Hirohiko Takeuchi

• PhD
• Professor (Assistant) at Nihon University

The Miyako toad, Bufo gargarizans miyakonis, is a subspecies endemic to the Miyako Islands of the Ryukyu Archipelago. The distribution of B. g. miyakonis is curious since no toads are found on other islands in the remaining part of the Ryukyu Archipelago. In this study, we conducted phylogenetic estimation and population genetic analyses using sequ...

A new nematode species, Rhabdias kiri sp. nov., which is a lung parasite in a microhylid frog Microhyla okinavensis Stejneger, 1901 from Ishigakijima island in the Yaeyama Islands of Ryukyu Archipelago, Japan is described and illustrated. This new species differs from other congeners inhabiting East Asia and the Russian Far East in its features: i....

The genus Rhabdophis is a group of widely distributed snakes with more than 20 species. Recent field msurveys uncovered a species in southwestern China, which has long been considered as R. pentasupralabialis. Combined molecular and morphological analyses revealed it as a new species Rhabdophis chiwen sp. nov. Based on 12 specimens, this new specie...

A new nematode species that is lung parasitic to a bufonid toad, Rhabdias kafunata sp. nov., is described and illustrated from Miyakojima island, Okinawa Prefecture, Japan. Although the new species was previously identified as R. incerta Wilkie, 1930, it is clearly distinguishable from that species by the characteristics of body proportion, buccal...

Significance Animals protected by sequestered toxins must employ an alternative source of defensive chemicals when a shift in diet evolves. Snakes of the genus Rhabdophis possess defensive glands that store powerful defensive toxins known as bufadienolides. The ancestral prey of Rhabdophis consists of anuran amphibians, including toads (Bufonidae)...

A large body of evidence indicates that evolutionary innovations of novel organs have facilitated the subsequent diversification of species. Investigation of the evolutionary history of such organs should provide important clues for understanding the basis for species diversification. An Asian natricine snake, Rhabdophis tigrinus, possesses a serie...

In coastal and insular regions, both climatic and sea-level changes during the Pleistocene had great influence on the population sizes and/or ranges of terrestrial animals. We investigated the intraspecific phylogeography of the Japanese ratsnake (Elaphe climacophora) to examine the differences in demographic patterns between regions with different...

Cane Toads (Rhinella marina) are invasive pests in many parts of the world, including the Japanese island of Ishigaki. Extensive research in Australia has identified promising new methods for control, but also has shown that toads exhibit geographic variation in many traits (suggesting that methods developed in one location may not work in another)...

Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na+/K+-ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effect...

Understanding negative effects of native species on introduced taxa may suggest novel ways to control the invasive species by enhancing such effects. Previous studies have reported that the larvae of invasive cane toads (Rhinella marina) are suppressed by competition with the larvae of native anurans in Australia, but not in North America. We condu...

Many animals are equipped with specialized defensive systems that function in a coordinated manner involving morphological structure, physiological processes and behaviour. Nucho-dorsal glands, unusual organs known in a few Asian natricine snakes, are believed to function in avoidance of predation, based on the defensive function of similar organs...

We investigated the phylogenetic status and pattern of geographic variation in Rhabdophis lateralis on the basis of samples from across conti-nental China, southeastern Russia, and the Korean Peninsula. The results confirmed the monophyly of the species and also revealed its extremely low genetic divergence. The population genetic analyses suggeste...

A new species, Rhabdophis guangdongensis sp. nov., is described from the Guangdong Province, China. It can be easily distinguished from other known congeners by cyt b and c-mos sequences, and by the following combination of morphological characters: body size small; head distinct from the neck; 20 maxillary teeth, the three most posterior teeth str...

Genetic diversity in the Japanese popu-lation of Zootoca vivipara was investigated using partial sequences of mitochondrial cytochrome b (706 bp) gene for 24 individuals from three sites. The phylogenetic status of the Japanese popula-tion was also examined using data from the current and previous studies. Only one haplotype was recognized in the J...

Several Asian natricine snakes are known to possess special organs called nuchal glands. Extensive studies on the nuchal glands of Rhabdophis tigrinus have shown that the glands contain cardiac steroidal toxins known as bufadienolides, which are sequestered from its toad prey and are stored in the nuchal glands as defensive substances. In addition,...

We investigated intraspecific phylogenetic relationships in the natricine snake, Rhabdophis tigrinus. A partial sequence of mitochondrial cytochrome b gene (990 bp) was sequenced for 220 individuals from 112 populations. The phylogeny indicated monophyly of the Japanese populations against the continental and Taiwanese populations, sister relations...