Misako Urabe - Academia.edu (original) (raw)

Papers by Misako Urabe

Journal of Ethology, 1999

The frequency and pattern of interactions between males and females of sika deerCervus nippon wer... more The frequency and pattern of interactions between males and females of sika deerCervus nippon were surveyed in 3 sites of Nara Park, central Japan, mainly via observation of allogrooming frequency and aggressive behavior throughout the breeding ...

Folia Parasitologica, 2020

Eudiplozoon nipponicum (Goto, 1891) Khotenovsky, 1985 (Monogenea: Diplozoidae), is known to paras... more Eudiplozoon nipponicum (Goto, 1891) Khotenovsky, 1985 (Monogenea: Diplozoidae), is known to parasitise Cyprinus car-pio Linnaeus and species of Carassius. In this study, we conducted a taxonomic re-examination of E. nipponicum using genetic analysis and morphological comparisons from different host species from a single water system. rDNA nucleotide sequences of the internal transcription spacer 2 (ITS-2) region (645 bp) showed interspecific-level genetic differences among diplozoids from species of Carassius and C. carpio (p-distance: 3.1-4.0%) but no difference among those from different species of Carassius (0-0.4%) or between those from C. carpio collected in Asia and Europe (0-1.1%). Large variation was observed among 346 bp cytochrome c oxidase subunit I (COI) sequences (0.3-16.0 %); the topology of the phylogenetic tree showed no relationship to host genera or geographical regions of origin. Morphological observation showed that average clamp size of diplozoids from C. carpio was larger than those from Carassius spp. The number of folds on the hindbody was 10-25 for diplozoids from C. carpio and 12-19 for those from Carassius spp. Thus, our ITS-2 sequence and morphological comparison results indicate that diplozoids from C. carpio and species of Carassius belong to different species. The scientific name E. nipponicum should be applied to the species infected to the type host, Carassius sp. of Nakabo (2013) (Japa-nese name ginbuna). The diplozoid infecting C. carpio (Eurasian type) should be established as a new species: Eudiplozoon kamegaii sp. n. A neotype of E. nipponicum is designated in this report because the original E. nipponicum specimens are thought to have been lost.

Parasitology International, 2007

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji
River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and
Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the
second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first
intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first
intermediate host has not been identified.

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first intermediate host has not been identified.

Japanese Journal of Limnology (Rikusuigaku Zasshi), 1993

We found that in natural conditions, the freshwater snail Semisulcospira libertina was distribute... more We found that in natural conditions, the freshwater snail Semisulcospira libertina was distributed in deeper sites when infected with trematode larvae than when uninfected, and examined whether water-depth selection was different between infected and uninfected snails in the laboratory. We compared the mean size of infected and uninfected snails, and the correlation between mean water depth and shell size in uninfected snails. Small uninfected snails (up to 11 mm in shell width) showed a correlation between shell width and water depth, while large snails (larger than 11 mm) did not, but used deeper sites on average than smaller snails. In the small-size class, snails infected with mature cercariae used significantly deeper sites than uninfected snails. On the other hand, in the large-size class, snails infected with immature cercariae used significantly shallower sites than uninfected snails. In each size class, snails infected with mature cercariae used deeper sites than snails infected with immature cercariae or parthenitae. Thus, the influence of trematode infection to host behavior varies according to the development stage of trematodes. In the field, snails infected with mature and immature cercariae had a tendency to occur in deeper sites than uninfected snails of both small and large size classes. These results suggest that some factor other than active selection of water depth by snails determined the distribution pattern of infected snails in natural conditions.

Zoological science, 2015

Irrigation ditches are the major habitat of lotic unionid mussels in Japan. To conserve and rebui... more Irrigation ditches are the major habitat of lotic unionid mussels in Japan. To conserve and rebuild irrigation ditches facilitating mussel conservation, suitable physical environments must be clarified. The effect on mussels of paddy fields connected to ditches also needs to be determined. In this study, physical environmental factors that affect the density of unionid mussels were studied in irrigation ditches in Hikone City, Shiga Prefecture, Japan, to examine whether mussel densities were higher around paddy fields. Generalized linear models were used to analyze physical and paddy field environmental variables affecting mussel density. Our results show that sediment type, sediment softness, water depth, and flow velocity of irrigation ditches affect the density of unionid mussels; the effects of each environment factor and their relative importance differed by species. Specifically, the density of Nodularia douglasiae biwae was higher in ditches with sand-gravel sediment, soft se...

Limnology, 2009

Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea; Opecoelidae; Plagioporinae) i... more Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea; Opecoelidae; Plagioporinae) in its definitive host, the ayu Plecoglossus altivelis, in the Chikugo River, Kyushu, Japan, was examined. Natural ayu are amphidromous. In the upper Chikugo River, ayu fry raised in hatcheries are released into the river every spring because the migration of ayu is completely blocked by a dam that

Limnoperna Fortunei, 2015

Parasitology international, 2009

The morphology of a type specimen of Lophotaspis orientalis Faust and Tang, 1936 (Aspidogastrea: ... more The morphology of a type specimen of Lophotaspis orientalis Faust and Tang, 1936 (Aspidogastrea: Aspidogasteridae) was compared with the morphology of the original description of L. corbiculae Moriya, 1944 and of newly collected specimens from Corbicula species in China and Japan. The original description of L. orientalis was revised by the re-examination of the type specimen. Consequently, some key characteristics of these two species described by Moriya (1944) became invalid. The gonad size of the L. orientalis type specimen was out of the range of all other investigated specimens and past records, suggesting that the L. orientalis type specimen (host: soft-shell turtle) is a different species from the other investigated specimens (host: freshwater clam).

Parasitology international, 2007

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first intermediate host has not been identified.

Limnology, 2013

Potamopyrgus antipodarum, a well-known invasive species, has both sexual and asexual forms in its... more Potamopyrgus antipodarum, a well-known invasive species, has both sexual and asexual forms in its native area, and is generally asexual in exotic areas. potamopyrgus antipodarum was sampled from ten locations in central and western Japan, and the sex distribution was analyzed. Males were found in two of the ten localities; the percentages of males in these localities were 7 .2 arrd'l .3 Vo, which is within the range of that observed in asexual populations in native and introduced areas. A flow cytometry analysis showed that populations with a low percentage of males (Kanro) and populations consisting only of females (Banyu Park, Hadano and Yugawara) and perhaps the population reported as having a high male percentage in a previous study (Chiba;29.8 Vo) were triploid. Males from Chiba and Kanro produced sperm. Most of the females from Chiba stored sperm in their seminal receptacle, showing that they had copulated, but no females from Kanro stored sperm. Fertilization by males, normal development of fertilized eggs, and the fecundity ofjuveniles should be evaluated in further studies to demonstrate the sexual reproduction of P. antipodarum in Japan.

Parasitology International, 2011

The life cycle of Liolope copulans Cohn, 1902 (Trematoda: Digenea: Liolopidae), an intestinal par... more The life cycle of Liolope copulans Cohn, 1902 (Trematoda: Digenea: Liolopidae), an intestinal parasite of the Japanese giant salamander Andrias japonicus (Temminck) (Amphibia: Caudata: Cryptobranchidae), was studied in the field and laboratory in Japan. This is the first description of mother sporocyst, daughter sporocyst and cercariae of a liolopid species. Non-oculate longifurcate pharyngeate cercariae were formed in lanceolate-cylindrical daughter sporocysts in Semisulcospira libertina (Gould) (Gastropoda: Sorbeoconcha: Pleuroceridae). They successfully developed to encapsulated metacercariae in cyprinid fishes, Nipponocypris sieboldii (Temminck and Schlegel) and Rhynchocypris lagowskii (Dybowski), by experimental infection. Cercariae had a V-shaped excretory vesicle with two looped arms, as in metacercariae and adults. Developmental stages from mother sporocyst to adult are described and illustrated. DNA sequencing was conducted for 28S and 18S rDNA of mother and daughter sporocysts, cercariae, and an adult. The result of molecular phylogenetic analysis suggests that L. copulans may be one of the basal taxa of the order Diplostomida Olson, Cribb, Tkach, Bray, and Littlewood, 2003, but its systematic position is still unclear because of the topological inconsistence between the 28S and 18S trees. Therefore, we tentatively place the family Liolopidae in the superfamily Diplostomoidea, mainly based on the morphology of sporocysts and cercariae. As regards the systematic position, the family Liolopidae Odhner, 1912 with Liolope as the type genus [11] has previously been placed, together with the family Clinostomidae Lühe, 1901, in the superfamily Clinostomoidea Lühe, 1901. Recently, the classification of the Digenea has been reconstructed based on the molecular phylogenetic analysis of nuclear ribosomal DNA , and the Clinostomidae was included in the superfamily Schistosomatoidea Stiles and Hassall, 1898 [13]. However, the larval morphology and DNA sequence data of no liolopid species have been analyzed, and the taxonomic position of the Liolopidae has remained uncertain .

Parasitology International, 2004

We describe the intermediate and definitive hosts of the fish nematodes Rhabdochona coronacauda a... more We describe the intermediate and definitive hosts of the fish nematodes Rhabdochona coronacauda and R. denudata honshuensis and discuss the relationships between parasitism and the feeding habitats of their intermediate hosts. We found that the principal intermediate hosts of the two nematodes were filter-feeding mayflies of the genera Ephemera, Photamanthus and Isonychia. Ephemera strigata seemed to be the most important intermediate host of these nematodes. Adult R. coronacauda were found mainly in Hemibarbus longirostris and Rhinogobius flumineus, which are benthic fishes that feed on benthic aquatic insects, including E. strigata. For R. coronacauda, therefore, the feeding habits of the definitive hosts facilitate host alternation by this species. However, adult R. denudata honshuensis were found in cyprinids. In particular, Zacco temmincki was the principal natural definitive host in our study area. Since Z. temmincki is a swimming predator, E. strigata nymphs that burrow in the substrate are not the main prey of this species. This indicates that the transmission of R. denudata honshuensis hardly occurs from E. strigata nymph to Z. temmincki, suggesting another, unknown transmission route.

Parasitology International, 2001

A total of 17 737 individuals of prosobranch snails, Semisulcospira spp., were collected from Lak... more A total of 17 737 individuals of prosobranch snails, Semisulcospira spp., were collected from Lake Biwa and its tributaries, central Japan, from 1995 to 1999. They were examined for trematode larvae. One species of Aspidogastrea and 28 species of Digenea were detected. This paper briefly describes five of the 28 digeneans: a tetracotyle Ž . Ž metacercaria from S. niponica, Cercaria A cystophorous cercaria from S. reticulata, Cercaria B echinostomatid . Ž . Ž . cercaria from S. libertina, Cercaria C magnacauda cercaria from S. niponica and Cercaria D mutabile cercarium from S. nakasekoae. They were rare and every one of them was obtained from one snail only once. ᮊ

Parasitology International, 2003

The parasite fauna of prosobranch snails of the genus Semisulcospira was surveyed in Lake Biwa an... more The parasite fauna of prosobranch snails of the genus Semisulcospira was surveyed in Lake Biwa and the adjacent water system. One aspidogastrean and 28 digenetic trematode taxa were detected in 19 209 snails consisting of 10 morphological species. There was no trematode species peculiar to members of the subgenus Biwamelania that is endemic to the Lake Biwa water system. However, one species, Notocotylus magniovatus, was found only in the non-endemic subgenus Semisulcospira. Of 23 digenean taxa detected in more than one host, 13 were distributed in both the lake and the tributaries. Seven of these had host taxa, more than 1% of which were infected with the parasite in both the lake and the tributaries, four had such hosts only in the tributaries, and two had no such hosts. Three species detected only in Lake Biwa were previously reported from other rivers in Japan. In the seven species detected only in the tributaries, two species had life cycles that could be maintained only in rivers. These results indicate that the core areas for the distribution of parasites of Semisulcospira are tributaries, and the lake is a sink for these species. These results contradict the expectation that the parasite fauna should be richer in the lake than in tributaries because the lake is a stable habitat over a geological time scale and has more divergent freshwater animals than the adjacent water system. ᮊ

Journal of Parasitology, 2012

A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was dev... more A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was developed for the molecular identification of 2 introduced bucephalid trematodes, Prosorhynchoides ozakii and Parabucephalopsis parasiluri . The method was applied for sporocysts and cercariae obtained from the golden mussel Limnoperna fortunei collected in the Uji River, Japan. The PCR-RFLP method showed that L. fortunei is the intermediate host of both trematode species. The present study thus recognizes the risk of L. fortunei , an invasive molluscan species, as a potential host for pathogenic trematodes.

Journal of Ethology, 1999

The frequency and pattern of interactions between males and females of sika deerCervus nippon wer... more The frequency and pattern of interactions between males and females of sika deerCervus nippon were surveyed in 3 sites of Nara Park, central Japan, mainly via observation of allogrooming frequency and aggressive behavior throughout the breeding ...

Folia Parasitologica, 2020

Eudiplozoon nipponicum (Goto, 1891) Khotenovsky, 1985 (Monogenea: Diplozoidae), is known to paras... more Eudiplozoon nipponicum (Goto, 1891) Khotenovsky, 1985 (Monogenea: Diplozoidae), is known to parasitise Cyprinus car-pio Linnaeus and species of Carassius. In this study, we conducted a taxonomic re-examination of E. nipponicum using genetic analysis and morphological comparisons from different host species from a single water system. rDNA nucleotide sequences of the internal transcription spacer 2 (ITS-2) region (645 bp) showed interspecific-level genetic differences among diplozoids from species of Carassius and C. carpio (p-distance: 3.1-4.0%) but no difference among those from different species of Carassius (0-0.4%) or between those from C. carpio collected in Asia and Europe (0-1.1%). Large variation was observed among 346 bp cytochrome c oxidase subunit I (COI) sequences (0.3-16.0 %); the topology of the phylogenetic tree showed no relationship to host genera or geographical regions of origin. Morphological observation showed that average clamp size of diplozoids from C. carpio was larger than those from Carassius spp. The number of folds on the hindbody was 10-25 for diplozoids from C. carpio and 12-19 for those from Carassius spp. Thus, our ITS-2 sequence and morphological comparison results indicate that diplozoids from C. carpio and species of Carassius belong to different species. The scientific name E. nipponicum should be applied to the species infected to the type host, Carassius sp. of Nakabo (2013) (Japa-nese name ginbuna). The diplozoid infecting C. carpio (Eurasian type) should be established as a new species: Eudiplozoon kamegaii sp. n. A neotype of E. nipponicum is designated in this report because the original E. nipponicum specimens are thought to have been lost.

Parasitology International, 2007

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji
River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and
Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the
second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first
intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first
intermediate host has not been identified.

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first intermediate host has not been identified.

Japanese Journal of Limnology (Rikusuigaku Zasshi), 1993

We found that in natural conditions, the freshwater snail Semisulcospira libertina was distribute... more We found that in natural conditions, the freshwater snail Semisulcospira libertina was distributed in deeper sites when infected with trematode larvae than when uninfected, and examined whether water-depth selection was different between infected and uninfected snails in the laboratory. We compared the mean size of infected and uninfected snails, and the correlation between mean water depth and shell size in uninfected snails. Small uninfected snails (up to 11 mm in shell width) showed a correlation between shell width and water depth, while large snails (larger than 11 mm) did not, but used deeper sites on average than smaller snails. In the small-size class, snails infected with mature cercariae used significantly deeper sites than uninfected snails. On the other hand, in the large-size class, snails infected with immature cercariae used significantly shallower sites than uninfected snails. In each size class, snails infected with mature cercariae used deeper sites than snails infected with immature cercariae or parthenitae. Thus, the influence of trematode infection to host behavior varies according to the development stage of trematodes. In the field, snails infected with mature and immature cercariae had a tendency to occur in deeper sites than uninfected snails of both small and large size classes. These results suggest that some factor other than active selection of water depth by snails determined the distribution pattern of infected snails in natural conditions.

Zoological science, 2015

Irrigation ditches are the major habitat of lotic unionid mussels in Japan. To conserve and rebui... more Irrigation ditches are the major habitat of lotic unionid mussels in Japan. To conserve and rebuild irrigation ditches facilitating mussel conservation, suitable physical environments must be clarified. The effect on mussels of paddy fields connected to ditches also needs to be determined. In this study, physical environmental factors that affect the density of unionid mussels were studied in irrigation ditches in Hikone City, Shiga Prefecture, Japan, to examine whether mussel densities were higher around paddy fields. Generalized linear models were used to analyze physical and paddy field environmental variables affecting mussel density. Our results show that sediment type, sediment softness, water depth, and flow velocity of irrigation ditches affect the density of unionid mussels; the effects of each environment factor and their relative importance differed by species. Specifically, the density of Nodularia douglasiae biwae was higher in ditches with sand-gravel sediment, soft se...

Limnology, 2009

Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea; Opecoelidae; Plagioporinae) i... more Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea; Opecoelidae; Plagioporinae) in its definitive host, the ayu Plecoglossus altivelis, in the Chikugo River, Kyushu, Japan, was examined. Natural ayu are amphidromous. In the upper Chikugo River, ayu fry raised in hatcheries are released into the river every spring because the migration of ayu is completely blocked by a dam that

Limnoperna Fortunei, 2015

Parasitology international, 2009

The morphology of a type specimen of Lophotaspis orientalis Faust and Tang, 1936 (Aspidogastrea: ... more The morphology of a type specimen of Lophotaspis orientalis Faust and Tang, 1936 (Aspidogastrea: Aspidogasteridae) was compared with the morphology of the original description of L. corbiculae Moriya, 1944 and of newly collected specimens from Corbicula species in China and Japan. The original description of L. orientalis was revised by the re-examination of the type specimen. Consequently, some key characteristics of these two species described by Moriya (1944) became invalid. The gonad size of the L. orientalis type specimen was out of the range of all other investigated specimens and past records, suggesting that the L. orientalis type specimen (host: soft-shell turtle) is a different species from the other investigated specimens (host: freshwater clam).

Parasitology international, 2007

The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999... more The morphology of two species of bucephalids (Bucephalidae; Digenea; Trematoda), which since 1999 has caused a fish disease at the Uji River, Kyoto Prefecture, Japan, is described. Parabucephalopsis parasiluri Wang, 1985 was first recorded in the Uji River in 2000, and Prosorhynchoides ozakii (Nagaty, 1937) in 2005. The definitive host of both species is the Lake Biwa catfish (Silurus biwaensis), and the second intermediate hosts include many fish species from several families. P. parasiluri is an introduced parasite that invaded with its first intermediate host, golden mussels (Limnoperna fortunei), from the Asian continent. P. ozakii may also be an introduced species, although its first intermediate host has not been identified.

Limnology, 2013

Potamopyrgus antipodarum, a well-known invasive species, has both sexual and asexual forms in its... more Potamopyrgus antipodarum, a well-known invasive species, has both sexual and asexual forms in its native area, and is generally asexual in exotic areas. potamopyrgus antipodarum was sampled from ten locations in central and western Japan, and the sex distribution was analyzed. Males were found in two of the ten localities; the percentages of males in these localities were 7 .2 arrd'l .3 Vo, which is within the range of that observed in asexual populations in native and introduced areas. A flow cytometry analysis showed that populations with a low percentage of males (Kanro) and populations consisting only of females (Banyu Park, Hadano and Yugawara) and perhaps the population reported as having a high male percentage in a previous study (Chiba;29.8 Vo) were triploid. Males from Chiba and Kanro produced sperm. Most of the females from Chiba stored sperm in their seminal receptacle, showing that they had copulated, but no females from Kanro stored sperm. Fertilization by males, normal development of fertilized eggs, and the fecundity ofjuveniles should be evaluated in further studies to demonstrate the sexual reproduction of P. antipodarum in Japan.

Parasitology International, 2011

The life cycle of Liolope copulans Cohn, 1902 (Trematoda: Digenea: Liolopidae), an intestinal par... more The life cycle of Liolope copulans Cohn, 1902 (Trematoda: Digenea: Liolopidae), an intestinal parasite of the Japanese giant salamander Andrias japonicus (Temminck) (Amphibia: Caudata: Cryptobranchidae), was studied in the field and laboratory in Japan. This is the first description of mother sporocyst, daughter sporocyst and cercariae of a liolopid species. Non-oculate longifurcate pharyngeate cercariae were formed in lanceolate-cylindrical daughter sporocysts in Semisulcospira libertina (Gould) (Gastropoda: Sorbeoconcha: Pleuroceridae). They successfully developed to encapsulated metacercariae in cyprinid fishes, Nipponocypris sieboldii (Temminck and Schlegel) and Rhynchocypris lagowskii (Dybowski), by experimental infection. Cercariae had a V-shaped excretory vesicle with two looped arms, as in metacercariae and adults. Developmental stages from mother sporocyst to adult are described and illustrated. DNA sequencing was conducted for 28S and 18S rDNA of mother and daughter sporocysts, cercariae, and an adult. The result of molecular phylogenetic analysis suggests that L. copulans may be one of the basal taxa of the order Diplostomida Olson, Cribb, Tkach, Bray, and Littlewood, 2003, but its systematic position is still unclear because of the topological inconsistence between the 28S and 18S trees. Therefore, we tentatively place the family Liolopidae in the superfamily Diplostomoidea, mainly based on the morphology of sporocysts and cercariae. As regards the systematic position, the family Liolopidae Odhner, 1912 with Liolope as the type genus [11] has previously been placed, together with the family Clinostomidae Lühe, 1901, in the superfamily Clinostomoidea Lühe, 1901. Recently, the classification of the Digenea has been reconstructed based on the molecular phylogenetic analysis of nuclear ribosomal DNA , and the Clinostomidae was included in the superfamily Schistosomatoidea Stiles and Hassall, 1898 [13]. However, the larval morphology and DNA sequence data of no liolopid species have been analyzed, and the taxonomic position of the Liolopidae has remained uncertain .

Parasitology International, 2004

We describe the intermediate and definitive hosts of the fish nematodes Rhabdochona coronacauda a... more We describe the intermediate and definitive hosts of the fish nematodes Rhabdochona coronacauda and R. denudata honshuensis and discuss the relationships between parasitism and the feeding habitats of their intermediate hosts. We found that the principal intermediate hosts of the two nematodes were filter-feeding mayflies of the genera Ephemera, Photamanthus and Isonychia. Ephemera strigata seemed to be the most important intermediate host of these nematodes. Adult R. coronacauda were found mainly in Hemibarbus longirostris and Rhinogobius flumineus, which are benthic fishes that feed on benthic aquatic insects, including E. strigata. For R. coronacauda, therefore, the feeding habits of the definitive hosts facilitate host alternation by this species. However, adult R. denudata honshuensis were found in cyprinids. In particular, Zacco temmincki was the principal natural definitive host in our study area. Since Z. temmincki is a swimming predator, E. strigata nymphs that burrow in the substrate are not the main prey of this species. This indicates that the transmission of R. denudata honshuensis hardly occurs from E. strigata nymph to Z. temmincki, suggesting another, unknown transmission route.

Parasitology International, 2001

A total of 17 737 individuals of prosobranch snails, Semisulcospira spp., were collected from Lak... more A total of 17 737 individuals of prosobranch snails, Semisulcospira spp., were collected from Lake Biwa and its tributaries, central Japan, from 1995 to 1999. They were examined for trematode larvae. One species of Aspidogastrea and 28 species of Digenea were detected. This paper briefly describes five of the 28 digeneans: a tetracotyle Ž . Ž metacercaria from S. niponica, Cercaria A cystophorous cercaria from S. reticulata, Cercaria B echinostomatid . Ž . Ž . cercaria from S. libertina, Cercaria C magnacauda cercaria from S. niponica and Cercaria D mutabile cercarium from S. nakasekoae. They were rare and every one of them was obtained from one snail only once. ᮊ

Parasitology International, 2003

The parasite fauna of prosobranch snails of the genus Semisulcospira was surveyed in Lake Biwa an... more The parasite fauna of prosobranch snails of the genus Semisulcospira was surveyed in Lake Biwa and the adjacent water system. One aspidogastrean and 28 digenetic trematode taxa were detected in 19 209 snails consisting of 10 morphological species. There was no trematode species peculiar to members of the subgenus Biwamelania that is endemic to the Lake Biwa water system. However, one species, Notocotylus magniovatus, was found only in the non-endemic subgenus Semisulcospira. Of 23 digenean taxa detected in more than one host, 13 were distributed in both the lake and the tributaries. Seven of these had host taxa, more than 1% of which were infected with the parasite in both the lake and the tributaries, four had such hosts only in the tributaries, and two had no such hosts. Three species detected only in Lake Biwa were previously reported from other rivers in Japan. In the seven species detected only in the tributaries, two species had life cycles that could be maintained only in rivers. These results indicate that the core areas for the distribution of parasites of Semisulcospira are tributaries, and the lake is a sink for these species. These results contradict the expectation that the parasite fauna should be richer in the lake than in tributaries because the lake is a stable habitat over a geological time scale and has more divergent freshwater animals than the adjacent water system. ᮊ

Journal of Parasitology, 2012

A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was dev... more A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was developed for the molecular identification of 2 introduced bucephalid trematodes, Prosorhynchoides ozakii and Parabucephalopsis parasiluri . The method was applied for sporocysts and cercariae obtained from the golden mussel Limnoperna fortunei collected in the Uji River, Japan. The PCR-RFLP method showed that L. fortunei is the intermediate host of both trematode species. The present study thus recognizes the risk of L. fortunei , an invasive molluscan species, as a potential host for pathogenic trematodes.