Takeshi Igawa

Dr. Takeshi Igawa

Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2010 in Zoological Science
Verified
Journal Article
Closed access
NKNia Kurniawan
Nia Kurniawan
MIMohammed Mafizul Islam
Mohammed Mafizul Islam
TDTjong Hon Djong
Tjong Hon Djong
TITakeshi Igawa
Takeshi Igawa
MDM. Belabut Daicus
M. Belabut Daicus
MSMasayuki Sumida
Masayuki Sumida
To elucidate genetic divergence and evolutionary relationship in Fejervarya cancrivora from Indonesia and other Asian countries, allozyme and molecular analyses were carried out using 131 frogs collected from 24 populations in Indonesia, Thailand, Bangladesh, Malaysia, and the Philippines. In the allozymic survey, seventeen enzymatic loci were examined for 92 frogs from eight representative localities. The results showed that F. cancrivora is subdivided into two main groups, the mangrove type and the large- plus Pelabuhan ratu types. The average Nel's genetic distance between the two groups was 0.535. Molecular phylogenetic trees based on nucleotide sequences of the 16S rRNA and Cyt b genes and constructed with the ML, MP, NJ, and BI methods also showed that the individuals of F. cancrivora analyzed comprised two clades, the mangrove type and the large plus Pelabuhan ratu / Sulawesi types, the latter further split into two subclades, the large type and the Pelabuhan ratu / Sulawesi type. The geographical distribution of individuals of the three F. cancrivora types was examined. Ten Individuals from Bangladesh, Thailand, and the Philippines represented the mangrove type; 34 Individuals from Malaysia and Indonesia represented the large type; and 11 individuals from Indonesia represented the Pelabuhan ratu / Sulawesi type. Average sequence divergences among the three types were 5.78–10.22% for the 16S and 12.88–16.38% for Cyt b. Our results suggest that each of the three types can be regarded as a distinct species

1 January 2008 in Gene
Verified
Journal Article
Closed access
TITakeshi Igawa
Takeshi Igawa
AKAtsushi Kurabayashi
Atsushi Kurabayashi
CUChisako Usuki
Chisako Usuki
TFTamotsu Fujii
Tamotsu Fujii
MSMasayuki Sumida
Masayuki Sumida

24 August 2015 in Journal of Biogeography
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Journal Article
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PDF file
SKShohei Komaki
Shohei Komaki
TITakeshi Igawa
Takeshi Igawa
SLSi‐Min Lin
Si‐Min Lin
KTKoji Tojo
Koji Tojo
MMMi‐Sook Min
Mi‐Sook Min
MSMasayuki Sumida
Masayuki Sumida

1 March 2012 in Zoological Science
Verified
Journal Article
Closed access
MHMahmudul Hasan
Mahmudul Hasan
MIMohammed Mafizul Islam
Mohammed Mafizul Islam
MKMukhlesur Rahman Khan
Mukhlesur Rahman Khan
MAMohammad Shafiqul Alam
Mohammad Shafiqul Alam
AKAtsushi Kurabayashi
Atsushi Kurabayashi
MSMasayuki Sumida
Masayuki Sumida
To survey the diversity of anuran species in Bangladesh, we compared mitochondrial 16S rRNA gene sequences (approximately 1.4 kbp) from 107 Bangladesh frog specimens. The results of genetic divergence and phylogenetic analyses incorporating data from related species revealed the occurrence of at least eight cryptic species. Hoplobatrachus tigerinus from two districts diverged considerably, indicating the involvement of a cryptic species. Two Fejervarya sp. (large and medium types) and Hylarana cf. taipehensis formed lineages distinct from related species and are probably new species. Microhyla cf. ornata differed from M. ornata with respect to type locality area and involved two distinct species. In addition, we found that Hylarana sp. and Microhyla sp. did not match congeners examined to date in either morphology or 16S rRNA sequence. The occurrence of M. fissipes was tentatively suggested. Consequently, at least, 19 species were found from Bangladesh in this study. These findings revealed a rich anuran biodiversity in Bangladesh, which is unexpected considering the rather simple topographic features of the country.

1 January 2006 in Molecular Phylogenetics and Evolution
Verified
Journal Article
Closed access
TITakeshi Igawa
Takeshi Igawa
AKAtsushi Kurabayashi
Atsushi Kurabayashi
MNMidori Nishioka
Midori Nishioka
MSMasayuki Sumida
Masayuki Sumida

1 March 2020 in Freshwater Science
Verified
Journal Article
Open access
PDF file
TTTeruhiko Takahara
Teruhiko Takahara
NINoriko Iwai
Noriko Iwai
KYKiyomi Yasumiba
Kiyomi Yasumiba
TITakeshi Igawa
Takeshi Igawa
For conservation of endangered species, basic ecological information is indispensable. Environmental DNA (eDNA) is increasingly used to estimate the presence/absence of aquatic organisms such as frog species. However, the efficiency of detecting eDNA may depend on the ecological characteristics of the target frog species. Here, we adopted an eDNA approach for detecting 3 endangered Japanese species (Babina subaspera, Odorrana splendida, and O. amamiensis). We compared eDNA detection with a traditional acoustic survey method in 3 different seasons. Detection of species was not always consistent between the 2 methods, probably because acoustic surveys target only calling adult males but eDNA detects individuals of both sexes and at any life-history stage in water. Moreover, the differences in detection patterns between the 2 methods among species may be correlated with different characteristics of mating behavior (e.g., calling volume) and life history of tadpoles (e.g., migration ability). The opti...