Hokkaido Aquatic Biology

Eniwa, Japan

Hokkaido Aquatic Biology

Eniwa, Japan
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Ito T.,Hokkaido Aquatic Biology
Zootaxa | Year: 2017

The taxonomy of the genus Microptila Ris in Japan is revised. Microptila orienthula Kjærandsen and Ito, 2009, the only East Palearctic species in the genus, is redescribed with new records and two new species, M. genka sp. nov. and M. nakama sp. nov., are described for adults from Ryukyu Islands, far southern Japan, in the Oriental region. © 2017 Magnolia Press.


Tomikawa K.,Hiroshima University | Kyono M.,Sapporo Technical College | Kuribayashi K.,Hokkaido Aquatic Biology | Nakano T.,Hiroshima University
Invertebrate Systematics | Year: 2017

Amphipod crustaceans are dominant in subterranean habitats, and members of eight genera are endemic to groundwater environments in the Japanese Archipelago. The taxonomic status of two of these genera remains unclear, because their original descriptions were incomplete. The descriptions of the enigmatic subterranean monotypic genus Awacaris and its type species, A. kawasawai Uéno, 1971, are revisited here. Awacaris kawasawai was originally described based on specimens from a subterranean stream at Himise Cave, Tokushima Prefecture, Shikoku, Japan. Recently, a new population of A. kawasawai was found at Saruta Cave, Kochi Prefecture, Shikoku. Detailed observation of the newly collected specimens reveals the presence of sternal gills, which is the diagnostic character of the pontogeneiid genus Sternomoera, making the validity of Sternomoera open to question. Phylogenetic analyses using nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I markers demonstrate that A. kawasawai forms a well-supported clade with the subterranean S. morinoi Tomikawa and Ishimaru, 2014. In addition, phylogenetic analysis reveals cryptic diversity in epigean species of Sternomoera. Ancestral state reconstruction suggests that catadromous Sternomoera species have evolved from freshwater ancestors. Based on our morphological and phylogenetic analysis of Awacaris and Sternomoera species, it is concluded here that Sternomoera should be treated as a subjective junior synonym of Awacaris. © CSIRO 2017.


Ito T.,Hokkaido Aquatic Biology
Pan-Pacific Entomologist | Year: 2016

Protogyny is uncommon in caddisflies (Trichoptera) but does occur. I found protogyny in Lepidostoma satoi (Kobayashi, 1968) and L. complicatum (Kobayashi, 1968), while the congeneric L. itoae (Kumanski & Weaver, 1992) had a simultaneous emergence pattern of males and females. Dissection of the female internal reproductive organs revealed that the former two species had rather immature eggs, while the latter species had nearly mature eggs in the ovaries at emergence. Immature eggs needed 3 to 5 days to mature, but nearly mature eggs needed only 0 to 2 days. The mean longevity of females was 11.6 days in L. satoi, 10.4 days in L. complicatum, and 13.7 days in L. itoae. Male longevity in the former two species (4.6 days and 6.6 days, respectively) was less than the latter species (15.8 days). These results suggest that protogyny in L. satoi and L. complicatum is advantageous, allowing males to mate with mature females in a more timely manner, as the males can mate from the day of emergence. Protogyny at emergence may synchronize the mating period of the both sexes.


A new species of hydroptilid caddisfly, Palaeagapetus fukuiensis sp. nov., is described based on adult and immature stages from Japan. The habitat and food of this species are noted. This species is more closely similar to the Russian Far Eastern species of Palaeagapetus than to the Japanese species. © The Japanese Society of Limnology 2009.


Ito T.,Hokkaido Aquatic Biology | Saito R.,Shinshu University
Zootaxa | Year: 2016

The tropical and subtropical caddisfly genus Plethus Hagen (Hydroptilidae) is recorded from Japan for the first time. The species, Plethus ukalegon Malicky and Chantaramongkol 2007, originally described from Taiwan, is redescribed based on material from Iriomote-jima and Ishigaki-jima, southern Ryukyu Islands, the southernmost region of Japan. Female and immature stages are newly described and compared with Indonesian congeners. The early instar larva was associated with the adult through mitochondrial DNA sequence comparisons, and is described in the genus Plethus for the first time. Larvae live in fast-flowing waters such as hygropetric zones, rapid streams, and waterfalls. Final instar larvae make flattened cases of silk that they attach tightly on smooth rock surfaces. Copyright © 2016 Magnolia Press.


Ito T.,Hokkaido Aquatic Biology | Nagasaka Y.,Forestry Research Institute
Pan-Pacific Entomologist | Year: 2015

Cases of final instar larvae of Brachycentrus kuwayamai Wiggins, Tani and Tanida, 1985 and B. americanus (Banks, 1899) (Brachycentridae) were observed in Hokkaido, northern Japan. Their cases were four-sided, tapered, and constructed of transversely arranged, narrow pieces of plant materials. Slender leaf pieces were fastened longitudinally on cases of final instar larvae of B. kuwayamai, but not on those of B. americanus. In B. kuwayamai, occurrence of the long pieces was variable in populations, with only 1-4 pieces on 32% of the larvae at one site, but 4-18 pieces on 100% of the larvae at another site. The longest attached piece was 3×the case length, and 23 pieces was the most found attached to a single case. This is the first report of attachment of long vegetal pieces to larval cases in the Brachycentridae.


Ito T.,Hokkaido Aquatic Biology | Ohkawa A.,Hokkaido University | Hattori T.,Komagata dori
Zootaxa | Year: 2011

The Japanese species of Hydroptila Dalman (Trichoptera, Hydroptilidae) are reviewed, confirming 10 described species, and introducing 2 new species. For clear comparisons and to include new details, males and females of all species, including the 2 new species, H. ogasawaraensis Ito and H. nanseiensis Ito, are redescribed or described anew. Hydroptila itoi Kobayashi is synonymized with H. dampfi Ulmer and H. thuna Oláh and H. botosaneanui Kumanski are recorded for the Japanese fauna for the first time. Hydroptila usuguronis Matsumura is reassigned to the genus Psychomyia Latreille (Psychomyiidae). © 2011 Magnolia Press.


A total of 68 species of genus Lepidostoma Rambur (Trichoptera; Lepidostomatidae) has been reported from the Asian Far East. L. coreanum (Kumanski & Weaver 1992) was originally described from North Korea. Detail examination of specimens of this species and its related specimens collected in the Asian Far East revealed the hypothetical definition of L. coreanum and the presence of 4 new related species, L. niigataense sp. nov., L. hattorii sp. nov., L. yuwanense sp. nov., and L. ishigakiense sp. nov. The species assemblage is named as the Lepidostoma coreanum Species Complex. Copyright © 2016 Magnolia Press.


Ito T.,Hokkaido Aquatic Biology | Hayashi Y.,Teruha Forest Association | Shimura N.,Nagatsuta
Zootaxa | Year: 2012

We reviewed the Japanese species of Anisocentropus McLachlan (Trichoptera, Calamoceratidae) and confirmed 3 species, Anisocentropus (Anisocentropus) kawamurai (Iwata, 1927), A. (A.) pallidus (Martynov, 1935) and A. (A.) magnificus Ul-mer, 1907. The last species is recorded from Japan for the first time. For clear comparisons, adult and immature stages of the three species are described based on associations established by rearing larvae. The male, female and pupa of A. (A.) kawamurai, female and pupa of A. (A.) pallidus and female and immature stages of A. (A.) magnificus are newly described. Anisocentropus (A.) minutus (Martynov, 1930), known from southeastern Asia, is synonymized with A. (A.) kawamurai (Iwata, 1927). © 2012 Magnolia Press.


PubMed | Shinshu University and Hokkaido Aquatic Biology
Type: Journal Article | Journal: Zootaxa | Year: 2016

The tropical and subtropical caddisfly genus Plethus Hagen (Hydroptilidae) is recorded from Japan for the first time. The species, Plethus ukalegon Malicky and Chantaramongkol 2007, originally described from Taiwan, is redescribed based on material from Iriomote-jima and Ishigaki-jima, southern Ryukyu Islands, the southernmost region of Japan. Female and immature stages are newly described and compared with Indonesian congeners. The early instar larva was associated with the adult through mitochondrial DNA sequence comparisons, and is described in the genus Plethus for the first time. Larvae live in fast-flowing waters such as hygropetric zones, rapid streams, and waterfalls. Final instar larvae make flattened cases of silk that they attach tightly on smooth rock surfaces.

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