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Last Updated :2024/11/15

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Master

Affiliation (Master)

  • Faculty of Science　Biological Sciences　Biodiversity

Affiliation (Master)

  • Faculty of Science　Biological Sciences　Biodiversity

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Profile and Settings

Affiliation

  • Hokkaido University, The Hokkaido University Museum

Profile and Settings

  • Contact Point

    kajiharaeis.hokudai.ac.jp

  • Name (Japanese)

    Kajihara

  • Name (Kana)

    Hiroshi

  • Name

    N-4562-2019, 200901025781611078

Alternate Names

Affiliation

  • Hokkaido University, The Hokkaido University Museum

Achievement

Research Interests

  • 系統   紐形動物   海産無脊椎動物   分類学   taxonomy   invertebrates   

Research Areas

  • Life sciences / Biodiversity and systematics

Research Experience

  • 2022/04 - Today 北海道大学大学院理学研究院 教授
  • 2004/04 - Today Hokkaido University The Hokkaido University Museum
  • 2010/04 - 2022/03 北海道大学大学院 理学研究院 准教授
  • 2007/04 - 2010/03 北海道大学大学院 理学研究院 助教
  • 2004/04 - 2008/03 Hokkaido University of Education
  • 2006/04 - 2007/03 北海道大学大学院 理学研究院 助手
  • 2003/04 - 2006/03 北海道大学大学院 理学研究科 助手
  • 2002/04 - 2003/03 国立環境研究所 日本学術振興会 科学技術特別研究員
  • 2002/01 - 2002/03 国立環境研究所 科学技術振興事業団 科学技術特別研究員
  • 2001/10 - 2001/12 Hokkaido University School of Science
  • 2001/04 - 2001/12 札幌科学技術専門学校 非常勤講師

Education

  • 1998/04 - 2001/03  北海道大学大学院
  • 1995/04 - 1998/03  北海道大学大学院
  • 1992/10 - 1995/03  Hokkaido University  Faculty of Pharmaceutical Sciences
  • 1991/04 - 1992/09  Hokkaido University

Committee Memberships

  • 2024/10 - Today   World Register of Marine Species (WoRMS)   Taxonomic editor (Nemertea)

Awards

  • 2008/09 日本動物学会 Zoological Science Award
     
    受賞者: 柁原 宏
  • 2007/09 日本動物学会 奨励賞
     
    受賞者: 柁原 宏

Published Papers

  • Yuki Kita, Masato Nitta, Hiroshi Kajihara
    Systematic Parasitology 101 (6) 0165-5752 2024/11/04 [Refereed][Not invited]
  • Yuki Kita, Tsukasa Waki, Hiroshi Kajihara
    Species Diversity 29 (2) 317 - 325 1342-1670 2024/10/10 [Refereed][Not invited]
  • Naoto Jimi, Yoshihiro Fujiwara, Hiroshi Kajihara
    Species Diversity 29 (2) 281 - 316 1342-1670 2024/09/03 [Refereed][Not invited]
  • Hiroshi Kajihara, Ikumasa Ganaha, Keitaro Okuno, Naoki Yamada, Hisanori Kohtsuka
    Species Diversity 29 (2) 235 - 237 1342-1670 2024/08/23 [Refereed][Not invited]
  • Yuki Kita, Masato Nitta, Hiroshi Kajihara
    Acta Parasitologica 1230-2821 2024/08/10 [Refereed][Not invited]
  • Yuki Oya, Akiteru Maeno, Aoi Tsuyuki, Hisanori Kohtsuka, Hiroshi Kajihara
    Zoological Science 41 (5) 0289-0003 2024/06/27 [Refereed][Not invited]
  • Natsumi Hookabe, Naoto Jimi, Shinta Fujimoto, Hiroshi Kajihara
    Royal Society Open Science 11 (6) 2024/06/19 [Refereed][Not invited]
     
    Polychaetes are typically found in marine environments with limited species adapting to semi-terrestrial habitats. The genus Stygocapitella comprises interstitial polychaetes dwelling in sandy beach areas around or above the high-water line. Based on molecular data, previous studies suggested the presence of multiple cryptic species in some different localities in the world lumped together as Stygocapitella subterranea . In Japan, reports on Stygocapitella were scarce, with only one species having been documented 40 years ago at Ishikari Beach in Hokkaido by the name of S. subterranea . We revisited these earlier findings and uncovered the presence of two distinct species in Stygocapitella . One of these species is herein named Stygocapitella itoi sp. nov., while the other corresponds to S. budaevae , originally described from the Russian Far East. Stygocapitella itoi sp. nov. possesses a chaetal pattern similar to that of S. australis , S. furcata and S. pacifica but can be distinguished from the congeners by two characters: a slightly forked pygidium and forked chaetae consisting of two teeth and two outer prongs. Our multi-locus phylogenetic analysis showed close relationships across the Pacific Ocean in two separated lineages in the genus, suggesting ancient dispersal or allopatric speciation after vicariance events.
  • Yuki Kita, Masato Nitta, Hiroshi Kajihara
    Species Diversity 29 (1) 171 - 178 1342-1670 2024/05/24 [Refereed][Not invited]
  • Haruki Ishiyama, Yuki Oya, Nerida G. Wilson, Hiroshi Kajihara
    Species Diversity 29 (1) 141 - 150 1342-1670 2024/04/24 [Refereed][Not invited]
  • Eric Odle, Siratee Riewluang, Kentaro Ageishi, Hiroshi Kajihara, Kevin C. Wakeman
    European Journal of Protistology 126080 - 126080 0932-4739 2024/03 [Refereed][Not invited]
  • Jamael C. Abato, Alexei V. Chernyshev, Natsumi Hookabe, Aoi Tsuyuki, Gauri Kaushik, Hiroshi Kajihara
    Frontiers in Ecology and Evolution 12 2024/02/16 [Refereed][Not invited]
     
    Three new species of the monostiliferous hoplonemertean genus Oerstedia Quatrefages, 1864, are herein described using morphological and molecular data—Oerstedia pseudoculata sp. nov., from Akkeshi Bay and Oshoro Bay, Hokkaido, Japan, and from Aniwa Bay, Sakhalin, Russia; Oerstedia rugosa sp. nov. from Sagami Bay, Misaki, Kanagawa, Japan, and Van Phong Bay, Vietnam; and Oerstedia viridifusca sp. nov. from Manazuru, Kanagawa, Japan. As to the external morphology, O. pseudoculata sp. nov. can be differentiated from O. oculata only by its bright-orange ocelli visible on both sides of the head, and a proboscis pore opening at the ventral tip of the head. These two sister species repeat each other’s color patterns, a phenomenon that can be explained by Vavilov’s law of homologous series. Oerstedia rugosa sp. nov. can be identified by its carmine or deep-red to brownish-red body with several longitudinal, intertwined white lines or wrinkles running from the head to the posterior body, and by 17–23 vaguely bordered white bands composed of variedly sized dots encircling the body, arranged at irregular intervals. Oerstedia viridifusca sp. nov. can be distinguished from other Oerstedia by (i) the entire body flecked with minute greenish-brown dots, especially densely on the anterior portion of the dorsal surface, but sparsely on the posterior half of the ventral surface; (ii) a collar-like portion encircling the body along the posterior cephalic furrow where the greenish-brown dots are absent; (iii) the anterolateral edges of the head lacking the greenish-brown dots; and (iv) the ocelli being brownish-orange in color. Oerstedia phoresiae (Kulikova, 1987) is reported for the first time from Japan, in addition to its previous distribution record in Russia and in South Korea. Phylogenetic analyses based on the 16S, 18S, 28S ribosomal RNA, cytochrome c oxidase subunit I, and histone H3 genes show that the new species are true congeners of the genus Oerstedia with O. pseudoculata sp. nov. and O. viridifusca sp. nov. nested within the clade Paroerstediella whereas O. rugosa sp. nov. in the clade Oerstedia. This taxonomic work emphasizes the importance of DNA barcode sequence in the taxonomy and systematics of the polymorphic congeners of the genus Oerstedia.
  • Naohiro Hasegawa, Hiroshi Kajihara
    Species Diversity 29 (1) 53 - 64 1342-1670 2024/02/01 [Refereed][Not invited]
  • Naohiro Hasegawa, Natsumi Hookabe, Yoshihiro Fujiwara, Naoto Jimi, Hiroshi Kajihara
    Zoosystematics and Evolution 100 (1) 129 - 140 1435-1935 2024/01/26 [Refereed][Not invited]
     
    Fimbrora Monniot & Monniot, 1991, a macrophagous ascidian genus within the family Ascidiidae Adams & Adams, 1858, is currently monotypic, represented by F. calsubia Monniot & Monniot, 1991, a species previously recorded from the bottom of the South Pacific at depths of 1000–1860 m. The taxonomic status of Fimbrora has remained ambiguous because characteristics in its branchial papillae and neural-gland opening are incompletely known in previous studies, while these traits are essential for distinguishing other ascidiid genera. So far, no nucleotide sequence representing F. calsubia is available. In this study, we collected a single specimen of F. calsubia at a depth of 2027 m, about 400 km off the Pacific coast of Honshu, Japan. This is the deepest record, as well as the first report from the North Pacific, for the species. Our examination indicates that Fimbrora is morphologically similar to another ascidiid genus, Psammascidia Monniot, 1962, by having only secondary branchial papillae in the pharynx. Our phylogenetic analysis, based on the 18S ribosomal RNA and cytochrome c oxidase subunit I genes, along with those of 27 ascidian species available in public databases, showed that F. calsubia was more closely related to Ascidia zara Oka, 1935, Phallusia fumigata (Grube, 1864) and Phallusia mammilata (Cuvier, 1815) than to Ascidia ceratodes (Huntsman, 1912), Ascidiella aspersa (Müller, 1776) and Ascidiella scabra (Müller, 1776). Our results also indicated that acquisitions of macrophagous feeding by deep-sea members happened independently at least three times in the evolutionary history of the entire Ascidiacea.
  • Hiroshi Kajihara, Audrey Falconer, Alexei V. Chernyshev
    Journal of Tropical Ecology 40 (e2) 1 - 3 2024/01/04 [Refereed][Not invited]
  • Hiroshi Kajihara, Jamael Abato, Maho Matsushita
    Russian Journal of Marine Biology 49 (6) 522 - 527 1063-0740 2024/01 [Refereed][Not invited]
  • Naohiro Hasegawa, Shin Matsubara, Akira Shiraishi, Honoo Satake, Noa Shenkar, Hiroshi Kajihara
    bioRxiv 2023/12/27 [Not refereed][Not invited]
     
    Abstract The size of organisms has consistently intrigued researchers across various disciplines in biology. However, the evolutionary process of zooid miniaturization in colonial animals remained an enigmatic topic. The family Styelidae, within the ascidian order Stolidobranchia, showcases a diverse spectrum of coloniality, positioning it as an ideal candidate for delving into the intricacies of colonial evolution. In this research, we inferred a phylogenomic relationship mainly within Styelidae using transcriptomes of a total of 42 ascidians; from 17 species sampled in Israel and Japan and transcriptome data from 25 species sourced from a previous study and a database. Through ancestral-state reconstruction, our analysis indicated a clear directional change: following the acquisition of coloniality, zooids tended to become progressively smaller. This miniaturization is likely an adaptive response, enabling organisms to swiftly colonize limited marine substrate. We formulated a mathematical model suggesting that zooid miniaturization, due to living space constraints, would result in a faster asexual cycle and accelerated expansion in a colony. Our data also suggested that coloniality evolved independently three times within Styelidae. Moreover, once colonial traits are established, they appear to be consistently preserved, underscoring their biological importance in the colonial lineage.
  • Occurrence of Baseodiscus quinquelineatus (Quoy and Gaimard, 1833) (Pilidiophora: Heteronemertea) in Mindanao, Philippines
    Jamael Abato, Hiroshi Kajihara, Laurence Calagui, Archie Along, Julius Anthony Leones, Shirlamaine Irina Calagui, Israel Isaac Salo
    Philippine Journal of Science 152 (6B) 2413 - 2418 2023/12 [Refereed][Not invited]
  • Yuki Kita, Hiroshi Kajihara
    Systematic Parasitology 0165-5752 2023/10/19 [Refereed][Not invited]
  • Daisuke Shimada, Shimpei F. Hiruta, Kazuhiro Takahoshi, Hiroshi Kajihara
    Animal Gene 30 200161 - 200161 2352-4065 2023/10 [Refereed][Not invited]
  • Yu Matsumoto, Hiroshi Kajihara, Keiichi Kakui
    Zootaxa 5336 (4) 577 - 589 1175-5326 2023/08/24 [Refereed][Not invited]
     
    We establish the new podocerid genus Capropodocerus gen. nov. for the two new species Capropodocerus tagamaru gen. et sp. nov. (collected from 775–800 m depth in the Kumano Sea, Japan) and Capropodocerus kamaitachi gen. et sp. nov. (collected from 840–873 m depth off the eastern coast of Miyagi, Japan). Capropodocerus shares elongate pereonites 1–3 with Neoxenodice but differs from the latter in lacking uropod 2 and in having pereonite 3 at least twice as long as pereonite 4. Capropodocerus is also similar to Laetmatophilus and Leipsuropus in having only two pairs of uropods but differs from them in having i) pereonite 1 longer than the head and ii) pereonite 3 at least twice as long as pereonite 4; Capropodocerus has three urosomes and Laetmatophilus has two urosomes. The two species in Capropodocerus differ in i) the length ratio of the antenna 1 peduncle to the flagellum, ii) the shape of the gnathopod 2 palm, iii) the presence or absence of a mid-posterior triangular projection on the gnathopod 2 dactylus, and iv) the length ratio of the basis to the merus of pereopod 3. A key to all genera in Podoceridae is provided.
  • Hiroshi Kajihara, Jamael Abato, Maho Matsushita
    Deep Sea Research Part I: Oceanographic Research Papers 104075 - 104075 0967-0637 2023/08 [Refereed][Not invited]
  • Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
    Zoosystematics and Evolution 99 (2) 363 - 373 1435-1935 2023/07/05 [Refereed][Not invited]
     
    In this study, we describe a new species of elongated marine flatworm, Eucestoplana ittanmomensp. nov., collected from the intertidal zone of the Okinawa Islands, Japan. Eucestoplana ittanmomensp. nov. is distinguished from other congeners based on the following characteristics: i) its translucent body lacking coloration, ii) its dome-shaped penis sheath, iii) the absence of cilia on the inner wall of the male atrium except outside the penis sheath, and iv) the presence of an adhesive organ at the posterior end of the body. Additionally, we report the occurrence of E. cf. cuneata (Sopott-Ehlers & Schmidt, 1975) in Japan; E. cuneata has previously been documented in the Galapagos and Fiji Islands. We conducted phylogenetic analyses to infer the positions of the two Eucestoplana species within Cestoplanidae using a concatenated dataset comprising partial 18S and 28S rDNA sequences from E. cf. cuneata and E. ittanmomensp. nov. from Japan, as well as four known Cestoplana species with sequences available in public databases. Our phylogenetic analyses revealed that Cestoplana and Eucestoplana were reciprocally monophyletic. Furthermore, the genetic distance of the 16S rDNA sequences supported the genetic independence of the two sister species, E. cf. cuneata and E. ittanmomensp. nov.
  • Yuki Kita, Shimpei F. Hiruta, Mizuki Sasaki, Hiroshi Kajihara
    Parasitology International 94 102731 - 102731 1383-5769 2023/06 [Refereed][Not invited]
  • Aoi Tsuyuki, Yuki Oya, Naoto Jimi, Natsumi Hookabe, Shinta Fujimoto, Hiroshi Kajihara
    Zoological Science 40 (3) 0289-0003 2023/05/18 [Refereed][Not invited]
  • Jamael Abato, Ryuta Yoshida, Hiroshi Kajihara
    Zootaxa 5249 (5) 589 - 597 1175-5326 2023/03/06 [Refereed][Not invited]
     
    We provide a morphological and molecular-based description of the eumonostiliferous hoplonemertean Oerstedia fuscosparsa sp. nov. based on two specimens dredged from a depth between 11 and 18 m off Kouyatsu, Tateyama, Chiba, Japan. This Oerstedia differs from its congeners by having a deep brownish pigmentation in the head, four orange ocelli, and imprecise dorsal and ventral transverse bands composed of numerous small brown spots. One of the specimens, herein designated as the holotype, has deep brown spots situated mid-dorsally onto the transverse bands running throughout the body. These dorsal markings are absent in the other specimen designated as a paratype. Internally, the species has accessory lateral nerves, and the proboscis nerves are not distinct. Molecular phylogenetic analyses based on partial sequences of the 16S, 18S, 28S rRNA, cytochrome c oxidase subunit I, and histone H3 gene markers along with the sequences from 22 Oerstedia species available in public databases confirmed that our species is sister to Oerstedia phoresiae (Kulikova, 1987) and belongs to the recently established Paroerstediella clade within the genus Oerstedia.
  • Razy Hoffman, Hiroshi Kajihara
    Oceanography & Fisheries 15 (5) 555922  2023/02 [Refereed][Not invited]
  • Yu Matsumoto, Hiroshi Kajihara, Keiichi Kakui
    Nauplius 31 2023/02 [Refereed][Not invited]
  • Hai-Long Liu, Hiroshi Kajihara, Shi-Chun Sun
    Frontiers in Marine Science 9 2022/12/08 [Refereed][Not invited]
     
    The genus Ototyphlonemertes Diesing, 1863, consisting of 33 named species and numerous unnamed morphospecies/molecular entities, is a unique group of nemerteans that possess cerebral statocysts and specifically live in coarse-grained sands. Only eight named species of this genus have yet been recorded from the Indo-Polynesian biogeographic province, which harbors the highest marine biodiversity in the world. In recent years, Ototyphlonemertes were collected from eight sites along the South China Sea coasts. Nine species/entities were revealed by four phylogenetic markers (COI, 16S, 18S, 28S) analyzed by three species delimitation methods: Automatic Barcode Gap Discovery (ABGD), Poisson Tree Process (PTP), and Generalized Mixed Yule Coalescent model (GMYC). Six entities are described as new species based on integration of morphological and molecular species delimitations: Ototyphlonemertes conicobasis sp. nov., Ototyphlonemertes coralli sp. nov., Ototyphlonemertes similis sp. nov., Ototyphlonemertes sinica sp. nov., Ototyphlonemertes subrubra sp. nov., and Ototyphlonemertes yingge sp. nov. No morphological differences were detected between two entities and Ototyphlonemertes chernyshevi Kajihara et al., 2018, despite large genetic differences, so are treated as candidate species. Ototyphlonemertes ani Chernyshev, 2007 is first recorded in China. Based mostly on results of phylogenetic analyses, two previously established subgenera are re-defined, and a new subgenus, Procso subgen. nov., is established. Through reviewing the existing studies, we recognize 101 species/entities of Ototyphlonemertes, which are distributed in 18 marine biogeographic provinces. Most (88.1%) of them are endemic to a single biogeographic province, and evolutionary lineages endemic to a geographic area are not uncommon. Maximum diversity has been recorded in the Indo-Polynesian Province (22 species), though sampling to date has covered only a small part of the biogeographic province.
  • Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
    PLOS ONE 17 (11) e0276847 - e0276847 2022/11/23 [Refereed]
     
    Tiny animals in various metazoan phyla inhabit the interstices between sand and/or gravel grains, and adaptive traits in their body plan, such as simplification and size reduction, have attracted research attention. Several possible explanations of how such animals colonized interstitial habitats have been proposed, but their adaptation to this environment has generally been regarded as irreversible. However, the actual evolutionary transitions are not well understood in almost all taxa. In the present study, we show reversible evolutionary shifts from interstitial to epibenthic habitats in the lineage of the polyclad flatworm genus Boninia. In addition, we establish two new species of this genus found from different microhabitats on a single beach in Okinawa Island, Japan: (i) the interstitial species Boninia uru sp. nov. from gravelly sediments and (ii) the epibenthic species Boninia yambarensis sp. nov. from rock undersurfaces. Our observations suggest that rigid microhabitat segregation exists between these two species. Molecular phylogenetic analyses based on the partial 18S and 28S rDNA sequences of the new Boninia species and four other congeners, for which molecular sequences were available in public databases [Boninia antillara (epibenthic), Boninia divae (epibenthic), Boninia neotethydis (interstitial), and an unidentified Boninia sp. (habitat indeterminate)], revealed that the two interstitial species (B. neotethydis and B. uru sp. nov.) were not monophyletic among the three epibenthic species. According to ancestral state reconstruction analysis, the last common ancestor of the analyzed Boninia species inhabited interstitial realms, and a shift to the epibenthic environment occurred at least once. Such an “interstitial to noninterstitial” evolutionary route seems to be rare among Animalia; to date, it has been reported only in acochlidian slugs in the clade Hedylopsacea. Our phylogenetic tree also showed that the sympatric B. uru sp. nov. and B. yambarensis sp. nov. were not in a sister relationship, indicating that they colonized the same beach independently rather than descended in situ from a common ancestor that migrated and settled at the beach.
  • Yuki Oya, Hiroki Nakajima, Hiroshi Kajihara
    Marine Biodiversity 52 (5) 1867-1616 2022/10 [Refereed]
  • Yuki Oya, Aoi Tsuyuki, Hiroshi Kajihara
    Zootaxa 5178 (5) 433 - 452 1175-5326 2022/08/30 [Refereed][Not invited]
     
    We describe two new species of Armatoplana Faubel, 1983, namely, A. albomaculata sp. nov. and A. kaburakii sp. nov., from Japan. This is the first record of the genus from the West Pacific. Armatoplana albomaculata sp. nov. has the following characteristics: i) no nuchal tentacles; ii) white spots on the dorsal surface of the body; iii) an elongated oval prostatic vesicle directing posteriorly but curving dorsally in the distal part; iv) a long, curved penis stylet; and v) a small, oval Lang’s vesicle without accessory vesicles. Armatoplana kaburakii sp. nov. is distinguished from other congeners by having i) no nuchal tentacles; ii) a large, elongated Lang’s vesicle without accessory vesicles; and iii) gonopores opening closely to each other. We propose to re-circumscribe Armatoplana so that it would not become a junior synonym of Candimboides Prudhoe, 1982 and Phylloplana Laidlaw, 1903. We provide partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene as DNA barcodes for the two new species. Our phylogenetic analyses based on concatenated sequences of the 16S, 18S, and 28S ribosomal DNA and COI revealed that A. albomaculata sp. nov. and A. kaburakii sp. nov. were sister taxa; however, they did not form a monophyletic clade with Armatoplana divae (Marcus, 1947) and Armatoplana leptalea (Marcus, 1947).
  • Hiroshi Kajihara, Shushi Abukawa, Alexei V. Chernyshev
    Zoological Journal of the Linnean Society 196 (1) 503 - 548 0024-4082 2022/08/26 [Refereed][Not invited]
     
    Abstract With about 480 known species, Pilidiophora (phylum Nemertea) has been regarded as consisting of Hubrechtiiformes (~20 spp.) and Heteronemertea (~460 spp.). Most (~87%) of the latter belong to Lineidae (> 400 spp.), while the systematics of non-lineid heteronemerteans remains largely untouched. To explore the phylogeny of non-hubrechtiiformid, non-lineid pilidiophorans, we performed multilocus molecular phylogenetic analyses with five genes (18S, 28S, H3, 16S and COI) from 41 newly sequenced specimens. Pilidiophora comprised Hubrechtellidae, Lineidae, Valenciniidae, the new family Eopilidiidae and a not formally named family-level heteronemertean taxon. Eopilidion misakiense gen. et sp. nov. is described from a specimen from Japan, but whether it belongs to Heteronemertea remains unclear. Apart from this new species, the following 11 new species of valenciniids are established, based on molecular sequences and external morphology (localities in parentheses): Baseodiscus giribeti sp. nov. (Panama), B. kakuii sp. nov. (Japan), B. komatsui sp. nov. (Japan), B. narusei sp. nov. (Japan), B. ohtsukai sp. nov. (Japan), B. paracelensis sp. nov. (Vietnam), B. profundus sp. nov. (Russian Far East), B. urgorrii sp. nov. (Spain), B. zebra sp. nov. (Japan), Oxypolella hiebertae sp. nov. (Vietnam) and Valencinura jambio sp. nov. (Japan).
  • Jamael Abato, Ryuta Yoshida, Hiroshi Kajihara
    Journal of Natural History 56 (29-32) 1265 - 1277 0022-2933 2022/08/18 [Refereed][Not invited]
  • Natsumi Hookabe, Hiroshi Kajihara, Alexei V. Chernyshev, Naoto Jimi, Naohiro Hasegawa, Hisanori Kohtsuka, Masanori Okanishi, Kenichiro Tani, Yoshihiro Fujiwara, Shinji Tsuchida, Rei Ueshima
    Frontiers in Marine Science 9 2022/07/26 [Refereed][Not invited]
     
    Nemerteans, or ribbon worms, have been reported from intertidal to hadal depths, often showing bathymetrically wide distribution in genus levels. Although current nemertean systematics practices require to provide DNA sequences and infer phylogenetic relationships with suitable molecular markers, previous molecular systematics on nemerteans are mostly biased toward shallow-water species. Members in the genus Nipponnemertes occur worldwide, from tropical to polar waters and intertidal to bathyal waters. Molecular phylogenetic studies are scarce for the genus; only six shallow-water species of 18 species in the genus were subject to molecular phylogeny. Thus, Nipponnemertes is one candidate that needs to be assessed by genetic approaches. In this study, we performed molecular phylogenetic analyses using 59 specimens in 23 species based on partial sequences of two mitochondrial (16S rRNA and cytochrome c oxidase subunit I) and three nuclear gene markers (18S rRNA, 28S rRNA, and histone H3). Our extensive sampling from intertidal to bathyal waters in the Northwest Pacific significantly updated the fauna of Nipponnemertes in this region from four to 17 species. We herein establish 10 new species and provide an updated species list concisely summarizing all the congeners known from the world. Our phylogenetic tree indicated three major lineages within the genus (herein referred to as “Clade A, B, and C”), each presumably characterized by the combination of morphological characters in the head region. Members in Clade A are: Nipponnemertes pulchra (Johnston, 1837), Nipponnemertes ogumai (Yamaoka, 1947), and several unidentified congeners, characterized by having demarcated head without cephalic patches; members in Clade B are: Nipponnemertes crypta sp. nov., Nipponnemertes jambio sp. nov., Nipponnemertes neonilae sp. nov., and Nipponnemertes ojimaorum sp. nov., species having demarcated head with cephalic patches; members in Clade C are: Nipponnemertes ganahai sp. nov., Nipponnemertes kozaensis sp. nov., Nipponnemertes lactea sp. nov., Nipponnemertes notoensis sp. nov., Nipponnemertes ornata sp. nov., Nipponnemertes sugashimaensis sp. nov., and two unidentified forms collected off Jogashima (Japan) and Guam (USA), species with non-demarcated head lacking cephalic patches. Furthermore, we discuss the evolution of remarkably small body size retained among Clade C.
  • Aoi Tsuyuki, Hisanori Kohtsuka, Natsumi Hookabe, Hiroshi Kajihara
    Plankton and Benthos Research 17 (2) 147 - 155 1880-8247 2022/05/30 [Refereed][Not invited]
  • Natsumi Hookabe, Hirohito Motobayashi, Naoto Jimi, Hiroshi Kajihara, Rei Ueshima
    Parasitology International 89 102567 - 102567 2022/03/02 [Refereed]
     
    The carcinonemertid monostiliferan Ovicides paralithodis Kajihara and Kuris, 2013 was originally described as an egg predator of the red-king crab Paralithodes camtschaticus (Tilesius, 1815) in the Sea of Okhotsk, the Bering Sea, and the Gulf of Alaska. In the present study, several carcinonemertid specimens were obtained from the egg mass of the snow crab Chionoecetes opilio (O. Fabricius, 1788) in the Sea of Japan. Partial sequences of the mitochondrial cytochrome c oxidase subunit I gene (COI) determined from two specimens of the carcinonemertid were identical with a barcode sequence from the holotype of O. paralithodis, indicating that the host range of the species covers at least the two decapod species, P. camtschaticus and C. opilio.
  • Hiroshi Kajihara, Ikumasa Ganaha, Hisanori Kohtsuka
    Zoological Science 39 (1) 62 - 80 0289-0003 2022/01/03 [Refereed][Invited]
  • Natsumi Hookabe, Hiroshi Kajihara
    Zoological Science 39 (1) 81 - 86 0289-0003 2022/01/03 [Refereed][Invited]
  • Hiroshi Kajihara
    Species Diversity 27 (1) 25 - 35 1342-1670 2022/01/01 [Refereed][Not invited]
  • Case 3849 – Emplectonematidae Bürger, 1904 and Emplectonema Stimpson, 1857 (Nemertea, Monostilifera): proposed conservation of current usage by reversal of precedence of the family name with respect to Eunemertidae Joubin, 1894 and designation of a new type species for the genus
    Hiroshi Kajihara, Mark J. Grygier, Sónia C. S. Andrade, Thomas Bartolomaeus, Irina A. Chernyeva, Alexei V. Chernyshev, Jörn von Döhren, Christina I. Ellison, Ray Gibson, Gonzalo Giribet, Terra C. Hiebert, Natsumi Hookabe, Juan Junoy, Sebastian Kvist, Svetlana A. Maslakova, Cecili B. Mendes, Jon L. Norenburg, Neonila E. Polyakova, Christina Sagorny, Megan L. Schwartz, Malin Strand, Shichun Sun, James M. Turbeville, Eduardo E. Zattara
    Bulletin of Zoological Nomenclature 78 184 - 200 2021/12 [Refereed][Not invited]
  • Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
    Marine Biology Research 17 (9-10) 946 - 959 1745-1000 2021/11/26 [Refereed][Not invited]
  • Yuki Oya, Aoi Tsuyuki, Hiroshi Kajihara
    Proceedings of the Biological Society of Washington 134 (1) 0006-324X 2021/11/02 [Refereed][Not invited]
  • Natsumi Hookabe, Hisanori Kohtsuka, Hiroshi Kajihara
    Marine Biology Research 17 (5-6) 467 - 474 1745-1000 2021/10/20 [Refereed][Not invited]
     
    We provide a histology-free description of the eumonostiliferous hoplonemertean Tetrastemma cupido sp. nov. based on specimens collected subtidally at a depth of 100 m in Sagami Bay, Japan. In T. cupido sp. nov., the ocelli are arranged in two, anterior and posterior, pairs of clusters, each consisting of up to eight and four ocelli, respectively. This feature is unique to T. cupido sp. nov. among similar to 110 congeners in the genus Tetrastemma Ehrenberg, 1828, where the ocelli are unexceptionally four in number. The generic affiliation of the new species was confirmed with a molecular phylogenetic analysis based on partial sequences of cytochrome c oxidase subunit I, 16S rRNA, 18S rRNA and 28S rRNA genes among 31 species of eumonostiliferans. In the resulting tree, T. cupido sp. nov. was nested in a clade comprised of 11 species of Tetrastemma including the type species Tetrastemma flavidum Ehrenberg, 1828. Tetrastemma cupido sp. nov. is morphologically similar to Amphiporus superbus (Girard in Stimpson W. 1854. Marine Invertebrata of Grand Manan. Smithsonian Contr Knowl. 6:5-67), but can be distinguished from the latter by having a mid-dorsal white stripe.
  • Hiroaki Nakano, Naoto Jimi, Takenori Sasaki, Hiroshi Kajihara
    Zoological Science 39 (1) 7 - 15 0289-0003 2021/10/06 [Refereed][Invited]
  • Alexei V. Chernyshev, Neonila E. Polyakova, Jon L. Norenburg, Hiroshi Kajihara
    Zoologica Scripta 50 (6) 824 - 836 0300-3256 2021/09/02 [Refereed][Not invited]
  • Hiroshi Kajihara, Eric N. Smith
    Bulletin of Zoological Nomenclature 78 (2) 112 - 130 0007-5167 2021/08/30 [Refereed][Not invited]
  • Aida Verdes, María Belén Arias, Juan Junoy, Megan L. Schwartz, Hiroshi Kajihara
    Systematics and Biodiversity 19 (7) 895 - 905 1477-2000 2021/08/26 [Refereed][Not invited]
  • Yuki Kita, Hiroshi Kajihara
    Parasitology International 85 102430 - 102430 1383-5769 2021/07/30 [Refereed][Not invited]
  • Phylum Entoprocta
    Tohru Iseto, Hiroshi Kajihara
    Invertebrate Zoology: A Tree of Life Approach. Schierwater, B. & DeSalle, R. (Eds), CRC Press, Boca Raton, 644 pp. 379 - 388 2021/07 [Refereed][Invited]
  • Phylum Nemertea
    Hiroshi Kajihara
    Invertebrate Zoology: A Tree of Life Approach. Schierwater, B. & DeSalle, R. (Eds), CRC Press, Boca Raton, 644 pp. 357 - 368 2021/07 [Refereed][Invited]
  • Tomoya Takahashi, Kenjiro Tadakuma, Masahiro Watanabe, Eri Takane, Natsumi Hookabe, Hiroshi Kajihara, Takeshi Yamasaki, Masashi Konyo, Satoshi Tadokoro
    IEEE Robotics and Automation Letters 6 (3) 5413 - 5420 2021/04/15 [Refereed]
  • Description of a new species of the marine flatworm Prosthiostomum (Platyhelminthes: Polycladida) and its three known congeners from Misaki, Japan, with inference of their phylogenetic positions within Prosthiostomidae
    Aoi Tsuyuki, Hisanori Kohtsuka, Hiroshi Kajihara
    Zoological Studies 60 29  2021/04 [Refereed][Not invited]
  • Jumpei Ikenaga, Hiroshi Kajihara, Manabu Yoshida
    Zoological Science 38 (2) 193 - 202 0289-0003 2021/04 [Refereed][Not invited]
     
    The heteronemertean Kulikovia alborostrata (Takakura, 1898) was originally described as Lineus alborostratus based on material from Misaki, Japan. Although this species was regarded as consisting of two color variants, purple and brown-yellow, the identity of these variants has never been examined based on topotypes. In this study, we performed a multi-locus phylogeny reconstruction, species delimitation analyses, and cross-fertilization experiments to examine the species status of Takakura's original taxon concept consisting of these color variants. Our results suggest that the purple type is identical to Lineus alborostratus Takakura, 1898 auct. (currently Kulikovia alborostrata), whereas the brown-yellow type is conspecific with Lineus fulvus Iwata, 1954, originally established from Hokkaido. These two species appear to have a sister-taxon relationship and are reproductively isolated from each other by prezygotic mechanisms involving gamete incompatibility, minimally separated with 2.8% (16S rRNA) and 14.4% (COI) uncorrected p-distances. We propose that the purple type be considered as representing the true identity of the nominal species Lineus alborostratus (currently assigned to the genus Kulikovia) to maintain the common usage of the name. Although Takakura's type material is not extant, we consider that neotypification is unnecessary in this case because no taxonomic/nomenclatural confusion persists. We also propose to transfer Lineus fulvus to yield Kulikovia fulva comb. nov.
  • Natsumi Hookabe, Cong-Mei Xu, Aoi Tsuyuki, Naoto Jimi, Shi-Chun Sun, Hiroshi Kajihara
    Invertebrate Systematics 35 350 - 359 1445-5226 2021/03/24 [Refereed][Not invited]
     
    Among ~1300 species of world nemerteans, seven species in five genera of lineid heteronemerteans have been known to possess a branched proboscis. In this paper, we describe the eighth branched-proboscis species: Gorgonorhynchus citrinus sp. nov. from Okinawa, Japan. We also report Gorgonorhynchus cf. repens Dakin & Fordham, 1931 with uniformly orange body, as a new member for the Japanese nemertean fauna. We infer the phylogenetic relationships between these forms and other members of Lineidae McIntosh, 1874 for which partial sequences of the mitochondrial 16S rRNA and cytochrome c oxidase subunit I, and the nuclear 18S rRNA, 28S rRNA, and histone H3 genes are available in public databases, along with newly sequenced data of another branched-proboscis heteronemertean, Polydendrorhynchus zhanjiangensis (Yin & Zheng, 1984) from China. In the resulting tree, Gorgonorhychus Dakin & Fordham, 1931 was sister group to non-branched-proboscis Dushia Corrêa, 1963, whereas P. zhanjiangensis was sister group to likewise non-branched-proboscis Cerebratulus lacteus (Leidy, 1851). http://zoobank.org/urn:lsid:zoobank.org:pub:685992C5-F595-4C28-9178-256D945E595A
  • Yuki Oya, Hiroshi Kajihara
    Journal of the Marine Biological Association of the United Kingdom 101 (1) 81 - 88 0025-3154 2021/02 [Refereed][Not invited]
     
    AbstractWe establish a new genus of planocerid polyclad, Heteroplanocera gen. nov., based on a new species, H. katoi sp. nov., collected at a depth of 245 m off the coast of the Izu Peninsula, West Pacific, Japan. Heteroplanocera gen. nov. is distinguished from other planocerid genera by the following characteristics: (i) a pair of nuchal tentacles, (ii) a muscular bulb, (iii) a pair of spermiducal bulbs (instead of a seminal vesicle), (iv) a free prostatic vesicle, (v) a pair of accessory organs with teeth, (vi) a Lang's vesicle, and (vii) the lack of a bursa copulatrix. We provide a partial sequence of the cytochrome c oxidase subunit I (COI) gene (712 bp) as a DNA barcode of the new species. Furthermore, we estimate the phylogenetic position of Heteroplanocera gen. nov. among Planoceridae based on partial sequences of COI and 16S, 18S, and 28S ribosomal DNA. Based on our findings, we discuss the evolution and function of the (i) vaginal cuticularized structure and (ii) accessory organs among planocerid flatworms.
  • Hiroshi Kajihara
    Zootaxa 4920 (2) 151 - 199 1175-5326 2021/01/28 [Refereed][Not invited]
     
    The nemertean order Monostilifera consists of 594 species in 127 genera and is distributed worldwide. Within the Monostilifera, two suborders have been recognized, Cratenemertea and Eumonostilifera. Within the latter, two, unranked clade names, Oerstediina and Amphiporina, were recently proposed without formal taxonomic definition. In this article, I give morphological circumscriptions and clade definitions for Cratenemertea, Eumonostilifera, Oerstediina, Plectonemertidae, Oerstediidae, and Amphiporina. Oerstediina and Amphiporina are placed on the Linnaean rank of infraorder. Constituent genera and species for each higher taxon are tabulated. The genus Amphiporella Friedrich, 1939 is herein replaced with Germanemertes nom. nov. to avoid homonymy with the Carboniferous fossil bryozoan genus Amphiporella Girty, 1910. Loxorrhochmidae Diesing, 1862 is declared a nomen oblitum relative to Tetrastemmatidae Hubrecht, 1897, a nomen protectum under Article 23.9 of the International Code of Zoological Nomenclature. There remain 308 species of eumonostiliferans whose infraorder affiliation is uncertain due to the lack of information on vascular morphology and molecular sequence data. The suborder affiliation of the two species Cinclidonemertes mooreae Crandall, 2010 and Verrillianemertes schultzei Senz, 2001 is left uncertain.
  • Naoto Jimi, Taeko Kimura, Akito Ogawa, Hiroshi Kajihara
    Systematics and Biodiversity 19 (1) 13 - 21 1477-2000 2021/01/02 [Refereed][Not invited]
     
    Up to now, 19 species in eight genera and two families (Dorvilleidae and Oenonidae) of polychaetes are known to be endoparasitic in the body of other polychaetes. In this paper, we describeEndovermis seisuiaegen. et sp. nov. as the first representative of Phyllodocidae parasitizing other polychaetes. Specimens ofE. seisuiaewere found in the body cavity ofAphroditasp. (Aphroditidae) andLepidonotussp. (Polynoidae) collected from muddy sediment, 216-218 m deep, off central Japan, the western North Pacific. Our multi-locus molecular phylogenetic analysis based on COI, 16S, 18S, and 28S sequences along with other phyllodocids for which sequences were available in public databases suggested thatEndovermisas sister to the clade formed byParanaitisSouthern, 1914 andEteoneSavigny, 1922.
  • Shohei Yamauchi, Hiroshi Kajihara
    Species Diversity 24 (1) 1342-1670 2021 
    Due to an oversight, Dr. Jordi Paps’ family name was misspelled for his publication (Paps and Riutort 2012) as a citation in Yamauchi and Kajihara (2018). His name appeared in two places across the paper, which should be corrected as follows.
  • Aoi Tsuyuki, Yuki Oya, Naoto Jimi, Hiroshi Kajihara
    Zootaxa 4894 (3) 403 - 412 1175-5326 2020/12/10 [Refereed][Not invited]
     
    We describe a new species of polyclad flatworm, Pericelis flavomarginata sp. nov., from the intertidal and subtidal zones along localities on the Pacific coast of Japan. Pericelis flavomarginata sp. nov. is characterized by i) the dorsal surface of the body fringed by a lemon-yellow line except for the tip of tentacles, with a narrow brown midline running from the anterior edge of the body to the posterior end of the pharynx, ii) the pair of marginal tentacles with the tips extending and tapering, and iii) the presence of a common gonopore. Our molecular phylogenetic analysis revealed that selected Pericelis species were divided into two clades, each of which may be agreed with a characteristic dorsal color pattern. Additionally, we report an observation on the feeding behavior of P. flavomarginata sp. nov. on the polychaete Iphione muricata (Savigny in Lamarck, 1818).
  • Natsumi Hookabe, Masashi Asai, Hiroaki Nakano, Taeko Kimura, Hiroshi Kajihara
    Proceedings of the Biological Society of Washington 133 (1) 0006-324X 2020/11/30 [Refereed][Not invited]
  • Natsumi Hookabe, Hiroshi Kajihara
    Zoological Science Zoological Society of Japan 37 (5) 467 - 475 0289-0003 2020/10 [Refereed][Not invited]
  • Natsumi Hookabe, Hiroshi Kajihara
    Marine Biodiversity 50 (5) 1867-1616 2020/10 [Refereed][Not invited]
     
    © 2020, Senckenberg Gesellschaft für Naturforschung. Members of the lineid heteronemertean genus Euborlasia Vaillant, 1890 are relatively large-bodied ribbon worms, often with mottled, dark coloration. We describe Euborlasia maycoli sp. nov. from Bocas del Toro, Panama, which represents the 11th member, as well as the first Caribbean representative of the genus. We infer the phylogenetic position of the new species among the family Lineidae based on phylogenetic analyses using partial sequences of the mitochondrial 16S rRNA and cytochrome c oxidase subunit I, the nuclear 18S and 28S rRNA, and histone H3 genes. The resulting phylogenetic tree suggests that Euborlasia is likely related closely to Corsoua Corrêa, 1963.
  • Razy Hoffman, Hiroshi Kajihara
    Mediterranean Marine Science 1108-393X 2020/09/30 [Refereed][Not invited]
     
    The ribbon worm Evelineus mcintoshii is reported for the first time from the Mediterranean Sea. Observations that took place, during two algal surveys, on the intertidal abrasion platforms at the middle of the Levantine Sea of Israel indicated that this species is hiding inside a mixture of local and non-indigenous marine seaweeds. It is probably another alien species, one of many, that adopted the Levantine basin of the Eastern Mediterranean due to tropical environmental conditions that characterize this sea. We discuss the first record of this species and its possible origins as well as the first report of Notospermus geniculatus, the other marine nemertean species recently reported from Israel.
  • Yuki Oya, Aoi Tsuyuki, Hiroshi Kajihara
    Species Diversity 25 (2) 189 - 196 1342-1670 2020/09/18 [Refereed][Not invited]
     
    © 2020. We describe a new species of ilyplanid polyclad, Zygantroides serpulidicola sp. nov., from Amakusa, Kumamoto, Japan. This is the third member of Zygantroides Faubel, 1983 and the first record of the genus from the Pacific Ocean. Zygantroides serpulidicola sp. nov. is characterized by i) the mouth opening near the common gonopore, ii) the sperm ducts separately entering a pear-shaped seminal vesicle, iii) an elongated Lang's-vesicle duct, and iv) the horseshoe-shaped Lang's vesicle located posterior to the common gonopore. We provide a partial sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene (712 bp) as a DNA barcode for the species. Our phylogenetic analyses based on concatenated sequences of the 16S, 18S, and 28S ribosomal DNA and COI indicate that Z. serpulidicola sp. nov. is nested in a clade comprised of Discocelidae and Ilyplanidae; the latter does not appear to be monophyletic.
  • Naoto Jimi, Takuya Minokawa, Toru Miura, Hiroshi Kajihara
    Species Diversity 25 (2) 213 - 218 1342-1670 2020/09/18 [Refereed][Not invited]
  • Natsumi Hookabe, Kentaro Watanabe, Megumu Tsujimoto, Hiroshi Kajihara
    Polar Science 25 100535  1873-9652 2020/09 [Refereed][Not invited]
     
    © 2020 Elsevier B.V. and NIPR The Antarctic heteronemertean Parborlasia corrugata (McIntosh, 1876) (originally Lineus corrugatus) shows a circumpolar distribution in the Southern Ocean, putatively with high dispersal capacity of the planktonic larva. From the eastern coast of Lützow-Holm Bay near Syowa Station (69°00′S, 39°35′E), several records of heteronemerteans have been made under the name of Lineus corrugatus. However, they have never been explicitly identified by molecular data. In the present study, we determined a partial sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene for 11 specimens of P. corrugata collected from depths of 17–27 m under sea ice near Syowa Station. A haplotype-network analysis along with other COI sequences from 66 individuals collected at different places in the Antarctic and sub-Antarctic islands, available at public databases, resulted in that all the 11 specimens from Lützow-Holm Bay possessed either of two major haplotypes detected in previous studies. It reflects the effective dispersal of the species between the localities including Lützow-Holm Bay.
  • Natsumi Hookabe, Shinji Tsuchida, Yoshihiro Fujiwara, Hiroshi Kajihara
    Species Diversity 25 (2) 183 - 188 1342-1670 2020/08 [Refereed][Not invited]
     
    © 2020 The Japanese Society of Systematic Zoology. The monostiliferous hoplonemertean Proamphiporus kaimeiae sp. nov. is described based on a single specimen collected from the bottom of the Northwest Pacific, 262 m deep, off Tohoku in Japan, by use of a remotely operated vehicle during a cruise organized by Tohoku Ecosystem-Associated Marine Sciences (TEAMS) research project in 2019. The position of the cerebral organs in the new species, being posterior to the proboscis insertion, is unusual for Eumonostilifera, which is one of the diagnostic traits of the so-far monospecific Proamphiporus Chernyshev and Polyakova, 2019, and Amphiporus rectangulus Strand, Herrera-Bachiller, Nygren, and Kånneby, 2014. The latter is herein transferred to Proamphiporus to yield a new combination, Proamphiporus rectangulus comb. nov., based on the reported internal morphology. Molecular phylogenetic analyses based on 16S rRNA, cytochrome c oxidase subunit I, 18S rRNA, 28S rRNA, and histone H3 genes placed P. kaimeiae in a clade comprised of Proamphiporus crandalli Chernyshev and Polyakova, 2019 and Proamphiporus rectangulus.
  • Natsumi Hookabe, Naoto Jimi, Shinji Tsuchida, Yoshihiro Fujiwara, Hiroshi Kajihara
    Zoological Studies 59 1021-5506 2020/07 [Refereed][Not invited]
     
    Lacydonia japonica sp. nov. (Annelida, Lacydoniidae) is described based on material found in sediments collected off the Pacific coast of northern Honshu, Japan, at depths of 262 m and 407 m. The sediments were obtained by a remotely operated vehicle equipped with a suction sampler during a Tohoku Ecosystem-Associated Marine Sciences (TEAMS) project in 2019. Lacydonia japonica sp. nov. belongs to the eyeless group of lacydoniids and is discriminated from the morphologically most similar congener, Lacydonia papillata Uschakov, 1958 by its reddish pigments on both the dorsal and ventral parapodial cirri and four pigment spots on the pygidium. To assess the phylogenetic position of the new species among other lacydoniids for which sequence data are available in public databases, analyses were performed using the mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA, as well as the nuclear 18S rRNA and 28S rRNA genes. We additionally obtained some lacydoniids by sledging off western Japan, but these were severely fragmented and broken during collection. Using the paucity of morphological data, they were left unidentified as Lacydonia sp. but included in the molecular analyses. Genetic distances between Lacydonia eliasoni Hartmann-Schroder, 1996, Lacydonia japonica, and Lacydonia sp. off western Japan were 10.4-17.1% uncorrected p-distance (11.3-18.6% K2P) in terms of 658-bp COI sequences.
  • Hiroshi Kajihara
    Zootaxa 4819 (2) 295 - 315 1175-5326 2020/07 [Refereed][Not invited]
     
    The heteronemertean Cerebratulus orochi sp. nov. is described based on material collected intertidally at a muddy beach in Akkeshi, northern Japan. For the last 80 years, the species has been confused with Cerebratulus marginatus Renier, 1804; the latter was originally described from the Adriatic and once believed to occur in many places in the northern hemisphere including Japan. Cerebratulus orochi sp. nov. is morphologically different from all the congeners including C. marginatus by the following combination of characters: several layers of diagonal-muscle meshwork coated with connective tissue, proximo-distally distributed in cross section from the distal portion of the body-wall outer longitudinal muscle layer to the cutis-gland zone throughout the anterior portion of the body from the precerebral to the foregut regions; the cephalic vascular system consisting of lateral and mid-dorsal vessels; and the sub-rhynchocoelic vessel possessing a pair of antero-lateral diverticula before the former forks posteriorly into a pair of lower lateral vessels in the post-cerebral, pre-oral region. Previous records of C. marginatus from Japanese waters are no longer considered to be substantiated. Multi-locus phylogenetic analyses based on the mitochondrial 16S rRNA and cytochrome c oxidase subunit I (COI), as well as the nuclear 18S rRNA, 28S rRNA, and histone H3 genes among heteronemerteans comprising the "Cerebratulus clade" indicated that C. orochi sp. nov. was closely related to C. cf. marginatus from the US Pacific coast. A MegaBLAST search at the NCBI website with the 16S rRNA gene sequence from C. orochi sp. nov. followed by a couple of species delimitation analyses suggests that larvae of the species are also distributed in Vostok Bay, Far East Russia.
  • Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
    Check List 16 (3) 773 - 779 2020/06/26 [Refereed][Not invited]
     
    © The authors. The polyclad flatworm Stylostomum ellipse (Dalyell, 1853) has hitherto been recorded from the Antarctic region, Mediterranean Sea, Patagonian region, Scandinavia, South Africa, and South Georgia Island. In this study, we report S. ellipse for the first time from the Pacific Ocean based on specimens collected in Hokkaido, northern Japan. Our specimens are morphologically identifiable as S. ellipse, but may represent a biologically different species from a population of the Mediterranean Sea. This is because, based on the previous genetic data of other cotylean species, the observed uncorrected p-distance 0.02160 between the two distinct populations in terms of a partial 972 bp region of the 28S rDNA sequence may be great enough to separate the species biologically.
  • Yuki Oya, Hiroshi Kajihara
    Zoological Science 37 (3) 271 - 279 0289-0003 2020/06 [Refereed][Not invited]
     
    © 2020 Zoological Society of Japan. Acotylea is a suborder of Polycladida (Rhabditophora, Platyhelminthes) characterized by lack of a cotyl (sucker-like structure) on the ventral surface of the body. We newly determined partial sequences of two mitochondrial (16S ribosomal RNA and cytochrome c oxidase subunit I) and two nuclear (18S and 28S ribosomal RNA) genes from 24 acotylean species (12 families and 14 genera). Based on these sequences in addition to those available in public databases, we inferred the phylogeny of 16 families and 27 genera of Acotylea from molecular phylogenetic analyses (maximum likelihood and Bayesian inference) based on concatenated gene sequences. Our analyses supported three clades corresponding to Discoceloidea, Leptoplanoidea, and Stylochoidea. The phylogenetic position of Callioplanidae remains unclear. Among family-or genus-level taxa, Gnesiocerotidae, Stylochoplanidae, and Comoplana were not monophyletic. We discuss the validities of Notocomplanidae and Koinostylochus, and the family-level assignment of Mirostylochus.
  • Natsumi Hookabe, Hiroshi Kajihara
    Check List 16 (2) 265 - 269 2020/03/13 [Refereed][Not invited]
     
    © 2020, Pensoft Publishers. All rights reserved. A single specimen of a monostiliferous hoplonemertean, collected from a depth of 25 m in Akkeshi Bay, northern Japan, represents the first record of Gurjanovella littoralis Uschakov, 1926 from the Northwest Pacific. The species has been known only from the type locality, White Sea, Russia, although some planktonic larvae from Oregon, USA, and a juvenile from the Sea of Okhotsk have been identified as a member of the genus by molecular sequence data. Our specimen differs from a topotype from the White Sea by 2.9% of uncorrected p-distance and 3.0% of K2P in terms of partial 658-bp sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Our COI phylogenetic tree indicates that each of the larvae from Oregon and the Sea of Okhotsk belongs in Gurjanovella but represents a different species from G. littoralis.
  • Aoi Tsuyuki, Hiroshi Kajihara
    ZooKeys 2020 (918) 15 - 28 1313-2989 2020/03/12 [Refereed][Not invited]
     
    © Aoi Tsuyuki, Hiroshi Kajihara. We describe a new species of polyclad flatworm, Enchiridium daidai sp. nov., from the rocky subtidal zone in the East China Sea along the coasts of the Kyushu and Okinawa Islands, Japan. Enchiridium daidai sp. nov. is characterized by i) the entire periphery of the dorsal surface narrowly fringed with orange, ii) a marginal-eyespot band extending to the position of the mouth (about anterior one-eighth of body), and iii) two prostatic vesicles covered by a common muscle sheath, which is penetrated by the ejaculatory duct. We performed a molecular phylogenetic analysis based on 945-bp 28S rDNA sequences of 16 species of Prosthiostomidae currently available in public databases in addition to those of E. daidai sp. nov. and Prosthiostomum torquatum Tsuyuki et al., 2019. In the resulting tree, our new species was nested in a clade composed of Enchiridium species. The tree topology was in favor of a taxonomic view that Enchiridium should be defined by having i) a common muscle sheath that encloses two prostatic vesicles and ii) marginal eyespots that may or may not surround the periphery of the dorsal surface.
  • Record of the heteronemertean Cerebratulus signatus (Nemertea: Pilidiophora: Lineidae) from off Rishiri Island, Hokkaido
    Hiroshi Kajihara, Shinri Tomioka
    Rishiri Studies 39 19 - 21 2020/03 [Not refereed][Not invited]
  • Hiroshi Kajihara, Ayuta Kato, Takafumi Nakano, Yi-Te Lai
    Taiwania College of Life Science, National Taiwan University & Biodiversity Association of Taiwan 65 (1) 81 - 85 0372-333X 2020/01/20 [Refereed][Not invited]
     
    We report the freshwater heteronemertean Apatronemertes albimaculosa Wilfert & Gibson, 1974 for the first time from Taiwan based on specimens collected under stones and rocks on gravelly bottom near the shore of a brook in Nantun District, Taichung City. Species identification was corroborated by mitochondrial cytochrome c oxidase subunit I gene sequences. The species had been reported from aquaria with tropical freshwater plants in Germany, Austria, USA, Spain, and Japan, before it was discovered from wild environment in Panama. Our report represents the second instance of field-caught A. albimaculosa in the world.
  • Yuki Higashida, Naoto Jimi, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 25 (2) 329 - 342 1342-1670 2020 [Refereed][Not invited]
     

    A new species of flabelligerid polychaete, Lamispina miurai sp. nov., has been described based on material collected at a depth of 226–228 m in the Pacific Ocean, off Aomori, Japan. Lamispina miurai sp. nov. can be differentiated from other congeners by the following features: i) the body is not covered with sand or large sediment particles; ii) the lamispines are present on the chaetiger 4 and succeeding chaetigers; iii) the tip of the lamispine is curved and subdistally serrated; iv) the cephalic cage is formed by chaetigers 1–3; and v) the length of the cephalic cage is twice as long as the body width.

  • Hiroshi Kajihara
    Species Diversity 日本動物分類学会 25 (2) 251 - 273 1342-1670 2020 [Refereed][Not invited]
     

    Three species of nemerteans, Balionemertes cf. australiensis Sundberg, Gibson, and Olsson, 2003 (Palaeonemertea), Prosadenoporus olympiae sp. nov. (Hoplonemertea: Eumonostilifera), and Coella gloriae sp. nov. (Hoplonemertea: Polystilifera: Reptantia), are reported based on material collected intertidally at a rocky shore in Cebu Island, Republic of the Philippines. Cytochrome c oxidase subunit I (COI) barcode sequences of these species have earlier been published elsewhere. The Cebu specimen that is herein identified tentatively as Balionemertes cf. australiensis posseses i) small black dots on the ventral body surface, ii) a neurochord in the lateral nerve, iii) serial rhynchocoelic septa, and iv) nephrostomes, characters that were not mentioned in the original description of the species from Australia; the exact species identification requires barcode sequences from topotypes. Prosadenoporus olympiae can be differentiated morphologically from other congeners by having three accessory-stylet pouches; when alive, worms of this species showed negative hydrotaxis. Coella gloriae differs from all the reptantic polystiliferans by having i) four rows of the eyes, ii) the cephalic furrows, iii) no dorsal marking, iv) separate mouth and proboscis openings, v) blind-ending extracerebral vessels, vi) non-forked fibre core in the dorsal ganglia, vii) the subdorsal nerves, and viii) the cerebral organs partly overlapping the brain.

  • Hiroshi Kajihara, Atsushi Yamaguchi
    Plankton and Benthos Research 日本プランクトン学会、日本ベントス学会 15 (4) 337 - 341 1880-8247 2020 [Refereed][Not invited]
     

    The three currently recognized species comprising the pelagic polystiliferous hoplonemertean genus Protopelagonemertes Brinkmann, 1917 are supposedly distinguishable chiefly with respect to the number of proboscis nerves: 29 (varying from 22 to 30) in P. hubrechti (Brinkmann, 1917); 19–21 (varying from 19 to 22) in P. beebei Coe, 1936; and 36 in P. joculatori Van der Spoel, 1988. A single specimen collected off the Pacific coast of Hokkaido, Japan, herein identified as P. beebei, was found to possess 19–23 primary proboscis nerves. In addition to the primary proboscis nerves, the material also possessed 12–16 secondary proboscis nerves, which are discernible from the primary nerves in that they coexist with putative glial cells. Although secondary proboscis nerves have been identified in some other species in the Pelagica, they have not previously been described for any members of the Protopelagonemertes. Our findings thus prompted us to question the validity of morphological species delimitation within this genus, given that the distinction between primary and secondary proboscis nerves has previously not been taken into consideration. Close examination of the specimen in the living state revealed that it is characterized by a pair of cephalic furrows, a structure commonly found in benthic representatives of the phylum, but herein confirmed for the first time among the Pelagica. A 658-bp partial sequence of the mitochondrial cytochrome c oxidase subunit I gene from the newly examined specimen was found to be identical to sequences derived from two other specimens previously collected in Sagami Bay, thereby indicating that P. beebei may occur commonly in Japanese meso- to bathypelagic waters.

  • Woo Sau Pinn, Kajihara Hiroshi, Byrne Maria, Fujita Toshihiko
    MARINE BIODIVERSITY 49 (6) 2519  1867-1616 2019/12 [Refereed][Not invited]
  • Sau Pinn Woo, Hiroshi Kajihara, Maria Byrne, Toshihiko Fujita
    Marine Biodiversity 49 (6) 2499 - 2518 1867-1616 2019/12 [Refereed][Not invited]
     
    A new genus of Holothuroidea, Notostichopus, from Australia is described and its phylogenetic relationship examined. The new genus is based on two species within the family Stichopodidae, previously attributed to Stichopus. Notostichopus is characterized by the absence of rosette ossicles and the presence of table ossicles with at most one crossbeam in dorsal body wall. The two species revised here (N. ludwigi and N. ellipes) are distributed in the shallow, tropical, and temperate waters of Australia. Phylogenetic analyses indicate that this genus is closely related to the genera Isostichopus and Stichopus but is distinct based on ossicles and phylogenetic analyses. We describe the ossicle assemblages of both species.
  • A new species of Polyodontes (Annelida: Acoetidae) from Japan
    Naoto Jimi, Shinri Tomioka, Ryo Orita, Hiroshi Kajihara
    Species Diversity 24 275 - 279 2019/11 [Refereed][Not invited]
  • Natsumi Hookabe, Megan L. Schwartz, Hiroshi Kajihara, Jon L. Norenburg
    Zootaxa 4691 (4) zootaxa.4691.4.2 - 358 1175-5326 2019/11 [Refereed][Not invited]
     
    The heteronemertean genus Dushia Corrêa, 1963 was established for what was identified as D. atra (Girard, 1851) (originally Meckelia atra) based on material from littoral, shallow waters in Curaçao, while the nominal species Meckelia atra was originally described from deep water off Florida Cape. In this paper, we conclude that the type species for Dushia has been misidentified. Based on specimens from the Caribbean, we establish D. wijnhoffae Schwartz & Norenburg sp. nov. to represent the true identity of the genus, according to Article 70.3.2 of the International Code of Zoological Nomenclature; Meckelia atra should be regarded as a nomen dubium. While the genus has remained monotypic since its establishment, our molecular analysis discovered a second member—or rather a group of members—from the West Pacific. This ‘group of members’, herein termed Dushia nigra (Stimpson, 1855) species complex comb. nov., involves i) at least two genetically separated biological entities, 0.136–0.148 (p-distance) and 0.152–0.168 (K2P) apart in terms of 513-bp COI sequences, which we interpret as likely to represent cryptic species, ii) three color forms, orange, brown, and black, with the last one occurring most frequently, and iii) four nominal species, Meckelia nigra Stimpson, 1855 (now Cerebratulus niger), Meckelia rubella Stimpson, 1855 (now Cerebratulus rubellus), Micrura formosana Yamaoka, 1939, and Micrura japonica Iwata, 1952. At present, however, we have no objective ground as to which of the four potentially available names (i.e., formosana, japonica, nigra, and rubella) should be allotted to the two cryptic species discovered in the analysis, because i) a single locality can harbor two cryptic species, ii) a single cryptic species may contain three different color morphs (i.e., orange, brown, black), and iii) no data from the type localities for these four nominal species are available at the moment. Our multi-locus analysis of heteronemerteans—for which 16S rRNA, COI, 18S rRNA, 28S rRNA, histone H3 genes are available in public databases—shows that Dushia wijnhoffae sp. nov. and Dushia nigra species complex comb. nov. form a clade, which is closely related to Gorgonorhynchus albocinctus Kajihara, 2015 and an undetermined heteronemertean that has been misidentified as Cerebratulus leucopsis (Coe, 1901). Members of Dushia thus show a vicariant Caribbean–West-Pacific distribution, indicating that the lineage predates the rise of the Isthmus of Panama.
  • Jumpei Ikenaga, Natsumi Hookabe, Hisanori Kohtsuka, Manabu Yoshida, Hiroshi Kajihara
    Zoological Science 36 (4) 348 - 353 0289-0003 2019/08 [Refereed][Not invited]
  • Yuki Oya, Taeko Kimura, Hiroshi Kajihara
    ZooKeys (864) 1 - 13 1313-2989 2019/07 [Refereed][Not invited]
     
    We describe a new species of polyclad flatworm, Paraplehnia seisuiae sp. nov., from 298-310 m depths in the Sea of Kumano, West Pacific, Japan. Paraplehnia seisuiae sp. nov. is characterized by i) a developed muscular wall proximally occupying about one-third of the prostatic vesicle, ii) no common duct between the spermiducal bulbs and the prostatic vesicle, and iii) a genital pit between the male and female gonopores. We provide a partial sequence (712 bp) of the mitochondrial cytochrome c oxidase subunit I gene as a DNA barcode for the species. Our phylogenetic analyses based on 603-bp 28S rDNA sequences indicate that P. seisuiae sp. nov. is nested in a Glade consisting of stylochoid species along with unidentified species of Stylochus. It suggests that Plehniidae belongs to Stylochoidea, although this should be confirmed by future studies that contain Plehnia arctica (Plehn, 1896), the type species of the type genus of the family. The interfamily relationship among the superfamily Stylochoidea remains poorly resolved.
  • Daiki Wakita, Toshihiko Fujita, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 24 (2) 119 - 135 1342-1670 2019/07 [Refereed][Not invited]
     
    <p>The subgenus <i>Setihenricia</i> Chichvarkhin and Chichvarkhina, 2017 currently consists of 32 out of 94 species of sea stars in the genus <i>Henricia</i> Gray, 1840. However, only 10 have been molecularly ascertained as to the phylogenetic position. Based on seven mitochondrial gene markers (16S rRNA, COI, tRNA-Ala, tRNA-Leu, tRNA-Asn, tRNA-Gln, and tRNA-Pro), we performed molecular analyses to assess the monophyly of <i>Setihenricia</i> using 16 species of <i>Henricia</i> from Japanese waters, as well as other congeners for which sequences were available in public databases. The monophyletic <i>Setihenricia</i> was only weakly recovered because the support values were low, but we assume this taxon may be valid in consideration of a morphological key. <i>Henricia kinkasana</i> Hayashi, 1940 is herein identified as a new member of <i>Setihenricia</i>, based on molecular and morphological evidence. Sequences in the public databases previously identified as <i>H. compacta</i> (Sladen, 1889) and <i>H. obesa</i> (Sladen, 1889) were nested in the <i>Setihenricia</i> clade; these two species are also likely members of <i>Setihenricia</i>. Our morphological assessment yielded three findings: (1) the number of the rows of spines on each inferomarginal plate, being three or more, appears to be a useful diagnostic character for <i>Setihenricia</i>, as has been suggested in previous studies, (2) the degree of spine tapering turned out to be less relevant in diagnosing the subgenus than previously supposed, (3) two newly introduced characters—(<i>i</i>) the width of adambulacral plates and (<i>ii</i>) the ratio of two measurements in ambulacral plates to the length of interradius—may be effective to distinguish members of this apparent <i>Henricia</i> subclade from other members of the genus.</p>
  • Naohiro Hasegawa, Hiroshi Kajihara
    ZooKeys 857 (857) 1 - 15 1313-2989 2019/06/24 [Refereed][Not invited]
  • Park Taesco, Lee Sang-Hwa, Sun Shi-Chun, Kajihara Hiroshi
    ZooKeys (852) 31 - 51 1313-2989 2019/06/05 [Refereed][Not invited]
  • Hiroshi Kajihara, Maho Ikoma, Hiroshi Yamasaki, Shimpei F. Hiruta
    Zoological Science 36 (3) 250 - 258 0289-0003 2019/06 [Refereed][Not invited]
     
    A new species of stygobiontic interstitial annelid, Diurodrilus kunii sp. nov., is described based on material collected from medium sand sediment (ϕ = 1.2-1.7) at groundwater level (40-100 cm in depth; 5-15 m inland from splash zone) in the intertidal beach slope on Ishikari Beach, facing the Sea of Japan, Hokkaido, Japan. The new species differs from six known congeners in the arrangement of the anterior-head ventral ciliophores, the degree of development in the primary and secondary toes, and the shape of the spermatozoa. We inferred the phylogenetic position of the new species among other congeners for which 18S rRNA, 28S rRNA, and COI gene sequences were available in public databases. This is the first representative of the genus from the Northwest Pacific.
  • Hiroshi Kajihara
    Fauna Norvegica 39 39 - 76 2019/06 [Refereed][Not invited]
     
    The taxonomic identity of the palaeonemertean Cephalothrix linearis (Rathke, 1799) has been obscure for nearly two centuries, because its original description applies to almost any congeners, including Cephalothrix filiformis (Johnston 1828) and Cephalothrix rufifrons (Johnston, 1837), which occur commonly in the North Sea and adjacent waters. In this paper, I redescribe C. linearis based on two topotypes from Bergen, one herein designated as the neotype for C. linearis, because Rathke’s original material is not extant; I invoke Article 70.3.2 of the International Code of Zoological Nomenclature to fix Planaria linearis Rathke, 1799 as the type species of Cephalothrix Örsted, 1843 for the sake of stability. From the neotype, I determined sequences of the 28S rRNA, 16S rRNA, and cytochrome c oxidase subunit I (COI) genes. Using the COI sequence, I inferred the phylogenetic position of C. linearis along with 316 cephalotrichid sequences currently available in public databases. A tree-based species delimitation analysis detected 43 entities among them, with 34 in Cephalothrix and nine in either
    Balionemertes or Cephalotrichella. I apply valid species names to 12 of the 34 entities in Cephalothrix. I tabulated a total of 36 nominal species that are likely the members of the genus; the following five were excluded even though their specific names were originally combined with Cephalothrix: Cephalothrix armata Ulyanin, 1870 [Monostilifera, possibly Emplectonema gracile (Johnston, 1837)], Cephalothrix fragilis Bürger, 1892 [now Cephalotrichella signata (Hubrecht, 1879)], Cephalothrix signata Hubrecht, 1879 [now in Cephalotrichella], Cephalothrix unipunctata Parfitt, 1867 [now Tetrastemma melanocephalum (Johnston, 1837) (Monostilifera)], and Cephalothrix viridis Chapuis, 1886 [possibly Heteronemertea]. The five names cephalothrix Diesing, 1850 (as Borlasia cephalothrix), kroyeri Diesing, 1850 (as Cephalothrix kroyeri), linearis Diesing, 1850 (as Borlasia linearis), lineata Claparède, 1862 (as Cephalothrix lineata), and oerstedii Diesing, 1850 (as Cephalothrix oerstedii) are
    declared nomenclaturally unavailable.
  • Naoto Jimi, Chong Chen, Kajihara Hiroshi
    Check List 15 (3) 523 - 526 2019/06 [Refereed][Not invited]
     
    The hydrothermal vent-endemic polychaete Archinome jasoni Borda et al., 2013 is known from the Atlantic, Indian, and Southwest Pacific oceans. In this study, we report A. jasoni from Okinawa Trough, Japan, which represents the first record of this species and the genus from the Northwest Pacific. We determined 16S and 28S rRNA gene sequences from 1 of the 7 specimens collected. We compared our Northwest Pacific specimens to specimens from the Southwest Pacific, Atlantic, and Indian oceans, and our specimen was genetically most closely related to individuals from the Southwest Pacific.
  • Alexei V. Chernyshev, Hiroshi Kajihara
    Zoomorphology 138 (2) 193 - 207 0720-213X 2019/06 [Refereed][Not invited]
  • Yuki Oya, Hiroshi Kajihara
    Marine Biodiversity 49 (2) 905 - 911 1867-1616 2019/04 [Refereed][Not invited]
     
    We describe Cestoplana nopperabo sp. nov. from 292- to 439-m depths in Sagami Bay, Japan. This is the eighth member of the genus, representing the first report of a bathyal polyclad from the Indo-West Pacific. Cestoplana nopperabo sp. nov. is characterized by lacking eyespots; it shows no color pattern on the dorsal surface of the body, unlike other congeners. Based on partial 28S rDNA sequence, we infer the phylogenetic position of this species among other polyclads, for which sequences were available in public databases. The molecular phylogeny demonstrates that Cestoplana nopperabo sp. nov. is sister to the rest of the cestoplanids included in the analysis.
  • Hiroshi Kajihara, Natsumi Hookabe
    Tropical Natural History 19 (1) 39 - 42 2019/04 [Refereed][Not invited]
  • Hiroshi Kajihara, Ryuta Yoshida, Tohru Naruse
    Fauna Ryukyuana 48 45 - 47 2019/03 [Refereed][Not invited]
  • Luis E. Chira Siaden, Kevin C. Wakeman, Stephen C. Webb, Kazunori Hasegawa, Hiroshi Kajihara
    Zootaxa 4551 (4) 415 - 431 1175-5326 2019/02/04 [Refereed][Not invited]
     
    This study deals with four species of marine microgastropods of the family Rissoellidae. Rissoella elatior (Golikov, Gulbin Sirenko, 1987), R. golikovi (Gulbin, 1979), R. japonica n. sp., and Rissoella sp. 1 were collected in different locations around the island of Hokkaido, Japan. Light and scanning electron microscopy (SEM) were used to study the general morphology of the shell and radula, and a region of the mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified for 26 specimens. Rissoella elatior is morphologically characterized by a highly asymmetrical radula with a deep notch encircled by 10-13 minute secondary cusps on the left dorsal margin of the central tooth. Rissoella golikovi is characterized by a skeneiform shell and possession of three teeth per row on the radula. Rissoella japonica n. sp. shows five teeth per row on the radula; central tooth higher than wide; lateral and marginal teeth narrow with an outer lateral projection at the base; all teeth presenting numerous small cusps on the cutting edge. Rissoella sp. 1 is distinguished from R. japonica n. sp. in having i) very short oral lobes, ii) a mantle with a large, black patch and whitish blotches inside, and iii) different color patterns associated with the visceral mass. Although Rissoella sp. 1 probably represents an undescribed species, additional specimens are needed to complete its description. This study represents a first molecular approach to the family Rissoellidae. Studies of traditional morphological characters indicated four species, the addition of COI data raised the count to eight potential species, suggesting the occurrence of cryptic species among rissoellids.
  • Naoto Jimi, Takeya Moritaki, Hiroshi Kajihara
    Systematics and Biodiversity 17 (1) 80 - 85 1477-2000 2019/01/02 [Refereed][Not invited]
  • Kenjiro Tadakuma, Tomoya Takayashi, Natsumi Hookabe, Masahiro Watanabe, Yu Ozawa, Tori Shimizu, Eri Takane, Hiroshi Kajihara, Takeshi Yamazaki, Masashi Konyo, Satoshi Tadokoro
    International Symposium on Micro-NanoMechatronics and Human Science(MHS) 1 - 4 2019
  • Aoi Tsuyuki, Yuki Oya, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 24 (2) 137 - 143 1342-1670 2019 [Refereed][Not invited]
     

    We describe a new species of polyclad flatworm, Prosthiostomum torquatum sp. nov., from the rocky intertidal zone in Shirahama, on the Pacific coast of middle Honshu, Japan. Prosthiostomum torquatum is characterised by a unique dorsal colouration, which is comprised of i) numerous orange maculae and blue dots dispersed all over the dorsal surface, ii) a transverse dark-brown line in the anterior part of the body running slightly anterior to another transverse white line, both of which are slightly bent backwards at mid-point, and iii) an incomplete, mesh-like, median band made by dark-brown pigments, fading away posteriorly. By this dorsal colour pattern, the new species can be distinguished from similar congeners such as P. trilineatum Yeri and Kaburaki, 1920 and P. komaii Kato, 1944. We performed a molecular phylogenetic analysis based on 462-bp partial mitochondrial cytochrome c oxidase subunit I (COI) sequences of four species of Prosthiostomidae currently available in public databases in addition to that of P. torquatum. In the resulting tree, P. torquatum was sister to Lurymare clavocapitata Marquina, Aguado, and Noreña, 2015 originally described from Lizard Island, Australia. While these two share a similar dorsal colouration, P. torquatum can be distinguished from L. clavocapitata by i) the absence of a common muscle bulb/sheath enclosing the whole male copulatory apparatus, ii) the median mesh-like band comprised of dark-brown pigments, and iii) COI uncorrected p-distance being 0.094. As a result, our phylogenetic tree indicates the possibility that Prosthiostomum and Lurymare as currently diagnosed may not be monophyletic, and that the common muscle bulb enclosing the whole male copulatory apparatus may not be appropriate as a diagnostic character for Lurymare.

  • Jiseon Park, Hiroshi Kajihara, Jongwoo Jung
    Animal Systematics, Evolution and Diversity 35 (1) 33 - 36 2019/01 [Refereed][Not invited]
  • Yuki Oya, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 24 (1) 1 - 6 1342-1670 2019 [Refereed][Not invited]
     

    We describe a new species of polyclad flatworm, Phaenoplana kopepe sp. nov., from Chichijima island in the Ogasawara Islands, Japan. This is the first report of Phaenoplana from Japan. Phaenoplana kopepe sp. nov. is characterized by i) a vagina that curves anteriorly, ii) gonopores well-separated from each other, and iii) a Lang's duct that is shorter than the vagina. We provide a partial sequence (610 bp) from the mitochondrial cytochrome c oxidase subunit I gene as a DNA barcode for the species.

  • Malin Strand, Jon Norenburg, Jose E. Alfaya, Fernando Angel Fernandez-Alvarez, Hakan S. Andersson, Sónia C. S. Andrade, Thomas Bartolomaeus, Patrick Beckers, Gregorio Bigatti, Irina Cherneva, Alexey Chernyshev, Brian M. Chung, Joern von Doehren, Gonzalo Giribe, Jaime Gonzalez-Cueto, Alfonso Herrera-Bachiller, Terra Hieber, Natsumi Hookabe, Juan Junoy, Hiroshi Kajihara, Daria Kraemer, Sebastian Kvis, Timur Yu Magarlamov, Svetlana Maslakova, Cecili B. Mendes, Robert Okazaki, Christina Sagorny, Megan Schwartz, Shi-Chun Sun, Per Sundberg, James M. Turbeville, Cong-Mei Xu
    Zoologica Scripta 48 (1) 118 - 119 0300-3256 2019/01 [Refereed][Not invited]
  • Shohei Yamauchi, Hiroshi Kajihara
    Species Diversity 23 (2) 183 - 192 1342-1670 2018/11 [Refereed][Not invited]
  • Interstitial hoplonemertean Ototyphlonemertes norenburgi (Nemertea: Monostilifera) from Okinawa, Japan
    Hiroshi Kajihara, Kotaro Tamura, Hiroshi Yamasaki
    Fauna Ryukyuana 46 1 - 3 2018/10 [Refereed][Not invited]
  • Shinri Tomioka, Keiichi Kakui, Hiroshi Kajihara
    Zoological Science 35 (5) 436 - 445 0289-0003 2018/10 [Refereed][Not invited]
     
    Capitellids have emerged as monophyletic in most but not all recent molecular phylogenies, indicating that more extensive taxon sampling is necessary. In addition, monophyly of most or all capitellid genera was questionable, as some diagnostic characters vary ontogenetically within individuals. We tested the monophyly of Capitellidae and eight capitellid genera using phylogenetic analyses of combined 18S, 28S, H3, and COI gene sequences from 36 putative capitellid species. In our trees, Capitellidae formed a monophyletic sister group to Echiura, and Capitella was also monophyletic, separated by a long branch from other capitellids. Well-supported clades each containing representatives of different genera, or containing a subset of species within a genus, indicated that Barantolla, Heteromastus, and Notomastus are likely not monophyletic. We mapped three morphological characters traditionally used to define capitellid genera (head width relative to width of first segment, number of thoracic segments, and number of segments with capillary chaetae) onto our tree. While Capitella showed unique character states, states in the other genera were decidedly not phylogenetically informative. Morphology-based capitellid taxonomy will require a fine-scale reevaluation of character states and detection of new characters.
  • Hiroshi Kajihara
    Zootaxa 4450 (2) 291 - 292 1175-5326 2018/07/24 [Refereed][Not invited]
  • Naoto Jimi, Yoshihiro Fujiwara, Hiroshi Kajihara
    Zootaxa 4450 (5) 575 - 580 1175-5326 2018/07 [Refereed][Not invited]
     
    A new species of polynoid annelids, Bathykermadeca thanatos sp. nov., is described based on specimens collected from sunken whale bones in the Nansei-Shoto Trench in the Philippine Sea at a depth of 4974 m. The cetacean-carcass community at the site exceeds the deepest record reported to date. This new species can be distinguished from other members of the genus by the following features: i) there is only one type of neurochaetae, ii) the teeth lack serration and grow inwardly, iii) median antenna extends beyond the tip of frontal filament, iv) nephridial papillae are present in segments 12-15, and v) there are about 50 notochaetae in each parapodium.
  • Naoto Jimi, Noriko Yasuoka, Hiroshi Kajihara
    北九州市立自然史・歴史博物館研究報告 A類 自然史 (16) 1‐4  1348-2653 2018/03/31 [Refereed][Not invited]
  • Alexei V. Chernyshev, Neonila E. Polyakova, Sergei V. Turanov, Hiroshi Kajihara
    Systematics and Biodiversity 16 (1) 55 - 68 1478-0933 2018/01/02 [Refereed][Not invited]
     
    The heteronemertean genus Lineus Sowerby, 1806 has been badly in need of revision because of its apparent non-monophyly. In this paper, we focus on Lineus torquatus Coe, 1901, one of the heteronemertean species that occur commonly in waters around the North Pacific, as well as a few other allied species distributed in the western North Pacific, including Lineus alborostratus Takakura, 1898 and Cerebratulus montgomeryi Coe, 1901. Based on phylogenetic analyses using 16S, COI, 28S, 18S, and H3 gene and ITS sequences, we detected a well-supported clade comprised of heteronemerteans with a frontal white band on the head, to which we add Kulikovia gen. nov. This genus is nested within a more comprehensive, highly supported clade, here named the Siphonenteron-clade, which contains Tenuilineus bicolour (Verrill, 1892), Lineus flavescens Coe, 1905, Siphonenteron bilineatum (Renier, 1804), S. cf. bilineatum, Lineus cf. caputornatus, and Lineus sp. from Guam. Our analyses confirmed the presence of a cryptic species of what was formerly known as the cherry-red and reddish forms of Lineus torquatus, herein described as Kulikovia manchenkoi sp. nov. based on some external characters, internal morphology, and the four genetic markers (COI, 16S, H3, and ITS). In contrast to the species pair K. torquata–K. manchenkoi, the reddish form of K. alborostrata does not differ genetically from the typical form of this species. The significance of the external and internal characters for distinguishing cryptic species is discussed. http://zoobank.org/urn:lsid:zoobank.org:pub:9BECBC60-9C82-48EC-AD36-FC564D82A5BChttp://zoobank.org/urn:lsid:zoobank.org:act:D02B2339-4F65-4517-9B13-DD4AAB0C55C5http://zoobank.org/urn:lsid:zoobank.org:act:8D239B62-E655-4721-90F0-A4944DD8A3C7.
  • Naoto Jimi, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 23 (1) 39 - 42 1342-1670 2018 [Refereed][Not invited]
     

    A new species of flabelligerid polychaete, Lamispina ammophila sp. nov., is described from off the coast of Shimoda, Japan. The species can be discriminated from the other congeners by the following features: i) dorsal region of body being adhered to by sediment particles, ii) lamispines without accessory tooth, present from chaetiger 4 and succeeding chaetigers, and iii) cephalic cage 1.5–2.0 times as long as body width. A partial mitochondrial cytochrome c oxidase subunit I (COI) gene sequence from the paratype is provided as a DNA barcode for the new species.

  • Naoto Jimi, Taeko Kimura, Akito Ogawa, Hiroshi Kajihara
    ZooKeys 2018 (738) 81 - 88 1313-2970 2018 [Refereed][Not invited]
     
    A new species of amphinomid polychaete, Benthoscolex seisuiae sp. n., is described from the Sea of Kumano, Japan, from depths of 487–596 m. The species is distinguishable from its congeners by the following features: i) palps 1.8 times as long as lateral antennae ii) branchiae do not reach to the tip of the notochaetae. This is the first record of Benthoscolex from Japan. A partial mitochondrial cytochrome c oxidase subunit I gene sequence from the holotype of B. seisuiae sp. n. is provided for reliable species identification in the future.
  • Hiroshi Kajihara, Kotaro Tamura, Shinri Tomioka
    Species Diversity 23 (1) 13 - 37 1342-1670 2018 [Refereed][Not invited]
     
    Seven (including six new) species of interstitial hoplonemerteans in the genus Ototyphlonemertes Diesing, 1863 are described from southern Vietnam. The descriptions are based on light microscopic examination of internal structures as well as three methods of molecular species delimitation analyses, i) Automatic Barcode Gap Discovery (ABGD), ii) Poisson Tree Process (PTP), and iii) statistical parsimony, on the basis of ~658-bp cytochrome c oxidase subunit I gene sequences that have been i) newly determined from the Vietnamese specimens and ii) deposited in the public databases for other Ototyphlonemertes species. Three taxa are circumscribed as 'species groups' and placed at an infra-subgeneric, supra-specific rank, each represented by O. duplex Bürger, 1895, O. macintoshi Bürger, 1895, and O. parmula Corrêa, 1950. Of the seven Vietnamese species, one is identified as Ototyphlonemertes (species group macintoshi) ani Chernyshev, 2007, which is molecularly confirmed to be distributed from Vietnam (Phu Quoc and Nha Trang) to Japan (Okinawa and Wakayama). The other six are new to science, to which formal taxonomic descriptions are given: these are O. (duplex) chernyshevi sp. nov., O. (duplex) envalli sp. nov., O. (duplex) norenburgi sp. nov., O. (parmula) lei sp. nov., O. (parmula) nakaoae sp. nov., and O. (parmula) tsukagoshii sp. nov.
  • Naoya Takeda, Hiroshi Kajihara
    Species Diversity 23 (1) 1 - 11 1342-1670 2018 [Refereed][Not invited]
     
    We have described a new genus and five new species of free-living marine flatworms in Schizorhynchia (Platyhelminthes: Rhabdocoela: Kalyptorhynchia) based on the material collected from sandy intertidal zones around Hokkaido, Northern Japan. These include Freddius tricaudatus gen. et sp. nov. (Cheliplanidae) and Proschizorhynchella caudociliata sp. nov., P. magnoliae sp. nov., P. shibazakii sp. nov., and P. shuttlecock sp. nov. (Schizorhynchidae). Based on this study, the number of confirmed species in the suborder Kalyptorhynchia discovered in Japanese waters has increased from one to six. Freddius tricaudatus gen. et sp. nov. possesses proboscis hooks that are so peculiar among Cheliplanidae that they warrant the establishment of a new genus.
  • Naoto Jimi, Masaatsu Tanaka, Hiroshi Kajihara
    Species Diversity 22 (2) 133 - 141 1342-1670 2017/12/01 [Refereed][Not invited]
     
    A new species of hesionid polychaetes, Leocratides kimuraorum sp. nov., is described based on material collected from the Shima Peninsula and Sagami Bay (middle Honshu, Japan), as well as museum specimens collected from Sagami Bay, Suruga Bay, and Shirahama. Leocratides kimuraorum sp. nov. is the third species in this genus and can be discriminated from the two congeners, L. filamentosus Ehlers, 1908 and L. ehlersi (Horst, 1921), by i) the length of the antennae, which are as long as palps, ii) the presence of pharyngeal terminal papillae, and iii) the absence of a papillose peristomial membrane. On the other hand, L. filamentosus, originally described from offWestern Sumatra, Indonesia, was also collected from Sagami Bay, and represents a new record of this species for Japanese waters. Partial mitochondrial cytochrome c oxidase subunit I gene sequences from the holotype of L. kimuraorum sp. nov. and newly collected specimen of L. filamentosus are provided for reliable species identification in the future.
  • Shinri Tomioka, Ryuta Yoshida, Hiroshi Kajihara
    Species Diversity 22 (2) 127 - 132 1342-1670 2017/12/01 [Refereed][Not invited]
     
    We describe a new capitellid species, Mastobranchus uru sp. nov., from a tidal flat on Iriomote Island, Okinawa, southern Japan. This species differs from its three congeners in having capillary chaetae only on the notopodia in chaetiger 1 and in the number and arrangement of teeth on hooks. We also provide for this new species a barcode nucleotide sequence from the mitochondrial 16S rRNA gene.
  • Naoto Jimi, Takeya Moritaki, Hiroshi Kajihara
    Parasitology International 66 (6) 841 - 847 1383-5769 2017/12 [Refereed][Not invited]
     
    The rare myzostomid genus Asteriomyzostomum Jagersten, 1940 consists of two species, both parasitizing sea stars. The phylogenetic position of this genus among Myzostomida has not been previously shown using molecular data. In this study, three species of Asteriomyzostomum were collected from the Kumano Sea, Japan, and are described as A. hercules sp. nov., A. jinshou sp. nov., and A. monroeae sp. nov. Additional specimens of the genus Asteromyzostomum Wagin, 1954 were also collected from the Kumano Sea and briefly reported as Asteromyzostomum sp. A molecular phylogeny based on four gene markers (COI, 16S, 18S, H3) suggests that the three families Asteriomyzostomidae, Asteromyzostomidae, and Protomyzostomidae comprise a Glade. The resulting topology of the tree indicates that a host change from Crinozoa (sea lilies and feather stars) to Asterozoa (asteroids and ophiuroids) occurred only once in the evolutionary history of Myzostomida.
  • Luis E. Chira Siaden, Jorge Chaname Cespedes, Hiroshi Kajihara
    American Malacological Bulletin 35 (2) 163 - 169 0740-2783 2017/11 [Refereed][Not invited]
     
    In this paper, a new species in the genus Graphis Jeffreys, 1867 is described. Graphis peruviana sp. nov. from Cherrepe Beach (7 degrees 10 ' 34 '' S, 79 degrees 41 ' 25 '' W), Lambayeque, Peru, represents the first report of a member of the genus Graphis in the eastern South Pacific.
  • Sau Pinn Woo, Akito Ogawa, Shau Hwai Tan, Zulfigar Yasin, Hiroshi Kajihara, Toshihiko Fujita
    Zootaxa 4350 (1) 121 - 135 1175-5326 2017/11 [Refereed][Not invited]
     
    Complete redescriptions of sea cucumbers in the genus Apostichopus Liao, 1980 are provided using the type specimens and specimens deposited in the National Museum of Nature and Science, Tsukuba, Japan. The genus consists of A. armatus (Selenka, 1867) and A. japonicus (Selenka, 1867), which can be distinguished by some spicules in the dorsal body wall; the rim of reduced table spicules in A. armatus is spinous, while that in A. japonicus is smooth. Spicules from the tentacles, papillae, tube feet, and cloaca are similar for both species.
  • Naoto Jimi, Yoshihiro Fujiwara, Hiroshi Kajihara
    Zootaxa 4337 (3) 344 - 360 1175-5326 2017/10 [Refereed][Not invited]
     
    Seven new species of Diplocirrus are described from Japan: D. asamushiensis sp. nov., D. imajimai sp. nov., D. mamoi sp. nov., D. ohtsukai sp. nov., D. seisuiae sp. nov., D. tohokuensis sp. nov., and D. toyoshioae sp. nov. These species are distinguished from all the known species of Diplocirrus by the following features: length of the cephalic cage, length of lateral papillae, presence of gonopodial lobe, adhering pattern of sediment particles, length of caruncle, length and morphological feature of branchiae, articles and morphological features of neurochaetae, and swollen area along the body.
  • Shimpei F. Hiruta, Maho Ikoma, Toru Katoh, Hiroshi Kajihara, Matthew H. Dick
    Hydrobiologia 799 (1) 151 - 179 0018-8158 2017/09 [Refereed][Not invited]
     
    The expansion-contraction (EC) model of Pleistocene biogeography and the concept of refugia are of dubious applicability for rocky-shore marine species along the northwest Pacific coast, which was not glaciated at the last glacial maximum (LGM) and likely remained largely habitable by marine communities. We examined the population structure and historical demography of two ecologically similar rocky-intertidal idoteid isopods, Idotea ochotensis and Cleantiella isopus, in northern Japan based on mitochondrial COI and (for I. ochotensis) nuclear ITS nucleotide sequences. We concluded that I. ochotensis persisted in northern Japan across one or more glacial cycles, whereas C. isopus recolonized northern Japan after the LGM. We present an alternative general model for Pleistocene biogeography in temperate to subtropical, non-glaciated coastal regions, wherein species tend to retain large population size and high genetic diversity across glacial cycles in a zone of persistence, with flanking zones of expansion and contraction where the geographical range cyclically expands and contracts (i.e., undergoes latitudinal displacements) with climatic oscillations. We also found that local sea straits had less effect in determining phylogeographic boundaries than a long stretch of unfavorable shore habitat, and that late Holocene sea current patterns appear to have affected fine-scale phylogeographic patterns.
  • Yuki Oya, Hiroshi Kajihara
    Zootaxa 4282 (3) 526 - 542 1175-5326 2017/06 [Refereed][Not invited]
     
    We describe Notocomplana hagiyai sp. nov. from Ishikari Bay, Hokkaido, northern Japan. Notocomplana hagiyai sp. nov. is characterized by i) a larger prostatic vesicle relative to the seminal vesicle and ii) a Lang's duct that is shorter than the long axis of Lang's vesicle. Melloplana japonica (Kato, 1937) is transferred to the genus Notocomplana Faubel, 1983 based on the structure of its prostatic vesicle, and we record the finding of N. koreana (Kato, 1937) and N. septentrionalis (Kato, 1937) in western Hokkaido. A pair of new cytochrome c oxidase subunit I (COI) primers was designed to infer the phylogeny among the four species, and we concluded that COI is more informative than 16S rRNA for barcoding polyclad flatworms.
  • Hiroshi Kajihara
    Species Diversity of Animals in Japan 419 - 444 2509-5536 2017 [Refereed][Invited]
  • Hiroshi Kajihara, Keiichi Kakui
    Species Diversity of Animals in Japan 25 - 45 2509-5536 2017 [Refereed][Invited]
  • Sau Pinn Woo, Hiroshi Kajihara, Nozomu Iwasaki, Toshihiko Fujita
    Species Diversity 22 (1) 45 - 52 1342-1670 2017 [Refereed][Not invited]
     
    The sea cucumber, Holothuria (Cystipus) dura Cherbonnier and Féral, 1981, previously known only from the Philippines and New Caledonia, is newly recorded from Japanese waters this is also the first record of the subgenus Cystipus from Japan. The two specimens described here were collected from the sublittoral bottoms near Hahajima island (126-261 m depth) and Okinoshima island (100-120 m depth). The morphology of the Japanese specimens is briefly described. In-situ photographs of the living individuals and scanning electron micrographs (SEM) of ossicles are provided for the first time for this species. The table ossicles in the dorsal body and in the papillae are highly modified fenestrated spheroids that have not been depicted previously. Some of the ventrolateral conical papillae, especially those in the middle part of the body, were bifurcated, perhaps indicative of increased surface area against the bottom for powerful propulsion while 'walking. Some notes on locomotion are given, inferred from the in-situ photographs and the morphology of the ventrolateral conical papillae.
  • Naoto Jimi, Sergio I. Salazar-Vallejo, Hiroshi Kajihara
    ZooKeys 657 (657) 29 - 41 1313-2989 2017 [Refereed][Not invited]
     
    The hesionid polychaete Hesione reticulata von Marenzeller, 1879 was described from Enoshima Island, Japan and has been recorded also from the Red Sea. Depending on researchers, it has been regarded as either a distinct species or synonymous with older established ones. The type specimen has been lost. In order to clarify its taxonomic status, H. reticulata is herein redescribed, illustrated, and a neotype is proposed based on recent material collected near the type locality. The diagnostic features include the presence of several dorsal, discontinuous longitudinal bands, interrupted by pale segmental spots; prostomium with tiny antennae; a tuberculated dorsal integument; acicular lobes double; and neurochaetal blades with guards approaching the distal tooth. The dorsal color pattern in life enables a clear distinction from similar species such as H. intertexta Grube, 1878 amongst others. Mitochondrial COI barcoding sequences are deposited in the DNA Data Bank of Japan. A key to Hesione species from Japan is also included.
  • Naoto Jimi, Megumu Tsujimoto, Kentaro Watanabe, Keiichi Kakui, Hiroshi Kajihara
    Zootaxa 4221 (4) 477 - 485 1175-5326 2017/01 [Refereed][Not invited]
     
    A new species of polychaete, Flabegraviera fujiae sp. nov., is described and the first report of F. mundata (Gravier, 1906) from the shallow water around Syowa Station, Antarctica, is presented. Flabegraviera fujiae sp. nov. resembles F. profunda Salazar-Vallejo, 2012 but is discriminated from the latter by having eyes and an exposed cephalic cage. The specimen of F. mundata was collected from a depth of 8 m, providing the shallowest record of this species to date.
  • Per Sundberg, Sonia C. S. Andrade, Thomas Bartolomaeus, Patrick Beckers, Joern von Doehren, Daria Kraemer, Ray Gibson, Gonzalo Giribet, Alfonso Herrera-Bachiller, Juan Junoy, Hiroshi Kajihara, Sebastian Kvist, Tobias Kanneby, Shi-Chun Sun, Martin Thiel, James M. Turbeville, Malin Strand
    ZOOLOGICA SCRIPTA 45 (6) 579 - 582 0300-3256 2016/11 [Refereed][Not invited]
  • Tabitha Lindsay, Julie Kelly, Anton Chichvarkhin, Sean Craig, Hiroshi Kajihara, Joshua Mackie, Angel Valdes
    Journal of Molluscan Studies 82 (4) 564 - 574 0260-1230 2016/11 [Refereed][Not invited]
     
    Molecular and morphological evidence indicates that the widespread North Pacific species Diaulula sandiegensis is a complex of two pseudocryptic species. One ranges from the Sea of Japan to northern California, whereas the other is found from northern California to Baja California. The name Diaulula sandiegensis applies to the southern species and Diaulula odonoghuei Steinberg, 1963 to the northern species; a neotype is designated for the latter. The two have consistent differences in colour pattern that were overlooked in previous studies. Field observations from San Diego, California, to Bamfield, British Columbia, revealed that the ranges of the two species partially overlap: D. odonoghuei is restricted to intertidal and bay habitats from Fort Bragg, California northwards, whereas D. sandiegensis is found throughout the entire region and is more common in subtidal habitats. Both species feed primarily on a sponge, Haliclona sp., in intertidal habitats, but faecal analysis indicated that D. sandiegensis in subtidal habitats feeds on Neopetrosia problematica. Haplotype-network analyses reveal substantial levels of genetic diversity in both species, which is highly structured in D. odonoghuei, suggesting a complex history for this species. Field surveys, a common garden experiment and a mating study were conducted to investigate the presence of assortative mating. During two mating trials, individuals that encountered one another for the first time always mated with the same species (11 matings). Reproductive isolation in the form of premating barriers may explain the absence of gene flow between these geographically overlapping sister species. A molecular-clock analysis indicates that glacial events may have played a role in speciation and the origin of population structure in the D. sandiegensis species complex, possibly through climate-driven vicariant events.
  • Shinri Tomioka, Tomohiko Kondoh, Waka Sato-Okoshi, Katsutoshi Ito, Keiichi Kakui, Hiroshi Kajihara
    Zoological Science 33 (5) 545 - 554 0289-0003 2016/10 [Refereed][Not invited]
     
    Capitella teleta Blake et al., 2009 is an opportunistic capitellid originally described from Massachusetts (USA), but also reported from the Mediterranean, NW Atlantic, and North Pacific, including Japan. This putatively wide distribution had not been tested with DNA sequence data; intraspecific variation in morphological characters diagnostic for the species had not been assessed with specimens from non-type localities, and the species status of the Japanese population(s) was uncertain. We examined the morphology and mitochondrial COI (cytochrome c oxidase subunit I) gene sequences of Capitella specimens from two localities (Ainan and Gamo) in Japan. Specimens from Ainan and Gamo differed from C. teleta from Massachusetts in methyl-green staining pattern, shape of the genital spines, and shape of the capillary chaetae; we concluded that these characters vary intraspecifically. Species delimitation analyses of COI sequences suggested that worms from Ainan and Massachusetts represent C. teleta; these populations share a COI haplotype. The specimens from Gamo may represent a distinct species and comprise a sister group to C. teleta s. str.; we refer to the Gamo population as Capitella aff. teleta. The average Kimura 2-parameter (K2P) distance between C. teleta s. str. and C. aff. teleta was 3.7%. The COI data indicate that C. teleta actually occurs in both the NW Atlantic and NW Pacific. Given the short planktonic larval duration of C. teleta, this broad distribution may have resulted from anthropogenic dispersal.
  • Shimpei F. Hiruta, Norio Kobayashi, Toru Katoh, Hiroshi Kajihara
    Zoological Science 33 (2) 179 - 185 0289-0003 2016/04 [Refereed][Not invited]
     
    With the aim of exploring phylogenetic relationships within Cypridoidea, the most species-rich superfamily among the podocopidan ostracods, we sequenced nearly the entire 18S rRNA gene (18S) and part of the 28S rRNA gene (28S) for 22 species in the order Podocopida, with representatives from all the major cypridoid families. We conducted phylogenetic analyses using the methods of maximum likelihood, minimum evolution, and Bayesian analysis. Our analyses showed monophyly for Cyprididae, one of the four families currently recognized in Cypridoidea. Candonidae turned out to be paraphyletic, and included three clades corresponding to the subfamilies Candoninae, Paracypridinae, and Cyclocypridinae. We propose restricting the name Candonidae s. str. to comprise what is now Candoninae, and raising Paracypridinae and Cyclocyprininae to family rank within the superfamily Cypridoidea.
  • Nonillon M. Aspe, Hiroshi Kajihara, Samuel W. James
    European Journal of Soil Biology 73 119 - 125 1164-5563 2016/03 [Refereed][Not invited]
     
    The knowledge on earthworm taxonomic studies in the Philippines over the past decade dramatically increased and the results indicate an astonishingly high diversity and high local endemicity of earthworms in the country. The earthworm fauna of the Philippines is composed of pheretimoid species of the family Megascolecidae. A molecular phylogenetic study was done in attempt to infer phylogenetic relationships among the pheretimoid species in Mindanao and associated islands. Gene markers used include the mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA, and the nuclear 28S rRNA and protein-coding histone H3 genes. Despite having limited taxa and limited genes included in the analyses, the combined data set generated a phylogeny more or less consistent with morphology-based expectation. Sims and Easton's classification scheme published in 1972 does not reflect the phylogeny with respect to the genus Amynthas and the subgenus Parapheretima; the characters they used to define these taxa are homoplasious. The species groupings in Pheretima based on the location of spermathecae are partially reflected the pheretimoid phylogeny. Particularly, members of the Pheretima sangirensis group formed a Glade supported with 0.99 posterior probability with the inclusion of P. (Parapheretima) pandanensis (also with spermathecal pores at 7/8), the monothecate Pheretima vergrandis with spermathecal pore at 7/8, and an athecate conspecific of Pheretima apoensis. The members of the Pheretima urceolata group also form a weakly supported Glade with the inclusion of the monothecate P. (Parapheretima) boaensis (with spermathecal pores at 5/6) and the athecate Amynthas dinagatensis. Moreover, loss of spermatheca or fusion of two spermathecae into one can occur in pheretimoid evolution, such as in the case of the monothecate P. vergrandis and the athecate conspecific of P. apoensis. Several of the branch nodes of the tree based on combined data set have support values that are very weak and formed polytomies, which is most likely due to insufficient data. The results could have improved if more data were available. The addition of genes with divergence rates slower than that of COI and 16S but faster than that of 28S and H3, such as 12S and ITS2, may also improve the resolution. Further molecular work including more taxa is needed to be able to establish a more robust system of classification of the pheretimoid species and come up with a better-resolved phylogeny. A consolidated phylogenetic study in the East Asian archipelagos will provide insights into the evolutionary, biogeographic, and ecological processes involved in island radiations of soil-dwelling animals. (C) 2016 Elsevier Masson SAS. All rights reserved.
  • Hiroshi Kajihara, Mariko Takibata, Mark J. Grygier
    Species Diversity 21 (2) 105 - 110 1342-1670 2016 [Refereed][Not invited]
     
    The freshwater heteronemertean Apatronemertes albimaculosa Wilfert and Gibson, 1974 has previously been reported from Germany, Austria, and the USA. All these records were from aquarium tanks with commercially distributed tropical and/or subtropical water plants by hiding among their roots, the worms are thought to have been introduced from an unidentified place of origin. We report the occurrence of A. Albimaculosa for the first time from Japan, based on specimens found in private home aquaria for guppy breeding, with a total of 18 species of water plants grown for different periods and lengths of time but not all at the same time. Histological examination confirmed the presence of diagnostic features of this species, including a complex precerebral vascular system and hermaphroditism. The partial sequence of the mitochondrial cytochrome c oxidase subunit I gene (607 bp) of the Japanese material is identical with that of a heteronemertean specimen from a freshwater tank in Madrid, Spain, which had been deposited in the public databases but left unidentified as to its species, genus, or family. Apatronemertes albimaculosa appears unlikely to be able to survive below 10°C for more than about a week, which suggests that its native locality is in the tropics or subtropics, not the temperate zone. The barcoding sequence herein determined will serve in future studies to help locate the natural place of origin.
  • Hiroshi Kajihara, Ira Hosokawa, Koji Hosokawa, Ryuta Yoshida
    Fauna Ryukyuana 28 59 - 65 2016 [Refereed][Not invited]
  • Eijiroh Nishi, Kanako Matsuo, Maria Capa, Shinri Tomioka, Hiroshi Kajihara, Elena K. Kupriyanova, Gianluca Polgar
    Zootaxa 4052 (5) 555 - 568 1175-5334 2015/12/07 [Refereed][Not invited]
     
    A new species of the genus Sabellaria Lamarck, 1818 (Annelida: Polychaeta: Sabellariidae) is described from the intertidal zone of Jeram, Selangor, Malaysia. Sabellaria jeramae n. sp. is a gregarious species that constructs large reefs several hundreds of meters long and 50-200 m wide. The new species is distinguished from other congeners by the character combination of the presence of a single kind of middle paleae with conspicuous morphology, and outer paleae with long frayed teeth. Morphological features of the species are described and compared to those of all congeneric species. We also compare the reef structure and geographical distribution of the new species to those of the members of the family Sabellariidae around the world, demonstrating the ecological traits of the reefs.
  • Yue Hao, Hiroshi Kajihara, Alexei V. Chernyshev, Robert K. Okazaki, Shi-Chun Sun
    Zoological Science 32 (6) 571 - 578 0289-0003 2015/12 [Refereed][Not invited]
     
    Of the 14 nominal species that are now or have ever been assigned to the genus Paranemertes Coe, 1901, four have been reported to have stylets with a spirally fluted or braided appearance. Although differentiation in color patterns has been documented among species/populations, these nemerte-ans share similar external characters. Using the sequence datasets of mitochondrial cytochrome coxidase subunit I (COI), 16S rRNA, and nuclear 28S rRNA genes of specimens from 14 localities of Canada, USA, Russia, Japan, and China, we analyzed the genetic differentiation and reconstructed the phylogenetic trees for these nemerteans. In conjunction with the external characters, we discuss their taxonomy and species delimitation. An analysis based on COI dataset showed high genetic variations among populations and even among worms from the same geographic area. The analyzed 111 individuals were assigned into seven networks by statistical parsimony analysis. The inter-network uncorrected p-distances ranged from 0.044 to 0.172 and the mean intra-network uncorrected p-distances varied from 0.001 to 0.005. With the exception of two networks that contain specimens from the East China Sea, all networks were well-supported by the results of Bayesian and neighbor-joining analyses on the COI data. Phylogenetic trees based on 16S rRNA and 28S rRNA datasets were basically similar to the COI trees, but specimens in some networks were merged into larger clades. Present molecular analyses support the validity of P. sanjuanensis and the synonymization of P. cylindracea with P. peregrina. Nemerteans previously recorded as P. peregrina may contain several species and sympatric speciation might have been occurred in this nemertean group.
  • Hiroshi Kajihara, Keiichi Kakui, Hiroshi Yamasaki, Shimpei F. Hiruta
    Zoological Science 32 (6) 596 - 604 0289-0003 2015/12 [Refereed][Not invited]
     
    Based on specimens collected subtidally (similar to 10 m in depth) in Tomioka Bay, Japan, we describe the palaeonemertean Tubulanus tamias sp. nov., which differs from all its congeners in body coloration. In molecular phylogenetic analyses based on partial sequences of the nuclear 18S and 28S rRNA genes and histone H3, as well as the mitochondrial 16S rRNA and cytochrome c oxidase subunit I genes, among selected palaeonemerteans, T. tamias nested with part of the congeners in Tubulanus, while the genus as currently diagnosed appears to be non-monophyletic. Molecular cloning detected polymorphism in 28S rDNA sequences in a single individual of T. tamias, indicating incomplete concerted evolution of multiple copies. Tubulanus tamias is peculiar among tubulanids in having 9-10 pigment-cup eyes in the epidermis on either side of the head anterior to the cerebral sensory organs, and remarkably there are two types of eyes. The anterior 8-9 pairs of eyes, becoming larger from anterior to posterior, are completely embedded in the epidermis and proximally abutting the basement membrane; each pigment cup contains bundle of up to seven, rod-shaped structure that resemble a rhabdomeric photoreceptor cell. In contrast, the posterior-most pair of eyes, larger than most of the anterior ones, have an optical cavity filled with long cilia and opening to the exterior, thus appearing to have ciliary-type photoreceptor cells. The size and arrangement of the eyes indicate that the posterior-most pair of eyes are the remnant of the larval (or juvenile) eyes.
  • Shi-Chun Sun, Hiroshi Kajihara, Alexei V. Chernyshev
    Zoological Science 32 (6) 499 - 500 0289-0003 2015/12 [Refereed][Not invited]
     
    This issue is dedicated to Dr. Jacques Bierne and Dr. Frank Crandall, who made lasting, important contributions to the study of the development, reproduction, morphology, and taxonomy of nemerteans.
  • Hiroaki Nakano, Keiichi Kakui, Hiroshi Kajihara, Michitaka Shimomura, Naoto Jimi, Shinri Tomioka, Hayate Tanaka, Hiroshi Yamasaki, Masaatsu Tanaka, Takato Izumi, Masanori Okanishi, Yutaro Yamada, Hideo Shinagawa, Toshihiko Sato, Yasutaka Tsuchiya, Akihito Omori, Mamoru Sekifuji, Hisanori Kohtsuka
    Regional Studies in Marine Science 2 77 - 81 2352-4855 2015/11 [Not refereed][Not invited]
     
    JAMBIO, Japanese Association for Marine Biology, has been organizing JAMBIO Coastal Organism Joint Surveys at Shimoda Marine Research Center, University of Tsukuba, and Misaki Marine Biological Station, the University of Tokyo. The aims of the Surveys are to uncover the benthic marine fauna of the coastal areas in and around Sagami Bay, and to form a collaborative network between marine biologists across Japan. We have so far performed six surveys, with over 100 participants in total, using common equipment such as dredges, bottom mud samplers, and epibenthic sleds. Even in Sagami Bay, one of the most intensively studied marine environments in the world, we have succeeded in collecting about 50 probable undescribed species. Other species were collected for the first time from Sagami Bay or found from previously unreported depth. The Surveys could be useful for ecological and environmental studies as well. We plan to continue the JAMBIO Coastal Organism Joint Surveys to further reveal the rich biodiversity within and around Sagami Bay and to accelerate nationwide research collaborations. We also hope to expand the Surveys to include plants and protists, and to perform them at other areas in Japan. Through the Surveys, we aim to develop new cross-disciplinary research areas and to record the long-term transition of biota along the Japanese coast. (C) 2015 Elsevier B.V. All rights reserved.
  • Hiroshi Kajihara
    Publications of the Seto Marine Biological Laboratory 43 92 - 102 2015/09 [Refereed][Not invited]
  • Hiroshi Kajihara, Maho Ikoma, Hiroshi Yamasaki, Shimpei F. Hiruta
    Zoological Science 32 (4) 405 - 417 0289-0003 2015/08 [Refereed][Not invited]
     
    The marine interstitial annelid Trilobodrilus itoi sp. nov., the sixth member of the genus, is described on the basis of specimens collected intertidally at Ishikari Beach, Hokkaido, Japan; this is the second species in the genus described from the Pacific Rim. In addition, T. nipponicus Uchida and Okuda, 1943 is re-described based on fresh topotypic material from Akkeshi, Hokkaido, Japan. From both species, we determined sequences of the nuclear 18S and 28S rRNA genes, and the mitochondrial cytochrome c oxidase subunit I (COI) gene. Molecular phylogenetic trees based on concatenated sequences of the three genes showed that T. itoi and T. nipponicus form a clade, which was the sister group to a clade containing the two European congeners T. axi Westheide, 1967 and T. heideri Remane, 1925. The Kimura two-parameter distance for COI was 22.5-22.7% between T. itoi and T. nipponicus, comparable with interspecific values in other polychaete genera. We assessed the taxonomic utility of epidermal inclusions and found that the known six species can be classified into three groups.
  • Hiroshi Kajihara, Eijiroh Nishi, Michiyo Kawabata, Hisanori Kohtsuka, Daisuke Uyeno
    Marine Biodiversity 45 (2) 175 - 182 1867-1616 2015/06 [Refereed][Not invited]
     
    Recent records of the occurrence of a little-known ribbon worm, Nipponnemertes ogumai (Yamaoka 1947), along the Pacific coast of Honshu, Japan, are summarized with a map of known distribution. Photographs of the worm in its living state are provided, with brief descriptions of external morphology and behavior. Sequences of the nuclear 18S rDNA (1,785 bp) and 28S rDNA (2,215 bp), as well as the mitochondrial 16S rDNA (452 bp) and cytochrome c oxidase subunit I (COI) gene (621 bp) were determined. Preliminary maximum-likelihood phylogenetic analyses were performed together with some other congeners, viz., N. bimaculata (Coe 1901), N. pulchra (Johnston 1837), N. punctatula (Coe 1905), and two unidentified forms, for which sequences were available in the public databases. In the resulting tree, N. ogumai was nested within the congeners, consolidating the previous alteration of the generic placement of the species from Amphiporus Ehrenberg (1828-1831), to Nipponnemertes Friedrich 1968. A contaminated cytochrome c oxidase subunit I (COI) sequence implied that N. ogumai may feed on caridean shrimps.
  • Hiroshi Kajihara, Shinri Tomioka, Keiichi Kakui, Tohru Iseto
    Species Diversity 日本動物分類学会 20 (1) 83 - 88 1342-1670 2015 [Refereed][Not invited]
     
    The solitary entoproct Loxosoma axisadversum Konno, 1972 was found on the body surface of the maldanid polychaete Nicomache personata Johnson, 1901 obtained among roots of the seagrass Phyllospadix iwatensis Makino collected at a depth of about 1m in Oshoro Bay, Hokkaido, Japan. The species had previously been known from elsewhere in northern Japan, attached to another maldanid, Nicomache minor Arwidsson, 1907. The morphology of the new material is briefly described with photographs taken in life. A preliminary phylogenetic analysis using concatenated partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene, as well as the nuclear 18S and 28S rRNA genes, placed L. axisadversum as the sister taxon to all the rest of Solitaria included in the analysis, indicating non-monophyly of the genus Loxosoma Keferstein, 1862.
  • Alexei V. Chernyshev, Shushi Abukawa, Hiroshi Kajihara
    Deep-Sea Research II 111 119 - 127 0967-0645 2015/01 [Refereed][Not invited]
     
    Approximately 129 nemertean specimens were obtained in the material collected by the Russian-German KuramBio expedition 2012 to the abyssal plain adjacent to the Kuril-Kamchatka Trench (KKT). Due to deformed, fragmentary condition of most of the collected nemerteans they were identified to the order level only. Both archi- and heteronemerteans were very rare, and tubulanid palaeonemerteans and hoplonemerteans were predominant in the KuramBio epibenthic sledge (EBS) samples. Before the KuramBio expedition, only three species of the World fauna of benthic nemerteans had been known from depths exceeding 3000 m; according to data of Vityaz expedition in the KKT, published in 1955, unidentified nemerteans were found in all trawl samples from depths 1000 to 4640 m, but only one specimen of unidentified nemertean was collected from depths exceeding 5000 m. A reliable estimation of the actual species diversity of the present KuramBio samples could have been made primarily based on molecular genetic analyses; almost all the collected specimens are likely to represent undescribed species. In this study, a new species of the heteronemertean, Sonnenemertes cantelli gen. et sp. nov., from a depth of approximately 4870 m is described. This is the deepest record for an identified benthic nemertean, as well as the first species of the subfamily Oxypolellinae from the North Pacific. A single specimen was examined by light microscopy, scanning electron microscopy, and confocal laser scanning microscopy with phalloidin and antibody labeling. Morphologically, this species is similar to those in the genus Oxypolella. A preliminary molecular phylogenetic analysis based on partial 16S rDNA among the selected heteronemertean species indicated that S. cantelli formed a monophyletic group with Oxypolella alba Bergendal, 1903 together as a sister to the genus Baseodiscus. Systematic positioning of Oxypolella, Sonnenemertes, and related genera is discussed. (C) 2014 Elsevier Ltd. All rights reserved.
  • Jose E. F. Alfaya, Gregorio Bigatti, Hiroshi Kajihara, Malin Strand, Per Sundberg, Annie Machordom
    Zoological Studies 54 10  1021-5506 2015/01 [Refereed][Not invited]
     
    Background: Nemerteans of the genus Malacobdella live inside of the mantle cavity of marine bivalves. The genus currently contains only six species, five of which are host-specific and usually found in a single host species, while the sixth species, M. grossa, has a wide host range and has been found in 27 different bivalve species to date. The main challenge of Malacobdella species identification resides in the similarity of the external morphology between species (terminal sucker, gut undulations number, anus position and gonad colouration), and thus, the illustrations provided in the original descriptions do not allow reliable identification. In this article, we analyse the relationships among three species of Malacobdella: M. arrokeana, M. japonica and M. grossa, adding new data for the M. grossa and reporting the first for M. japonica, analysing 658 base pairs of the mitochondrial cytochrome c oxidase subunit I gene (COI). Based on these analyses, we present and discuss the potential of DNA barcoding for Malacobdella species identification. Results: Sixty-four DNA barcoding fragments of the mitochondrial COI gene from three different Malacobdella species (M. arrokeana, M. japonica and M. grossa) are analysed (24 of them newly sequenced for this study, along with four outgroup specimens) and used to delineate species. Divergences, measured as uncorrected differences, between the three species were M. arrokeana-M. grossa 11.73%, M. arrokeana-M. japonica 10.62% and M. grossa-M. japonica 10.97%. The mean intraspecific divergence within the ingroup species showed a patent gap with respect to the interspecific ones: 0.18% for M. arrokeana, 0.13% for M. grossa and 0.02% for M. japonica (ranges from 0 to 0.91%). Conclusions: We conclude that there is a clear correspondence between the molecular data and distinguishing morphological characters. Our results thus indicate that some morphological characters are useful for species identification and support the potential of DNA barcoding for species identification in a taxonomic group with subtle morphological external differences.
  • Sau Pinn Woo, Zulfigar Yasin, Shau Hwai Tan, Hiroshi Kajihara, Toshihiko Fujita
    ZooKeys (545) 1 - 26 1313-2989 2015 [Refereed][Not invited]
     
    Five sea cucumber species including one new species of the genus Stichopus are reported from the shallow coral reefs of Straits of Malacca. The new species Stichopus fusiformiossa has unusual fusiform spicules in the tentacles, which are not found in the other species of the genus. Pseudo-tables and large perforated plates are newly recorded for Stichopus hermanni Semper, 1868 and Stichopus vastus Sluiter, 1887, respectively.
  • 幸塚 久典, 角井 敬知, 柁原 宏
    日本生物地理学会会報 日本生物地理学会 69 185 - 188 0067-8716 2014/12/20 [Not refereed][Not invited]
  • Eijiroh Nishi, Kanako Matsuo, Maki Kazama-Wakabayashi, Atsushi Mori, Shinri Tomioka, Hiroshi Kajihara, Masami Hamaguchi, Naoto Kajihara, Pat Hutchings
    Zootaxa Magnolia Press, NZ 3895 (3) 433 - 445 1175-5334 2014/12/16 [Refereed][Not invited]
     
    Eight species of Pectinariidae de Quatrefages, 1866 were recorded from Japan and adjacent waters. We studied four spe-cies of the family and redescribe the poorly known species from the Seto Inland Sea and Ariake Sound, Kyushu based on recently collected material. The species covered in this study are Amphictene japonica (Nilsson, 1928), Lagis bocki (Hessle, 1917), Pectinaria okudai (Imajima & Hartman, 1964) and Pectinaria hiuchiensis Kitamori, 1965.
  • Sónia C. S. Andrade, Horacio Montenegro, Malin Strand, Megan L. Schwartz, Hiroshi Kajihara, Jon L. Norenburg, James M. Turbeville, Per Sundberg, Gonzalo Giribet
    Molecular Biology and Evolution 31 (12) 3206 - 3215 0737-4038 2014/12 [Refereed][Not invited]
     
    Resolving the deep relationships of ancient animal lineages has proven difficult using standard Sanger-sequencing approaches with a handful of markers. We thus reassess the relatively well-studied phylogeny of the phylum Nemertea (ribbon worms)-for which the targeted gene approaches had resolved many clades but had left key phylogenetic gaps-by using a phylogenomic approach using Illumina-based de novo assembled transcriptomes and automatic orthology prediction methods. The analysis of a concatenated data set of 2,779 genes (411,138 amino acids) with about 78% gene occupancy and a reduced version with 95% gene occupancy, under evolutionary models accounting or not for site-specific amino acid replacement patterns results in a well-supported phylogeny that recovers all major accepted nemertean clades with the monophyly of Heteronemertea, Hoplonemertea, Monostilifera, being well supported. Significantly, all the ambiguous patterns inferred from Sanger-based approaches were resolved, namely the monophyly of Palaeonemertea and Pilidiophora. By testing for possible conflict in the analyzed supermatrix, we observed that concatenation was the best solution, and the results of the analyses should settle prior debates on nemertean phylogeny. The study highlights the importance, feasibility, and completeness of Illumina-based phylogenomic data matrices.
  • Hiroshi Yamasaki, Shimpei F. Hiruta, Hiroshi Kajihara, Matthew H. Dick
    Zoological Science 31 (7) 421 - 429 0289-0003 2014/07 [Refereed][Not invited]
     
    We investigated the geographic population structures of two intertidal kinorhynch species, Echinoderes sensibilis and Echinoderes sp. A, in the vicinity of Tsugaru Strait between Honshu and Hokkaido Islands, Japan, to examine whether the distribution or connectivity of populations of either species has been constrained by the strait. For each species, we examined the geographic distribution of COI haplotypes, constructed a median-joining haplotype network, and calculated statistics of genetic variation and connectivity. Tsugaru Strait is the northern range limit for E. sensibilis, which comprises a large, evolutionarily stable metapopulation that appears to have undergone a reduction in size followed by expansion; connectivity is low among most local populations, including across Tsugaru Strait. A divergent haplotype lineage showing no variation occurred only at Horozuki, suggesting recent immigration there from outside the study area. Echinoderes sp. A underwent a severe population bottleneck followed by rapid expansion. It occurred at all sampling sites on both sides of the strait, with high connectivity between populations across the strait. There is a zone of secondary contact between moderately divergent, presumably previously allopatric lineages in eastern Hokkaido. Present-day conditions in the strait have existed only for the past 8000 years, and differences in these species' distributions and apparent connectivity across the strait may relate to conditions existing in the strait when the species underwent population expansions or shifts in range; these historical events were not necessarily concurrent between the species, and occurred more than 8000 years ago. We discuss dispersal mechanisms for kinorhynchs, which could include suspension transport or rafting.
  • New Record of Mediomastus opertaculeus Tomioka, Hiruta & Kajihara, 2013 (Annelida: Polychaeta) from Rishiri Island
    Tomioka S, Yamasaki H, Ikoma M, Kajihara H
    Rishiri Studies 33 17 - 22 2014/03 [Not refereed][Not invited]
  • Masato Hirose, Ryuma Fukiage, Toru Katoh, Hiroshi Kajihara
    ZooKeys 398 (398) 1 - 31 1313-2989 2014 [Refereed][Not invited]
     
    We describe Phoronis emigi sp. n. as the eighth member of the genus based on specimens collected from a sandy bottom at 33.2 m depth in Tomioka Bay, Amakusa, Japan. The new species is morphologically similar to P. psammophila Cori, 1889, but can be distinguished from the latter by the number of longitudinal muscle bundles in the body wall (56-72 vs. 25-50 in P. psammophila) and the position of the nephridiopores (situated level with the anus vs. lower than the anus in P. psammophila). Using sequences of the nuclear 18S and 28S rRNA genes and the mitochondrial cytochrome c oxidase subunit I (COI) gene, we inferred the relationship of P. emigi to other phoronids by the maximum likelihood method and Bayesian analysis. The analyses showed that P. emigi is closely related to P. hippocrepia Wright, 1856 and P. psammophila Cori, 1889. We describe the morphology of the topotypes and additional material for P. ijimai Oka, 1897. Neither our morphological observations of P. ijimai, nor the phylogenetic analyses based on 18S and COI sequences, contradicts that P. vancouverensis Pixell, 1912 is conspecific with P. ijimai, a synonymy that has long been disputed.
  • Hiroshi Kajihara
    Munis Entomology and Zoology 9 (1) 588 - 588 2014 [Refereed][Not invited]
  • Daisuke Shimada, Hiroshi Kajihara
    Nematology 16 (4) 437 - 451 1388-5545 2014 [Refereed][Not invited]
     
    Two new species of free-living marine nematodes, Adoncholaimus daikokuensis sp. nov. and A. pseudofervidus sp. nov., from the coastal area of northern Japan, are described and illustrated. Adoncholaimus daikokuensis sp. nov. is similar to five congeners, A. derjugini, A. punctatus, A. oxyuroides, A. squalus comb. nov. and A. filicauda comb. nov. in the absence of a gubernaculum, but differs in the absence of a ventral swelling on tail, spicule length and buccal cavity length. Adoncholaimus pseudofervidus sp. nov. is similar to A. fervidus in having large body size, short tail, similar positions of the excretory pore and nerve ring, short spicules, arrangement of subventral setae in posterior region of body in males, and a single pair of terminal pores of the Demanian system surrounded by small gland cells in females. Adoncholaimus pseudofervidus sp. nov. differs from A. fervidus in having smaller, more anteriorly located amphids, longer buccal cavity, absence of gubernaculum in the male, and a different position of the terminal pores in the female. Partial sequences of the mitochondrial cytochrome c oxidase subunit I gene (309-337 bp) of the new species are provided for identification based on the DNA barcoding method. Metoncholaimoides is proposed as a junior synonym of Adoncholaimus. The new diagnosis of Adoncholaimus and a key to species are provided. Adoncholaimus squalus comb. nov., Adoncholaimus filicauda comb. nov., and Admirandus papillatus comb. nov. are proposed.
  • Shinri Tomioka, Eijiroh Nishi, Hiroshi Kajihara
    ZooKeys (422) 115 - 126 1313-2989 2014 [Refereed][Not invited]
     
    Two undescribed species of polychaetes in Mediomastus (Annelida: Capitellidae) were collected from intertidal to shallow habitats in Tokyo Bay, Japan. These are M. duobalteus sp. n. and M. hanedaensis sp. n. Mediomastus duobalteus sp. n. is distinguishable from all congeners by the following characters: 1) segments 3, 4, 8-11 stainable with methyl green, 2) thoracic capillary chaetae unilimbate, 3) abdominal capillary chaetae absent, 4) paddle-like chaetae in the thorax absent, and 5) abdominal hooded hooks not flared. Mediomastus hanedaensis sp. n. is similar to M. warrenae Green, 2002, but differs from the latter in the shapes of the thoracic capillary chaetae and the abdominal hooded hooks, and the staining pattern with methyl green. In addition, a key to all Mediomastus species is provided.
  • Hiroshi Kajihara, Shi-Chun Sun, Alexei V. Chernyshev, Hai-Xia Chen, Katsutoshi Ito, Manabu Asakawa, Svetlana A. Maslakova, Jon L. Norenburg, Malin Strand, Per Sundberg, Fumio Iwata
    Zoological Science 30 (11) 985 - 997 0289-0003 2013/11 [Refereed][Not invited]
     
    We compared the anatomy of the holotype of the palaeonemertean Cephalothrix simula (Iwata, 1952) with that of the holotypes of Cephalothrix hongkongiensis Sundberg, Gibson and Olsson, 2003 and Cephalothrix fasciculus (Iwata, 1952), as well as additional specimens from Fukue (type locality of C. simula) and Hiroshima, Japan. While there was no major morphological discordance between these specimens, we found discrepancies between the actual morphology and some statements in the original description of C. simula with respect to supposedly species-specific characters. Our observation indicates that these three species cannot be discriminated by the anatomical characters so far used to distinguish congeners. For objectivity of scientific names, topogenetypes of the mitochondrial cytochrome c oxidase subunit I (COI) sequences are designated for C. simula, C. hongkongiensis, and C. fasciculus. Analysis of COI sequence showed that the Hiroshima population can be identified as C. simula, which has been found in previous studies from Trieste, Italy, and also from both the Mediterranean and Atlantic coasts of the Iberian Peninsula, indicating an artificial introduction via (1) ballast water, (2) ship-fouling communities, or (3) the commercially cultured oyster Crassostrea gigas (Thunberg, 1793) brought from Japan to France in 1970s. Cephalothrix simula is known to be toxic, as it contains large amounts of tetrodotoxin (TTX). We report here that the grass puffer Takifugu niphobles (Jordan and Snyder, 1901)-also known to contain TTX-consumes C. simula. We suggest that the puffer may be able to accumulate TTX by eating C. simula. © 2013 Zoological Society of Japan.
  • Shinri Tomioka, Shimpei F. Hiruta, Hiroshi Kajihara
    Species Diversity 日本動物分類学会 18 (1) 105 - 110 1342-1670 2013/05 [Refereed][Not invited]
     
    We describe a new species of capitellid polychaete, Mediomastus opertaculeus sp. nov., from an intertidal rocky shore in Hokkaido, northern Japan. This new species is distinguishable from all other 13 congeners by such characteristics as (1) staining pattern with methyl green (presumably indicating glandular cells in the epidermis), (2) absence of capillary chaetae in the abdomen, (3) absence of paddle-like chaetae in the thorax, and (4) shapes of the thoracic capillary chaetae and hooded hooks. Aligned partial sequences (624 bases) of cytochrome c oxidase subunit I gene from four paratypes of M. opertaculeus differed at 1-4 sites, corresponding to Kimura two-parameter (K2P) distances of 0.002-0.006. K2P distances were 0.216-0.218 between our sequences and that from an unidentified Mediomastus sp. from Darwin Harbor, Australia, indicating these are not conspecific.
  • Hiroshi Yamasaki, Shimpei F. Hiruta, Hiroshi Kajihara
    Molecular Phylogenetics and Evolution 67 (2) 303 - 310 1055-7903 2013/05 [Refereed][Not invited]
     
    We reconstructed kinorhynch phylogeny using maximum-likelihood and Bayesian analyses of nuclear 18S and 28S rRNA gene sequences from 30 species in 13 genera (18S) and 23 species in 12 genera (28S), representing eight families and both orders (Cyclorhagida and Homalorhagida) currently recognized in the phylum. We analyzed the two genes individually (18S and 28S datasets) and in combination (18S + 28S dataset). We detected four main clades (I-IV). Clade I consisted of family Echinoderidae. Cade II contained representatives of Zelinkaderidae, Antygomonidae, Semnoderidae, Centroderes, and Condyloderes, the latter two currently classified in Centroderidae; within Clade II, Zelinkaderidae, Antygomonidae, and Semnoderidae comprised a clade with strong nodal support. Cade III contained only two species in Campyloderes, also currently classified in the Centroderidae, indicating polyphyly for this family. Clades I-Ill, containing all representatives of Cyclorhagida included in the analysis except for Dracoderes abei, formed a clade with high nodal support in the 285 and 18S + 28S trees. Clade IV, resolved in the 18S and 18S + 28S trees with high nodal support, contained only species in order Homalorhagida, with the exception of the cyclorhagid Dracoderes abei. Order Cyclorhagida as it currently stands is thus polyphyletic, and order Homalorhagida paraphyletic. Our results indicate that Dracoderidae has been misplaced in Cyclorhagida based on homoplasious characters. Our analyses did not resolve the relationships among Clades I-Ill within Cyclorhagida. Neither gene alone nor the combined dataset resolved all nodes in trees, indicating that additional markers will be needed to reconstruct kinorhynch phylogeny. (C) 2013 Elsevier Inc. All rights reserved.
  • Manabu Asakawa, Katsutoshi Ito, Hiroshi Kajihara
    Toxins 5 (2) 376 - 395 2072-6651 2013/02 [Refereed][Not invited]
     
    In 1998, during a toxicological surveillance of various marine fouling organisms in Hiroshima Bay, Japan, specimens of the ribbon worm, Cephalothrix simula (Nemertea: Palaeonemertea) were found. These ribbon worms contained toxins with extremely strong paralytic activity. The maximum toxicity in terms of tetrodotoxin (TTX) was 25,590 mouse units (MU) per gram for the whole worm throughout the monitoring period. The main toxic component was isolated and recrystallized from an acidified methanolic solution. The crystalline with a specific toxicity of 3520 MU/mg was obtained and identified as TTX by high performance liquid chromatography (HPLC)-fluorescent detection (FLD) (HPLC-FLD), electrospray ionization-mass spectrometry (ESI-MS), infrared (IR), nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). The highest toxicity of C. simula exceeded the human lethal dose per a single worm. A toxicological surveillance of C. simula from 1998 to 2005 indicated approximately 80% of the individuals were ranked as "strongly toxic" (>= 1000 MU/g). Forty-eight percent of the specimens possessed toxicity scores of more than 2000 MU/g. Seasonal variations were observed in the lethal potency of C. simula. Specimens collected on January 13, 2000 to December 26, 2000 showed mean toxicities of 665-5300 MU/g (n = 10). These data prompted a toxicological surveillance of ribbon worms from other localities with different habitats in Japan, including Akkeshi Bay (Hokkaido) under stones on rocky intertidal beaches, as well as Otsuchi (Iwate) among calcareous tubes of serpulid polychaetes on rocky shores. Within twelve species of ribbon worms examined, only C. simula possessed extremely high toxicity. Therefore, C. simula appears to show generally high toxicity irrespective of their locality and habitat.
  • Hiroshi Kajihara, Eijiroh Nishi
    Check List 9 (4) 826 - 828 1809-127X 2013 [Not refereed][Not invited]
     
    The heteronemertean Euborlasia nigrocincta Coe, 1940 was previously known exclusively from the eastern Pacific. A specimen collected on the Izu Peninsula, Honshu, Japan, herein identified as E. nigrocincta, represents the first record of the species from the western Pacific, increasing the western extent of the species' known range by more than 8300 km and indicating an amphi-Pacific distribution. © 2013 Check List and Authors.
  • Hiroshi Kajihara, Armand M. Kuris
    ZooKeys 258 (258) 1 - 15 1313-2989 2013 [Refereed][Not invited]
     
    Ovicides paralithodis sp. n. is described from the egg mass of the red king crab Paralithodes camtschaticus (Tilesius, 1815) from the Sea of Okhotsk, off Hokkaido, Japan, and Alaska, USA. Among four congeners, O. paralithodis can be distinguished from O. julieae Shields, 2001 and O. davidi Shields and Segonzac, 2007 by having no eyes from O. jonesi Shields and Segonzac, 2007 by the presence of basophilic, vacuolated glandular lobes in the precerebral region and from O. jasoni Shields and Segonzac, 2007 by the arrangement of the acidophilic submuscular glands, which are not arranged in a row. Ovicides paralithodis represents the third described species of egg-predatory nemertean from P. camtschaticus, the second described carcinonemertid species from Japan, and the 21st described species in the family. The intensity of infestations may exceed 24,000 worms per a single egg-bearing pleopod of P. camtschaticus. A preliminary molecular phylogenetic analysis based on sequences of 28S rRNA and cytochrome c oxidase subunit I genes among selected monostiliferous hoplonemertean species supported the monophyly of Carcinonemertidae, suggesting that within the lineage of the family, evolution of the unique vas deferens, Takakura's duct, preceded loss of accessory stylets and accessory-stylet pouches. © Hiroshi Kajihara, Armand M. Kuris.
  • Luna Yamamori, Mamiko Hirose, Hiroshi Kajihara
    Marine Biodiversity Records 6 1755-2672 2013 [Not refereed][Not invited]
     
    The heteronemertean Baseodiscus hemprichii is widely distributed in tropical to temperate Indo-Pacific waters, with the northern limit of its range formerly at Shirahama, Japan. A specimen collected intertidally at Tateyama, Japan, extends the northern boundary of the species' distribution by about 1°18′ in latitude. This northward range extension may be in response to warming ocean temperatures. © Marine Biological Association of the United Kingdom 2013.
  • Hiroshi Yamasaki, Hiroshi Kajihara, Shunsuke F. Mawatari
    Zootaxa 3425 (3425) 23 - 41 1175-5326 2012/08 [Refereed][Not invited]
     
    We describe and illustrate Pycnophyes oshoroensis sp. nov. from Hokkaido, northern Japan. This species is characterized by (1) a trunk 646-775 mu m long, and a presence of (2) middorsal elevation on segments 2-9, (3) anterior middorsal projection on segment 2, (4) even anterior tergal margin of segment 1, (5) reticulate cuticular area on anterior margin of tergal, episternal, and midsternal plates of segment 1, (6) laterodorsal setae on segments 2-9, (7) paralateral setae on segments 1, 2, 4, 6, 7, 8 and 10, (8) ventrolateral setae on segments 1, 5 and 10, (9) ventromedial setae on segments 3-9, and (10) subcuticle thickening areas in paraventral position on segments 9 and 10. In addition, we provide morphological descriptions for two species found from Hokkaido, Japan in this study: Cephalorhyncha asiatica (Adrianov, 1989) and Kinorhynchus yushini Adrianov, 1989. This is the first report of kinorhynchs from Hokkaido and the first report of C. asiatica from Japanese waters.
  • Sónia C. S. Andrade, Malin Strand, Megan Schwartz, Haixia Chen, Hiroshi Kajihara, Joern von Doehren, Shichun Sun, Juan Junoy, Martin Thiel, Jon L. Norenburg, James M. Turbeville, Gonzalo Giribet, Per Sundberg
    Cladistics 28 (2) 141 - 159 0748-3007 2012/04 [Refereed][Not invited]
     
    The phylogenetic relationships of selected members of the phylum Nemertea are explored by means of six markers amplified from the genomic DNA of freshly collected specimens (the nuclear 18S rRNA and 28S rRNA genes, histones H3 and H4, and the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I). These include all previous markers and regions used in earlier phylogenetic analyses of nemerteans, therefore acting as a scaffold to which one could pinpoint any previously published study. Our results, based on analyses of static and dynamic homology concepts under probabilistic and parsimony frameworks, agree in the non-monophyly of Palaeonemertea and in the monophyly of Heteronemerta and Hoplonemertea. The position of Hubrechtella and the Pilidiophora hypothesis are, however, sensitive to analytical method, as is the monophyly of the non-hubrechtiid palaeonemerteans. Our results are, however, consistent with the main division of Hoplonemertea into Polystilifera and Monostilifera, the last named being divided into Cratenemertea and Distromatonemertea, as well as into the main division of Heteronemertea into Baseodiscus and the remaining species. The study also continues to highlight the deficient taxonomy at the family and generic level within Nemertea and sheds light on the areas of the tree that require further refinement.
  • Keiichi Kakui, Norio Kobayashi, Hiroshi Kajihara
    Journal of Crustacean Biology 32 (1) 127 - 139 0278-0372 2012/02 [Refereed][Not invited]
     
    Lack of an ischium on pereiopods 1-6 was previously considered a synapomorphy for the tanaidacean superfamily Tanaoidea, although descriptions of Arctotanais alascensis (Richardson, 1899), the sole species in Arctotanais, indicated presence or absence of the ischium. To resolve this ambiguity, we examined newly collected specimens of A. alascensis (including males, which had not previously been described) from Hokkaido, Japan, using light and scanning electron microscopy. We also conducted molecular phylogenetic analyses based on partial sequences of the 18S rRNA gene to examine the phylogenetic position of A. alascensis. Here we describe in detail the morphology of the male of A. alascensis, which proved to be similar to that of the females. This species bears an ischium on pereiopods 1-6, which contradicts the current diagnoses of Tanaoidea and Tanaidae, although other synapomorphies remain valid. Molecular phylogenetic analyses strongly supported the placement of A. alascensis in Tanaoidea, and consequently we amended the diagnoses for Tanaoidea and Tanaidae to include either presence or absence of the ischium on the pereiopods.
  • Hiroshi Yamasaki, Hiroshi Kajihara
    Species Diversity 17 109 - 118 2012 [Refereed][Not invited]
  • Daisuke Shimada, Keiichi Kakui, Hiroshi Kajihara
    Species Diversity 17 (2) 221 - 226 2012 [Refereed][Not invited]
  • Hiroshi Kajihara, Ryuta Yoshida, Daisuke Uyeno
    Check List 8 (4) 754 - 755 2012 [Refereed][Not invited]
  • Junko Inoue, Hiroshi Kajihara
    Species Diversity 17 (1) 15 - 20 2012 [Refereed][Not invited]
  • Yoshie Takahashi, Hiroshi Kajihara, Shunsuke F. Mawatari
    ZooKeys (175) 69 - 74 1313-2989 2012 [Refereed][Not invited]
     
    We describe Hedgpethia spinosa sp. n. based on a single male specimen obtained from 197-207 m depth, south of Yaku Island, Kagoshima Prefecture, Japan. Among 15 previously known congeners, the new species resembles H. bicornis (Losina-Losinsky & Turpaeva, 1958), H. chitinosa (Hilton, 1943), and probably H. brevitarsis (Losina-Losinsky & Turpaeva, 1958), in having a mid-dorsal tubercle on the posterior rim on each trunk segment. The new species, however, is distinguishable from those by a pair of horns on the anterior margin of the cephalic segment, spines on the first coxae, and denticulate spines on the strigilis. The new species represents the fifth member of the genus so far known from Japanese waters, in addition to H. brevitarsis (Losina-Losinsky & Turpaeva, 1958), H. chitinosa (Hilton, 1943), H. dofleini (Loman, 1911), and H. elongata Takahashi, Dick & Mawatari, 2007.
  • Taiki Yoshihara, Shimpei F. Hiruta, Toru Katoh, Hiroshi Kajihara
    ZooKeys (187) 45 - 62 1313-2989 2012 [Refereed][Not invited]
     
    We describe two new species and redescribe one in the polychaete genus Amphicorina Claparede, 1864 (Sabellidae) from Hokkaido, Japan. Amphicorina ascidicola sp. n. differs from its 38 congeners chiefly in the reduction of the collar, but also in having three pairs of radioles, one pair of ventral radiolar appendages, a bifurcate ventral lobe on the anterior peristomial ring, six abdominal chaetigers, and a large anterior tooth on the abdominal uncini. Amphicorina ezoensis sp. n. has a crenulated collar, three pairs of radioles, and more than eight (12) abdominal chaetigers; A. ezoensis sp. n. shares these character states with A. anneae (Rouse, 1994), A. eimeri (Langerhans, 1880), and A. persinosa (Ben-Eliahu, 1975), but differs from them in having two pairs of ventral radiolar appendages and a non-oblique collar. Amphicorina mobilis (Rouse, 1990) was previously known only from the type locality (New South Wales, Australia), but we identify our Japanese material as conspecific on the basis of morphological and molecular similarity.
  • Yoshie Takahashi, Hiroshi Kajihara, Shunsuke F. Mawatari
    JOURNAL OF NATURAL HISTORY 46 (21-22) 1337 - 1358 0022-2933 2012 [Refereed][Not invited]
     
    We provide descriptions for five species in the pycnogonid genus Nymphon J.C. Fabricius, 1794 based on material from waters around the Nansei Islands, Japan. These species are: Nymphon falcatum Utinomi, 1955; Nymphon japonicum Ortmann, 1890; Nymphon nagannuense sp. nov.; Nymphon ortmanni Helfer, 1938; and Nymphon plectrum sp. nov. Examination of the paratype specimens of N. ortmanni revealed that this species has multi-pored cement glands on both the femur and first tibia, a condition not previously known. Nymphon plectrum is the 12th member of the Nymphon aequidigitatum group, for which we provide a revised key to species.
  • Keiichi Kakui, Toru Katoh, Shimpei F. Hiruta, Norio Kobayashi, Hiroshi Kajihara
    Zoological Science 28 (10) 749 - 757 0289-0003 2011/10 [Refereed][Not invited]
     
    Phylogenetic relationships within Tanaidacea were analyzed based on sequence data for the 18S rRNA gene. Our results strongly supported a monophyletic group composed of Neotanaidae, Tanaoidea, and Paratanaoidea, with the first two taxa forming a clade. These results contradict three previously suggested hypotheses of relationships. Based on the molecular results, and considering morphological similarities/differences between Neotanaidomorpha and Tanaidomorpha, we demoted Suborder Neotanaidomorpha to Superfamily Neotanaoidea within Tanaidomorpha; with this change, the classification of extant tanaidaceans becomes a two-suborder, four-superfamily system. This revision required revision of the diagnoses for Tanaidomorpha and its three superfamilies. The results for Apseudomorpha were ambiguous: this taxon was monophyletic in the maximum likelihood and Bayesian analyses, but paraphyletic in the maximum parsimony and minimum evolution analyses.
  • Hiroshi Kajihara, Minerva Olympia, Norio Kobayashi, Toru Katoh, Hai-Xia Chen, Malin Strand, Per Sundberg
    Zoological Journal of the Linnean Society 161 (4) 695 - 722 0024-4082 2011/04 [Refereed][Not invited]
     
    We provide a redescription of the poorly known distromatonemertean, Diplomma serpentina ( Stimpson, 1855), a species that has not been reported since its original description. One of the freshly obtained topotypes is designated as a neotype. Based on examination of the new material, as well as the type specimens of three known species, we present a taxonomic revision of the so-far monotypic genus Diplomma Stimpson, 1857, which has been regarded as a dubious taxon since 1904. The following three nominal species are transferred to Diplomma: Paramphiporus albimarginatus Kirsteuer, 1965, Poseidonemertes bothwellae Gibson, 1982, and Correanemertes polyophthalma Gibson & Sundberg, 2001. The genus Paramphiporus Kirsteuer, 1965 is regarded as a junior synonym of Diplomma. Comparison of cytochrome c oxidase subunit I gene ( COI) sequences indicates that D. serpentina is distributed in Indonesia, the Philippines, and Japan. Phylogenetic analyses based on partial sequences of nuclear 28S rRNA and 18S rRNA genes, as well as COI, from a selected number of distromatonemerteans fail to specify the sister relation to Diplomma, although it is suggested that the genus is more closely related to Antarctonemertes, Gononemertes, Nemertellina, Tetraneuronemertes, Oerstedia, and Vulcanonemertes, than to Amphiporus, Cyanophthalma, Geonemertes, Malacobdella, Paranemertes, Poseidonemertes, Prostoma, Tetrastemma, and Zygonemertes. (C) 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161, 695-722.
  • Hiroshi Kajihara, Toru Katoh, Dhugal J. Lindsay
    Marine Biodiversity Records 4 e13  2011/04 [Refereed][Not invited]
     
    Two specimens of the pelagic nemertean Protopelagonemertes beebei Coe, 1936 were collected in Sagami Bay, Japan. Kimura-2-parameter distance based on the partial sequences (616 base pairs) of cytochrome c oxidase gene between the present material and that previously reported as an unidentified specimen of the genus Protopelagonemertes collected from off California, USA was 5.6%, implying that these are closely related, and may belong to the same species. A description of the internal morphology based on serial transverse sections of the body is provided. The material showed an intermediate character state in the number of proboscis nerves between what had formerly been reported as P. beebei and P. hubrechti (Brinkmann, 1917), posing a question on the species delimitation. © 2011 Marine Biological Association of the United Kingdom.
  • Keiichi Kakui, Hiroshi Kajihara
    Bulletin of the National Museum of Nature and Science, Series A National Museum of Nature and Science Supplement 5 53 - 70 1881-9052 2011 [Refereed][Not invited]
  • Hiroshi Kajihara, Hiroshi Yamasaki, Sónia C, S. Andrade
    Species Diversity 日本動物分類学会 16 (3) 149 - 165 1342-1670 2011 [Refereed][Not invited]
     
    Carinoma hamanako sp. nov., the ninth member of the genus, is described based on three specimens collected in Lake Hamana, Shizuoka Prefecture, Pacific coast of Honshu, Japan. The new species can be distinguished from its congeners by the blind-ending rhynchocoelic villar vessels, the lateral rhynchocoel vessels rejoining the lateral vessels, the unbranched excretory canals, the situation of the posterior part of the mid-dorsal nerve within the longitudinal muscle layer of the body wall, and the absence of a vascular plexus in the foregut region. A phylogenetic analysis based on the nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I genes shows that C. hamanako sp. nov. forms a clade with two congeners, C. mutabile Griffin, 1898 and C. tremaphoros Thompson, 1900, thus supporting the generic placement of the new species.
  • Masato Hirose, Ryuma Fukiage, Hiroshi Kajihara
    Biogeography Biogeographical Society of Japan 13 105 - 110 1345-0662 2011 [Refereed][Not invited]
  • Shushi Abukawa, Hiroshi Kajihara
    Zootaxa 2732 (2732) 68 - 68 1175-5326 2011/01 [Refereed][Not invited]
  • Haixia Chen, Malin Strand, Jon L. Norenburg, Shichun Sun, Hiroshi Kajihara, Alexey V. Chernyshev, Svetlana A. Maslakova, Per Sundberg
    PLOS ONE 5 (9) e12885  1932-6203 2010/09 [Refereed][Not invited]
     
    Background: It has been suggested that statistical parsimony network analysis could be used to get an indication of species represented in a set of nucleotide data, and the approach has been used to discuss species boundaries in some taxa. Methodology/Principal Findings: Based on 635 base pairs of the mitochondrial protein-coding gene cytochrome c oxidase I (COI), we analyzed 152 nemertean specimens using statistical parsimony network analysis with the connection probability set to 95%. The analysis revealed 15 distinct networks together with seven singletons. Statistical parsimony yielded three networks supporting the species status of Cephalothrix rufifrons, C. major and C. spiralis as they currently have been delineated by morphological characters and geographical location. Many other networks contained haplotypes from nearby geographical locations. Cladistic structure by maximum likelihood analysis overall supported the network analysis, but indicated a false positive result where subnetworks should have been connected into one network/species. This probably is caused by undersampling of the intraspecific haplotype diversity. Conclusions/Significance: Statistical parsimony network analysis provides a rapid and useful tool for detecting possible undescribed/cryptic species among cephalotrichid nemerteans based on COI gene. It should be combined with phylogenetic analysis to get indications of false positive results, i.e., subnetworks that would have been connected with more extensive haplotype sampling.
  • Hiroshi Kajihara, Dhugal J. Lindsay
    Zootaxa 2429 (2429) 43 - 51 1175-5326 2010/04 [Refereed][Not invited]
     
    A new species of bathypelagic polystiliferous nemertean Dinonemertes shinkaii is described based on the holotype obtained by the manned submersible Shinkai 6500 from a depth of 2343 m in Japan Trench, Northwest Pacific. Dinonemertes shinkaii can be distinguished from its congeners in having a translucent body, 24 proboscis nerves, two pairs of intestinal caecal diverticula, and about 25 pairs of intestinal lateral diverticula. This species represents the first dinonemertid to have pseudostriated muscle fibres in the rhynchocoel circular muscle layers.
  • Hiroshi Kajihara
    Journal of Natural History 44 (37-40) 2321 - 2329 0022-2933 2010 [Refereed][Not invited]
     
    The morphology of the rhynchocoel blood vessel was studied in 26 specimens representing 14 species of the family Cephalotrichidae. In eight specimens the vascular system could not be traced because of their small size, poor fixation, or contraction during fixation. In the other 18 specimens, a short mid-dorsal rhynchocoel vessel was found. In Cephalothrix adriatica, C.hongkongiensis, C.kefersteini, C.oestrymnica, C.orientalis, C.rufifrons, C. cf. fasciculus and C.cf. simula, the mid-dorsal rhynchocoel vessel penetrates the dorsal side of the proboscis insertion, and extends backward abutting the mid-dorsal rhynchocoel wall (Type A). In C.filiformis sensu Iwata (1954), the vessel is pendant in the rhynchocoel above the proboscis (Type B). In C.filiformis s.str., the vessel runs in the proboscis wall, after passing through the proboscis insertion (Type C). Morphology of the rhynchocoelic vessel might have taxonomic significance in cephalothrichids.
  • Keiichi Kakui, Hiroshi Kajihara, Shunsuke F. Mawatari
    ZooKeys 33 (33) 1 - 17 1313-2989 2010 [Refereed][Not invited]
     
    The new species Nesotanais ryukyuensis sp. n. is described from Japan. Nesotanais ryukyuensis most closely resembles N. rugula Bamber, Bird & Angsupanich, 2003, but can be distinguished by the length of simple seta on maxillipedal basis and the shape of cheliped in male. A key to species of the genus Nesotanais is given. The male chelipeds of N. rugula are redescribed. The serial ridges on the inner surface of the chelipedal propodus and dactylus in Nesotanais ryukyuensis and N. rugula are likely to be stridulating ridges that might produce sound.
  • Per Sundberg, Alexey V. Chernyshev, Hiroshi Kajihara, Tobias Kanneby, Malin Strand
    Zoological Journal of the Linnean Society 157 (2) 264 - 294 0024-4082 2009/10 [Refereed][Not invited]
     
    Ribbon worms (phylum Nemertea) have traditionally been described and classified based on a combination of internal and external morphological characters. The extent, and wealth of details, of these descriptions vary both over time and amongst authors. In addition, definitions of characters and character states are in many cases vague, causing problems both for identification and in phylogenetic analyses. Here, we suggest a system of describing nemerteans based on a list of characters and their states with the actual description in the form of a vector of character state symbols. We argue that this system makes it easier for other systematists to extract the necessary characters/character states for comparative and phylogenetic analyses. The proposed list of characters can also act as a checklist for nemertean description, whereby hopefully ambiguities (such as does the nonmentioning of a character actually mean 'missing' or just not looked for) can be avoided in the future. We describe two new species and one new genus Carinina ochracea sp. nov. and Raygibsonia bergi gen. et sp. nov. using this concept in combination with molecular analyses based on 18S and cytochrome oxidase I (COI) DNA sequences. (C) 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157, 264-294.
  • Baseodiscus hemprichii (phylum Nemertea) from Phuket, Thailand
    Hiroshi Kajihara, Tetsuya Kato
    Phuket Marine Biological Center Research Bulletin 69 1–5  2009 [Refereed][Not invited]
  • Daisuke Shimada, Hiroshi Kajihara, Shunsuke F. Mawatari
    Species Diversity 14 137–150  2009 [Refereed][Not invited]
  • Hiroshi Kajihara, Alexei V. Chernyshev, Shi-Chun Sun, Per Sundberg, Frank B. Crandall
    Species Diversity 13 245–274  2008 [Refereed][Not invited]
  • Hiroshi Kajihara, Yuji Ise
    Bulletin of the Kitakyushu Museum of Natural History and Human History, Series A (Natural History) 6 1–12  2008 [Refereed][Not invited]
  • Hiroshi Kajihara
    Zootaxa 1146 (1446) 43 - 58 1175-5326 2007/04 [Refereed][Not invited]
     
    Two species of the monostiliferous hoplonemerteans, Nemertopsis quadripunctata (Quoy & Gaimard, 1833) and Nemertopsis mitellicola sp. nov., are reported from Shirahama, Wakayama, Japan, based on material obtained among the goose-neck barnacle, Capitulum mitella (Linnaeus, 1767). Redescription of Nemertopsis quadripunctata provides some anatomical features not reported in previous literature; these include: the rhynchodaeum opening to the dorsal portion of the oesophagus in front of the brain, and the oesophagus leading farther anteriorly to open subterminally to the exterior as a mouth; mid-dorsal vessel entering the rhynchocoel to form a single vascular plug; and the epidermis possessing a small pit in cross section, the pit being antero-posteriorly continuous, forming a complete sagittal furrow in the post-cerebral region of the body for at least 1 cm in length. Nemertopsis mitellicola sp. nov differs from all the congeners in having a spirally sculptured central stylet, lateral diverticula on the intestinal caecum, and a cephalic patch, from which two longitudinal dorsal stripes extend backward.
  • Hiroshi Kajihara
    Zootaxa 1454 (1454) 39 - 47 1175-5326 2007/04 [Refereed][Not invited]
     
    Callinera emiliae sp. nov., the ninth member of the genus, is described based on three specimens collected in Dumaguete, Negros Island, Republic of the Philippines. The new species can be distinguished from its congeners by the following characteristics: lateral sensory organs present; sub-epidermal glandular cells absent; blood vascular system without a ventral cephalic connective; nervous system with two dorsal cerebral commissures; and foregut nerves fused to form a ganglion in front of the mouth. In living specimens, epidermal constrictions were observed in the intestinal region; the presence of intestinal sphincters was confirmed in sectioned material and these correspond with the epidermal constrictions.
  • Hiroshi Kajihara
    Zoological Science 24 (4) 287 - 326 0289-0003 2007/04 [Refereed][Not invited]
     
    A literature-based taxonomic catalogue of the nemertean species (Phylum Nemertea) reported from Japanese waters is provided, listing 19 families, 45 genera, and 120 species as valid. Applications of the following species names to forms previously recorded from Japanese waters are regarded as uncertain: Amphiporus cervicalis, Amphiporus depressus, Amphiporus lactifloreus, Cephatothrix filiformis, Cephatothrix finearis, Cerebratulus fuscus, Lineus vegetus, Lineus bilineatus, Lineus gesserensis, Lineus grubei, Lineus longifissus, Lineus mcintoshii, Nipponnemertes putchra, Oerstedia venusta, Prostoma graecense, and Prostoma grande. The identities of the taxa referred to by the following four nominal species require clarification through future investigations: Cosmocephala japonica, Dicelis rubra, Dichilus obscurus, and Nareda serpentina. The nominal species established from Japanese waters are tabulated. In addition, a brief history of taxonomic research on Japanese nemerteans is reviewed.
  • Preliminary report on the nemertean fauna (phylum Nemertea) in the Philippines
    Hiroshi Kajihara, Minerva Olympia, Emilia S. Yap, Gloria Gomez-Delan, Mercy B. Quilantang, Michitaka Shimomura, Shigeto Taniyama, Manabu Asakawa
    UPV Journal of Natural Science 12 (1) 123 - 128 2007 [Refereed][Not invited]
  • Keiichi Kakui, Hiroshi Kajihara, Shunsuke F. Mawatari
    Zootaxa 1563 (1563) 37 - 54 1175-5326 2007 [Refereed][Not invited]
     
    Two new species, Kudinopasternakia balanorostrata and Pseudosphyrapus quintolongus are described from Japan. Kudinopasternakia balanorostrata is characterized by an acorn-shaped rostrum. It most closely resembles K. siegi (Viskup & Heard, 1989), but can be distinguished by the shape of the rostrum, the number of setae on article 2 of the mandibular palp, and the setation on the outer lobe of the fixed endite of the maxilla. Pseudosphyrapus quintolongus is characterized by an unusually large lateral process on pleonite 5, which distinguishes it from all other species in the genus. Keys to species of Kudinopasternakia and Pseudosphyrapus are given.
  • Hiroshi Kajihara
    Species Diversity 12 57 - 66 2007 [Refereed][Not invited]
  • Hiroshi Kajihara
    Zootaxa 1163 (1) 1 - 1 1175-5326 2006/03/30 [Refereed][Not invited]
     
    Four species of palaeonemerteans, including Carinina plecta sp. nov., Callinera nishikawai sp. nov., Hubrechtella ijimai comb. nov., and Hubrechtella kimuraorum sp. nov., are described from the Pacific coast of Honshu Island, Japan. The genus Coeia Takakura, 1922 is considered to be a subjective junior synonym of Hubrechtella Bergendal, 1902. Carinina plecta sp. nov. can be distinguished from other congeners by possessing a rhynchocoel wall principally composed of interwoven circular and longitudinal muscle fibres, a condition similar to that in another palaeonemertean genus, Carinoma, as well as certain members in the Hoplonemertea. Callinera nishikawai sp. nov. possesses a remarkable stylet-like apparatus in the proboscis, a feature that has never been reported for any other palaeonemertean. The characteristic ‘tail’ in Hubrechtella (= Coeia) ijimai comb. nov. can be regarded as a heterochronic retention of the structure that appears only in juveniles of other congeners. Hubrechtella kimuraorum sp. nov. has a broad U-shaped blood lacuna in the foregut region before it ramifies into a vascular plexus.
  • Noriko Matsumoto, Hiroshi Kajihara, Shunsuke F. Mawatari
    Species Diversity 日本動物分類学会 10 (1) 27–36 - 36 1342-1670 2005 [Refereed][Not invited]
     
    Three similar species of water mite in the subgenus Hygrobates (genus Hygrobates) are reported from middle Honshu, Japan. These include two recently described lacustrine species, Hygrobates (Hygrobates) biwaensis Tuzovskij, 2003 and H. (H.) rarus Tuzovskij, 2003, which are known only from Lake Biwa, and one new fluvial species, H. (H.) capillus sp. nov. The new species is distinguished from the other two by the truncate P-2 ventral projection; the female genital plates being longer than the genital opening and extending to the post-genital sclerite; the anterior border of the flat male genital plate; and the larger body size (408-603μm). Two or three setae are confirmed to be present on the female pre-genital sclerites in the three species reported herein; this character state has never so far been recorded in any member of this subgenus.
  • Hiroshi Kajihara
    Archives of Natural History 31 (2) 208 - 213 0260-9541 2004/10 [Refereed][Not invited]
  • Mohosena Begum Tanu, Yahia Mahmud, Osamu Arakawa, Tomohiro Takatani, Hiroshi Kajihara, Kentaro Kawatsu, Yonekazu Hamano, Manabu Asakawa, Keisuke Miyazawa, Tamao Noguchi
    Toxicon 44 (5) 515 - 520 0041-0101 2004/10 [Refereed][Not invited]
     
    Tetrodotoxin (TTX) was localized as brown color in different tissues of an undescribed species of the nemertean genus Cephalothrix (phylum Nemertea) and a turbellarian Planocera reticulata (phylum Platyhelminthes) on light microscopy by means of a monoclonal anti-TTX antibody. In the Cephalothrix sp., TTX was recognized in the vesicles apically arranged in the bacillary cells in the epidermis, basal lamina, the granular cells in the proboscis epithelium, rhynchocoel epithelium, and the vesicles in the basal portion of the intestinal wall near the blood vessels and rhynchocoel. The excretory system and the ovum also showed positive reaction of TTX antigen-antibody. On the other hand, the hermaphrodite flatworm P. reticulata exhibited TTX antigen-antibody complex only in their ovum. To our knowledge, this is the first experimental effort on micro-distribution of TTX in invertebrates. (C) 2004 Elsevier Ltd. All rights reserved.
  • Manabu Asakawa, Tadayoshi Toyoshima, Katsutoshi Ito, Kentaro Bessho, Chisato Yamaguchi, Shogo Tsunetsugu, Yasuo Shida, Hiroshi Kajihara, Shunsuke F. Mawatari, Tamao Noguchi, Keisuke Miyazawa
    Toxicon 41 (7) 747 - 753 0041-0101 2003/06 [Refereed][Not invited]
     
    Paralytic toxicity of ribbon worms 'himomushi' in Japanese, identified as undescribed species of the genus Cephalothrix, found on the surface of the shells of cultured oysters in Hiroshima Bay, Hiroshima Prefecture was examined between April 1998 and December 2001. The toxicity study showed that all of specimens were found to contain toxins with strong paralytic action in mice; the highest toxicity (as tetrodotoxin, TTX) was 25,590 mouse units (MU) per gram for whole body throughout the monitoring period. The main toxic component of this himomushi toxin (HMT) was isolated from a pooled specimen (390 g; total toxicity 2,897,000 MU) by a method that consisted of treatment with activated charcoal, chromatography on Bio-Gel P-2 and Bio-Rex 70 (H+ form), and finally crystallization from an acidified methanolic solution. The recrystallized toxin showed a specific toxicity of 3520 MU/mg. This toxin showed (M + H)(+) and (M + H-H2O)(+) ion peaks at m/z 320 and 302, respectively, by electrospray ionization-mass spectrometry (ESI-MS). The absorption band at 3353, 3235, 1666, 1612 and 1076 cm(-1) were observed in infrared spectrum of this toxin. This spectrum was indistinguishable from that of TTX The H-1-NMR spectrum for the recrystallized toxin was the same as that for TTX. The pair of doublets centered at 2.33 (J = 10.0 Hz) and 5.48 ppm (J = 10.0 Hz) which are characteristic of TTX, were shown to be coupled by double irradiation. Furthermore, by gas chromatography-mass spectrometry (GC-MS) of the alkali-hydrolyzate of this toxin indicated the presence of quinazoline skeleton (C9-base) specific to TTX. (C) 2003 Elsevier Science Ltd. All rights reserved.
  • Hiroshi Kajihara, Ray Gibson, Shunsuke F. Mawatari
    Zoological Science 20 (4) 491 - 500 0289-0003 2003/04 [Refereed][Not invited]
     
    Potamostoma shizunaiense gen. et sp. nov. (Nemertea: Hoplonemertea: Monostilifera) is described from the mouth of the River Shizunai, Hokkaido, Japan. This genus is readily distinguished from other monostiliferans by an oesophagus opening far anteriorly into the rhynchodaeum, a well developed excretory system extending the whole body length, terminals of the excretory collecting tubules situated between the body wall circular muscle layer and the dermis, and bilobed testes in males.
  • The situation of the taxonomic studies on ‘minor’ invertebrates in Asia:the phylum Nemertea as a test case.
    Hiroshi Kajihara, Junko Shimura, Fumie Kasai, Makoto M. Watanabe
    Research Report from the National Institute for Environmental Studies, Japan 175 193–200  2003 [Not refereed][Not invited]
  • Dennis P. Gordon, Shunsuke F. Mawatari, Hiroshi Kajihara
    Zoological Journal of the Linnean Society 136 (2) 199 - 216 0024-4082 2002/10 [Refereed][Not invited]
     
    As presently recognized, the small cheilostome bryozoan family Eurystomellidae (superfamily Catenicelloidea) comprises just two genera: Eurystomella Levinsen, 1909, with three Recent species, and Selenoriopsis Maplestone, 1913; with one Recent and two fossil species, Within Eurystomella sensu lato, colonies range from uni-/biserial to multi-serial and the smooth gymnocystal frontal shields of zooids may be entire or have one to several large foramina. Here we describe seven new Recent species of encrusting eurystomellids from New Zealand and Japan. Including species of Selenariopsis, a cladistic analysis was carried out on 11 eurystomellid species and five outgroup species, the latter representing the families Cribrilinidae, Euthyroididae, Petalostegidae, and Catenicellidae. The results of the analysis support restricting Eurystomella to multiserial species with large frontal foramina, median suboral sutures, and basal pore-chambers. Two new genera, both with imperforate frontal shields and uniporous mural septula, are segregated from Eurystomella: uni-/biserial Zygopalme, with a median suboral suture and accessory perforations in the ovicellular kenozooid, and multiserial Integripelta, lacking the suture and accessory perforations. (C) 2002 The Linnean Society of London.
  • Hiroshi Kajihara
    Species Diversity 7 (2) 121 - 143 2002 [Refereed][Not invited]
  • Hiroshi Kajihara, Ray Gibson, Shunsuke F. Mawatari
    Hydrobiologia 456 (1/3) 187 - 198 0018-8158 2001/07/15 [Refereed][Not invited]
     
    A new genus and species of monostiliferous hoplonemertean, Diopsonemertes acanthocephala gen. et sp. nov., is described from Otsuchi Bay, Japan. Significant anatomical features of the new form include a body wall longitudinal musculature anteriorly divided into inner and outer layers by connective tissue, no pre-cerebral septum, the presence of a thin coat of diagonal muscle fibres between the body wall longitudinal and circular muscle layers in the foregut body region, cephalic retractor muscles derived only from the inner portion of the divided longitudinal muscles and a rhynchocoel more than half the body length.
  • Frank B. Crandall, Hiroshi Kajihara, Shunsuke F. Mawatari, Fumio Iwata
    Hydrobiologia 456 (1-3) 175 - 185 0018-8158 2001/07 [Refereed][Not invited]
     
    Yamaoka (1939, 1940a,b) described eight new species of nemerteans found in or near Japan. Several other new species he discovered remained in manuscript form until brief descriptions of Emplectonema mitsuii, Paranemertes katoi, Amphiporus ogumai, and Prostoma roseocephalum (now Tetrastemma roseocephalum) appeared, somewhat irregularly, in a faunal encyclopedia in 1947. The authors here present the case for recognizing the validity and availability of these species names and for their correct attribution and date. More complete English language descriptions for the four species, from the original Yamaoka manuscript, are included and are augmented by Yamaoka's original illustrations. One of the species, Amphiporus ogumai, is transferred to the family Cratenemertidae as Nipponnemertes ogumai comb. n.
  • Michitaka Shimomura, Tetsuya Kato, Hiroshi Kajihara
    Otsuchi Marine Science 東京大学 26 46 - 50 1344-8420 2001 [Refereed][Not invited]
  • Hiroshi Kajihara, Ray Gibson, Shunsuke F. Mawatari
    Zoological Science 17 (2) 265 - 276 0289-0003 2000 [Refereed][Not invited]
     
    Nemertellina minuta Friedrich, 1935, sensu Yamaoka, 1940, from Akkeshi Bay, Japan, is fully redescribed as a new species, Nemertellina yamaokai. The main characters distinguishing this taxon from N. minuta are the presence of two pairs of cephalic furrows and cephalic glands, and the absence of dorsoventral muscles from the intestinal region.

MISC

Books etc

Presentations

Association Memberships

  • 日本動物分類学会   日本動物学会   

Research Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2020/04 -2023/03 
    Author : 堀口 健雄, 柁原 宏, WAKEMAN KEVIN
     
    本年度は，北海道厚岸から採集したHaplozoon pugnus を用いてトランスクリプトーム解析を実施した。単細胞トランスクリプトーム解析の手法を用い，合計４個体からのトランスクリプトームデータを得ることができた（詳細は解析中）。また，当該データを用いて渦鞭毛藻類内の本属の系統的位置を正確に把握するための系統解析を実施中である。また本属は，寄生生物でありながら痕跡的葉緑体をもつことは我々の研究で明らかになっているが，本属の寄生性を進化させるプロセスが，近縁な他のミゾゾア（＝アピコンプレックス類と渦鞭毛藻類などからなる単系統群）の寄生生物における光合成能力欠失の進化パターンとどのように異なるか（同じか）を比較するために光合成関連の遺伝子に関しても解析を進めている。また，細胞学的な観点からは透過電鏡および共焦点顕微鏡を用いてtrophozoiteステージの細胞の膜系，チューブリン，セントリンの立体構造を明らかにしようと試みた。また，特に異なる細胞ステージ，すなわちtrophcytes，gonocytes，sporocytes間の連結部分の構造を明らかにする研究も実施した。さらに先端の可動性の刺の動作メカニズムも明らかにするべく電顕試料の準備を進めている。 現在，上述の大部分の研究に関しては解析およびデータ取得の最終段階に入っており， 2022年の夏頃までには一部の結果を国際誌に投稿する予定である。 また，宿主の多様性調査に関しては，2021年8月に厚岸での調査を予定したが、コロナウイルス蔓延の影響で中止とせざるを得なかった。11月と12月に千葉県館山と三重県菅島の海産無脊椎動物相を調査する機会を得，環形動物・扁形動物・紐形動物の標本においてハプロズーンの寄生の有無を調べたが，観察した全ての無脊椎動物標本において感染の痕跡は確認できなかった。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2020/04 -2023/03 
    Author : 柁原 宏
     
    2021年度はコロナウイルス蔓延の影響により、予定していたサンプリングがほぼ実施できなかった。かろうじて4月22日に石狩浜で調査を行うことが出来たが、その際に得られた原順列類は、これまで優先的に出現すると考えていたOtoplanidaeの2種だけでなく、極めて稀にしか出現しないと思われていた担爪類が20個体以上採集された。これらの標本から抽出したDNAを基にしてミトコンドリアゲノム決定の作業を開始した。GetOrganelleでのアセンブルはうまくいかなかったが、おそらくミトゲノムとrRNAも配列決定はできていると思われる。今後は引き続きアセンブルを行い、部分配列でもよいので、プライマーサイト設計に役立つと思われるCOIや16Sなどのいわゆるバーコード領域として従来用いられている遺伝子を優先的に決定することを目指す。簡易的な観察に基づく形態的特長からこれらは恐らくNematoplana属の一種と思われる。正確な種同定のためには成熟した個体の生殖器の構造を連続切片標本に基づいて観察する必要があるが、今年度はそのためのサンプル処理はせず、全ての個体をDNA抽出用に固定した。原順列類を構成する2つの高次分類群のうちのもう片方である担石類は石狩浜だけでなく厚岸その他の場所で多数出現することが分かっているが、確実に同種と思われるサンプルを、ミトコンドリアゲノム決定に必要な個体数（体積にもよるが恐らく20～50個体）一度にまとめて採集することに未だ成功していない。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2017/04 -2020/03 
    Author : Kajihara Hiroshi
     
    Positive relation between body size and the number of eggs per an ovary was detected among heteronemerteans. Comparisons of body lengths between three major nemertean subgroups (Palaeo-, Hetero-, and Hoplonemertea) suggested that the difference in body plan is not likely related to body length, as Hetero- and Palaeonemertea did not differ significantly, although Hoplonemertea differed significantly between Hetero- and Palaeonemertea.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2014/04 -2019/03 
    Author : Tsukagoshi Akira, Shimano Satoshi, Tanaka Hayato
     
    More than 200 materials of interstitial animals were collected from Viet Nam (in 2015), Guam and Saipan (in 2015), Malaysia (in 2016), and Palau (in 2017). Many specimens of Arthropoda, Nemertea, Echinodermata, Mollusca, Kinorhyncha, Loricifera and so on were found out from the materials. As a result of taxonomical works, very high biodiversity was recognized and many undescribed species were also found out. A part of them have been already published on scientific papers as new species. The development of study areas must rapidly progress in near future. Therefore the record of biodiversity in this survey will be more important as a record of the current time before developmental progresses.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2014/04 -2018/03 
    Author : Mawatari Shunsuke, KISHIMOTO Takeo, NAGAHAMA Yoshitaka
     
    It is the study that "the general study of the natural history treasure" that is a research theme will go through long in future and must continue. In this study, I was active targeted at the establishment of the National Museum of Natural History as the organization which accomplished this research theme for the future and got result. The concrete result at the symposium that reached in some areas for four years and bore fruit for the some ten magazine articles. As a result, the establishment of the National Museum of Natural History as the place of the natural history treasure study came on a third dimension. The national Okinawa natural history Museum establishment preparatory committee was made a general corporation, and homepage https://sites.google.com/view/okinawa-natural-history-museum/ was established, too. Based on this results of research, the progress of the natural history treasure study is expected in future.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2011/04 -2016/03 
    Author : Dick Matthew, KOGAME Kazuhiro, KAJIHARA Hiroshi, KATOH Toru
     
    Tsugaru Strait does not appear to be acting, and to have acted, as a strong marine dispersal barrier, as shown by population genetic and phylogeographic analyses of marine organisms in nine taxonomic groups that were sampled from the intertidal zone in the vicinity of the strait. Species with longer period of planktonic larval duration tended to show higher dispersal ability. In many of the target species, the results indicated that populations with a certain degree of size have been maintained before the last glacial period. This study also revealed the existence of multiple cryptic species, i.e., species that morphologically resemble each other but can be differentiated with molecular sequence data.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2013/04 -2015/03 
    Author : KAJIHARA Hiroshi, SHIMANO Satoshi, KIMURA Atsushi
     
    More than 20 animal phyla are known from minute environment between sand particles in beaches. A number of interstitial species are known in the phylum Annelida, a group that is mainly comprised of lugworms, earthworms, and leaches. At the onset of this study, 11 species in eight genera of interstitial annelids had been reported from Japanese waters. No representative of the genus Diurodrilus had been known in Japan, but there is an undescribed form in Ishikari Beach, Hokkaido. This study aimed to test the phylum affiliation of such interstitial annelids as Diurodrilus and Trilobodrilus, which was doubted by previous studies. The conclusion, however, was that both groups actually belong to the phylum Annelida.
  • ノーステック財団：研究開発助成事業 若手研究人材・ネットワーク育成補助金
    Date (from‐to) : 2011 -2012 
    Author : 柁原 宏
     
    北緯44度06分、東経144度32分、水深215ｍの地点で得られた雌タラバガニ20個体を調査したところ16個体が抱卵していた。そのうち3個体由来の卵塊からそれぞれ１個体ずつヒモムシが見つかった（寄生率約19%）。ヒモムシは雌の体長cm、雄は5mm程度で、卵塊の表面ではく奥の方に埋没していた。また雌個体はカニ卵塊中に自分の卵を紐状の分泌物中に産卵していた。16匹のカニの重さは1221g～1675g、卵塊重量は21g～143gで、ヒモムシが見つかったカニ（と卵塊重）は1289g (36g), 1526g (115g), 1675g (143g)だったが、ヒモムシの寄生とカニ重量との間に相関は認められなかった。ミトコンドリアのシトクロームc酸化酵素遺伝子と核の28SリボソームRNA遺伝子配列の解析はこれらがカニヒモムシ科に所属することを強く示唆した。
  • 成茂動物科学振興基金：
    Date (from‐to) : 2009 -2010 
    Author : 柁原 宏
  • スカンジナビア・ニッポンササカワ財団：
    Date (from‐to) : 2008 -2009 
    Author : 柁原 宏
  • 昭和聖徳記念財団：
    Date (from‐to) : 2008 -2009 
    Author : 柁原 宏
  • 財団法人水産無脊椎動物研究所：個別助成
    Date (from‐to) : 2008 -2009 
    Author : 柁原 宏
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2008 -2009 
    Author : KAJIHARA Hiroshi
     
    A taxonomic revision on a monostiliferous hoplonemertean genus was carried out based on molecular phylogeny and observations of actual type specimens. In addition, a catalogue of nemertean genera and species was compiled, a new species of bathypelagic polystiliferous hoplonemertean was described, and a heteronemertean was reported from Japanese waters for the first time. A new morphological character with respect to the cephalic blood vascular system was discovered in a group of palaeonemerteans.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2004 -2007 
    Author : MAWATARI Shunsuke F., KATAKURA Haruo, TAKAHASHI Hideki, SAITO Yutaka, YABE Mamoru, KAJIHARA Hiroshi
     
    Only after we know the biodiversity on Earth, it will be possible to protect the biodiversity, to solve the environmental problem, and to ensure the sustainability of human life. Nobody, however, at present could answer the question "How is the biodiversity?" The present study is the unprecedented try to reveal the whole figure of the biodiversity in an area and planed under the ground swell of solving the environmental problem we are facing. This study focused on the fauna and flora on and around Daikokujima Island which is 1 km^3 and located at the mouth of Akkeshi Bay, Hokkaido. As a result of four year survey, we successfully revealed whole figure of the biota including soil protists, collembolans, oribatid mites, parasitic mites on plants, soil mites, vascular plants, invertebrates, fishes, rodents etc., and reported five new species and 25 new records in Japan.
  • 日本学術振興会：科学研究費助成事業 若手研究(B)
    Date (from‐to) : 2004 -2006 
    Author : 柁原 宏
     
    ノルウェー・ベルゲン大学のエスペランド臨海実験所で採集を行い、Cephalothrix filiformis、 C. rufifrons, Cerebratulus fuscus, Lineus bilineatus, L. longissimus, Micrura fasciolata, M. purpurea Nipponnemertes pulchra, Oerstedia dorsalis, Tetrastemma candidum, T. vermiculum, Tubulanus annulatusの12種を得た。分子系統解析によって推定した系統樹に形態形質をマップさせることにより、従来用いられていた高次分類群の判別形質を再評価した。その結果、単針類において吻鞘壁が内縦走筋層・外環状筋層の2層からなる群は更に2群に分けられ、それは背血管が吻鞘壁に進入するかどうかという形質がこの2群の判別形質として重要であることが示唆された。背血管が吻鞘壁に進入しない群に含まれる最古参の名義科階級群名はOerstediidaeのようである。この知見に基づき、北西太平洋産種の分類学的再検討を行った。そのうちの1種cf. Diplomma serpentinaは1855年に沖縄から原記載されて以降これまで1例も報告がなく、ながらくその分類学的同一性は不明のままであった。本種と同定可能な多数のトポタイプ標本、および本州の3地点(神奈川県三崎、静岡県下田、和歌山県白浜)とフィリピンの1地点(パナイ島ティグバウアン)から得られた標本に基づいて、分子系統解析・比較形態学的研究を行った結果、本属種はOerstedia属を含むクレードの一員であり、さらに背血管が吻鞘壁に進入しないため、Oerstediidaeに所属させるのが妥当であるという結論を得ている。
  • Marine invertebrate systematics

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