論文 - 戸田　守

The evolutionary history and taxonomic reevaluation of the Japanese coral snake, Sinomicrurus japonicus (Serpentes, Elapidae), endemic to the Ryukyu Archipelago, Japan, by use of molecular and morphological analyses

Takuma Kaito, Hidetoshi Ota, Mamoru Toda

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH ( WILEY )  55 ( 2 ) 156 - 166   2017年05月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Sinomicrurus japonicus has a conspicuous colour pattern of longitudinal black stripes and transverse sets of black and white bands with an orange-reddish background colour. The pattern varies markedly among island populations, and thus, three subspecies have been recognized. We conducted molecular phylogenetic analyses on the island populations to clarify the evolutionary trajectory of such colour patterns and reevaluate the current classification accordingly. The results indicated relatively deep allopatric divergences within S. j. boettgeri, paraphyly of S. j. boettgeri against other two subspecies, and two independent derivations of S. j. takarai from boettgeri-like ancestors. Detailed morphological analyses revealed that variations in the boettgeri and takarai forms were more or less continuous and that differences between the two takarai populations were very small. From these results, we propose synonymizing S. j. takarai with S. j. boettgeri. Morphological differences between the genetically most distant populations of S. j. boettgeri were also small, whereas the japonicus form was distinct from the remainder. Considering the possible evolution of S. j. japonicus through peripheral isolation, we propose retention of these two subspecies. This study provides a basis for future work on the adaptive significance of geographic variation in the colour pattern of S. japonicus.

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The role of ecological factors in determining phylogeographic and population genetic structure of two sympatric island skinks (Plestiodon kishinouyei and P. stimpsonii).

Kurita K, Toda M

Genetica ( SPRINGER )  145 ( 2 ) 223 - 234   2017年04月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

We conducted comparative phylogeographic and population genetic analyses of Plestiodon kishinouyei and P. stimpsonii, two sympatric skinks endemic to islands in the southern Ryukyus, to explore different factors that have influenced population structure. Previous phylogenetic studies using partial mitochondrial DNA indicate similar divergence times from their respective closest relatives, suggesting that differences in population structure are driven by intrinsic attributes of either species rather than the common set of extrinsic factors that both presumably have been exposed to throughout their history. In this study, analysis of mtDNA sequences and microsatellite polymorphism demonstrate contrasting patterns of phylogeography and population structure: P. kishinouyei exhibits a lower genetic variability and lower genetic differentiation among islands than P. stimpsonii, consistent with recent population expansion. However, historical demographic analyses indicate that the relatively high genetic uniformity in P. kishinouyei is not attributable to recent expansion. We detected significant isolation-by-distance patterns among P. kishinouyei populations on the land bridge islands, but not among P. stimpsonii populations occurring on those same islands. Our results suggest that P. kishinouyei populations have maintained gene flows across islands until recently, probably via ephemeral Quaternary land bridges. The lower genetic variability in P. kishinouyei may also indicate smaller effective population sizes on average than that of P. stimpsonii. We interpret these differences as a consequence of ecological divergence between the two species, primarily in trophic level and habitat preference.

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ミヤコカナヘビの繁殖行動の観察および体表面の咬み痕について

笹井隆秀, 才木美香, 戸田守

Akamata   ( 26 ) 19 - 24   2016年11月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

野外におけるミナミヤモリの交尾の観察

戸田守, 高尾彰

■■■   ( 26 ) 16 - 18   2016年11月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

宮古島および伊良部島における希少なヘビ２種，ミヤコヒバァとサキシマバイカダの観察例

角田羊平, 青柳克, 徳山孟伸, 才木美香, 笹井隆秀, 戸田守, 前之園唯史

Akamata   ( 26 ) 25 - 30   2016年11月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

The biogeographical history of Asian keelback snakes of the genus Hebius (Squamata: Colubridae: Natricinae) in the Ryukyu Archipelago, Japan

Takuma Kaito, Mamoru Toda

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY ( WILEY-BLACKWELL )  118 ( 2 ) 187 - 199   2016年06月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

The islands of the central and southern parts of the Ryukyu Archipelago and Taiwan accommodate suites of allopatric endemics for many terrestrial vertebrates. These subregions, which were isolated as three independent islands since the Late Miocene period, became connected to the continent by the Early Pleistocene land bridge (EPL). Many endemics are considered to have emerged through vicariant events accompanied with the collapse of EPL, but this is not well corroborated. We conducted divergence dating analyses for samples of four allopatric keelback snakes from 20 islands using a published timeframe for natricine snakes. Phylogenetic analyses recognised the existence of eight subclades for the four species. Four of the five subclades in the Central Ryukyus have emerged after the initial isolation of three subregions but before the EPL collapse, indicating iterative divergences within the super-island and stagnation of diverged entities. In contrast, the Southern Ryukyus was subjected to multiple incursions from both Central Ryukyus and Taiwan, irrespective of the EPL connection. Consequently, among all seven nodes, only two were consistent with the assumption of vicariance. These findings suggest that dispersals and subsequent nonvicariant divergences have contributed to the formation of the current phylogeographical pattern in this continental island chain.

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Reevaluation of the Taxonomic Status of a Poorly Known Gecko, Gekko liboensis (Reptilia: Squamata)

Teppei Jono, Li Ding, Takuma Kait, Yezhong Tang, Mamoru Toda

ASIAN HERPETOLOGICAL RESEARCH ( SCIENCE PRESS )  6 ( 3 ) 229 - 236   2015年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Gekko liboensis Zhou and Li, 1982 is a poorly known gecko originating from Libo, Guizhou, southern China. Since the original description based on a single female from Libo, only three specimens (two females and one juvenile) have been reported from the type locality. Because of its close morphological resemblance to G. hokouensis Pope, 1927, G. liboensis is required to be reevaluated for its taxonomic status by studies based on additional specimens. Here we report for the first time the morphological features of 31 newly obtained specimens of G. liboensis from type locality and others, including males, and compare them with those of related species, chiefly on the basis of information from the literature. In addition, specimen-based comparisons were also made with G. hokouensis and an undescribed cryptic species known from the Ryukyus Islands, Japan. Results showed that the species is distinguished from its congeners in having a larger body size (60-91 mm), 0-2 small internasals, 10-13 supralabials, 10-13 infralabials, smooth enlarged tubercles present on the dorsum forming 4-10 irregular rows at the midbody but absent on the four limbs and tail, both fingers and toes without developed interdigital webs, a single cloacal spur on each side, and 10-12 precloacal pores in males. It most resembles G. hokouensis and its cryptic species but is clearly differentiated by having a larger body size, a predominantly absent internasal, fewer number of dorsal tubercle rows, larger number of precloacal pores, and conspicuous white marks on the dorsum and head. Judging from these results, we confirmed the taxonomic validity of G. liboensis. In addition, the geographic distribution of this gecko on the basis of obtained data was briefly discussed.

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The function of body coloration of the hai coral snake <i>Sinomicrurus japonicus boettgeri</i>.

Mochida K, Zhang WY, Toda M

Zoological studies ( SPRINGER HEIDELBERG )  54   e33   2015年 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Background: Prey animals often protect themselves from visual hunting predators via their body coloration, which encompasses various visual effects. When a prey animal displays a certain color pattern on its body surface, its protective function and effect are largely dependent on how a predator would encounter and perceive the prey animal. Asian coral snakes of the genus Sinomicrurus, which are venomous, display black bands and stripes on their orange body coloration. The banded pattern has been characterized as an aposematic signal in the New World coral snakes, but the stripes generally occur in cryptic snakes. We investigated the function of this complex color pattern, which might be interpreted as aposematic and cryptic, in Sinomicrurus japonicus boettgeri. Results: First, plasticine replica experiments were conducted to assess whether natural avian predators avoid the color pattern of S. japonicus boettgeri; the results showed that they attacked the coral snake replicas and the control replicas with coloration similar to another prey snake, suggesting that the body coloration of S. japonicus boettgeri did not function aposematically in the wild. Second, we evaluated the chromatic contrast of the snake coloration with backgrounds from their natural habitats based on the avian predator visual systems. The body coloration of S. japonicus boettgeri showed the same, or lower, contrast levels with natural backgrounds than those of sympatric cryptic snakes, suggesting that the coloration was ineffective as an aposematic signal. Conclusions: These results imply that the body coloration of S. japonicus boettgeri would work as crypsis through background matching or disruptive camouflage rather than aposematism.

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Genetic and morphological assessments of hybridization of two non-native geoemydid turtles, Mauremys reevesii and M. mutica, in north–central Japan

Fujii, R., Ota, H., and Toda, M.

Chelonean Conservation and Biology   13   191 - 201   2014年12月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

An investigation for population maintenance mechanism in a miniature garden: genetic connectivity or independence of small islet populations of the Ryukyu five-lined skink

Kurita, K., Hikida, T., & Toda, M.

Journal of Heredity   105   773 - 783   2014年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Isolation and validation of eight microsatellite loci in a damselfly Ischnura senegalensis (Odonata: Coenagrionidae) by pyrosequencing beads enriched library

Kurita, T., Aoyama, H., Saitoh, S., Shinzato, N., Sawada, K., Kuriwada, T., Hironaka, K., Inomata, N., Yamahira, K., Toda, M.

Applied Entomology and Zoology   43   623 - 626   2014年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Possible indirect long distance transportation of Hemidactylus flaviviridis (Squamata: Gekkonidae) to East Asia

Kurita, T., Toda, Mi., & Toda, Ma.

Current Herpetology   33   80 - 84   2014年08月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Phylogenetic relationships, genetic divergence, historical biogeography and conservation of an endangered gecko, Goniurosaurus kuroiwae (Squamata: Eublepharidae), from the Central Ryukyus, Japan

Honda, M. Kurita, T., Toda, M., & Ota, H.

Zoological Science   31   309 - 320   2014年02月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Limestone cave as a cradle of the Ryukyu ground gecko, Goniurosaurus kuroiwae.

Kurita, T., Kawamura, R., Toda, M.

Herpetological Review   44   569 - 572   2013年12月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Development and characterization of 24 microsatellite markers in a eublepharid gecko, Goniurosaurus kuroiwae

Kurita, T., Aoyama, H., Saitoh, S., Shinzato, N., Honda, M., and Toda, M.

Conservation Genetics Resources   6   247 - 249   2013年10月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Spatial and temporal instability of local biotic community mediate a form of aposematic defense in newts, consisting of carotenoid-based coloration and tetrodotoxin

Mochida, K., Kitada, M., Ikeda, K., Toda, M., Takatani, T., & Arakawa O.

Journal of Chemical Ecology   39   1186 - 1192   2013年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Origins of Laticauda laticaudata and Laticauda semifasciata (Elapidae: Laticaudinae) individuals collected from the main islands of Japan as inferred from molecular data

Tandavanitj, N., Mitani, S. and Toda, M.

Current Herpetology   32   135 - 141   2013年08月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Geographic genetic structures in two laticaudine sea kraits, Laticauda laticaudata and Laticauda semifasciata (Serpentes: Elapidae), in the Ryukyu-Taiwan region as inferred from the mitochondrial cytochrome b sequences

Tandavanitj, N., Ota, H., Cheng, Y-C. and Toda, M.

Zoological Science   30   633 - 641   2013年08月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Validation and application of skeletochronology for age determination of the Ryukyu ground gecko, Goniurosaurus kuroiwae (Squamata: Eublepharidae)

Kurita, T., Toda, M.

Asian Herpetological Research   4   233 - 241   2013年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Possible incursions of Gekko hokouensis (Reptilia:Squamata) into non-native area: an example from Yakushima Island of the Northern Ryukyus, Japan

Toda, M. and Hikida, T.

Current Herpetology   30   33 - 39   2011年02月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）