshi, KASE Tomoki, KAWATA Masakado, YAMASAKI Kazuhito

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2003 - 2005

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Ecological and genetic process of adaptive radiation were examined using endemic land snail genus Mandarina of the oceanic Ogasawara Islands in the northwestern Pacific. Based on the habitat analysis, morphological analysis, and examination of the mitochondrial DNA sequence variations, we showed that hybridization between sympatric species occurred by alteration of habitat use due to environmental change. This suggests that speciation and adaptive radiation are still in progress in Mandarina. In addition, populations with unique shell morphologies were found in a hybrid zone constituted between morphologically closely related species. This suggests that hybridization is an important source of creating novel morphology and evolutionary novelty. Phylogenetic relationship among the species of the land snails Euhadra in the mainland of Japan was estimated on the basis of mitochondrial DNA sequences. Repeated expansion and immigration have occurred in Euhadra, associated with climatic change during the Pleistocene. Complex spatial structure in genetic variations was created by mixing and isolation that were accompanied with the climatic change. Relationship between intertidal gastropoda Batillaria cumingii and its parasites was examined on the basis of ecological, morphological and genetic (mitochondrial DNA and nuclear ITS gene) analysis. Genetic analysis revealed that these parasites include a large number of cryptic species. These species showed less geographical variations in genetic variations. On the other hands, Batillaria showed a high level of geographical variations in genetic components. Ecological speciation due to habitat shift would be a main cause of diversification of parasites in intertidal gastropoda.
Paleobiological research on the history of earth organisms modeled by the submarine cave ecosystem

KASE Tomoki, KITAMURA Akihisa, SUZUKI Yutaro, KANO Yasunori, TABUKI Ryoichi, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: National Museum of Nature and Science, Tokyo

2003 - 2005

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1. We systematically described two new species of mysid crustaceans and one new genus and three new species of neritilid gastropods. 2. A unique ecological feature in submarine caves is the infrequency of predator animals, reminiscent of the mid-Mesozoic shallow marine ecosystem. To compare the ecological features between the modern submarine caves and mid-Mesozoic shallow marine ecosystem, we studied the history of shell-drilling, predatory naticid gastropods as they represent the best fossil records of predator-prey relationship. We showed that naticids first appeared in the end of Cretaceous and started drilling predation since that time. On the other hand, we examined drilling and crushing predation in shells of two submarine caves of Okinawa, southern Japan as low as 5%, the frequency is equivalent to those for the late Cretaceous shallow marine assemblages. This is the first documentation of predatory activity in submarine caves. 3. Neritilia cavernicala n. sp. was described from anchialine caves of two islands separated more than 200km apart in the Philippines. We presented the first genetic structure for anchailine cave organisms (mitochondrial cytochrome oxidase I), which shows no evidence of genetic isolation between the islands. All individuals are part of a panmictic population and their seemingly isolated cave habitats do not limit gene flow in this species. Larval dispersal may be widely applicable to anchialine stygobites with insular distributions. 4. A taxonomic study of Nerilitidae shows the species diversity is the highest in SE Asian islands and becomes smaller in accordance with the distance from the diversity center. Contrast to the previous, widely accepted view that cavericolous animals dispersed primarily by plate tectonics and vicariance, transoceanic dispersal should have played an important role, like most modern invertebrates in tropical coral-reef seas, in forming the present distribution of the cavericolous neritilids.
The effects of dispersal on the evolution of resource use and species diversity : a test using theoretical predictions and island communities.

KAWATA Masakado, CHIBA Satoshi, YOKOYAMA Jun

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2003 - 2005

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To test the hypothesis that niche partitioning can actually affect species diversity, we need to show that the resources are spatially heterogeneous, species use different resources and the resource distribution patter determines the species abundance pattern. However, there is no study showing these three conditions. In this study, we test the hypothesis by examining species diversity and island butterfly communities and their food plants diversity. Species diversity of butterfly comminutes was investigated for 5 islands and 2 mainlands in 2004 and 2005. The biomasses of the food plans were estimated by field research and using an aerial photograph on GIS. 27 to 36 species were found in each island, and 66 food plant species were identified. To measure the dissimilarity in species diversity and food plant distributions between communities, we used Odum's percentage difference as dissimilarity index. For the effects of food plant diversity and distance between communities on species diversity, the extension method to Manthel test was used. The results showed that butterfly species diversity was significantly related to plant species diversity (i.e., resource diversity), but was not related to geographic distances between communities. Hubble' neutral theories suggested that species diversity is determined random ecological drift and dispersal between communities. Thus, the theories can predict that dissimilarity of species diversity pattern between the communities should be related spatial distance between them. Previous studies have shown that in some communities, species used different resources. However, our studies first showed that resource abundant distribution significantly determine species diversity pattern.
Stoichiometric effects of pCO_2 on aquatic communities

URABE Jotaro, HINO Shuji, BAN Shuhei, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2003 - 2005

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The present study was performed to clarify (1) how land use/cover in the watershed affects on pCO2 in lake ecosystems, (2) how changes in pCO2 affects zooplankton communities through changes in species composition, abundance and stoichiometry of planktonic algae, and then (3) how local and global environmental changes influence on aquatic communities in lakes through these stoichiometric effects of pCO2. For these, we first examined limnological and biological characteristics of 48 lakes located at east-north area in Japan with GIS analyses on the watershed of these lakes. The analyses revealed that pCO2 in the lakes varied over 5 orders magnitude and highly related with land cover of vegetation in the watershed, water depth and food web structures, suggesting that effects of changes in land use and atmospheric pCO2 on lake carbon metabolisms differ depending on the basin morphometry and biota. To examine changes of pCO2 to aquatic communities, laboratory experiments with manipulation of pCO2 in water were made using several taxonomic group of algal plankton as primary producers and Daphnia as consumers. The experiments showed that algal competitive interactions differed depending on pCO2 and nutrient supplies. In any experiments with single algal species, increase of pCO2 increased algal abundance but decreased growth rate of consumers due to decrease in specific nutrient contents of the algal food. However, in experiments with multiple algal species, increase of pCO2 also increased algal abundance but did not decrease growth rate of consumers, probably due to complementary effects in nutrition of algae. These results suggest that algal species diversity functions to mitigate negative effects of increased pCO2 on community structures and mass transfer efficiency in lake ecosystems.
陸生貝類の分子古生物学的研究:小笠原諸島のカタマイマイ類を例として

遠藤一佳, 千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽研究

Category: 萌芽研究

Institution: 筑波大学

2003 - 2005

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本年度は,前年度に得られたEuhadra現生種のDermatopontinのアミノ酸配列に基づき,種間での保存性の高い領域で合成した人工ペプチドに対するポリクローナル抗体を作製し,有肺類の現生種・化石種各種の貝殻抽出との反応を調べた.その結果,(1)Dermatopontinがヒラマキガイ以外の有肺類でも貝殻基質タンパク質として使われていることを再確認し,(2)有肺類の中でも原始的と考えられるオカミミガイ科(Elloviidae)の種においても貝殻基質タンパク質として使われていることを明らかにした.また,化石種については,抗原となる貝殻抽出物を濃縮し,さらに段階的に希釈したさまざまな濃度の一次抗体を反応させてやることにより,小笠原諸島父島産の陸生貝類絶滅種ヒロベソカタマイマイ(Mandarina luhuana)の化石貝殻中にDeratopontinの断片が残されていることを明らかにした.一方,化石化に伴う免疫化学反応の低下は,種間のアミノ酸配列の違いによる反応性の違いよりも桁違いに大きいことも判明し,当該化石種が本土産のEuhadra属に近いのか,それとも小笠原諸島のMandarina属現生種に近いのかを抗体との反応性によって判別することが難しいことも明らかとなった.今後は,今回作製した抗体を用いて化石抽出物からDermatopontinをアフィニティ精製し,精製されたペプチドのアミノ酸配列を質量分析により直接決定するといったアプローチをとることが必要である.
巻貝の設計図:理論形態学と遺伝学の統合に向けて

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽研究

Category: 萌芽研究

Institution: 東北大学

2002 - 2003

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ヒダリマキマイマイおよびヒメマイマイを実験系統として用い、殻の形態が著しく異なる系統群を交配させ、F1の形態の解析を行った。交配実験と形態解析の結果、サイズ、扁平率などの形質に高い遺伝率の存在が認められた。しかし、ヒメマイマイの扁平-尖り型の固体群から得られたF1は、両者の中間型になる場合のほか、いずれかの親の形質により類似する場合があり、母性効果の存在が示唆された。このような母性効果は当初まったく予期していなかった意外な結果である。またヒダリマキマイマイや一部地域のヒメマイマイの交配により得られた子孫は、両親のいずれとも異なる性質をもつ子孫が得られることがあった。このことは、巻貝の形態形成にかかわる遺伝的背景は、当初想定していたものより、はるかに複雑であることが示唆する。次に形質間の遺伝相関を解析したところ、殻のサイズと高さ、周縁の角度などに遺伝相関の存在が認められた。しかし人為的な外套膜の操作実験により、極端に高い殻高の個体や周縁角を持つ個体が得られた。このことは殻形態には遺伝的要因以外の要因も強く関与している可能性を示唆する。さらにマイクロサテライトDNAを増幅するためのプライマーを作成し、PCR法によって増幅した断片を、増幅断片長解析によりDNA多型の検出を行った。マイクロサテライトDNAの分析により得られたDNA多型をマーカーとして、これらの形質との相関を検討した。しかしながら、形質間の遺伝的関係のマッピングはできなかった。これはマイクロサテライト遺伝子座の数が不足しているだけでなく、巻貝の殻の遺伝的背景が、予想以上に複雑で、多様な要因がかかわっているためであると考えられる。
海洋島における陸生貝類の種分化

千葉聡, ANGUS DAVISON, DAVISON A.

Offer Organization: 日本学術振興会

System: 科学研究費助成事業特別研究員奨励費

Category: 特別研究員奨励費

Institution: 東北大学

2001 - 2002

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小笠原諸島産カタマイマイ類について、生態調査およびマイクロサテライトDNA、ミトコンドリアDNAの分析を行い、本属の適応放散の状況、種分化の機構について明らかにした。母島において、ヌノメカタマイマイとコガネカタマイマイの出現頻度から生息場所の分化と活動時間の違いを検討した。その結果、両者は明らかに生活場所の分化、特に休息時の分化が顕著であることが明らかとなった。向島で生息分布の調査を行ったところ、母島の2種と同じように形態的に異なる2つのタイプがヌノメカタマイマイ個体群中に見出された。この2つのタイプは生息場所も異なっており、環境に対する選好性が異なると考えられる。マイクロサテライトDNAの変異から、この2つのタイプは同類交配していることがわかり、この島内で同所的種分化によって種分化が起きている可能性が示唆された。ミトコンドリアDNAの変異に基づき、カタマイマイ種群の系統推定を行った。その結果、従来、母島の種群は一回の父島からの移入の後、放散したと考えられていたが、父島から、ごく最近別の移住があったことが推定された。またカタマイマイには、遺伝子だけで区別できる隠蔽種が多く存在することが明らかになった。形態的な特徴と、ミトコンドリアDNA、マイクロサテライトDNAの変異の比較を行ったところ、特に母島諸島ではこれらがいずれも一致しないケースが認められた。これは、種間ないし地域集団間で、過去に雑種化が起こり、系統の異なる遺伝子群が集団中に流入したためと考えられる。以上のことから、カタマイマイ類の放散過程は同所的な分離と融合を繰り返す、網状の複雑な過程をたどったと考えられる。
COLONISATION OF THE LAND: A CASE STUDY IN GASTROPODA

CHIBA Satoshi, KAWATA Masakado, KASE Tomoki

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: TOHOKU UNIVERSITY

2000 - 2002

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1. Vertical zonation in the intertidal snail Batillaria cumingi, was studied to examine ecological cause of colonization of land in marine gastropoda. The snails found in the highest part of the muddy shore possessed a larger shell with a longer spire than the snails from the lower tidal sites. Based on observations in the laboratory, the former prefers to stay above water to a greater extent than the latter, which corresponds to the difference in their intertidal heights. Among snails transplanted from the upper and lower tidal sites to the position boundary, most moved back to their original sites. Although further genetic analyses are needed, the above results suggest that the preferences for height and air-exposed/submerged condition on a tidal area are diversified within the populations of B. cumingi. This raises the possibility that the vertical zonation in the distribution of Batillaria species has arisen by diversification of habitat preference within populations. 2. To estimate patterns of adaptive radiation in Neritopsine gastropoda, mplecular phylogenetic analysis using 28SrRNA sequences was conducted. This group was diversified into marine, flesh water and terrestrial habitat. The inferred phylogenetic relationsip suggests that colonization from marine to ground occur independently at least two times in different lineages and at different times. The ancestral lineages of the terrestrial group are living in marine cave at present. In addition, the colonization from marine to ground occurred through under ground water. 3. The rates of molecular evolution were compared by examining nuclear 28SrRNA and mtchondrial DNA sequences in marine and land gastropoda. High evolutionary rates were observed in both 28SrRNA and mtDNA sequences, and thus, colonization of the land follow acceleration in molecular evolution.
Habitat Structure and Evolution of density-dependence ; with regard to evolutionary significance of Population fluctuation

KAWATA Masakado, SHIMADA Masakazu, YOKOYAMA Jun, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2000 - 2002

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We examined the growth and reproductive rates of freshwater snails, Physa acuta, in two habitat types. In the Asabata habitat, snails lived in isolated water pools, which occasionally joined to form a single large pool ; in the Kakegawa habitat, they lived in a slow-running water way. Genetic structure assessments using three microsatellite loci supports the idea that a stable panmictic population occupies the Kakegawa habitat ; whereas alternate mixing populations, with individuals interacting and reproducing within patches, but occasionally mixing within a large global population, occupy the Asabata habitat. Laboratory experiments, using snails collected from the two habitats, showed that juvenile snails grew faster, laid more eggs, and laid them earlier in the Asabata habitat than in the Kakegawa habitat. Growth rates were lower at high density than at low density in the Kakegawa habitat ; the inverse was true in the Asabata habitat. Density-dependent response of individual snail reproduction was the same for the two habitats. The results support the hypothesis that spatial structure affects the evolution of density-dependent growth rates and of timing for reproduction.
Mechanisms of speciation

YOSHIMURA Jin, CHIBA Satoshi, KAWATA Masakado, HASEGAWA Takaihro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

Category: Grant-in-Aid for Scientific Research (C)

Institution: Shizuoka University

1999 - 2002

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The purpose of this study is to investigate the conditions that allows speciation that is the only source of species diversity of organisms. This study to scrutinize the speciation mechanisms is carried out by the theoretical studies and the empirical studies using fossil records and molecular phylogeny. Specifically, we build a basic individual-based model of sexual selection and studied the possibility and conditions of speciation. We examined how the likelihood of speciation depends on the distributions of a male sexual character and the associated female preference characters. We found that the frequency of speciation events increases with the overall variations in the male and female traits that depend on the duration of isolation of two conspecific populations. This indicates that the speciation events are not limited by ecological niche widths, rather it is unlimited due to the variation in mating preferences. This result suggests, that extraordinal species diversity seen in some communities, such as tropical forests and cichlid fishes in African lakes could be possible due to speciation by sexual selection. We carried out many extensions and related studies of biodiversity and mating behavior from the main project : (1) large-scale model of multiple speciations in relation to geographical spatial distributions and long-term environmental fluctuations (e.g., glacial periods), (2) the lattice model of stability and coexistence of many species (grassland community model) to evaluate the stability and coexistence of newly speciated species, (3) an individual-based mating behavior model of hilltopping behavior in insects and simulations, and (4) the quantitative analyses of stability and seasonality of animal sex ratios.
NATURAL HISTORY OF SUBMARINE CAVE ORGANISMS

KASE YOMOKI, TABUKI Ryoichi, HAYAMI Itaru, TAKEDA Masatsune, ENDO Kazuyoshi, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

1999 - 2001

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1.Two new genus and 4 new species of the family Pickworthiidae (characteristic in submarine caves) and a new genus and species of the family Scissurellidae were described from the Indo-Pacific submarine caves. One new genus and species whose shell morphology has not been known was also described. 2.Analysis of shell characters of the gastropod genus Pisulina resulted to recognize six species, of which two are new, and clarified that they constitute a monophyletic group together with the genus Neritilia and other related new genera. An anatomical study of Pisulina and Neritilia supported the result of our conchological study. 3.One fossil species previously identified questionably to a living neritid species is recognized as a new genus and species of the family Neritiliidae, indicating that the family adopted cryptic environments at least by an Oligocene time. 4.Two new genera and several new species of the family Neritiliidae were found from anchialine and hyporheic habitatas and river streams. This is the first discovery from mollusks from such environments except for a hydrobiid gastropod. 5.Anatomical and molecular phylogenic analyses of the superorder Neritopsisna including the family Neritiliidae show that the superorder invaded land at least three times in their history, and also show that neritiliids in river streams were derived from those once adapted to marine cryptic environments via the anchialine and hyporheic environments. 6.One new species of calanoid copepod genus Ridgewayia was described from a submarine cave in Palau This new species is related to a Caribbean species, suggesting westward dispersal from the Caribbean Sea. This study also found 4 new species of the mysid genus Heteromysoides and Heteromysis. One living fossil new genus and species of ostracod, Kasella ryukyuensis, was described from the submarine caves on Okinawa.
Calcification rate on the organic hard tissue based on the study of microstructure, mineralization mechanism and ecological condition of invertebrates

IKEYA Noriyuki, CHIBA Satoshi, IBARAGI Masako, KITAZATO Hiroshi, UBUKATA Takao, KITAMURA Akihisa

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: Shizuoka University

1998 - 2001

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Three different organisms, foraminerfers, Ostracodes and Molluscs, were examined for microstructure, mineralization mechanism and ecological condition of invertibrates. Foraminefers : Benthic foraminerfers were cultured under different temperature and salinity conditions. Morphology of the pores in the foraminerfer tests were examined, and the results indicate the pores are irregular in shape for specimens living in unfavorable conditions. Calcification process was continuously observed. It was found that in the beginning of the calcification, all the pores are irregular in shape. The pores become circular with the progress in calcification. This suggests that if the calcification rate is slow, the irregular shape of the pores will be retained. Ostracodes : Podocopida ostracode were cultured under different temperature and salinity conditions. The Sr/Ca and Mg/Ca ratios of carapace were analyzed with respect to different molting stages. The results show that Sr/Ca ratio is not affected by the sea water temperature, where as the Mg/Ca ratio is dependent on sea water temperature. When an infant was compared for the Sr/Ca and Mg/Ca ratios with an adult, the infant showed extraordinary high values for both the ratios. It is possible to consider that the growth rate of infant is far higher than the adult and this implies a vital effect on the chemical parameters. Molluscs : Geometric features of bivalvia were examined both theoretically and empirically. Fibrous prisms and foliated blades on the external shell surface and composite prisms in shell section parallel to the outer shell surface were studied. Computer stimulation and natural samples were compared. The results show a positive correlation between growth rate of prisms and the probability of nucleation of simple prisms. Prism size correlates with growth rate of the entire shell or prisms, and increases as the shell grows faster or prisms grow slower.
種分化による多様性創出のメカニズムの解明

河田雅圭, 横山潤, 牧雅之, 千葉聡, 久保田耕平, 曽田貞滋

Offer Organization: 日本学術振興会

System: 科学研究費助成事業基盤研究(C)

Category: 基盤研究(C)

Institution: 東北大学

2000 - 2000

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生殖隔離がどのようなメカニズムで進化したかという問題の解明は、地球上での多様性創出の原因を考える上でも重要なテーマの一つである。この問題を「種分化のメカニズムの解明」と「種分化と生物の多様性の関係」から探る研究を押し進めるために、2回の会合を東北大学(仙台)で開催した(11月と2月)。会合では、植物、動物、微生物の対象生物について、理論的研究、分子生物学的研究、生態学的研究、生物地理学的研究、古生物学的研究について討論が行われた。討論の結果、種分化メカニズムの解明のための研究には、(1)交配や資源利用にかかわる遺伝メカニズムを分子レベルで解明する必要性であること、(2)自然界での多様性のプロセスを解明するためには、グローバルな視点からの多様性のパターンの解析が必要であり、そのためには個体をベースとたデータベースが必要であるということ、(3)どのように生態的な要因が種分化の促進に関わっているかを実証研究すること、(4)実際の生物に応用できる理論的研究の発展がのぞましいこと、などが確認された。また、今後の新たな研究計画に利用できるように、種分化研究の文献データベースの作成や一部計測データのデータベースの作成を行った。今回の成果は、日本生態学会でのシンポジウム「生物多様性の進化機構の解明」などで公開されるほか、雑誌での特集記事として企画している。また、継続的に論議し、今後、大きなプロジェクト研究として計画予定である。
Establishment of Supporting System for evaluating Biological Environments based on Protistan DNA nucleotide sequences

KITAZATO Hiroshi, YAMAUCHI Kiyoshi, MISHIMA Kyoko, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Shizuoka University

1997 - 1999

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In order to establish a support system for assessing marine biological environments, a genetic database of protistan species, which are commonly used as environmental proxies, was constructed for ribosomal DNA sequences. DNA analyses. were carried out for LSU, SSU and ITS sequence regions of ribosomal DNA. Relationships between species and ambient environments were compiled, both from publications and unpublished theses of Shizuoka University, to provide ecological or morphological constraints for the database. Samples for analyses were collected from seven innerbays from north to south along the Japanese Islands. Six species of benthic foraminifera (Protista) were selected for analysis. All are commonly used as proxies for dysaerobic environment or eutrophicated condition within the inner bay environment. The database was constructed for DNA sequences of these species. Sequence data for each species were listed, together with intraspecific and/or interspecific divergences, as a dataset. Physiological, ecological and morphological responses to ambient environmental changes were compiled to characterize each species as a specific environmental proxy. For instance, Trochammina hadai Uchio, which dwells in eutrophic environments of brackish bays, changes its test morphology in relation to the dissolved oxygen concentration at the sediment-water interface. This species reproduces at a water temperature of 10〜18 ℃, salinity of 25〜30 ‰, and dissolved oxygen concentration of 6〜8 ml/L. Sequence data for this species are sufficiently unique to discriminate from similar taxa. LSU rDNA sequences show only 0.1% difference between distributional areas. The ITS region, where substitution occurs very frequent, shows 2.0% of sequence differences. Sequence divergence tends to be smaller in highly polluted area of the sea, where heavy deposition of organic carbon takes place, than in less-polluted area. This tendency can be used as a good proxy for assessing precise environmental changes in response to pollution.
進化の測定:量的遺伝学の手法を用いた化石記録の解析

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業萌芽的研究

Category: 萌芽的研究

1997 - 1999

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本研究では喜界島の陸貝であるトコヨマイマイ,オオシママイマイ,タメトモマイマイを材料とし,隔離された島のなかでこれらの種が遂げた進化過程とそれにともなう遺伝的変化を解析した。特に島の各所から産出する更新世の化石試料に注目し現生集団との比較を通して進化の様式について明らかにした。そして遺伝様式と進化速度の関係、および環境変化が進化に及ぼす効果について考察した。まず更新世の化石集団と現生集団の殻の量的変異の解析の結果、これらの3つの種で共通の時間的変化のパターンが存在することが明らかとなった。すなわち、現生集団は化石集団より小型で、かつ扁平である。従って殻の形態は、島の違いよりも時代の違いによる差のほうが著しく、異なる系統で同じ形態への平行進化が生じていることが明らかとなった。現生集団の成貝殻の特徴は、化石集団の幼貝殻の特徴に一致しており、この平行進化が幼形進化のプロセスを反映していることが示唆された次に小笠原諸島の化石,現世陸貝群集(カタマイマイ属)を材料とし,その進化過程と遺伝的変化を解析した.現生集団のmtDNAの変異の分析によれば、それぞれ島の群集は独立にそれぞれの島で異なる時代に分化してきたことがわかった.またその放散は著しく急速で10万年程度の間に地上性,樹上性という分化が生じることがわかった.さらに化石記録の解析から,1万年前後の間に種分化が起こっていることが分かり,遺伝的な解析から明らかになった見解を支持する結果となった.
Natural history of submarine cave organisms in Indo-Pacific

KASE Tomoki, CHIBA Satoshi, MORI Kei, TABUKI Ryoich, HAYAMI Itaru, TAKEDA Masatsune

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for international Scientific Research

Category: Grant-in-Aid for international Scientific Research

Institution: National Science Museum

1996 - 1998

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Kase & Kinjo (1996) found a cave nassaried gastropods and Kase (1998) described 16 new species of the Pickworthiidae typical of caves. Kase and Kano (in press) described an enigmatic new genus and species from a submarine cave of Palau, possibly with neritopsine affinity . Hayami (1998) presents a hypothesis from analyses of size changes of bivalves in time and space and reproductive adaptation of cave bivalves that oligotrophic condition are responsible for the mass extinctions caused by various geologic and astronomical events. Although various environmental factors may influence the body size of organisms, recent knowledge of deep-sea and submarine cave faunas indicates that food supply is of prime importance as a factor controlling the adult size and adaptive strategy of bivalves.Significant shell-size reductin of bivalves seems to have occurred at the same time with Permian/Triassic and Cretaceous/Tertiary mass extinctions, probably because large-sized species (or group) were selectively eliminated. Takeda (1998) described 6 species of crabs collected in submarine caves around Koror Island, Palau : Schizophyrys dahlak (Majidae), Carupa ohashii, Chair ybdis paucidentata and Laleonectes nipponensis (Pornidae), and Lentilumnus tatimanus and Pilumnus sp. (Pilumnidae). S.dahliak had been known only from the Red Sea and Ch. paucidentata from the western Indian Oceans. Species of the Majidae and Purtunidae seems to be cave inhabitants. A living fossil sigillid genus, Kasella, was first discovered from submarine caves (Tabuki & Hanai, in press). Sigillids are primitive podocopid ostracods having ancient characters Kasella is possibly derived from the sigillid Cardobairdia of deep-waters. It is likely that Kasella has successfully colonized hard substrates in caves, particularly exploiting the crevices on cave walls and ceilings as its microhabitat. Kasella may have adapted to this cryptic habitat in response to strong cytheracean competitors and predators such as gastropods that do not survive well in dark and oligotrophic submarine caves.
Studies of molecular genetics on the basis of protein and nucleic acid preserved in fossil materials.

CHIBA Satoshi, YOSHINAGA Koichi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Shizuoka University

1995 - 1997

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Condition of preservation of biomolecules such as protein and nucleic acid were examined, and potential of estimating phylongenetic relationship of fossil organisms by nsing these biomolecules was evaluated. Intracrystalline protein was extraced from four modern species (Patinopecten yessoensis, Umbonium giganteum, Sunetta menstrualis and Crassostrea gigas) and one fossil species (Patenipecten tokyoensis) of mollusca. Patenipecten tokyoensis were occurred from Pliocene deposits of Kakegawa fromation. Twenty-one species of protein were detected by electrophoretic analysis with SDS-PAGE.Protein molecules obtained from Patenipecten yessosensis and Patenipecten tokyoensis were restricted at the position of methionine. Restriction patterns of these molecules are coincident between modern species Patenipecten yessoensis and fossil species Patenipecten tokyoensis. Since these species are considered to be closely related, overall similarity of restriction patterns of protein between these species suggest that protein have been preserved in the fossil materials. Phylogenetic relationship among the molluscan species estimated on the basis of the variations in the species of protein possessed by these molluscan species well corresponded to the phylogenetic relationships on the basis of nuclear DNA sequence (lrRNA). This suggests that the preserved protein in the fossils are useful to assess phylogenetic relationships. Nuclear and mitochondrial DNA were extracted from fossil insects (Donaciinae, Carabidae, Hydrophilinae) correceted from the Pleistocene and Holocene peat. These DNAs were amplified via PCR,and 300bp of nuclear 18SrRNA and mitochondrial 16SrRNA were sequenced. Sequences of the fossil species of Hydrophilinae were the closest to those of living species of Hydrophilinae among sequences obtained from Genbank. This suggests that DNAs of fossil Hydrophilinae species are amplified successfully and sequenced. This also suggests that DNA was preserved in the fossil insects occurred from peat.
EVOLUTIONARY STUDY OF MARINE RELIC INVERTEBRATES

TANABE Kazushige, CHIBA Satoshi, KASE Tomoki, ENDO Kazuyoshi, UESHIMA Rei, OJI Tatuo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Category: Grant-in-Aid for Scientific Research (A)

Institution: THE UNIVERSITY OF TOKYO

1995 - 1996

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(1) Ecological and taxonomic research : Kase, Hayami, Hanai, Tabuki, and Mori have found a peculiar primitive invertebrate faunas in the submarine caves in the tropical and subtropical Western Pacific. They collected many live and dead samples of the faunas and analyzed their ecological and taxonomic characteristic as a basis for future evolutionary researches. (2) Developmental biological research : Tanabe has investigated the mode of embryonic shell development in the primitive ectocochliate cephalopod Nautilus with the help of Mr. K.Uchiyama of the Toba Aquarium, and recognized a disks-shaped univalved organic shell (cicatrix) in the early stage. A similar shaped disk-shaped or low cap shaped primary shell is also known in extant Monoplacophora, suggesting their phylogenetic relationships. (3) Molecular systematic research : Endo, Ueshima, Ozawa, and Chiba have conducted DNA analysis of some primitive invertebrates such as brachiopods and stalked crinoids to establish their phylogenetic relationships at higher taxonomic levels. (4) Theoretical research : Chiba constructed numerical models to explain the log-term phenotypic-level evolution based on the theory of quantitative genetics.
Evaluation of the meaning of foraminiferal test morphology based on DNA sequences

KITAZATO Hiroshi, YOSHINAGA Koichi, CHIBA Satoshi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Shizuoka University

1994 - 1996

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To evaluate the meaning of benthic foraminiferal test morphology, molecular phylogenetic analyzes have carried out for several selected genera. Glabratella and Bolivina and related genera were selected for analysis, because these genera have been well documented morphologically. Both DNA extractions and PCR techniques were mostly adopted from Pawlowski et al. (1995). We analyzed about 650 nucleotic acid base pairs from LSU ribosomal DNA.Specific primers for foraminifera were used for each PCR step. Amplified DNA fragments were cloned at plasmid vectors, then sequenced with an automatic sequencer. DNA sequences of forminifera show several interesting results. Genetic variation within local populations of Glabratella is lower than in Bolivina and Ammonia. This may reflect differences in mode of reproduction among foraminiferal genera. Molecular phylogenies calculated from nucleotide sequencing data had different cluster groups than a phylogeny based on morphological data. Calculations of the molecular phylogenetic trees were made with both parsimony and neighbor joining methods. Cluster groups of molecular data were, however, well related to morphological cluster groups that are based on functional morphology. For instance, radial grooves around the aperture area, which may be related to reproductive behavior, is similar among taxa grouped by molecular clustering. In Glabratella opercularis the variation within one of the populations was greater than that fpund within other entire species that we have studied. Whithin this population morphological variation is typical for foraminiferal populations and it is not possible to subdivide the population based on morphological characters. These results suggest that reevaluation of foraminiferal test morphology from the view point of functional morphology may enable creation of phylogenies based on morphology that are cnoformable with molecular phylogenies.
絶滅の機構と過程について-南西諸島における陸産貝類をモデルケースとして

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業奨励研究(A)

Category: 奨励研究(A)

Institution: 静岡大学

1994 - 1994

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本研究では,奄美大島,喜界島,北大東島において化石陸貝および現生陸貝の採取を行い,その分類,形態解析,遺伝的解析をおこなった.化石は海岸や段丘上の砂丘や石灰岩の割れ目,鍾乳洞の堆積物から産出した.炭素同位体法によって,各サンプルごとに時代決定を行った結果,これらの化石は更新世末期(2〜3万年前)から完新世(1万年以降)にかけてのものであることが明らかになった.島ごとに時代別の陸貝の種数,絶滅率,移入率をもとめたところ,特に喜界島で更新世終末期に著しい種の絶滅(63%)が認められた.また島から絶滅した種の現在の分布域を調べたところ.この絶滅種は多くが現在琉球列島よりも寒冷な地域(九州以北)に分布していることがわかった.従って完新世以降の温暖化がこの絶滅の要因のひとつと考えられた.また琉球列島の各島に分布する現生の陸貝の種数と島の面積に,べき乗の関係が認められ,かつ最終氷期の海面温度から推定された当時の面積と当時の種数が,この関係によく対応したことから,この絶滅には海面上昇に伴う島の面積の減少も大きくかかわっていたと考えられる. 次に,殻の10形質の計測値と,主成分分析に基づく形態解析の結果,喜界島における3種,北大東島における1種の陸貝で,最終氷期以降の体サイズの減少および幼形進化が,共通して認められた.遺伝的な解析の結果から,これらの種は各島ごとに隔離されており,島の中でそれぞれ独自の進化を遂げたものと考えられた.このように本研究により最終氷期以降の気候変化が,群集組成や表現型の著しい変化をもたらしたことが推定された.
Origin and evolution of echinoderm pentamery, a combined paleontological and molecular biological approach

OJI Tatsuo, CHIBA Satoshi, ENDO Kazuyoshi, TANABE Kazushige

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (A)

Category: Grant-in-Aid for General Scientific Research (A)

Institution: The University of Tokyo

1993 - 1994

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Echinoderms constitute one of the invertebrate animal phyla that originated in the Cambrian and survived to the Recent seas. The phylum is characterized by the pentamerous symmetry in the adult body plan. The purpose of this project has been to clarify when and how this character evolved, as well as its functional significance, from the viewpoints of paleontology, embryology and molecular biology. 1. Fossil records ; Because the late pre-Cambrian Tribrachidium has trimerous symmetry, some researchers consider that trimery presedes pentamery in echinoderms. However, it is dubious that Tribrachidium is an echinoderm. It is known that Cambrian echinoderms already had pentamerous symmetry. The pentamerous pattern of Cambrian echinoderms is in fact the '2-1-2 pattern', in which two of the three branches branches into two to make five branches. This pattern is wide spread in later echinoderms, therefore, it is reasonable to consider that the true pentamerous pattern evolved from the 2-1-2 pattern. 2. Embryology ; In the development of echinoderms, pentamerous symmetry first appear when the water vascular system is formed and where the water vascular system is segmented into five projections. Detailed observation of the development of water vascular systems is therefore important to understand the mechanisms of the formation of pentamerous symmetry. 3. Molecular biology ; It is not yet known what kind of genes control the formation of pentamerous body plan. From the known significance of homeogenes in body plan formation, it is not too much a speculation to consider that homeogenes are involved in the making of pentamery in echinoderms. In this study, DNA primers have been designed to PCR amplify a region of homeobox of some echinoids. As a result, some target DNA fragments have successfully amplified. The relationship between the expression of homeogenes and the formation of pentamery is now being investigated.
集団遺伝学に基づく化石個体群の解析-大東諸島の固有陸産貝類を例として

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業奨励研究(A)

Category: 奨励研究(A)

Institution: 静岡大学

1993 - 1993

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本研究では大東諸島の特産種であるヘソアキアツマイマイを材料とし、隔離された島のなかで本種が遂げた進化過程を解析した。特に島の各所から産出する更新世の化石試料に注目し現生集団との比較を通して進化の様式について明らかにした。そして遺伝様式と進化速度の関係、および環境変化が進化に及ぼす効果について考察した。まず更新世の化石集団と現生集団の殻の量的変異の解析の結果、北大東島南大東島のいずれの島でも共通の時間的変化のパターンが存在することが明らかとなった。すなわち、現生集団は化石集団より大型で、かつ殻の周縁に鋭い角があり、扁平である。従って殻の形態は、島の違いよりも時代の違いによる差のほうが著しく、異なる島で同じ形態への平行進化が生じていることが明らかとなった。現生集団の成貝殻の特徴は、化石集団の幼貝殻の特徴に一致しており、この平行進化が幼形進化のプロセスを反映していることが示唆される。現生集団の電気泳動分析による蛋白質多型の分析によれば、二つの島の集団は遺伝的な多様性に乏しく、また遺伝的にかなり異なっており、互いの島の間で移住はなかたと考えられる。このことから更新世以後の環境変化が集団の幼形進化をもたらしたと考えられる。集団の遺伝的多様性の乏しさは、集団が強い瓶首効果を経ている可能性をしさしており、この種の急速な幼形化は、これによって促進された可能性がある。
隔離された島嶼における生物相の進化学的解析-小笠原諸島の国有陸産貝類を例として

千葉聡

Offer Organization: 日本学術振興会

System: 科学研究費助成事業奨励研究(A)

Category: 奨励研究(A)

Institution: 静岡大学

1992 - 1992

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Social Activities 30

小笠原世界自然遺産講演会小笠原諸島の陸産貝類

2007/02/21 - 2007/02/22

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小笠原諸島の陸産貝類に関する講演
Sabah大学後援によるTropical Malacology Course

2005/02/28 - 2005/03/09

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ボルネオにて貝類に関する保全の普及のためのショートコース、講義、実習
TBS NEWS23

2020/06/23 -
東北大学リベラルアーツサロン第60回

2019/09/20 -
放送大学宮城学習センター公開講演会

2019/02/16 -
NHKスペシャル秘島探検東京ロストワールド第1集南硫黄島

2018/09/16 -
カタツムリの達人千葉聡 vs．ビートたけし

新潮45

2018/03 -
宮城一高理数系講演会

2015/12/21 -

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講演会
TBS「Ｎスタ」

2015/06/25 -
NHK総合ニュースおはよう日本

2015/06/24 -
NHK総合「ニュースウオッチ9」

2015/06/24 -
東北アジア研究センター公開講演会

2014/12/06 -

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「東北アジアの自然誌」-地球・自然のダイナミクス- 東北アジア地域の生物とその起源
宮城一高理数系講演会

2014/11/10 -

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宮城一高理数科の生徒を対象とした理数科講演会
仙台一高特別講義

2013/11/18 -

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仙台一高校において、SSH活動の一環として、講義を行った。
日本テレビ「真相報道バンキシャ」

2011/06/12 -
NHK BS1 「ほっと＠アジア」

2011/05/23 -
ＮＨＫラジオ第一放送「私もひとこと、夕方ニュース」

2011/05/19 -
ＮＨＫ総合「時論公論」

2011/05/19 -
希少生物残る南硫黄島

2008/02/20 -

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千葉が参加した南硫黄島調査の概要に加え、千葉が発見した陸貝新種について報道された。
生態系の再生に挑む

2007/11/30 -

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千葉が行ったマイマイカブリの研究が紹介された。
多様な世界のカタツムリ

2007/06/10 -

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千葉が行っている小笠原の陸貝の研究が紹介された。
小笠原の挑戦

2007/01/30 -
日本の自然遺産：環境ルネサンス

2007/01/17 -
巻貝移出で寄生虫広まる・日本から米国へ

2006/12/19 -
亜熱帯の小笠原諸島、世界遺産登録に難題

2006/12/06 -
カタツムリ、「新種」５種見つかる小笠原

2006/08/19 -
SCIENCE WALK 発見、進化の樹は網

2006/07/24 -
小笠原が世界自然遺産になるには

2006/07/21 -
特別博物展「海洋島小笠原～生き物の魅力とその危機～」

2005/04/22 -

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小笠原のカタツムリ保全に関する講演活動
カタツムリ王国小笠原

2004/11/14 -

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Media Coverage 21

カタツムリ、殻で天敵撃退北海道などの固有種で確認

日本経済新聞

2016/11/21

Type: Newspaper, magazine
Snail Hits Predator with Its Shell |

National Geographic News

2016/11/17

Type: Other
カタツムリ：殻を振り回し敵撃退

毎日新聞

2016/11/11

Type: Newspaper, magazine
The Economist, "Till death us do dart"

The Economist

2015/03/14

Type: Newspaper, magazine
National Geographic "Love Hurts: What Happens When Snails Stab Their Mates"

National Geographic

2015/03/10

Type: Newspaper, magazine
ラジオＴＢＳラジオ：夢夢Engine

2011/11/05

Type: Other
読売新聞わかるサイエンス：小笠原諸島のカタツムリ

読売新聞

2011/10/02

Type: Newspaper, magazine
ラジオ J-WAVE "JAM The WORLD"

2011/08/01

Type: Other
朝日新聞探究人：小笠原のカタツムリに驚く

2011/07/28

Type: Newspaper, magazine
毎日新聞小笠原のカタツムリ：食べられても生きてます

毎日新聞

2011/07/27

Type: Newspaper, magazine
National Geographiｃ News, "Snails Survive Being Eaten by Birds—A Mystery"

2011/07/19

Type: Other
BBC Nature News "Tiny snails survive digestion by birds"

2011/07/11

Type: Other
ラジオ FM東京東芝グリーンアースレディオ

2011/07/09

Type: Other
ＴＢＳ「THE世界遺産」

2011/07/03

Type: TV or radio program
毎日新聞「世界遺産：東京・小笠原を登録美しき島、誇りに－－カタツムリ研究の千葉さん」

2011/06/25

Type: Newspaper, magazine
毎日新聞「世界遺産：小笠原諸島の登録決定カタツムリの楽園」

2011/06/24

Type: Newspaper, magazine
・読売新聞「顔」

2010/07/09

Type: Newspaper, magazine
ダーウィンが来た！生きもの新伝説「南硫黄島ただいま進化中」

2009/02/01

Type: TV or radio program
世界遺産に一番近い島奇跡のワンダーランド小笠原5つの不思議

2008/12/07

Type: TV or radio program
サイエンスZERO：知られざる南硫黄島 25年ぶりの上陸調査

NHK

2007/11/29

Type: TV or radio program

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千葉が参加した南硫黄島の調査の成果と千葉が行った陸貝の捕食実験が紹介された。
中村桂子の生物進化４０億年の旅

Sky PerfecTV サイエンスチャンネル

2005/10/28

Type: TV or radio program

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Other 11

世界自然遺産を蝕む未知の侵入者：外来ヒモムシの生態系影響評価

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外来生物であるヒモムシが及ぼす小笠原の土壌動物生態系への影響評価
小笠原諸島の自然再生における絶滅危惧種の域内域外統合的保全手法の開発（(4)絶滅危惧陸産貝類の域内・域外保全および再導入手法の開発

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小笠原諸島の絶滅危惧陸産貝類の系統保存及び域外保全技術の開発と、そのための施策提案
東北アジアにおける貝類をモデルとした生物多様性形成機構の解明

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ロシア極東地域の陸・淡水貝類、および昆虫類を用いて、種多様性パターンの進化過程を推定し、種間相互作用が多様化に果たす役割を解明する。
捕食者ー被食者の共進化：赤の女王のテスト

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ボルネオの陸産巻貝とその捕食者をモデル系として、捕食と対捕食戦略のエスカレーションの仮説を検証する
太平洋島嶼地域の陸産貝類の生物地理学研究

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太平洋諸島の生物群集の成立過程および移動、分散、絶滅による生物地理パターンの形成過程を、これらの島に分布する陸貝をモデルとして解明する
Temporal and spatial patterns of species diversity in molluscs

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日本から北米カリフォルニアに至る太平洋海域における、貝類の種多様性の地理的パターンを明らかにし、その成因を歴史的な視点に注目して解明する
脆弱な海洋島をモデルとした外来種の生物多様性への影響とその緩和に関する研究

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小笠原諸島における外来種の排除、ならびに影響の緩和のための具体的な方策の立案に関する研究。
Sexual conflictが雌雄同体生物に及ぼす効果

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雌雄同体の生物で、なぜ交尾行動の際、相手を傷つけたり、毒を盛ったりするのか？という謎を、Sexual conflictの考えをベースに解明する。
海生生物の移入とその効果

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日本からアメリカに侵入した海産巻貝を材料に、その侵入プロセスを解明し、それが土着の生態系に与える影響を解明する
小笠原諸島における固有陸産貝類カタマイマイの多様性保全について

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小笠原諸島の陸貝Mandarina属の保全に関する基礎的な調査を行った。各種の分布域，および地域ごとの個体群密度を野外調査によって明らかにした。地域個体群や種ごとの絶滅リスクを評価するため、個体群密度に加えて、個体群の保有する遺伝的多様性を求めた．
陸産貝類のゲノム解読

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陸産貝類を材料とし、その形、模様、行動、生殖を決定している遺伝子機構を解明する

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