Noriyuki Koizumi

Origin of the two major distinct mtDNA clades of the Japanese population of the oriental weather loach Misgurnus anguillicaudatus (Teleostei: Cobitidae)

Abstract. The oriental weather loach Misgurnus anguillicaudatus (Teleostei: Cobitidae) inhabits the waters of East Asia including Japanese Islands. The Japanese population of M. anguillicaudatus includes two major mitochondrial DNA (mtDNA) clades, but their evolutionary origin is unknown. In this study, we conducted phylogeographic analyses of M. anguillicaudatus that were based on mtDNA cytochrome b sequences to clarify the evolutionary origin of the two distinct mtDNA clades. This newly obtained data were integrated with the mtDNA sequence data obtained in previous studies and reanalysed. The results showed that one major clade originated because of mtDNA introgression from a loach of the genus Cobitis. The geographic range of the populations carrying non-introgressed mtDNA tended to be limited to the peripheral areas of the Japanese Islands, whereas the range of the populations carrying introgressed mtDNA was spread over wide regions of the Japanese Islands. These distribution and divergence patterns suggested that M. anguillicaudatus populations carrying introgressed mtDNA have spread and replaced the range of populations carrying non-introgressed mtDNA.

Reassessment of the taxonomy of Mesopodopsis orientalis (Tattersall, 1908) (Crustacea, Mysida) and proposal of a new species for the genus with an appendix on M. zeylanica Nouvel, 1954

The Indo‐Australasian mysid Mesopodopsis orientalis (Tattersall, 1908) has been recorded throughout the southwestern coast of India and the Philippines. As a result of its abundance, this mysid is regarded as one of the most important species of the shallow‐water crustacean community. Recent ecological studies of this conventionally identified species have revealed significant differences in certain life history features among populations, in particular between coastal and estuarine populations, which seemed to be associated with some differences in morphology. Following the examination of the syntypes and topotypes, the identity of M. orientalis was redefined, and a new species, M. tenuipes, was subsequently proposed on the basis of the further assessment of morphological and DNA analyses. At several sites, these two species coexist, although M. tenuipes usually inhabits inner estuaries or less haline waters compared with M. orientalis. Our analyses also suggest a possibly higher allopatric diversification within each lineage along their geographical transitions. In addition, earlier records of M. orientalis from India need to be reanalysed to rectify confusion with M. zeylanica Nouvel, 1954.

Development and characterization of 23 polymorphic microsatellite markers for Sympetrum frequens

Twenty-three polymorphic microsatellite markers for Sympetrum frequens were developed and characterized. The number of distinct alleles per locus in 32 individuals ranged from 2 to 23. The observed heterozygosity ranged from 0.031 to 0.938, while the expected heterozygosity varied from 0.031 to 0.922. No loci deviated significantly from Hardy–Weinberg equilibrium, no linkage disequilibrium was observed between pairs of loci and no loci showed evidence of null alleles. These microsatellite markers are expected to contribute to future investigations of genetic variation and structure in S. frequens populations.

Influence of the domestic alien fish Rhynchocypris oxycephalus invasion on the distribution of the closely related native fish R. lagowskii in the Tama River Basin, Japan

In Japan, domestic freshwater fish are accidentally introduced into non-native freshwater habitats by human activity, such as the planting of fish. Introduction of the domestic alien fish may have a detrimental effect on native fish inhabitants. However, investigations on the distribution and establishment of such domestic alien fish in non-native river basins and their influence on native fish remains limited. Therefore, we investigated the distribution and establishment of the domestic alien fish Rhynchocypris oxycephalus and its influence on native fish in the Tama River Basin, Japan. Specifically, we used mitochondrial DNA and morphological analyses to clarify the influence of the invasion of this species on the distribution of the closely related fish R. lagowskii, which is native to the river basin. Fish sampled from the upstream section of the main river were mostly R. oxycephalus. This indicates that R. oxycephalus has replaced R. lagowskii in the upstream region. Fish sampled from the downstream section of the main river were mostly R. lagowskii. R. oxycephalus was also captured from agricultural canals linked to the Tama River, and in streams connected to the river via the canals. These observations indicate that the agricultural canal water networks facilitate the invasion of R. oxycephalus to peripheral habitats, such as canals and streams. In contrast, R. lagowskii was found in streams that flowed into the upstream section of the Tama River, with these streams having many large drop structures, indicating that drop structures prevent R. oxycephalus from invading aquatic habitats in these streams.

Thirty-two polymorphic microsatellite loci of the mysid crustacean Mesopodopsis tenuipes

Thirty-two polymorphic microsatellite loci were indentified and characterized from the mysid Crustacea Mesopodopsis tenuipes Hanamura et al., 2008. The number of observed alleles per locus in 32 individuals collected from its type locality in Malaysia ranged from 2 to 22. The observed heterozygosity ranged from 0.031 to 0.906, while the expected heterozygosity varied from 0.031 to 0.943. All loci conformed to Hardy–Weinberg equilibrium, no linkage disequilibrium was observed between pairs of loci and no loci showed evidence of null alleles. These 32 microsatellite loci could be used in future population genetics study of M. tenuipes.

Isolation and characterization of 19 polymorphic microsatellite DNA markers in the Japanese brown frog (Rana japonica)

We report the isolation and characterization of 19 polymorphic microsatellite DNA markers in the Japanese brown frog (Rana japonica). These markers were tested in 24 individuals each collected from three distinct populations in Ichikai‐machi, Tochigi Prefecture. The number of observed alleles per locus ranged from 3 to 24 across all populations, and the values of observed and expected heterozygosities ranged from 0.130 to 1 and from 0.125 to 0.941, respectively. These microsatellite loci will be useful for investigating the intraspecific genetic variation and population structure of this species.

Plant species identification using fecal DNAs from red-eared slider and Reeves’ pond turtle in agricultural canals for rural ecosystem conservation

Fecal DNA samples from the red-eared slider and Reeves’ pond turtle, suspected pests of lotus root paddies, were used to identify the plant species eaten by these turtles in order to develop a strategy for rural ecosystem conservation. The fecal samples were obtained from young and adult individuals (mostly female) of both species living in agricultural canals surrounding lotus root paddies in Tokushima Prefecture, Japan. The samples were screened for the presence or absence of DNA from nine plant species using PCR and plant species-specific primers for the rbcL gene of chloroplast DNA. In the red-eared slider, our analysis identified seven plant species in the fecal DNA samples of adults and three plant species in those of young individuals. In Reeves’ pond turtle, our analysis identified two plant species from adult fecal samples and one species from those of young individuals. Thus, adult red-eared sliders consume a greater range of plants than young red-eared sliders or Reeves’ pond turtles. Both turtle species, independently of age, consumed lotus plants and were likely to cause feeding damage to lotus roots. Considering the plant species detected in adult red-eared sliders and these plant habitats, we suggest that this adult turtle is likely to travel between the agricultural canals and the lotus root paddies. These findings will help the development of strategies for preventing damage to lotus roots by these turtles; furthermore, they indicate that fecal DNA analysis will be applicable to investigation of the feeding habits of other animal species.

Development of 18 novel polymorphic microsatellite markers for the mysid crustacean Mesopodopsis orientalis

We have developed microsatellite DNA markers for Mesopodopsisorientalis (Tattersall 1908), a widely distributed mysid crustacean in shallow waters of the coastal and estuarine systems across India to Indonesia and the Philippines. A total of 18 novel polymorphic microsatellite markers were identified in 32 individuals from a sandy beach at Teluk Kumbar in Penang Island, Malaysia. The number of alleles per locus ranged from 3 to 17. The observed and expected heterozygosities varied from 0.031–1.000 to 0.092–0.938, respectively. These polymorphic markers could be available for future investigations of genetic diversity and structure of M.orientalis populations.

Development and characterization of microsatellite loci for Rhinogobius sp. YB (Gobiidae)

Rhinogobius sp. YB (Gobiidae) distributed in the Ryukyu Archipelago is a fluvial species of gobies. We present 34 novel microsatellite loci that were tested on 32 individuals from the Okierabu-jima Island in Kagoshima Prefecture. Seventeen loci were polymorphic, while the remaining 17 were monomorphic. The number of alleles per the polymorphic loci ranged from 2 to 15. The observed heterozygosities ranged from 0.038 to 1.000 and the expected heterozygosities varied from 0.038 to 0.816. These microsatellite loci will enhance future investigations on the genetic differentiation and structure of populations of R. sp. YB.

Genetic Diversity and Population Structure of the Hotoke Loach, Lefua echigonia, a Japanese Endangered Loach

In Japan, conservation and regeneration projects have been actively conducted for largesized birds such as the Japanese crested ibis, Nipponia Nippon, the oriental white stork, Cico‐ nia boyciana and the intermediate egret, Ardea intermedia (Photo 1) that inhabit rural areas [1, 2]. Many people are highly interested in these projects and a lot of information about growth and breeding for large-sized birds is broadcasted through television, radio and internet me‐ dia. In such a situation, a conspicuous topic has been found in recent months, that is, 2 indi‐ viduals of the Japanese crested ibis displayed beriberi symptom along with human being, because of overeating great favorite food that is the Dojo loach, Misgurnus anguillicaudatus. Their beriberi symptom appeared to be caused by eating the Dojo loach raw. The 2 individu‐ als were diagnosed as follows; this beriberi symptom occurred as vitamin B1 in the individ‐ ual bodies was destroyed by tiaminase enzyme contained in the Dojo loach. At present the two individuals may have completely recovered from the beriberi symptom through vita‐ min B1 supplementation by injection.