Published Papers - Toda Mamoru

Highly rapid and diverse sex chromosome evolution in the Odorrana frog species complex.

Katsumi T, Shams F, Yanagi H, Ohnishi T, Toda M, Lin SM, Mawaribuchi S, Shimizu N, Ezaz T, Miura I

Development, growth & differentiation ( Development Growth and Differentiation )  64 ( 6 ) 279 - 289   2022.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Food Habits of the Taiwan Beauty Snake, Elaphe taeniura friesi, as an Introduced Species on Okinawajima Island

Asato H.

Current Herpetology ( 日本爬虫両棲類学会 )  41 ( 2 ) 205 - 214   2022.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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<p>The Taiwan beauty snake, <i>Elaphe taeniura friesi</i>, has established a stable population in the central part of Okinawajima Island, and there are concerns about the negative effects of the snakes’ predation on the native fauna. Thus, we examined the stomachs of 239 <i>E. t. friesi</i> specimens collected on Okinawajima Island from July 2018 to November 2019. Stomach contents were identified to the species level whenever possible based on morphological observations and/or DNA analyses. Of the 239 snake specimens, 39 (12 males, 16 females, and 11 juveniles) had contents in their stomach, including 67 prey items, 75% of which were mammals (Muridae and Soricidae) and the rest of which were birds (Pycnonotidae, Cisticolidae, and Columbidae). <i>Rattus rattus</i> occurred most frequently; 25 of the 39 snakes examined had this species in their stomachs. All avian prey items detected were nestlings and eggs. Twelve snakes had multiple prey items in their stomach, including in most cases either nestlings of passerine birds or infants or subadults of <i>R. rattus</i>. Therefore, <i>E. t. friesi</i> is an endotherm consumer that occasionally preys on nestlings and infant rats. These food habits suggested that <i>E. t. friesi</i> uses various habitats, from the humus layer on the ground to the branches of trees, for foraging. Several endangered endemic rodent and bird species exist in the northern area of Okinawajima Island; thus, our results provide a warning about potential negative impact on such animals when <i>E. t. friesi</i> expands its range to the northern part of the island.</p>

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Past inhabitation status of the Miyako grass lizard, Takydromus toyamai (Reptilia: Squamata), as inferred from the results of interview surveys to inhabitants of the Miyako Island Group

Tatetsu, M, Kamizato, H, Tokumine, K, Tokumine, M, Uechi, S, Igawa, K, Ishikawa, S, Gima, T, Gonda M, Toda, M, and Saiki, M.

Biological Magazine Okinawa   ( 60 ) 1 - 10   2022.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Development and evaluation of a loop-mediated isothermal amplification (LAMP) assay for quick identification of the Japanese salamander Hynobius tokyoensis.

Suzuki T, Nishikawa K, Sato Y, Toda M

Genes & genetic systems ( 日本遺伝学会 )  96 ( 5 ) 247 - 252   2022.02

Type of publication: Research paper (scientific journal)

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<p>Species identification using molecular techniques has recently become common for various taxa. Loop-mediated isothermal amplification (LAMP) is one of the easiest and least expensive molecular identification methods. Although few studies have developed LAMP assays for amphibians, we believe that LAMP is also useful for identifying endangered amphibians. <i>Hynobius tokyoensis</i> and <i>H. lichenatus</i> occur in Honshu, Japan, and have parapatric distributions. They are similar morphologically, especially at early developmental stages, including eggs and larvae. <i>Hynobius tokyoensis</i> has been listed as a national endangered species in Japan since 2020, and unambiguous identification of these species is therefore important for their conservation and management. In this study, we developed a LAMP primer set for the mitochondrial cytochrome b region to detect <i>H</i>. <i>tokyoensis</i>, and we evaluated the LAMP assay using total genomic DNA from four <i>H</i>. <i>tokyoensis</i> and three <i>H</i>. <i>lichenatus</i> individuals from across most of their ranges. Our LAMP primer set could distinguish these two species. This study should help to establish LAMP assays for other endangered species and morphologically similar species.</p>

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Number of oviposition, oviposition interval, and period of sperm storage in Gekko hokouensis and G. yakuensis in captivity

Okamoto, K, Jono, T, Toda, M.

  ( 30 ) 21 - 25   2021.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Field observations of prey on Nidirana okinavana by Hebius ishigakiensis

Fukuyama, I, and Tda, M.

  ( 30 ) 7 - 9   2021.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Predation on the Yaeyama least horseshoe bat, Rhinolophus perditus, by the Sakishima beauty snake, Elaphe taeniura schmackeri

ASATO, H, Yamamoto, T, and Toda, M.

  ( 30 ) 1 - 4   2021.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Addition of the Sea Snake, Hydrophis stokesii (Reptilia: Squamata: Elapidae), to the Herpetofauna of Japan

Sasai T.

Ｃｕｒｒｅｎｔ　ｈｅｒｐｅｔｏｌｏｇｙ ( 日本爬虫両棲類学会 )  40 ( 2 ) 190 - 196   2021.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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<p><i>Hydrophis stokesii</i> was collected in the coastal water of Okinawajima Island on 30 March 2021. This is the first record of the species from Japanese waters, extending its known range of occurrence toward east-northeast by more than 900 km. The snake was an adult female, 1,545 mm in snout-vent length, 203 mm in tail length, and 3,360 g in body mass. It had 11 well-developed yolked follicles in ovaries and a half-digested spiny puffer fish (<i>Diodon</i> sp.) in its stomach. This individual may possibly represent a stable population of <i>H. stokesii</i> in the Okinawan waters.</p>

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Population history and genomic admixture of sea snakes of the genus Laticauda in the West Pacific.

Kishida T, Toda M, Go Y, Tatsumoto S, Sasai T, Hikida T

Molecular phylogenetics and evolution ( Molecular Phylogenetics and Evolution )  155   107005   2021.02 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Visual adaptation of opsin genes to the aquatic environment in sea snakes.

Seiko T, Kishida T, Toyama M, Hariyama T, Okitsu T, Wada A, Toda M, Satta Y, Terai Y

BMC evolutionary biology ( BMC Evolutionary Biology )  20 ( 1 ) 158   2020.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Development of 22 Microsatellite Markers for Assessing Hybridization in the Genus Gekko (Squamata: Gekkonidae)

OKAMOTO KOTA, KURITA TAKAKI, NAGANO MASAHIRO, SATO YUKUTO, AOYAMA HIROAKI, SAITOH SEIKOH, SHINZATO NAOYA, TODA MAMORU

Current Herpetology ( 日本爬虫両棲類学会 )  39 ( 1 ) 66 - 74   2020.02 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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<p><i>Gekko yakuensis</i> and <i>G. tawaensis</i>, both endemic to western Japan, are threatened by genetic introgression from <i>G. hokouensis</i> and <i>G. japonicus</i>, respectively. To know detailed situation of their hybridizations for planning relevant conservation measures, development of sensitive genetic markers is desired. We here developed microsatellite markers based on the sequences obtained from <i>G. hokouensis</i> using 454 GS Junior sequencer, and tested stability of PCR amplification and species-specificity of alleles at each locus using <i>G. hokouensis</i>, <i>G. yakuensis</i>, <i>G. japonicus</i>, and <i>G. tawaensis</i>. The results showed that 22 loci were almost constantly amplified in more than one species. We further confirmed that there were fixed or nearly fixed allelic displacement between <i>G. hokouensis</i> and <i>G. yakuensis</i>, and between <i>G. japonicus</i> and <i>G. tawaensis</i> at 14 loci. Thus, these 22 loci are considered to be useful for evaluation of hybridizations between these pairs of species.</p>

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Loss of olfaction in sea snakes provides new perspectives on the aquatic adaptation of amniotes.

Kishida T, Go Y, Tatsumoto S, Tatsumi K, Kuraku S, Toda M

Proceedings. Biological sciences ( Proceedings of the Royal Society B: Biological Sciences )  286 ( 1910 ) 20191828 - 20191828   2019.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Marine amniotes, a polyphyletic group, provide an excellent opportunity for studying convergent evolution. Their sense of smell tends to degenerate, but this process has not been explored by comparing fully aquatic species with their amphibious relatives in an evolutionary context. Here, we sequenced the genomes of fully aquatic and amphibious sea snakes and identified repertoires of chemosensory receptor genes involved in olfaction. Snakes possess large numbers of the olfactory receptor (OR) genes and the type-2 vomeronasal receptor (V2R) genes, and expression profiling in the olfactory tissues suggests that snakes use the ORs in the main olfactory system (MOS) and the V2Rs in the vomeronasal system (VNS). The number of OR genes has decreased in sea snakes, and fully aquatic species lost MOS which is responsible for detecting airborne odours. By contrast, sea snakes including fully aquatic species retain a number of V2R genes and a well-developed VNS for smelling underwater. This study suggests that the sense of smell also degenerated in sea snakes, particularly in fully aquatic species, but their residual olfactory capability is distinct from that of other fully aquatic amniotes. Amphibious species show an intermediate status between terrestrial and fully aquatic snakes, implying their importance in understanding the process of aquatic adaptation.

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Relict distribution of Microhyla (Amphibia: Microhylidae) in the Ryukyu Archipelago: High diversity in East Asia maintained by insularization

戸田 守

Zoologica Scripta ( Zoologica Scripta )  48 ( 4 ) 440 - 453   2019.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Takydromus smaragdinus (Green Grass Lizard). Color polymorphism.

戸田 守

Herpetological Review   50 ( 2 ) 379 - 380   2019.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

ミナミヤモリの種子島からの記録

岡本康汰, 戸田守

Akamata   ( 28 ) 21 - 28   2018.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

下地島からのサキシマバイカダの初記録

和智仲是, 戸田守

Akamata   ( 28 ) 34 - 38   2018.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Body temperature of subtropical snakes at night: How cold is their blood?

Mori, A, Toda, M

Current Herpetology ( Current Herpetology )  37 ( 2 ) 151 - 157   2018.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Thermal reaction norms of locomotor performance in lacertid lizards of the genus Takydromus.

Mochida, K, Sasai, T, Kadota, Y, Nishikawa, M, Itou, M, Toda, M

Current Herpetology   37 ( 2 ) 114 - 123   2018.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Species delimitation and biogeography of the Ryukyu ground geckos, Goniurosaurus kuroiwae ssp. (Squamata: Eublepharidae), by use of mitochondrial and nuclear DNA analyses

Takaki Kurita, Masanao Honda, Mamoru Toda

Journal of Zoological Systematics and Evolutionary Research ( Blackwell Publishing Ltd )  56 ( 2 ) 209 - 222   2018.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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In the Ryukyu Archipelago, Japan, Goniurosaurus geckos are currently divided into six allopatric taxa among nearby islands. Recent studies suggested the occurrence of large genetic divergence within a single island and the possible non-monophyly of a few taxa, but their species delimitation is not well resolved. We investigated the taxonomic relationships between the possibly geographically overlapped, highly diverged entities as well as other island populations via dense sampling. Our mitochondrial and nuclear DNA analyses showed that the two genetic groups were distributed in parapatry within Okinawajima Island and that they were hybridizing in narrow area around the contact zone. Geohistorical evidence suggests that the restricted gene flow has been caused by some intrinsic isolation mechanisms. Thus, we conclude that the two lineages represent full species. Mitochondrial analysis also showed that the genetic differences among other island populations were comparable to those between these species, thereby suggesting the presence of seven full species, including one unnamed taxon. We also discuss the possible cause of this divergence and why it has occurred at such a fine geographic scale.

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Development of 21 polymorphic microsatellite markers for the black-banded sea krait, Laticauda semifasciata (Elapidae: Laticaudinae), and cross-species amplification for two other congeneric species.

Hyun YS, Kim IH, Song HY, Park D, Toda M, Tsai TS, An HS

Genes & genomics ( Genetics Society of Korea )  40 ( 4 ) 447 - 454   2018.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The genus Laticauda (Reptilia: Elapidae), commonly known as sea kraits, is venomous marine amphibious snakes distributed throughout the south and southeast Asian islands and mostly found in coastal waters. To facilitate genetic studies, we have developed microsatellite loci for L. semifasciata using the 454 GS-FLX pyrosequencing technique. A total of 65,680 sequences containing a minimum of five repeat motifs were identified from 451,659 reads. Among 80 loci containing more than nine repeat units, 34 primer sets (42.5%) produced strong PCR products, of which 21 were polymorphic among 36 samples of L. semifasciata. All loci exhibited high genetic variability, with an average of 7.38 alleles per locus, and the mean observed and expected heterozygosities were 0.73 and 0.76, respectively. The cross-species amplification of these loci in two laticaudine species, L. colubrina and L. laticaudata, revealed a high transferability (78.6%) and polymorphism (59.5%) of the loci. Our work demonstrated the utility of next-generation 454 sequencing as the rapid and cost-effective method for development of microsatellite markers. The high level of polymorphism in these microsatellite loci will be useful for the detection of population subdivision and the study of migration, gene flow, relatedness and philopatry of L. semifasciata and other laticaudine species.

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