研究者業績
基本情報
- 所属
- 兵庫県立大学 自然・環境科学研究所 教授
- 学位
- 理学修士(京都大学)博士（理学）(京都大学)
- 通称等の別名
- とし
- J-GLOBAL ID
- 200901063298720728
- researchmap会員ID
- 1000047308
研究キーワード
13経歴
5-
2009年4月 - 現在
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2004年4月 - 2009年3月
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1994年4月 - 2004年3月
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1989年1月 - 1994年3月
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1988年4月 - 1988年12月
学歴
3-
1986年4月 - 1988年12月
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1984年4月 - 1986年3月
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1980年4月 - 1984年3月
委員歴
61-
2023年1月 - 現在
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2019年5月 - 現在
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2019年5月 - 現在
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2019年4月 - 現在
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2017年1月 - 現在
受賞
3-
2003年
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2000年
論文
313-
Acta Herpetologica 9(1) 61-73 2014年2月 査読有り最終著者
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Current Herpetology 33(1) 1-7 2014年 査読有り最終著者Skeletal remains of the geoemydid turtle, Mauremys mutica, were recovered from the lower layer of the Tugurubama archeological site on Yonagunijima Island, which corresponds to the period from the late middle to early late Holocene (ca., 4,000 yBP). These represent the first concrete evidence for the prehistoric occurrence of this turtle in the Yaeyama Islands and offer strong support for the indigenous nature of the current Yaeyama populations of M. mutica.
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ZOOLOGICAL SCIENCE 30(8) 633-641 2013年8月 査読有りThe Ryukyu-Taiwan region is an island arch with intervening waters of varying distances and depths. This study examines the geographic genetic structure of two sympatric sea kraits, Laticauda laticaudata and L. semifasciata, in the region, to infer factors affecting the extent of dispersal and other biogeographical traits of these amphibious reptiles. Sequence analyses of the mitochondrial cytochrome b gene revealed four and 16 haplotypes for L. laticaudata (136 individuals) and L. semifasciata ( 177 individuals), respectively. For both species, population pairwise F-ST analyses revealed significant genetic differentiations among islands and island groups, which are separated by deep straits, suggesting that deep waters serve as obstacles for dispersal in both species. Significant genetic differentiation was detected even among islands of the same basin in L. laticaudata, but not in L. semifasciata, and the isolation by distance analyses revealed no significant correlation between geographic and genetic distances in the former species. These results further suggest that L. laticaudata has stronger site fidelity or degree of philopatry than L. semifasciata. Based on the geographic genetic patterns, the historical biogeography of the two species in the Ryukyu-Taiwan region is also discussed.
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Molecular Phylogenetics and Evolution 66(3) 654-667 2013年3月 査読有り最終著者We investigated the phylogenetic relationships and estimated the historical demography of the Japanese fire-bellied newt, Cynops pyrrhogaster, from Japanese mainlands using 1407-bp sequences of the mitochondrial DNA (NADH6, tRNAglu, cyt b) and 1208-bp sequences of nuclear DNA (Rag-1) genes. Phylogenetic trees based on mitochondrial DNA revealed four major haplotype clades (NORTHERN, CENTRAL, WESTERN, and SOUTHERN clades) within this species. Degree of genetic differentiation among major haplotype clades was very large for intraspecific variation, suggesting this species to be composed of four species lineages that replace each other geographically. Nuclear genetic variation presented no obvious patterns of geographic structure except for the distinctness of populations diagnosed by NORTHERN clade of mitochondrial haplotypes, suggesting results of incomplete lineage sorting. Current distribution and estimated divergence times for the genus Cynops suggest that the common ancestor of two Japanese species (C. pyrrhogaster and C. ensicauda from the Ryukyu Islands) had diverged at the edge of the continent corresponding to the present East China Sea and Central Ryukyus. Subsequent range expansion to Japanese mainland seems to have occurred in the middle Miocene. Population-genetic analyses indicated that all species lineages, except for the SOUTHERN one, experienced geographic population reductions and expansions associated with glacial and postglacial climatic oscillations. © 2012 Elsevier Inc.
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Acta Herpetologica 8(1) 19-34 2013年2月 査読有り最終著者
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Herpetological Review 44(1) 8-23 2013年2月 査読有り
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Zoologica Scripta 42(1) 54-70 2013年1月 査読有りWe investigated the phylogenetic and taxonomic relationships and estimated the history of species diversification and biogeography in the Asian rhacophorid genus Polypedates, focusing on the Polypedates leucomystax complex, whose members are notoriously difficult to classify. We first estimated phylogenetic relationships within the complex using 2005-bp sequences of the mitochondrial 12S rRNA, tRNA and 16S rRNA genes with maximum parsimony, maximum likelihood (ML) and Bayesian methods of inference. Polypedates exhibits well-supported monophyly, with distinct clades for P. otilophus, P. colletti, P. maculatus and the P. leucomystax complex, consisting of P. macrotis, and the Malay (Polypedates sp. from Malay Peninsula), North China (P. braueri), South China (Polypedates cf. mutus 1), Indochina (P. megacephalus), Sunda (P. leucomystax) and Laos (Polypedates cf. mutus 2) clades. In a subsequent phylogenetic analysis of 4696-bp sequences of the nuclear brain-derived neurotrophic factor (BDNF), sodium/calcium exchanger 1 (NCX), POMC, Rag-1, Rhod and Tyr genes using Bayesian methods of inference, all of these clades were recovered. Some clades of the P. leucomystax complex occur sympatrically and show high genetic diversity or morphological and acoustic differences. Similar tendencies were observed between some allopatric clades. Therefore, we consider each of these groups to be distinct specifically. We also estimated absolute divergence times within the genus using Bayesian methods. Divergence in Polypedates began with the divergence of a primarily South Asian Clade from the common ancestor of secondarily South-East Asia P. maculatus and South-East Asian members. The divergence between the latter occurred much later. The P. leucomystax complex diverged in the Pliocene, much later than other congeners, and seems to have been greatly affected by human-related dispersal after the Pleistocene. © 2012 The Authors Zoologica Scripta © 2012 The Norwegian Academy of Science and Letters. val
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BIOLOGICAL CONSERVATION 157 372-385 2013年1月 査読有りEffective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world's reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of human-induced habitat loss and harvesting, which are the predominant threats to reptiles. (C) 2012 Elsevier Ltd. All rights reserved.
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PLoS ONE 7(12) 2012年12月31日 査読有りComparative genome analysis of non-avian reptiles and amphibians provides important clues about the process of genome evolution in tetrapods. However, there is still only limited information available on the genome structures of these organisms. Consequently, the protokaryotypes of amniotes and tetrapods and the evolutionary processes of microchromosomes in tetrapods remain poorly understood. We constructed chromosome maps of functional genes for the Chinese soft-shelled turtle (Pelodiscus sinensis), the Siamese crocodile (Crocodylus siamensis), and the Western clawed frog (Xenopus tropicalis) and compared them with genome and/or chromosome maps of other tetrapod species (salamander, lizard, snake, chicken, and human). This is the first report on the protokaryotypes of amniotes and tetrapods and the evolutionary processes of microchromosomes inferred from comparative genomic analysis of vertebrates, which cover all major non-avian reptilian taxa (Squamata, Crocodilia, Testudines). The eight largest macrochromosomes of the turtle and chicken were equivalent, and 11 linkage groups had also remained intact in the crocodile. Linkage groups of the chicken macrochromosomes were also highly conserved in X. tropicalis, two squamates, and the salamander, but not in human. Chicken microchromosomal linkages were conserved in the squamates, which have fewer microchromosomes than chicken, and also in Xenopus and the salamander, which both lack microchromosomes in the latter, the chicken microchromosomal segments have been integrated into macrochromosomes. Our present findings open up the possibility that the ancestral amniotes and tetrapods had at least 10 large genetic linkage groups and many microchromosomes, which corresponded to the chicken macro- and microchromosomes, respectively. The turtle and chicken might retain the microchromosomes of the amniote protokaryotype almost intact. The decrease in number and/or disappearance of microchromosomes by repeated chromosomal fusions probably occurred independently in the amphibian, squamate, crocodilian, and mammalian lineages. © 2012 Uno et al.
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MOLECULAR PHYLOGENETICS AND EVOLUTION 65(2) 642-653 2012年11月 査読有り
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Molecular Phylogenetics and Evolution 63(3) 714-723 2012年6月 査読有りWe investigated the phylogenetic relationships and estimated the history of species diversification and character evolution in two ichthyophiid genera: Caudacaecilia and Ichthyophis. We estimated the phylogenetic relationships of 67 samples from 33 localities in Southeast Asia from 3840-bp sequences of the mitochondrial 12S rRNA, 16S rRNA, and cyt b genes using Bayesian inference, maximum likelihood, and maximum parsimony methods. The Southeast Asian samples formed a well-supported clade differentiated from a South Asian sample. The Southeast Asian clade was divided into two subclades, one containing samples from South China, Indochina, Malay Peninsula, and Java. The other consisted of samples from Borneo and the Philippines. Neither Caudacaecilia nor Ichthyophis was monophyletic, nor did samples with or without light stripes lateral to the body form clades. We found several distinct sympatric lineages and undescribed species, especially from Sundaland. © 2012 Elsevier Inc.
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Nature of Kagoshima (38) 1-8 2012年5月 筆頭著者
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Zoological Journal of the Linnean Society 165(1) 163-189 2012年5月 査読有りBlue-tailed skinks (genus Plestiodon) are a common component of the terrestrial herpetofauna throughout their range in eastern Eurasia and North and Middle America. Plestiodon species are also frequent subjects of ecological and evolutionary research, yet a comprehensive, well-supported phylogenetic framework does not yet exist for this genus. We construct a comprehensive molecular phylogeny of Plestiodon using Bayesian phylogenetic analyses of a nine-locus data set comprising 8308 base pairs of DNA, sampled from 38 of the 43 species in the genus. We evaluate potential gene tree/species tree discordance by conducting phylogenetic analyses of the concatenated and individual locus data sets, as well as employing coalescent-based methods. Specifically, we address the placement of Plestiodon within the evolutionary tree of Scincidae, as well as the phylogenetic relationships between Plestiodon species, and their taxonomy. Given our sampling of major Scincidae lineages, we also re-evaluate 'deep' relationships within the family, with the goal of resolving relationships that have been ambiguous in recent molecular phylogenetic analyses. We infer strong support for several scincid relationships, including a major clade of 'scincines' and the inter-relationships of major Mediterranean and southern African genera. Although we could not estimate the precise phylogenetic affinities of Plestiodon with statistically significant support, we nonetheless infer significant support for its inclusion in a large 'scincine' clade exclusive of Acontinae, Lygosominae, Brachymeles, and Ophiomorus. Plestiodon comprises three major geographically cohesive clades. One of these clades is composed of mostly large-bodied species inhabiting northern Indochina, south-eastern China (including Taiwan), and the southern Ryukyu Islands of Japan. The second clade comprises species inhabiting central China (including Taiwan) and the entire Japanese archipelago. The third clade exclusively inhabits North and Middle America and the island of Bermuda. A vast majority of interspecific relationships are strongly supported in the concatenated data analysis, but there is nonetheless significant conflict amongst the individual gene trees. Coalescent-based gene tree/species tree analyses indicate that incongruence amongst the nuclear loci may severely obscure the phylogenetic inter-relationships of the primarily small-bodied Plestiodon species that inhabit the central Mexican highlands. These same analyses do support the sister relationship between Plestiodon marginatus Hallowell, 1861 and Plestiodon stimpsonii (Thompson, 1912), and differ with the mitochondrial DNA analysis that supports Plestiodon elegans (Boulenger, 1887)+P. stimpsonii. Finally, because the existing Plestiodon taxonomy is a poor representation of evolutionary relationships, we replace the existing supraspecific taxonomy with one congruent with our phylogenetic results. © 2012 The Linnean Society of London.
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Bulletin of the Kagoshima Prefectural Museum (31) 59-65 2012年3月 査読有り筆頭著者責任著者
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Biological Journal of the Linnean Society 105(2) 395-408 2012年2月 査読有りWe investigated intraspecific phylogenetic relationships in the natricine snake, Rhabdophis tigrinus. A partial sequence of mitochondrial cytochrome b gene (990bp) was sequenced for 220 individuals from 112 populations. The phylogeny indicated monophyly of the Japanese populations against the continental and Taiwanese populations, sister relationships of the Japanese and continental populations, and monophyly of the whole species. The results strongly suggested substantial genetic divergences among population assemblages from those three regions. We thus consider both lateralis from the continent, which is often synonymized to R.tigrinus, and formosanus from Taiwan, which is usually regarded as a subspecies of the latter, as distinct full species based on the evolutionary species concept. In the Japanese populations, haplotypes were classified to in two major clades (I and II) that were parapatric to each other. Clade I consisted of three distinct subclades (I-A, I-B, and I-C), of which the former two were parapatric with each other, whereas the latter was sympatric with each of the former two subclades. The geographical haplotype structure exhibited by the Japanese populations is likely to have resulted from a series of allopatric differentiations with rapid range extensions of resultant lineages, leading to secondary contact or further admixture of mitochondrial haplotype clades and subclades. © 2011 The Linnean Society of London.
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CHELONIAN CONSERVATION AND BIOLOGY 10(2) 237-249 2011年12月 査読有り
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Zoological Science 28(11) 834-839 2011年11月 査読有りOdorrana ishikawae is listed as a class IB endangered species in the IUCN Red List and is protected by law in both Okinawa and Kagoshima Prefectures, Japan. Here, in an effort to help effectively preserve the genetic diversity of this endangered species in the laboratory, we tested a farming technique involving the artificial breeding of frogs, and also promoted natural breeding in the laboratory. Field-caught male/female pairs of the Amami and Okinawa Island populations were artificially bred using an artificial insemination method in the 2004, 2006, and 2008 breeding seasons (March to April). Although fewer than 50% of the inseminated eggs achieved metamorphosis, approximately 500, 300, and 250 offspring from the three respective trials are currently being raised in the laboratory. During the 2009 and 2010 breeding seasons, second-generation offspring were produced by the natural mating activities of the first offspring derived from the two artificial matings in 2004. The findings and the methods presented here appear to be applicable to the temporary protection of genetic diversity of local populations in which the number of individuals has decreased or the environmental conditions have worsened to levels that frogs are unable to survive by themselves. © 2011 Zoological Society of Japan.
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Scientific Papers, Museum of Natural History, University of Kansas (43) 1-20 2011年10月 査読有り
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Zootaxa (2744) 53-61 2011年4月 査読有り
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Systematic Biology 60(1) 3-15 2011年1月 査読有り最終著者Identifying and dating historical biological events is a fundamental goal of evolutionary biology, and recent analytical advances permit the modeling of factors known to affect both the accuracy and the precision of molecular date estimates. As the use of multilocus data sets becomes increasingly routine, it becomes more important to evaluate the potentially confounding effects of rate heterogeneity both within (e.g., codon positions) and among loci when estimating divergence times. Here, using Plestiodon lizards as a test case, we examine the effects of accommodating rate heterogeneity among data partitions on divergence time estimation. Plestiodon inhabits both East Asia and North America, yet both the geographic origin of the genus and timing of dispersal between the continents have been debated. For each of the eight independently evolving loci and a combined data set, we conduct single model and partitioned analyses. We found that extreme saturation has obscured the underlying rate of evolution in the mitochondrial DNA (mtDNA), resulting in severe underestimation of the rate in this locus. As a result, the age of the crown Plestiodon clade was overestimated by 15-17 Myr by the unpartitioned analysis of the combined loci data. However, the application of partition-specific models to the combined data resulted in ages that were fully congruent with those inferred by the individual nuclear loci. Although partitioning improved divergence date estimates of the mtDNA-only analysis, the ages were nonetheless overestimated, thus indicating an inadequacy of our current models to capture the complex nature of mtDNA evolution in over large time scales. Finally, the statistically incongruent age distributions inferred by the partitioned and unpartitioned analyses of the combined data support mutually exclusive hypotheses of the timing of intercontinental dispersal of Plestiodon from Asia to North America. Analyses that best capture the rate of evolution in the combined data set infer that this exchange occurred via Beringia ∼18.0-30 Ma. © The Author(s) 2010.
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Cytogenetics and Genome Research 127(2) 182-190 2010年4月 査読有り招待有り最終著者責任著者
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Molecular Phylogenetics and Evolution 54(3) 910-921 2010年3月 査読有りWe investigated the phylogenetic relationships and phylogeography among individuals of the endemic newt (Cynops ensicauda) of the Central Ryukyus, Japan based on the mitochondrial cytochrome b gene. The results of phylogenetic analyses showed the presence of remarkable differentiation between assemblages from the Amami and Okinawa Island Groups, supporting the validity of the subspecies C. e. popei described from the latter on morphological grounds. The group of individuals from Okinawa Island Group was further divided into two distinct subgroups unlike the results of previous morphological and allozyme studies. Geographic ranges of these subgroups overlapped in the northern part of Okinawajima Island. The phylogeographic pattern within the Okinawa Island Group suggests an initial division into two geographically isolated population lineages and subsequent secondary sympatry before formation of reproductive isolation. It is also likely that within the Okinawa Island Group emigration occurred from the central and northern parts of Okinawajima Island to its southern part, as well as to several small islets off its western coast. Within the Amami Island Group, recurring restricted gene flow with isolation by distance seems to have occurred around the southwestern region including three islets southwest of Amamioshima Island. © 2009 Elsevier Inc. All rights reserved.
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Zootaxa (2345) 33-42 2010年1月27日 査読有りSystematic relationships of fanged frogs usually associated with Limnonectes kuhlii are assessed using 15 samples from Japan, Chinese Mainland and Taiwan, Vietnam, Laos, Thailand, Malaysia (Borneo), and Indonesia. Phylogenetic relationship inferred from the mitochondrial 12S rRNA, tRNA , and 16S rRNA gene sequences revealed that fanged frogs sampled are not monophyletic with the topotypic L. kuhlii from Java. Samples from Yunnan of southern China (L. bannaensis), northern Laos and central Vietnam, and those from Jiangxi of eastern China (L. fujianensis), Taiwan and Japan (L. namiyei), respectively, form monophyletic groups, and are collectively sister to the Thai sample (L. megastomias). All these samples, L. fragilis from Hainan of southern China, and a group of Bornean samples show unresolved relationships with Javanese L. kuhlii. From the resultant phylogeny and genetic distances found among samples, L. "kuhlii" from Taiwan and L. fujianensis, and L. "kuhlii" from northern Laos and central Vietnam and L. bannaensis, respectively, are surmised to be conspecific. These fanged frogs are morphologically similar to, but phylogenetically distant from, L. kuhlii sensu stricto. Limnonectes namiyei, L. fujianensis, and L. bannaensis are considered to have a common ancestor whose chromosome number was 2n=22, unlike L. fragilis, L. kuhlii and many other frogs with 2n=26 chromosomes. Copyright © 2010 Magnolia Press. val
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PLoS ONE 5(6) 2010年 査読有り最終著者Oceanic islands are well known for harboring diverse species assemblages and are frequently the basis of research on adaptive radiation and neoendemism. However, a commonly overlooked role of some islands is their function in preserving ancient lineages that have become extinct everywhere else (paleoendemism). The island archipelago of Bermuda is home to a single species of extant terrestrial vertebrate, the endemic skink Plestiodon (formerly Eumeces) longirostris. The presence of this species is surprising because Bermuda is an isolated, relatively young oceanic island approximately 1000 km from the eastern United States. Here, we apply Bayesian phylogenetic analyses using a relaxed molecular clock to demonstrate that the island of Bermuda, although no older than two million years, is home to the only extant representative of one of the earliest mainland North American Plestiodon lineages, which diverged from its closest living relatives 11.5 to 19.8 million years ago. This implies that, within a short geological time frame, mainland North American ancestors of P. longirostris colonized the recently emergent Bermuda and the entire lineage subsequently vanished from the mainland. Thus, our analyses reveal that Bermuda is an example of a "life raft" preserving millions of years of unique evolutionary history, now at the brink of extinction. Threats such as habitat destruction, littering, and non-native species have severely reduced the population size of this highly endangered lizard. © 2010 Brandley et al.
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Pacific Science 63(4) 317-325 2009年12月 査読有り最終著者
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Current Herpetology 28(1) 29-33 2009年6月 査読有り最終著者Recent skeletal remains of anurans, collected from Yoronjima Island of the Amami Group, Central Ryukyus, were identified by detailed comparisons with skeletal specimens representing all extant anuran species of Japan. As a result, four frog species including Rhacophorus viridis were recognized. This rhacophorid frog does not occur on Yoronjima Island at present, but its occurrence there by the middle of the 20th Century has been tentatively suspected on the basis of several museum specimens. Present finding offers a substantial support to this view, and confirms the first known case of island-level extinction of an extant native amphibian in the Ryukyu Archipelago. © 2009 by The Herpetological Society of Japan.
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Chromosoma 118(1) 43-51 2009年 査読有りPopulations of the gecko lizard Gekko hokouensis (Gekkonidae, Squamata) on Okinawajima Island and a few other islands of the Ryukyu Archipelago, Japan, have the morphologically differentiated sex chromosomes, the acrocentric Z chromosome and the subtelocentric W chromosome, although the continental representative of this species reportedly shows no sex chromosome heteromorphism. To investigate the origin of sex chromosomes and the process of sex chromosomal differentiation in this species, we molecularly cloned the homologues of six chicken Z-linked genes and mapped them to the metaphase chromosomes of the Okinawajima sample. They were all localized to the Z and W chromosomes in the order ACO1/IREBP -RPS6 -DMRT1 -CHD1 -GHR -ATP5A1, indicating that the origin of ZW chromosomes in G. hokouensis is the same as that in the class Aves, but is different from that in the suborder Ophidia. These results suggest that in reptiles the origin of sex chromosomes varies even within such a small clade as the order Squamata, employing a variety of genetic sex determination. ACO1/IREBP, RPS6, and DMRT1 were located on the Z long arm and the W short arm in the same order, suggesting that multiple rearrangements have occurred in this region of the W chromosome, where genetic differentiation between the Z and W chromosomes has been probably caused by the cessation of meiotic recombination. © Springer-Verlag 2008.
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Chromosome Research 16(8) 1119-1132 2008年12月 査読有りCrocodilians have several unique karyotypic features, such as small diploid chromosome numbers (30-42) and the absence of dot-shaped microchromosomes. Of the extant crocodilian species, the Siamese crocodile (Crocodylus siamensis) has no more than 2n = 30, comprising mostly bi-armed chromosomes with large centromeric heterochromatin blocks. To investigate the molecular structures of C-heterochromatin and genomic compartmentalization in the karyotype, characterized by the disappearance of tiny microchromosomes and reduced chromosome number, we performed molecular cloning of centromeric repetitive sequences and chromosome mapping of the 18S-28S rDNA and telomeric (TTAGGG) n sequences. The centromeric heterochromatin was composed mainly of two repetitive sequence families whose characteristics were quite different. Two types of GC-rich CSI-HindIII family sequences, the 305 bp CSI-HindIII-S (G+C content, 61.3%) and 424 bp CSI-HindIII-M (63.1%), were localized to the intensely PI-stained centric regions of all chromosomes, except for chromosome 2 with PI-negative heterochromatin. The 94 bp CSI-DraI (G+C content, 48.9%) was tandem-arrayed satellite DNA and localized to chromosome 2 and four pairs of small-sized chromosomes. The chromosomal size-dependent genomic compartmentalization that is supposedly unique to the Archosauromorpha was probably lost in the crocodilian lineage with the disappearance of microchromosomes followed by the homogenization of centromeric repetitive sequences between chromosomes, except for chromosome 2. © 2008 Springer Science+Business Media B.V.
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Pacific Science 62(3) 423-430 2008年7月 査読有り責任著者We examined dietary habits of the introduced cane toad Bufo marinus at three sites representing different types of habitats (pond, forest, and rice paddy) on Ishigakijima Island, southern Ryukyus, Japan. Stomach contents analysis revealed that the toad mostly utilizes terrestrial arthropods, of which hymenopterans (mostly ants), adult coleopterans, hemipterans, and araneans dominated in the frequency of occurrence, hymenopterans in the numerical proportion, and larval lepidopterans, adult coleopterans, and larval dipterans in the volumetric proportion. Comparisons in taxonomic composition of the toad's stomach contents and pitfall and sweeping net samples suggested ignorance or avoidance of Amphipoda by the toad. Our results suggest the possibility of considerable predation pressure of B. marinus upon the native arthropods, and ants in particular, on Ishigakijima Island. © 2008 by University of Hawai'i Press. All rights reserved.
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Pacific Science 62(3) 395-402 2008年7月 査読有り責任著者The Quaternary terrestrial turtle fauna of the Ryukyu Archipelago was reviewed on the basis of recently excavated fossils, as well as literature information. As a result, five extinct species (four geoemydids [Cuora sp., Geoemyda amamiensis, Mauremys sp., and another species with undetermined generic and specific status] and one testudinid [Manouria oyamai]) were recognized from Late Pleistocene cave and fissure deposits. Two of the three turtles currently occurring in this archipelago (C. flavomarginata and G.japonica) were also recognized from comparable deposits on islands, including those where they do not occur at present. These records indicate that the terrestrial turtles of the Ryukyus were much more diverse during the Late Pleistocene than at present, and that extinction has occurred during the last few tens of thousands of years not only for those five fossil species bur also for some island populations of the extant species. Distributions of three of the extinct species (G. amamiensis, Cuora sp., and the geoemydid [genus and species undetermined]), confined to the central Ryukyus, are concordam with the currently prevailing hypothesis of Ryukyu paleogeography, which assumes a relatively long isolation of this region and much more recent insularization of the southern Ryukyus. In contrast, distributions of the remaining two extinct species (Man. oyamai and Mau. sp.) must be explained by some ad hoc scenario or, otherwise, drastic modification of the current hypothesis. © 2008 by University of Hawai'i Press. All rights reserved.
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Marine and Freshwater Biodiversity 1(e96) 1-4 2008年6月 査読有り最終著者責任著者
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COPEIA (2) 452-466 2008年6月 査読有り最終著者Populations of the genus Gekko from three southern islands of the Tokara Group, Ryukyu Archipelago are known to be unique in lacking distinct preanal pores even in adult males. Recently, we found an almost identical morphotype from five islands of the Amami Group, where only G. hokouensis, a species having distinct preanal pores in adult males, has hitherto been recorded. To clarify the taxonomic status of these poreless geckos from the Tokara and Amami Groups, we conducted allozyme and morphological comparisons of Gekko specimens collected from these eight islands and one adjacent island. Results of the allozyme analyses showed the presence of fixed allelic differences at 7-14 loci between samples of the poreless form and sympatric G. hokouensis from each of the Amami islands, confirming their reproductive isolation. Our data further revealed the presence of two genetically divergent groups within the poreless form that are distinct from each other by fixed allelic differences at no less than 30% of loci examined. Ranges of these two groups are contiguous with each other but do not overlap on a single island. Distance analysis showed that one of the two groups is genetically much closer to G. hokouensis than to the other. These results strongly suggest that each of them represents an evolutionarily independent unit and deserves recognition as a full species. We describe these species based on a set of characters that clearly discriminate them from all other congeneric species hitherto described, and we briefly discuss their historical biogeography.
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Current Herpetology 27(1) 23-27 2008年 査読有り責任著者Bufo marinus is a large toxic toad that was recently introduced to Ishigakijima of the Yaeyama Islands, Southern Ryukyus, Japan. In a previous study, the native Southern Ryukyu snake, Dinodon rufozonatum walli, did not die after ingestion of a single juvenile toad. Considering the current high density of the toads on Ishigakijima, however, it is highly likely that an individual snake may have an opportunity in the field to swallow more than one toad in succession. Therefore, we experimentally investigated the occurrence of voluntary multiple ingestions of juvenile toads by this snake and their effects on the snake. In addition, we obtained from the inhabitants of Ishigakijima some field records of dead snakes that had apparently been killed by the cane toads (sometimes larger than the juveniles used in our experiment). The experiment showed that the snake may often voluntarily seize two or more juvenile toads at once, and may die while swallowing them. These results and the field records suggest that the D. r. walli population on Ishigakijima has been seriously affected by the feral toad population by ingesting this toxic prey. © 2008, The Herpetological Society of Japan. All rights reserved.
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Zoological Science 24(4) 360-375 2007年4月 査読有りIn order to elucidate the genetic relationships and reproductive-isolation mechanisms among the Fejervarya limnocharis complex from Indonesia and other Asian countries, allozyme analyses and crossing experiments were carried out using 208 individuals from 21 localities in eight Asian countries. The allozyme analyses revealed that 17 enzymes examined were controlled by genes at 27 loci, and that 7.9 phenotypes were produced by 5.2 alleles on average. The two species recognized in F. limnocharis sensu lato from Southeast Asia (i.e., F. limnocharis sensu stricto and F. iskandari) were found to occur sympatrically at three localities (Bogor, Cianjur and Malingping), all on Java, Indonesia. Fejervaya iskandari was dominant at each of these localities and showed substantial geographic genetic variation. Laboratory-produced hybrids between F. limnocharis and F. iskandari from Java became underdeveloped and died at the tadpole stage, suggesting that these species are completely isolated by hybrid inviability. Hybrids between topotypic F. limnocharis and the Malaysian and Japanese conspecific populations developed normally to metamorphosis. Likewise, hybrids between topotypic F. iskandari and the Thailand and Bangladesh conspecific populations also showed normal viability throughout larval development. The present allozyme analyses and crossing experiments strongly suggested the presence of two distinct forms, the large type and the small type, in the F. limnocharis complex from Asia, and further subdivision of the large type into the F. limnocharis assemblage and the F. iskandari assemblage. The small type was found in samples from India, Thailand, Bangladesh and Sri Lanka, and included at least three different species. The sample from Pilok, Thailand, was considered to represent an undescribed species. © 2007 Zoological Society of Japan.
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Chelonian Research Monographs 4(1) 157-167 2007年3月 査読有り招待有り
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Cytogenetics and Genome Research 117(2) 92-102 2007年3月 査読有り
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Zoological Science 24(2) 189-197 2007年2月 査読有りWe examined allozyme variation in two camaenid tree snails, Amphidromus atricallosus and A. inversus, across two principal regions of Thailand and from Singapore, plus for A. inversus, one site in peninsular Malaysia. Using horizontal starch gel electrophoresis, 13 allozyme loci (11 polymorphic) were screened for A. atricallosus and 18 (5 polymorphic) for A. inversus. Heterozygosity was higher in A. atricallosus (Hexp=0.018-0.201, mean=0.085) than in A. inversus (Hexp=0-0.023, mean=0.002). Genetic heterogeneity among samples was higher in A. inversus (Fst=0.965) than in A. atricallosus (Fst=0.781). Within A. atricallosus, populations were more differentiated in southern Thailand (Fst=0.551) than in eastern Thailand (Fst=0.144). The high Fst and low Hexp in populations of A. inversus suggest that this species is likely to have experienced a series of strong bottlenecks, perhaps occurring chiefly on offshore continental-shelf islands. The low Fst values of A. atricallosus in eastern Thailand suggest frequent gene flows among populations in this region. The southern and eastern samples of A. atricallosus exhibited fixed allele differences at four loci and great genetic distance (Nei's D=0.485-0.946), suggesting that these two samples may actually represent, or else be evolving into, separate species. © 2007 Zoological Society of Japan.
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Current Herpetology 26(2) 65-79 2007年 査読有り最終著者The populations of a frog long identified as Fejervarya limnocharis from the Southern Ryukyus (=Sakishima in conventional regional name), Japan, considerably differ genetically and morphologically from the topotypic population of the species from Java. These Southern Ryukyu populations are therefore judged to represent a distinct biological species, which is described here as Fejervarya sakishimensis. This new species differs from F. limnocharis in larger snout-vent length (SVL). Also, it is distinguished from the latter in shorter head and tibia, smaller eye and narrower internarial space, all relative to SVL, and larger ratio of the first toe length to the inner metatarsal tubercle. From F. multistriata, F. sakishimensis differs by relatively larger tympanum, wider head, upper eyelid and anterior and posterior spaces of eyes, and longer forelimb and first toe, besides larger SVL. Furthermore, F. sakishimensis has a larger body, and relatively shorter head, tibia and hindlimb than F. iskandari. Also, this species is differentiated from all other nominate taxa of the F. limnocharis complex by a combination of some morphological characteristics. © 2007, The Herpetological Society of Japan. All rights reserved.
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Current Herpetology 26(1) 1-11 2007年 査読有りTurtle fossils discovered from the putative Upper Pleistocene fissure-filling deposit on Tokunoshima Island of the Amami Group is described as a new species, Geoemyda amamiensis (Chelonii: Geoemydidae). These fossils include a carapace exclusive of peripherals and a few other elements, fragments of a neural, a costal, eight peripherals, an anterior half of the plastron, two epiplastra, and an incomplete right humerus. Geoemyda amamiensis most resembles G. japonica, an extant species endemic to three islands of the Okinawa Group, but is distinguished from the latter by the presence in dorsal view of a short anterior projection in the entoplastron. These two species seem to have split from each other through vicariance within the central Ryukyus. © 2007, The Herpetological Society of Japan. All rights reserved.
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Journal of Natural History 40(4) 439-459 2006年5月 査読有り最終著者
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BIOCHEMICAL GENETICS 44(1-2) 1-17 2006年2月 査読有り最終著者The status of natural hybridization between the two Japanese geckos, Gekko tawaensis and Gekko japonicus, was surveyed by use of 15 diagnostic allozyme loci. Of 438 specimens examined, 9 were identified as F-l, 1 was a first backcross with G. japonicus, and 15 were identified as more successive generations. Hybridizations were detected at 7 of the 15 localities interspersed throughout a broad sympatric area of the two species, forming a mosaic hybrid zone. A comparison of species-hybrid composition between 2-year samples from a single locality and a 5-year interval showed no evidence for progressive introgression or establishment of a hybrid swarm, despite constant emergences of F-l hybrids. Nonprevalence of the hybrid genotypes was also indicated by the analysis using hybrid index scores for all other localities examined. These results suggest that strong selection acts against hybrid genotypes. Morphological features of hybrid individuals were also provided.
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Current Herpetology 25(1) 39-40 2006年 査読有り責任著者A female Hemidactylus frenatus, collected on 7 June 2004 and housed alone in a cage, produced a total of six clutches, each consisting of one or two eggs, until 24 June 2005. All eggs but one, including the one egg composing the last clutch, hatched to produce hatchlings that included a male. This indicates that females of this broadly distributed gecko can store functional sperms for more than one year. Such ability may have played an important role in the colonization by this gecko of tropical and particularly subtropical regions of Asia and the Pacific islands. © 2006, The Herpetological Society of Japan. All rights reserved.
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Current Herpetology 25(2) 79-92 2006年 査読有り責任著者Sexual dimorphism was examined in a population of the colubrid snake, Dinodon semicarinatum, from the northern part of Okinawajima Island. This snake exhibited a prominent male-larger sexual size dimorphism (SSD), and this was considered to have resulted from male-male combat for mating opportunity. The size of the head relative to snoutvent length was significantly larger in females than in males, suggesting that segregation for differential food items between sexes, often considered the major cause of SSD in snakes, does not account for the distinct SSD in D. semicarinatum. Patterns and causes of sexual dimorphism in other characters are also presented and discussed. © 2006, The Herpetological Society of Japan. All rights reserved.
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Current Herpetology 25(2) 97-99 2006年 査読有り筆頭著者責任著者Phelsuma laticauda is recorded from Moorea, French Polynesia, for the first time on the basis of a hatchling specimen collected from the westernmost tip of the island in early October 2006. A much larger individual was also observed in the same area, but was not captured. These, as well as information with photographs from an inhabitant of the island regarding observations of similar geckos in 2003, strongly suggest a recent artificial introduction of this prominent gecko to Moorea and its establishment as a breeding population at least in the western part of this island. © 2006, The Herpetological Society of Japan. All rights reserved.
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Current Herpetology 25(1) 29-34 2006年 査読有り筆頭著者責任著者Japalura polygonata is an arboreal agamid lizard native to the subtropical East Asian islands. Recently this lizard was found in large numbers in a coastal hilly area of southeastern Kyushu, which represents the temperate part of Japan. Morphological examination of the specimens collected revealed that this lizard assemblage belongs to the nominotypical subspecies (J. p. polygonata), which is endemic to the central Ryukyus. Specimens collected in the summer of 2005 included females with oviductal eggs. Another sampling carried out in the spring of 2006 yielded juveniles that supposedly hatched the previous summer and successfully overwintered. These, along with information from inhabitants and the local newspaper, strongly suggest that in the present area this subtropical tree lizard has already established a breeding population. The impact of this exotic species on the native ecosystem may be of substantial conservation concern. © 2006, The Herpetological Society of Japan. All rights reserved.
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Zoologica Scripta 35(1) 85-95 2006年 査読有り
MISC
154書籍等出版物
60講演・口頭発表等
63-
日本古生物学会 第173回例会 シンポジウム 琉球列島の地質と生物相: 成立から現在に至るまで 2024年1月26日 招待有り
担当経験のある科目(授業)
16-
2012年4月 - 現在課題研究指導（博士前期課程）（5名） (兵庫県立大学環境人間学研究科)
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2012年4月 - 現在系統分類学特論 (兵庫県立大学環境人間学研究科)
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2019年4月 - 2021年3月ネイチャーアンドライフ (兵庫県立大学国際商経学部グローバルビジネスコース)
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2013年12月 - 2013年12月生物地理学・生物地理学特論 (東北大学理学部・理学研究科（集中講義）)
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2010年12月 - 2010年12月進化生態学特殊講義 A（集中講義） (琉球大学（理学部学生、理工学研究科大学院生対象）)
所属学協会
18Works(作品等)
13共同研究・競争的資金等の研究課題
40-
日本学術振興会 科学研究費助成事業 基盤研究(B) 2018年4月 - 2023年3月
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日本学術振興会 科学研究費助成事業 基盤研究(C) 2017年4月 - 2023年3月
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日本学術振興会 科学研究費助成事業 基盤研究(C) 2015年4月 - 2018年3月
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日本学術振興会 科学研究費助成事業 基盤研究(A) 2012年4月 - 2017年3月
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世界自然保護基金日本委員会 研究助成 2015年4月 - 2016年3月