Researcher basic information

• 北海道大学 博士（理学）, 北海道大学

• https://researchmap.jp/kajihara?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=200901025781611078
• https://orcid.org/0000-0001-6510-9355
• https://sites.google.com/site/hubiodiv1/

• 30360895

• https://orcid.org/0000-0001-6510-9355

• N-4562-2019

• 200901025781611078

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

• Life Science, Biodiversity and systematics

• Bachelor's degree program, School of Science
• Master's degree program, Graduate School of Science
• Doctoral (PhD) degree program, Graduate School of Science

Research activity information

• Sep. 2008, 日本動物学会, Zoological Science Award
  柁原 宏
• Sep. 2007, 日本動物学会, 奨励賞
  柁原 宏

• Reversal of precedence for Notospermus over Ophiocephalus and validation of Notospermus viridis (Nemertea: Heteronemertea)
  Hiroshi Kajihara
  Australian Journal of Taxonomy, 132, 1, 6, Atlas of Living Australia, 15 Sep. 2026, [Peer-reviewed], [Lead author, Last author, Corresponding author], [International Magazine]
  English, Scientific journal, 50577324;50246748
• Systematic revision of the genus Thoracophelia (Annelida: Opheliidae) from Japan
  Kentaro Ageishi; Hiroshi Kajihara
  Zootaxa, 5853, 4, 528, 544, Magnolia Press, 23 Jul. 2026, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, Up to five species of the polychaete genus Thoracophelia Ehlers, 1897 have been reported from Japanese waters: T. arctica (Grube, 1866); T. ezoensis Okuda, 1936; T. japonica (Misaka & Sato, 2003); T. minuta Jimi, Fujimoto, Takehara & Imura, 2021; and T. yasudai Okuda, 1934. Our systematic revision reduces this number to three valid species, invalidating T. minuta and T. yasudai. We conclude that T. minuta is a junior synonym of Euzonus arcticus Grube, 1866 (now T. arctica), based on identical DNA barcode sequences. Morphological observations support the previously proposed—but not universally accepted—synonymy of T. yasudai with E. arcticus. Thoracophelia arctica may possess black rod-shaped spicules suspended in the coelomic fluid, which likely disappear either during ontogeny or under specific physiological conditions. In T. ezoensis, molecularly identified specimens exhibited a wider range of intraspecific morphological variation than previously recognized, particularly in the numbers of branchial pairs and anal cirri. Energy-dispersive X-ray spectroscopy coupled with scanning electron microscopy revealed that the black rod-shaped spicules in T. japonica are rich in calcium and magnesium, distinct from the calcium- and sulfur-rich spicules previously reported for T. arctica (as T. minuta). A molecular phylogenetic analysis of the subfamily Opheliinae based on four gene markers (16S rRNA, cytochrome c oxidase subunit I, 18S rRNA, and 28S rRNA) recovered the monophyly of Thoracophelia, albeit with moderate branch support. The phylogeny suggests that the capacity for spicule formation may have arisen early in the evolution of Opheliinae but was subsequently lost in some lineages or expressed conditionally depending on ontogeny or physiology.
• Diversity of convolutid acoels (Convolutidae, Acoela) in Hokkaido, Japan, including a description of the symbiont-bearing Amphiscolops ranshimensis n. sp.
  Siratee Riewluang; Regine C. Manglicmot; Shaun Cunningham; Matthew D. Hooge; Rintaro Ono; Hiroshi Kajihara; Brian S. Leander; Kevin C. Wakeman
  Zoologischer Anzeiger, 322, 96, 109, Elsevier BV, May 2026, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Improving the resolution of inter-familial relationships within Palaeacanthocephala by mitophylogenomics including Isthmosacanthidae (Polymorphida) and Transvenidae (Echinorhynchida)
  Yuki Kita; Shimpei F. Hiruta; Hiroshi Kajihara
  Zoological Science, 43, 3, Zoological Society of Japan, 13 Apr. 2026, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• 国際動物命名規約第4版の布告書46による2023年改正とその背景
  柁原 宏; 中野 隆文
  タクサ：日本動物分類学会誌, 60, 31, 36, 31 Mar. 2026, [Peer-reviewed], [Lead author], [Domestic magazines]
  Japanese, Scientific journal
• Morphology and phylogeny of Notospermus psittacinus comb. nov. (Nemertea: Pilidiophora: Lineidae) from Mindanao, Philippines
  Jamael Abato; Archie Along; Nonillon Aspe; Caryl Kaye Awa; Nick Anthony Burias; Laurence Calagui; Shirlamaine Irina Calagui; Meljan Demetillo; April Joy Jovita; Julius Anthony Leones; Allexc Mae Niez; Romell Seronay; Hiroshi Kajihara
  Zoological Science, 43, 2, Zoological Society of Japan, 04 Mar. 2026, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Unrecognized species-level diversity of terrestrial nemerteans in the UNESCO world heritage Ogasawara Islands revealed by mitogenomics
  Natsumi Hookabe; Shimpei F. Hiruta; Akinori Yabuki; Hiroki Yoshino; Yu Hisasue; Naoto Sawada; Rei Ueshima; Hiroshi Kajihara
  BMC Ecology and Evolution, 25, 1, Springer Science and Business Media LLC, 19 Dec. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 50246748
• Taxonomy and molecular phylogeny of the ribbon worm Tetrastemma luteum sp. nov. (Nemertea: Eumonostilifera: Tetrastemmatidae) and first record of Tetrastemma phaeobasisae Kulikova, 1987 from Japan
  Jamael C. Abato; Hiroshi Kajihara
  Zoological Studies, 64, 68, 10 Dec. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• First record of Cavisoma magnum (Acanthocephala: Echinorhynchida) from Japanese waters, with systematic revision on Cavisomatidae
  Yuki Kita; Hiroshi Kajihara
  Species Diversity, 30, 2, 241, 248, Japanese Society of Systematic Zoology, 30 Oct. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Species composition of the genus Baseodiscus Diesing, 1850 (Pilidiophora: Valenciniidae) in Japan and the Philippines with turbotaxonomy of two new species
  Jamael Abato; Millanie Abatay; Archie Along; Nonillon Aspe; Caryl Kaye Awa; Nick Anthony Burias; Laurence Calagui; Shirlamaine Irina Calagui; Warren Caneos; Merimee Dahilog-Caralde; Meljan Demetillo; April Joy Jovita; Julius Anthony Leones; Allexc Mae Niez; Romell Seronay; Hiroshi Kajihara
  Marine Biology Research, 1, 16, Informa UK Limited, 22 Oct. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Taxonomic revision of Sauranthura (Isopoda: Anthuroidea: Anthuridae), with the description of Sauranthura liangaensis sp. nov. from Surigao del Sur, Philippines
  Shoki Shiraki; Keiichi Kakui; Archie Along; Laurence Calagui; Shirlamaine Irina Calagui; Meljan Demetillo; Hiroshi Kajihara; Julius Anthony Leones; Amor Rojas-Salinas; Kris Angeli Sanchez-De los Reyes; Romell Seronay; Aoi Tsuyuki; Jamael Abato
  Marine Biology Research, 1, 15, Informa UK Limited, 15 Sep. 2025, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Morphological and molecular characteristics of Longicollum alemniscus (Acanthocephala: Echinorhynchida), with a taxonomic revision of the genus Longicollum
  Yuki Kita; Hakuyu Sekine; Wataru Nagata; Reina Doi; Tsukasa Waki; Hiroshi Kajihara
  Zoological Science, 42, 5, Zoological Society of Japan, 11 Sep. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new species of Pseudoacanthocephalus (Acanthocephala: Pseudoacanthocephalidae) from Sado Island, Japan, with a report of its accidental occurrence in a marine elasmobranch
  Yuki Kita; Masato Nitta; Harue Abe; Shigen Kaburagi; Takeshi Fujita; Kenji Toyota; Yusuke Kondo; Hiroshi Kajihara
  Folia Parasitologica, 72, Biology Centre, AS CR, 10 Sep. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new anthurid Amakusanthura camiguinensis sp. n. (Crustacea: Isopoda: Anthuroidea) from Camiguin Island, Philippines
  Shoki Shiraki; Keiichi Kakui; Millanie Abatay; Warren Caneos; Merimee Dahilog-Caralde; Hiroshi Kajihara; Aoi Tsuyuki; Jamael Abato
  Journal of Natural History, 59, 33-36, 2175, 2186, Informa UK Limited, 27 Aug. 2025, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Deep-sea nemerteans collected along the Japan Trench and the southern Kuril-Kamchatka Trench onboard the R/V Hakuho-maru with descriptions of two new species in Hoplonemertea
  Jamael C. Abato; Hiroshi Kajihara
  Deep Sea Research Part I: Oceanographic Research Papers, 224, 104549, 104549, Elsevier BV, Aug. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A taxonomic revision of the freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 (Nemertea: Eumonostilifera): a radical solution or an over-lumping?
  Hiroshi Kajihara
  Zootaxa, 5646, 4, 451, 500, Magnolia Press, 11 Jun. 2025, [Peer-reviewed], [Lead author, Last author, Corresponding author], [International Magazine]
  English, Scientific journal, The freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 is revised based on i) morphological examination of material from Lake Biwa, Japan, and type materials of P. kolasai Gibson & Moore, 1976 and P. canadiense Gibson & Moore, 1978; ii) a species delimitation analysis based on partial sequences of the cytochrome c oxidase subunit I gene determined from material collected in Norway, Sweden, and Japan, along with 62 sequences available in public databases from the UK, Sweden, Italy, Macedonia, New Zealand, Mexico, and the USA (California, Indiana, Massachusetts); and iii) a literature survey. The generic names regarded as synonymous with Prostoma are Emea Leidy, 1850; Stichostemma Montgomery, 1894; Koinoporus Sanchez & Moretto, 1988 syn. nov.; and Limnemertes Gibson & Wang, 2002 syn. nov. Prostoma now consists of the epigean P. clepsinoides Dugès, 1828 and the eyeless stygobiont P. puteale Beauchamp, 1932. Nominal species-group taxa regarded as synonymous with P. clepsinoides include P. lombricoideum Dugès, 1830 syn. nov.; Polia dugesii Quatrefages, 1849; Emea rubra Leidy, 1850 syn. nov.; Tetrastemma turanicum Fedchenko, 1872 syn. nov.; T. aquarumdulcium Silliman, 1884; T. lacustre Du Plessis, 1892 syn. nov.; T. graecense Böhmig in Mojsisovics, 1893 syn. nov.; Stichostemma eilhardi Montgomery, 1894 syn. nov.; S. asensoriatum Montgomery, 1896 syn. nov.; P. sebethis Monticelli, 1910 syn. nov.; S. grande Ikeda, 1913 syn. nov.; P. padanum Pierantoni, 1926 syn. nov.; P. cisalpinum Vialli, 1927 syn. nov.; P. jenningsi Gibson & Young, 1971 syn. nov.; P. kolasai syn. nov.; P. canadiense syn. nov.; Koinoporus mapochi Sanchez & Moretto, 1988 syn. nov.; P. eilhardi macradenum Sun & Yin, 1995 syn. nov.; P. ohmiense Chernyshev et al., 1998 syn. nov.; and Limnemertes poyangensis Gibson & Wang, 2002 syn. nov. Nominal species herein regarded as synonymous with P. puteale are P. communopore Senz, 1996 syn. nov. and P. hercegovinense Tarman, 1961 syn. nov. An annotated list of available species-group names that could potentially be combined with Prostoma is provided. Annexes are provided for i) species-group names originally but no longer combined with Prostoma, ii) T.E. Timofeev’s 1911 nemertean article, and iii) nomenclature on Prostoma Örsted, 1843 and Prostominae Örsted, 1844.
• Mouth-attaching copepod Salmincola markewitschi reduces the body condition and growth of juvenile salmonids, Salvelinus leucomaenis, by decreasing host feeding activity: evidence from parasite removal experiment
  Leo Murakami; Ryota Hasegawa; Nozomi Aruga; Nobuhiro Sato; Shingo Nakamura; Hiroshi Kajihara; Itsuro Koizumi
  Canadian Journal of Zoology, 103, 1, 8, Canadian Science Publishing, 27 May 2025, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Ectoparasitic copepods in the genus Salmincola Wilson, 1915 are considered harmful to host salmonids, yet experimental studies on the mechanism by which these copepods affect hosts are critically limited. We evaluated the effects of the mouth-attaching Salmincola markewitschi Shedko & Shedko, 2002 on juvenile white-spotted charr Salvelinus leucomaenis (Pallas, 1814). We used a parasite removal experiment where all individuals were artificially infected, and then parasites were removed in one group (i.e., treatment), while the copepods were left in another group (i.e., control). We hypothesized that the copepods reduce host feeding, thereby reducing host body condition and growth. The alternative hypothesis is that parasites do not change host feeding, or even increase because of the compensation for the negative effect. In this case, host condition and growth would not be reduced. The control group had lower food consumption, body condition, and growth compared to the treatment. Thus, S. markewitschi negatively affected hosts by reducing host feeding, and no behavioral compensation was observed. It remains unknown, however, whether reduced feeding was due to impaired swallowing or physiological stresses caused by infections. Further experiments on gill- and body surface-attaching Salmincola species could provide deeper insights into how these parasites influence host health.
• Description of a new species of Amphiscolops (Xenacoelomorpha: Convolutidae)
  Rintaro Ono; Hiroshi Kajihara
  Journal of Natural History, 59, 21-24, 1611, 1624, Informa UK Limited, 12 May 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A taxonomic review of the genus Prionocidaris (Echinodermata: Echinoidea: Cidaridae), with molecular phylogeny and emended diagnosis
  Leonard Yi Herng Tan; Sau Pinn Woo; Hiroshi Kajihara
  Journal of Natural History, 59, 17-20, 1395, 1416, Informa UK Limited, 28 Apr. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Species diversity of Tetranemertes (Nemertea: Monostilifera) in Japan
  Jamael C. Abato; Natsumi Hookabe; Hiroshi Kajihara
  Species Diversity, 30, 1, 71, 83, Japanese Society of Systematic Zoology, 17 Apr. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new heteronemertean genus with variable potential of anterior regeneration for species formerly belonging to Lineus (Nemertea: Pilidiophora)
  Jumpei Ikenaga; Svetlana A. Maslakova; Manabu Yoshida; Hiroshi Kajihara
  Zoological Science, 42, 2, Zoological Society of Japan, 27 Mar. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Phylogenetic position of the acoel Oxyposthia praedator (Xenacoelomorpha: Convolutidae)
  Rintaro Ono; Hiroshi Kajihara
  Plankton and Benthos Research, 20, 1, 101, 106, The Plankton Society of Japan/The Japanese Association of Benthology, 28 Feb. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Ribbons under the rocks: intertidal ribbon-worm fauna (phylum Nemertea) from selected islands in central and southern Philippines
  Jamael Abato; Millanie Abatay; Merimee Dahilog-Caralde; Warren Caneos; Nonillon Aspe; Archie Along; Laurence Calagui; Meljan Demetillo; Julius Anthony Leones; Saturnino Luke Sobrevega; Hiroshi Kajihara
  Philippine Journal of Systematic Biology, 18, 1, 16, 32, Jan. 2025, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Nomenclatural and taxonomic notes on two species of ribbon worms (Nemertea) collected during the La Recherche Expedition (1838–1840)
  Hiroshi Kajihara
  Bionomina, 39, 1, 10, 17, Magnolia Press, 04 Dec. 2024, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal, Illustrations of at least three unidentified species of nemerteans from the Nordic Seas, collected during the French La Recherche Expedition (1838–1840), were included in a work published around 1842–1848 as part of a series reporting the results of the expedition. Of these three species, two were later named based on the illustrations: Meckelia borealis Diesing, 1862 and Ditactorrhochma typicum Diesing, 1862, which were subsequently reclassified in 1904 as Cerebratulus borealis (Diesing, 1862) and Amphiporus typicus (Diesing, 1862), respectively, and have been accepted as valid to date. The genus Ditactorrhochma Diesing, 1862, established for D. typicum, has been synonymized with Amphiporus Ehrenberg, 1831 since 1904. In this article, the lineid heteronemertean Cerebratulus borealis is deemed a nomen dubium because it cannot be distinguished with certainty from several similar existing species, including those with higher priority, namely Lineus ruber (Müller, 1774) and L. viridis (Müller, 1774). Meanwhile, the monostiliferous hoplonemertean Amphiporus typicus is identified herein as a junior subjective synonym of Nipponnemertes pulchra (Johnston, 1837). Ditactorrhochma Diesing, 1862 is thus a senior subjective synonym of Nipponnemertes Gibson & Crandall, 1989. Ditactorrhochma has not been used as a valid name since 1900, whereas Nipponnemertes has been used prevalently, meeting the conditions stipulated in Article 23.9.1 of the International Code of Zoological Nomenclature (fourth edition). Therefore, Ditactorrhochma Diesing, 1862 is now declared a nomen oblitum with respect to Nipponnemertes Gibson & Crandall, 1989, the latter being a nomen protectum.
• Proseriate turbellarians (Platyhelminthes: Rhabditophora) in the egg mass of the commercially important horsehair crab, Erimacrus isenbeckii (Crustacea: Decapoda), from Hokkaido, Japan
  Robert K. Okazaki; Hiroshi Kajihara
  Zoologia (Curitiba), 41, e23080, FapUNIFESP (SciELO), 29 Nov. 2024, [Peer-reviewed], [Invited], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Systematics of Pseudocavisoma (Acanthocephala: Echinorhynchida): assessment of familial affiliation, establishment of a new species, and complementary redescription of the type species based on syntypes
  Yuki Kita; Masato Nitta; Hiroshi Kajihara
  Systematic Parasitology, 101, 6, Springer Science and Business Media LLC, 04 Nov. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Cystacanths of Bolbosoma (Acanthocephala: Polymorphidae) from six species of marine fish around Japan, with molecular information
  Yuki Kita; Tsukasa Waki; Hiroshi Kajihara
  Species Diversity, 29, 2, 317, 325, Japanese Society of Systematic Zoology, 10 Oct. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Evaluation of "Cirriformia tentaculata” (Annelida: Cirratulidae) from Japan as a pollution indicator in marine environments: is it truly a single species?
  Naoto Jimi; Yoshihiro Fujiwara; Hiroshi Kajihara
  Species Diversity, 29, 2, 281, 316, Japanese Society of Systematic Zoology, 03 Sep. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First record of Parahubrechtia rayi (Nemertea: Palaeonemertea) from Japan
  Hiroshi Kajihara; Ikumasa Ganaha; Keitaro Okuno; Naoki Yamada; Hisanori Kohtsuka
  Species Diversity, 29, 2, 235, 237, Japanese Society of Systematic Zoology, 23 Aug. 2024, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Molecular systematics and type-material-based redescription of Metarhadinorhynchus lateolabracis, with taxonomic revisions of Metarhadinorhynchus, Indorhynchus, and Neotegorhynchus (Acanthocephala: Palaeacanthocephala)
  Yuki Kita; Masato Nitta; Hiroshi Kajihara
  Acta Parasitologica, Springer Science and Business Media LLC, 10 Aug. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Microfocus X-ray computed tomography of Paraplanocera oligoglena (Platyhelminthes: Polycladida) with an evaluation of histological sections after scanning
  Yuki Oya; Akiteru Maeno; Aoi Tsuyuki; Hisanori Kohtsuka; Hiroshi Kajihara
  Zoological Science, 41, 5, Zoological Society of Japan, 27 Jun. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Revisiting Stygocapitella (Annelida, Parergodrilidae) in Japan, with insights into their amphi-Pacific diversification
  Natsumi Hookabe; Naoto Jimi; Shinta Fujimoto; Hiroshi Kajihara
  Royal Society Open Science, 11, 6, The Royal Society, 19 Jun. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• Morphological and molecular characteristics of two species of the genus Rhadinorhynchus (Palaeacanthocephala: Echinorhynchida) from the western Pacific
  Yuki Kita; Masato Nitta; Hiroshi Kajihara
  Species Diversity, 29, 1, 171, 178, Japanese Society of Systematic Zoology, 24 May 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Testing the species status of the chromodorid nudibranch Goniobranchus aureopurpureus (Mollusca: Gastropoda)
  Haruki Ishiyama; Yuki Oya; Nerida G. Wilson; Hiroshi Kajihara
  Species Diversity, 29, 1, 141, 150, Japanese Society of Systematic Zoology, 24 Apr. 2024, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Pacific marine gregarines (Apicomplexa) shed light on biogeographic speciation patterns and novel diversity among early apicomplexans
  Eric Odle; Siratee Riewluang; Kentaro Ageishi; Hiroshi Kajihara; Kevin C. Wakeman
  European Journal of Protistology, 126080, 126080, Elsevier BV, Mar. 2024, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Delimiting the polymorphic congeners of the genus Oerstedia Quatrefages, 1864 (Nemertea, Hoplonemertea), and descriptions of three new species from the Northwest Pacific
  Jamael C. Abato; Alexei V. Chernyshev; Natsumi Hookabe; Aoi Tsuyuki; Gauri Kaushik; Hiroshi Kajihara
  Frontiers in Ecology and Evolution, 12, Frontiers Media SA, 16 Feb. 2024, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• Graveyards of giant pandas at the bottom of the sea? A strange-looking new species of colonial ascidians in the genus Clavelina (Tunicata: Ascidiacea)
  Naohiro Hasegawa; Hiroshi Kajihara
  Species Diversity, 29, 1, 53, 64, Japanese Society of Systematic Zoology, 01 Feb. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Supplemental re-description of a deep-sea ascidian, Fimbrora calsubia (Ascidiacea, Enterogona), with an inference of its phylogenetic position
  Naohiro Hasegawa; Natsumi Hookabe; Yoshihiro Fujiwara; Naoto Jimi; Hiroshi Kajihara
  Zoosystematics and Evolution, 100, 1, 129, 140, Pensoft Publishers, 26 Jan. 2024, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• Upside-down behaviour of certain ribbon worms (phylum Nemertea)
  Hiroshi Kajihara; Audrey Falconer; Alexei V. Chernyshev
  Journal of Tropical Ecology, 40, e2, 1, 3, 04 Jan. 2024, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• New locality for the deep-sea acorn worm Quatuoralisia malakhovi (Hemichordata: Enteropneusta)
  Hiroshi Kajihara; Jamael Abato; Maho Matsushita
  Russian Journal of Marine Biology, 49, 6, 522, 527, Pleiades Publishing Ltd, Jan. 2024, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• From solitary to colonial with zooid miniaturization: ancestral-state reconstruction based on NGS data of stolidobranch ascidians
  Naohiro Hasegawa; Shin Matsubara; Akira Shiraishi; Honoo Satake; Noa Shenkar; Hiroshi Kajihara
  bioRxiv, Cold Spring Harbor Laboratory, 27 Dec. 2023, [Last author]
  English, 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, Dec. 2023, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Morphological and molecular characterization of a new species of the genus Echinorhynchus Zoega in Müller, 1776 (Acanthocephala: Echinorhynchidae) parasitizing the rock greenling Hexagrammos lagocephalus (Pallas) (Scorpaeniformes: Hexagrammidae) from eastern Hokkaido, Japan
  Yuki Kita; Hiroshi Kajihara
  Systematic Parasitology, Springer Science and Business Media LLC, 19 Oct. 2023, [Peer-reviewed], [Last author], [International Magazine]
  Bengali, Scientific journal
• Does atp8 exist in the mitochondrial genome of Proseriata (Metazoa: Platyhelminthes)?
  Daisuke Shimada; Shimpei F. Hiruta; Kazuhiro Takahoshi; Hiroshi Kajihara
  Animal Gene, 30, 200161, 200161, Elsevier BV, Oct. 2023, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
  English, Scientific journal
• Capropodocerus, a new genus in Podoceridae (Crustacea: Amphipoda) from Japan, with descriptions of two new species
  Yu Matsumoto; Hiroshi Kajihara; Keiichi Kakui
  Zootaxa, 5336, 4, 577, 589, Magnolia Press, 24 Aug. 2023, [Peer-reviewed], [International Magazine]
  English, Scientific journal, 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.
• Occurrence of an unidentified harrimaniid acorn worm in the genus Stereobalanus (Hemichordata: Enteropneusta) from the Japan Trench hadal zone
  Hiroshi Kajihara; Jamael Abato; Maho Matsushita
  Deep Sea Research Part I: Oceanographic Research Papers, 104075, 104075, Elsevier BV, Aug. 2023, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species of slender flatworm in the genus Eucestoplana and a record of E. cf. cuneata (Platyhelminthes, Polycladida) from the Okinawa Islands, Japan, with an inference of their phylogenetic positions within Cestoplanidae
  Aoi Tsuyuki; Yuki Oya; Hiroshi Kajihara
  Zoosystematics and Evolution, 99, 2, 363, 373, Pensoft Publishers, 05 Jul. 2023, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• Systematic position of the genus Metacanthocephalus Yamaguti, 1959 (Palaeacanthocephala: Echinorhynchida) inferred from molecular evidence, with a redescription of Metacanthocephalus ovicephalus (Zhukov, 1960)
  Yuki Kita; Shimpei F. Hiruta; Mizuki Sasaki; Hiroshi Kajihara
  Parasitology International, 94, 102731, 102731, Elsevier BV, Jun. 2023, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Theama japonica sp. nov., an interstitial polyclad flatworm showing a wide distribution along Japanese coasts
  Aoi Tsuyuki; Yuki Oya; Naoto Jimi; Natsumi Hookabe; Shinta Fujimoto; Hiroshi Kajihara
  Zoological Science, 40, 3, Zoological Society of Japan, 18 May 2023, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Species description and phylogenetics of Oerstedia fuscosparsa sp. nov. (Nemertea: Monostilifera: Oerstediidae) from Japan
  Jamael Abato; Ryuta Yoshida; Hiroshi Kajihara
  Zootaxa, 5249, 5, 589, 597, Magnolia Press, 06 Mar. 2023, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• Preliminary study of the marine ribbon worm species (Nemertea) along the Levantine Mediterranean shore of Israel
  Razy Hoffman; Hiroshi Kajihara
  Oceanography & Fisheries, 15, 5, 555922, Feb. 2023, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species of Leipsuropus Stebbing, 1899 (Amphipoda: Podoceridae) from Japan
  Yu Matsumoto; Hiroshi Kajihara; Keiichi Kakui
  Nauplius, 31, FapUNIFESP (SciELO), Feb. 2023, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Diversity of interstitial nemerteans of the genus Ototyphlonemertes (Nemertea: Monostilifera: Ototyphlonemertidae) in the South China Sea, with a comment on the distribution pattern of the genus
  Hai-Long Liu; Hiroshi Kajihara; Shi-Chun Sun
  Frontiers in Marine Science, 9, Frontiers Media SA, 08 Dec. 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• Reversible shifts between interstitial and epibenthic habitats in evolutionary history: molecular phylogeny of the marine flatworm family Boniniidae (Platyhelminthes: Polycladida: Cotylea) with descriptions of two new species
  Aoi Tsuyuki; Yuki Oya; Hiroshi Kajihara
  PLOS ONE, 17, 11, e0276847, e0276847, Public Library of Science (PLoS), 23 Nov. 2022, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• A new symbiotic relationship between a polyclad flatworm and a mantis shrimp: description of a new species of Emprosthopharynx (Polycladida: Acotylea) associated with Lysiosquilla maculata (Crustacea: Stomatopoda)
  Yuki Oya; Hiroki Nakajima; Hiroshi Kajihara
  Marine Biodiversity, 52, 5, Springer Science and Business Media LLC, Oct. 2022, [Peer-reviewed], [Last author], [International Magazine]
  Scientific journal
• Descriptions of two new species of Armatoplana (Polycladida: Stylochoplanidae) from the coasts of Japan, with their phylogenetic positions in Leptoplanoidea
  Yuki Oya; Aoi Tsuyuki; Hiroshi Kajihara
  Zootaxa, 5178, 5, 433, 452, Magnolia Press, 30 Aug. 2022, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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).
• Exploring the basal topology of the heteronemertean tree of life: establishment of a new family, along with turbotaxonomy of Valenciniidae (Nemertea: Pilidiophora: Heteronemertea)
  Hiroshi Kajihara; Shushi Abukawa; Alexei V. Chernyshev
  Zoological Journal of the Linnean Society, 196, 1, 503, 548, Oxford University Press (OUP), 26 Aug. 2022, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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).
• Histology-free description and phylogenetics of Tetrastemma parallelos sp. nov. (Nemertea: Eumonostilifera) from Japan
  Jamael Abato; Ryuta Yoshida; Hiroshi Kajihara
  Journal of Natural History, 56, 29-32, 1265, 1277, Informa UK Limited, 18 Aug. 2022, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular phylogeny of the genus Nipponnemertes (Nemertea: Monostilifera: Cratenemertidae) and descriptions of 10 new species, with notes on small body size in a newly discovered clade
  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, Frontiers Media SA, 26 Jul. 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• First record of Bulaceros porcellanus Newman & Cannon, 1996 (Platyhelminthes, Polycladida, Cotylea) from Japanese waters, with a revision of the generic diagnosis based on morphology and molecular phylogeny
  Aoi Tsuyuki; Hisanori Kohtsuka; Natsumi Hookabe; Hiroshi Kajihara
  Plankton and Benthos Research, 17, 2, 147, 155, The Plankton Society of Japan/The Japanese Association of Benthology, 30 May 2022, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First record of the decapod-egg predator Ovicides paralithodis (Nemertea, Carcinonemertidae) from the snow crab Chionoecetes opilio (Decapoda, Brachyura)
  Natsumi Hookabe; Hirohito Motobayashi; Naoto Jimi; Hiroshi Kajihara; Rei Ueshima
  Parasitology International, 89, 102567, 102567, 02 Mar. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, 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.
• Lineid heteronemerteans (Nemertea: Pilidiophora) from Sagami Bay, Japan, with some proposals for the family-level classification system
  Hiroshi Kajihara; Ikumasa Ganaha; Hisanori Kohtsuka
  Zoological Science, 39, 1, 62, 80, Zoological Society of Japan, 03 Jan. 2022, [Peer-reviewed], [Invited], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Description of Tubulanus misakiensis sp. nov. (Nemertea: Palaeonemertea) from Sagami Bay, Japan
  Natsumi Hookabe; Hiroshi Kajihara
  Zoological Science, 39, 1, 81, 86, Zoological Society of Japan, 03 Jan. 2022, [Peer-reviewed], [Invited], [Last author], [International Magazine]
  English, Scientific journal
• Reversal of precedence for Lineidae McIntosh, 1874 over its senior synonyms Borlasiidae Diesing, 1862 and Nemertidae Ehrenberg, 1831 (Nemertea: Heteronemertea)
  Hiroshi Kajihara
  Species Diversity, 27, 1, 25, 35, Japanese Society of Systematic Zoology, 01 Jan. 2022, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• 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, Dec. 2021, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Two new species of the marine flatworm Pericelis (Platyhelminthes: Polycladida) from southwestern Japan with an amendment of the generic diagnosis based on phylogenetic inference
  Aoi Tsuyuki; Yuki Oya; Hiroshi Kajihara
  Marine Biology Research, 17, 9-10, 946, 959, Informa UK Limited, 26 Nov. 2021, [Peer-reviewed], [Last author]
  English, Scientific journal
• Description of a new species of Alloioplana (Polycladida: Stylochoplanidae) with an inference on its phylogenetic position in Leptoplanoidea
  Yuki Oya; Aoi Tsuyuki; Hiroshi Kajihara
  Proceedings of the Biological Society of Washington, 134, 1, The Biological Society of Washington, 02 Nov. 2021, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A histology-free description of Tetrastemma cupido sp. nov. (Nemertea: Eumonostilfera) from Sagami Bay, Japan
  Natsumi Hookabe; Hisanori Kohtsuka; Hiroshi Kajihara
  Marine Biology Research, 17, 5-6, 467, 474, 20 Oct. 2021, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Sinking down or floating up? Current state of taxonomic studies on marine invertebrates in Japan inferred from the number of new species published between the years 2003 and 2020
  Hiroaki Nakano; Naoto Jimi; Takenori Sasaki; Hiroshi Kajihara
  Zoological Science, 39, 1, 7, 15, Zoological Society of Japan, 06 Oct. 2021, [Peer-reviewed], [Invited], [Last author, Corresponding author], [International Magazine]
  English, Scientific journal
• A molecular phylogeny of Tetrastemma and its allies (Nemertea, Monostilifera)
  Alexei V. Chernyshev; Neonila E. Polyakova; Jon L. Norenburg; Hiroshi Kajihara
  Zoologica Scripta, 50, 6, 824, 836, Wiley, 02 Sep. 2021, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Case 3850 – Micruridae Dunn, 1931 (Reptilia, Serpentes) and Lineidae McIntosh, 1874 (Nemertea, Pilidiophora): proposed conservation by suppression of Micruridae Ehrenberg, 1831 (Nemertea, Pilidiophora)
  Hiroshi Kajihara; Eric N. Smith
  Bulletin of Zoological Nomenclature, 78, 2, 112, 130, Bulletin of Zoological Nomenclature, 30 Aug. 2021, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Species delimitation and phylogenetic analyses reveal cryptic diversity within Cerebratulus marginatus (Nemertea: Pilidiophora)
  Aida Verdes; María Belén Arias; Juan Junoy; Megan L. Schwartz; Hiroshi Kajihara
  Systematics and Biodiversity, 19, 7, 895, 905, Informa UK Limited, 26 Aug. 2021, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Morphological and molecular characterization of the marine-teleost parasitizing acanthocephalan Echinorhynchus hexagrammi (Syndermata: Palaeacanthocephala) from a new host, Liparis sp. (Actinopterygii: Scorpaeniformes)
  Yuki Kita; Hiroshi Kajihara
  Parasitology International, 85, 102430, 102430, Elsevier BV, 30 Jul. 2021, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• 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, Jul. 2021, [Peer-reviewed], [Invited], [Last author]
  English, In book
• Phylum Nemertea
  Hiroshi Kajihara
  Invertebrate Zoology: A Tree of Life Approach. Schierwater, B. & DeSalle, R. (Eds), CRC Press, Boca Raton, 644 pp., 357, 368, CRC Press, Jul. 2021, [Peer-reviewed], [Invited], [Lead author, Corresponding author]
  English, In book
• Eversion robotic mechanism with hydraulic skeleton to realize steering function
  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, Institute of Electrical and Electronics Engineers (IEEE), 15 Apr. 2021, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• 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, Apr. 2021, [Peer-reviewed], [Last author]
  English, Scientific journal
• Kulikovia alborostrata and Kulikovia fulva comb. nov. (Nemertea: Heteronemertea) are sister species with prezygotic isolating barriers.
  Jumpei Ikenaga; Hiroshi Kajihara; Manabu Yoshida
  Zoological Science, 38, 2, 193, 202, Zoological Society of Japan, Apr. 2021, [Peer-reviewed], [International Magazine]
  English, Scientific journal, 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.
• A new nemertean with a branched proboscis, Gorgonorhynchus citrinus sp. nov. (Nemertea: Pilidiophora), with molecular systematics of the genus
  Natsumi Hookabe; Cong-Mei Xu; Aoi Tsuyuki; Naoto Jimi; Shi-Chun Sun; Hiroshi Kajihara
  Invertebrate Systematics, 35, 350, 359, CSIRO Publishing, 24 Mar. 2021, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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
• Description and phylogenetic relationships of a new genus of Planoceridae (Polycladida, Acotylea) from Shimoda, Japan
  Yuki Oya; Hiroshi Kajihara
  Journal of the Marine Biological Association of the United Kingdom, 101, 1, 81, 88, Cambridge University Press (CUP), Feb. 2021, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, We 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.
• Higher classification of the Monostilifera (Nemertea: Hoplonemertea)
  Hiroshi Kajihara
  Zootaxa, 4920, 2, 151, 199, Magnolia Press, 28 Jan. 2021, [Peer-reviewed], [Lead author, Corresponding author]
  English, Scientific journal, 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.
• Alien worm in worm: a new genus of endoparasitic polychaete (Phyllodocidae, Annelida) from scale worms (Aphroditidae and Polynoidae, Annelida)
  Naoto Jimi; Taeko Kimura; Akito Ogawa; Hiroshi Kajihara
  Systematics and Biodiversity, 19, 1, 13, 21, 02 Jan. 2021, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Corrigendum to “Marine Macrodasyida (Gastrotricha) from Hokkaido, Northern Japan”
  Shohei Yamauchi; Hiroshi Kajihara
  Species Diversity, 24, 1, Japanese Society of Systematic Zoology, 2021
  English, Scientific journal
• Description of Pericelis flavomarginata sp. nov. (Polycladida: Cotylea) and its predatory behavior on a scaleworm
  Aoi Tsuyuki; Yuki Oya; Naoto Jimi; Hiroshi Kajihara
  Zootaxa, 4894, 3, 403, 412, Magnolia Press, 10 Dec. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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).
• A new bathyal tubulanid nemertean, Tubulanus izuensis sp. nov. (Nemertea: Palaeonemertea), from Japanese waters
  Natsumi Hookabe; Masashi Asai; Hiroaki Nakano; Taeko Kimura; Hiroshi Kajihara
  Proceedings of the Biological Society of Washington, 133, 1, The Biological Society of Washington, 30 Nov. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Taxonomic reappraisal of Lineus longifissus auct. (Nemertea: Pilidiophora) from Japan for the first time in 122 years
  Natsumi Hookabe; Hiroshi Kajihara
  Zoological Science, 37, 5, 467, 475, Zoological Society of Japan, Oct. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Euborlasia Vaillant, 1890 (Nemertea: Pilidiophora) from Bocas del Toro: description of a new species, with comments on the systematics of the genus
  Natsumi Hookabe; Hiroshi Kajihara
  Marine Biodiversity, 50, 5, Oct. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First report of Evelineus mcintoshii (Langerhans, 1880) (Heteronemertea, Lineidae) from the Mediterranean Sea
  Razy Hoffman; Hiroshi Kajihara
  Mediterranean Marine Science, National Documentation Centre (EKT), 30 Sep. 2020, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• A New Species of Zygantroides (Platyhelminthes: Polycladida) from Amakusa, Japan
  Yuki Oya; Aoi Tsuyuki; Hiroshi Kajihara
  Species Diversity, 25, 2, 189, 196, Japanese Society of Systematic Zoology, 18 Sep. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Meiobenthic polychaete Dinophilus sp. cf. gyrociliatus (Annelida: Dinophilidae) from Japan with SEM observation and DNA barcodes
  Naoto Jimi; Takuya Minokawa; Toru Miura; Hiroshi Kajihara
  Species Diversity, 25, 2, 213, 218, Japanese Society of Systematic Zoology, 18 Sep. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular identity of the Antarctic heteronemertean Parborlasia corrugata (Nemertea: Pilidiophora) from Lützow-Holm Bay
  Natsumi Hookabe; Kentaro Watanabe; Megumu Tsujimoto; Hiroshi Kajihara
  Polar Science, 25, 100535, Elsevier {BV}, Sep. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new species of bathyal nemertean, Proamphiporus kaimeiae sp. nov., off Tohoku, Japan, and molecular systematics of the genus (nemertea: Monostilifera)
  Natsumi Hookabe; Shinji Tsuchida; Yoshihiro Fujiwara; Hiroshi Kajihara
  Species Diversity, 25, 2, 183, 188, Aug. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Lacydoniidae (Annelida) off the coast of north-eastern Japan: a description of Lacydonia japonica sp. nov.
  Natsumi Hookabe; Naoto Jimi; Shinji Tsuchida; Yoshihiro Fujiwara; Hiroshi Kajihara
  Zoological Studies, 59, Jul. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Redescription of Cerebratulus marginatus auct. (Nemertea: Pilidiophora) from Hokkaido, Japan, as a new species
  Hiroshi Kajihara
  Zootaxa, 4819, 2, 295, 315, Jul. 2020, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• First record of Stylostomum ellipse (Dalyell, 1853) (Platyhelminthes, Polycladida) from the Pacific Ocean
  Aoi Tsuyuki; Yuki Oya; Hiroshi Kajihara
  Check List, 16, 3, 773, 779, Pensoft Publishers, 26 Jun. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular phylogenetic analysis of Acotylea (Platyhelminthes: Polycladida)
  Yuki Oya; Hiroshi Kajihara
  Zoological Science, 37, 3, 271, 279, Zoological Society of Japan, Jun. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• New record of the monostiliferous hoplonemertean Gurjanovella littoralis Uschakov, 1926 from Japan (Nemertea, Hoplonemertea, Monostilifera)
  Natsumi Hookabe; Hiroshi Kajihara
  Check List, 16, 2, 265, 269, 13 Mar. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A giant new species of Enchiridium (Polycladida, Prosthiostomidae) from southwestern Japan
  Aoi Tsuyuki; Hiroshi Kajihara
  ZooKeys, 2020, 918, 15, 28, 12 Mar. 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Record of the heteronemertean Cerebratulus signatus (Nemertea: Pilidiophora: Lineidae) from off Rishiri Island, Hokkaido
  Hiroshi Kajihara; Shinri Tomioka
  Rishiri Studies, 39, 19, 21, Mar. 2020, [Lead author, Corresponding author], [Domestic magazines]
  English, Research institution
• Occurrence of the freshwater heteronemertean Apatronemertes albimaculosa (Nemertea: Pilidiophora) in Taiwan
  Hiroshi Kajihara; Ayuta Kato; Takafumi Nakano; Yi-Te Lai
  Taiwania, 65, 1, 81, 85, College of Life Science, National Taiwan University & Biodiversity Association of Taiwan, 20 Jan. 2020, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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., 25740729
• Lamispina miurai sp. nov. (Annelida: Flabelligeridae) from off Aomori, Japan
  Yuki Higashida; Naoto Jimi; Hiroshi Kajihara
  Species Diversity, 25, 2, 329, 342, The Japanese Society of Systematic Zoology, 2020, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal,

  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.

• Three species of ribbon worms (Nemertea) from Cebu, the Philippines
  Hiroshi Kajihara
  Species Diversity, 25, 2, 251, 273, The Japanese Society of Systematic Zoology, 2020, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal,

  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.

• A morphological note on the pelagic polystiliferous hoplonemertean Protopelagonemertes beebei (Nemertea: Pelagica)
  Hiroshi Kajihara; Atsushi Yamaguchi
  Plankton and Benthos Research, 15, 4, 337, 341, The Plankton Society of Japan, The Japanese Association of Benthology, 2020, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal,

  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.

• Description and phylogenetic relationships of a new genus of sea cucumbers from Australia, with two new combinations (Holothuroidea, Stichopodidae) (10.1007/s12526-019-00974-8, 2019)
  Woo Sau Pinn; Kajihara Hiroshi; Byrne Maria; Fujita Toshihiko
  MARINE BIODIVERSITY, 49, 6, 2519, Dec. 2019, [Peer-reviewed]
• Description and phylogenetic relationships of a new genus of sea cucumbers from Australia, with two new combinations (Holothuroidea, Stichopodidae)
  Sau Pinn Woo; Hiroshi Kajihara; Maria Byrne; Toshihiko Fujita
  Marine Biodiversity, 49, 6, 2499, 2518, Dec. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species of Polyodontes (Annelida: Acoetidae) from Japan
  Naoto Jimi; Shinri Tomioka; Ryo Orita; Hiroshi Kajihara
  Species Diversity, 24, 275, 279, Nov. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular systematics of the heteronemertean genus Dushia (Nemertea, Pilidiophora), with descriptions of D. wijnhoffae sp. nov. and D. nigra species complex comb. nov.
  Natsumi Hookabe; Megan L. Schwartz; Hiroshi Kajihara; Jon L. Norenburg
  Zootaxa, 4691, 4, zootaxa.4691.4.2, 358, Magnolia Press, Nov. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• A population without females: males of Baseodiscus delineatus (Nemertea: Heteronemertea) reproduce asexually by fragmentation
  Jumpei Ikenaga; Natsumi Hookabe; Hisanori Kohtsuka; Manabu Yoshida; Hiroshi Kajihara
  Zoological Science, 36, 4, 348, 353, Aug. 2019, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
  English, Scientific journal
• Description of a new species of Paraplehnia (Polycladida, Stylochoidea) from Japan, with inference on the phylogenetic position of Plehniidae
  Yuki Oya; Taeko Kimura; Hiroshi Kajihara
  ZooKeys, 864, 1, 13, Jul. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular systematics and morphological analyses of the subgenus Setihenricia (Echinodermata: Asteroidea: Henricia) from Japan
  Daiki Wakita; Toshihiko Fujita; Hiroshi Kajihara
  Species Diversity, 24, 2, 119, 135, 日本動物分類学会, Jul. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, <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>
• A redescription of Syncarpa composita (Ascidiacea, Stolidobranchia) with an inference of its phylogenetic position within Styelidae
  Naohiro Hasegawa; Hiroshi Kajihara
  ZooKeys, 857, 857, 1, 15, 24 Jun. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Morphological and molecular study on Yininemertes pratensis (Nemertea, Pilidiophora, Heteronemertea) from the Han River Estuary, South Korea, and its phylogenetic position within the family Lineidae
  Park Taesco; Lee Sang-Hwa; Sun Shi-Chun; Kajihara Hiroshi
  ZooKeys, 852, 31, 51, 05 Jun. 2019, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Diurodrilus kunii sp. nov. (Annelida: Diurodrilidae) and a molecular phylogeny of the genus
  Hiroshi Kajihara; Maho Ikoma; Hiroshi Yamasaki; Shimpei F. Hiruta
  Zoological Science, 36, 3, 250, 258, Jun. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Resolving a 200-year-old taxonomic conundrum: neotype designation for Cephalothrix linearis (Nemertea: Palaeonemertea) based on a topotype from Bergen, Norway
  Hiroshi Kajihara
  Fauna Norvegica, 39, 39, 76, Jun. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal, 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.
• New record of the hydrothermal vent-endemic polychaete Archinome jasoni Borda et al., 2013 (Annelida, Amphinomidae) from the Northwest Pacific
  Naoto Jimi; Chong Chen; Kajihara Hiroshi
  Check List, 15, 3, 523, 526, Jun. 2019, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• Comparative muscular morphology in Archinemertea (Nemertea: Palaeonemertea)
  Alexei V. Chernyshev; Hiroshi Kajihara
  Zoomorphology, 138, 2, 193, 207, Jun. 2019, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new bathyal species of Cestoplana (Polycladida: Cotylea) from the West Pacific Ocean
  Yuki Oya; Hiroshi Kajihara
  Marine Biodiversity, 49, 2, 905, 911, Apr. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Anterior regeneration in Baseodiscus hemprichii (Nemertea: Heteronemertea)
  Hiroshi Kajihara; Natsumi Hookabe
  Tropical Natural History, 19, 1, 39, 42, Apr. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal, 25740729
• Gorgonorhynchus albocinctus (Nemertea: Heteronemertea) from Sotobanari, Yaeyama Islands, Japan.
  Hiroshi Kajihara; Ryuta Yoshida; Tohru Naruse
  Fauna Ryukyuana, 48, 45, 47, Mar. 2019, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  English, Scientific journal
• Morphological and molecular diversity of rissoellids (Mollusca, Gastropoda, Heterobranchia) from the Northwest Pacific island of Hokkaido, Japan
  Luis E. Chira Siaden; Kevin C. Wakeman; Stephen C. Webb; Kazunori Hasegawa; Hiroshi Kajihara
  Zootaxa, 4551, 4, 415, 431, 04 Feb. 2019, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Polychaete meets octopus: symbiotic relationship between Spathochaeta octopodis gen. et sp. nov. (Annelida: Chrysopetalidae) and Octopus sp. (Mollusca: Octopodidae)
  Naoto Jimi; Takeya Moritaki; Hiroshi Kajihara
  Systematics and Biodiversity, 17, 1, 80, 85, 02 Jan. 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Nemertea proboscis inspired extendable mechanism.
  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, IEEE, 2019, [Peer-reviewed]
  International conference proceedings
• A new species of Prosthiostomum (Platyhelminthes: Polycladida) from Shirahama, Japan
  Aoi Tsuyuki; Yuki Oya; Hiroshi Kajihara
  Species Diversity, 24, 2, 137, 143, The Japanese Society of Systematic Zoology, 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal,

  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.

• First record of the interstitial annelid Pharyngocirrus uchidai (Annelida: Saccocirridae) from Korea, confirmed by topotypic DNA barcoding data from Japan
  Jiseon Park; Hiroshi Kajihara; Jongwoo Jung
  Animal Systematics, Evolution and Diversity, 35, 1, 33, 36, Jan. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species of Phaenoplana (Platyhelminthes: Polycladida) from the Ogasawara Islands
  Yuki Oya; Hiroshi Kajihara
  Species Diversity, 24, 1, 1, 6, The Japanese Society of Systematic Zoology, 2019, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal,

  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.

• Nemertean taxonomy—implementing changes in the higher ranks, dismissing Anopla and Enopla
  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, Jan. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Marine Macrodasyida (Gastrotricha) from Hokkaido, northern Japan
  Shohei Yamauchi; Hiroshi Kajihara
  Species Diversity, 23, 2, 183, 192, Nov. 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Interstitial hoplonemertean Ototyphlonemertes norenburgi (Nemertea: Monostilifera) from Okinawa, Japan
  Hiroshi Kajihara; Kotaro Tamura; Hiroshi Yamasaki
  Fauna Ryukyuana, 46, 1, 3, Oct. 2018, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  English, Scientific journal
• Molecular phylogeny of the family Capitellidae (Annelida)
  Shinri Tomioka; Keiichi Kakui; Hiroshi Kajihara
  Zoological Science, 35, 5, 436, 445, Oct. 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A nomenclatural and taxonomic note on Micrella Punnett, 1901 (Nemertea: Heteronemertea)
  Hiroshi Kajihara
  Zootaxa, 4450, 2, 291, 292, 24 Jul. 2018, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• New annelid species from the deepest known whale-fall environment: Bathykermadeca thanatos sp. nov. (Annelida: Polynoidae).
  Naoto Jimi; Yoshihiro Fujiwara; Hiroshi Kajihara
  Zootaxa, 4450, 5, 575, 580, Jul. 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• Polychaetes collected from floats of oyster-farming rafts in Kure, the Seto Inland Sea, Japan, with notes on the pest species Polydora hoplura (Annelida: Spionidae)
  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, 31 Mar. 2018, [Peer-reviewed], [Last author], [Domestic magazines]
  English, Research institution
• Taxonomy and phylogeny of Lineus torquatus and allies (Nemertea, Lineidae) with descriptions of a new genus and a new cryptic species
  Alexei V. Chernyshev; Neonila E. Polyakova; Sergei V. Turanov; Hiroshi Kajihara
  Systematics and Biodiversity, 16, 1, 55, 68, 02 Jan. 2018, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species, Lamispina ammophila sp. nov. (Annelida: Flabelligeridae), from Shimoda, Japan
  Naoto Jimi; Hiroshi Kajihara
  Species Diversity, 23, 1, 39, 42, The Japanese Society of Systematic Zoology, 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new species of the rare, deep-sea polychaete genus Benthoscolex from the Sea of Kumano, Japan (Annelida, Amphinomidae)
  Naoto Jimi; Taeko Kimura; Akito Ogawa; Hiroshi Kajihara
  ZooKeys, 2018, 738, 81, 88, Pensoft Publishers, 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Histology-free descriptions for seven species of interstitial ribbon worms in the genus Ototyphlonemertes (nemertea: Monostilifera) from Vietnam
  Hiroshi Kajihara; Kotaro Tamura; Shinri Tomioka
  Species Diversity, 23, 1, 13, 37, Japanese Society of Systematic Zoology, 2018, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• A new genus and five new species of Kalyptorhynchia (Platyhelminthes: Rhabdocoela) discovered in northern Japan
  Naoya Takeda; Hiroshi Kajihara
  Species Diversity, 23, 1, 1, 11, Japanese Society of Systematic Zoology, 2018, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Leocratides (Annelida: Hesionidae) from the Pacific coast of Middle Honshu, Japan, with a description of Leocratides kimuraorum sp. nov.
  Naoto Jimi; Masaatsu Tanaka; Hiroshi Kajihara
  Species Diversity, 22, 2, 133, 141, Japanese Society of Systematic Zoology, 01 Dec. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Description of Mastobranchus uru sp. nov. (Annelida: Capitellidae) from Iriomote Island, Japan
  Shinri Tomioka; Ryuta Yoshida; Hiroshi Kajihara
  Species Diversity, 22, 2, 127, 132, Japanese Society of Systematic Zoology, 01 Dec. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Rare endoparasitic Asteriomyzostomum (Annelida: Asteriomyzostomidae) from Japan, including three new species descriptions and their phylogenetic position within Myzostomida
  Naoto Jimi; Takeya Moritaki; Hiroshi Kajihara
  Parasitology International, 66, 6, 841, 847, Dec. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First report of the genus Graphis (Gastropoda: Tofanellidae) in the eastern South Pacific, with a description of a new species
  Luis E. Chira Siaden; Jorge Chaname Cespedes; Hiroshi Kajihara
  American Malacological Bulletin, 35, 2, 163, 169, Nov. 2017, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A taxonomic revision of the genus Apostichopus (Holothuroidea: Stichopodidae) from Japan
  Sau Pinn Woo; Akito Ogawa; Shau Hwai Tan; Zulfigar Yasin; Hiroshi Kajihara; Toshihiko Fujita
  Zootaxa, 4350, 1, 121, 135, Nov. 2017, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Remarkable biodiversity of flabelligerids in Japan: seven new species of Diplocirrus (Annelida: Flabelligeridae) from Japanese waters
  Naoto Jimi; Yoshihiro Fujiwara; Hiroshi Kajihara
  Zootaxa, 4337, 3, 344, 360, Oct. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A matter of persistence: differential Late Pleistocene survival of two rocky-shore idoteid isopod species in northern Japan
  Shimpei F. Hiruta; Maho Ikoma; Toru Katoh; Hiroshi Kajihara; Matthew H. Dick
  Hydrobiologia, 799, 1, 151, 179, Sep. 2017, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Description of a new Notocomplana species (Platyhelminthes: Acotylea), new combination and new records of Polycladida from the northeastern Sea of Japan, with a comparison of two different barcoding markers
  Yuki Oya; Hiroshi Kajihara
  Zootaxa, 4282, 3, 526, 542, Jun. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Species diversity of Japanese ribbon worms (Nemertea)
  Hiroshi Kajihara
  Species Diversity of Animals in Japan, 419, 444, Springer Japan, 2017, [Peer-reviewed], [Invited], [Lead author, Corresponding author], [International Magazine]
  English, In book
• An overview of recent marine biodiversity research in Japan
  Hiroshi Kajihara; Keiichi Kakui
  Species Diversity of Animals in Japan, 25, 45, Springer Japan, 2017, [Peer-reviewed], [Invited], [Lead author, Corresponding author]
  English, In book
• First record of Holothuria (Cystipus) dura (Echinodermata: Holothuroidea) from Japan, with notes on locomotion
  Sau Pinn Woo; Hiroshi Kajihara; Nozomu Iwasaki; Toshihiko Fujita
  Species Diversity, 22, 1, 45, 52, Japanese Society of Systematic Zoology, 2017, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Designation of a neotype and redescription of Hesione reticulata von Marenzeller, 1879 from Japan (Annelida, Hesionidae)
  Naoto Jimi; Sergio I. Salazar-Vallejo; Hiroshi Kajihara
  ZooKeys, 657, 657, 29, 41, 2017, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A new species and the shallowest record of Flabegraviera Salazar-Vallejo, 2012 (Annelida: Flabelligeridae) from Antarctica
  Naoto Jimi; Megumu Tsujimoto; Kentaro Watanabe; Keiichi Kakui; Hiroshi Kajihara
  Zootaxa, 4221, 4, 477, 485, Jan. 2017, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• The future of nemertean taxonomy (phylum Nemertea)—a proposal
  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, Nov. 2016, [Peer-reviewed]
  English, Scientific journal
• Changing spots: pseudocryptic speciation in the North Pacific dorid nudibranch Diaulula sandiegensiso (Cooper, 1863) (Gastropoda: Heterobranchia)
  Tabitha Lindsay; Julie Kelly; Anton Chichvarkhin; Sean Craig; Hiroshi Kajihara; Joshua Mackie; Angel Valdes
  Journal of Molluscan Studies, 82, 4, 564, 574, Nov. 2016, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Cosmopolitan or cryptic species? A case study of Capitella teleta (Annelida: Capitellidae)
  Shinri Tomioka; Tomohiko Kondoh; Waka Sato-Okoshi; Katsutoshi Ito; Keiichi Kakui; Hiroshi Kajihara
  Zoological Science, 33, 5, 545, 554, Oct. 2016, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Molecular phylogeny of cypridoid freshwater ostracods (Crustacea: Ostracoda), inferred from 18S and 28S rDNA sequences
  Shimpei F. Hiruta; Norio Kobayashi; Toru Katoh; Hiroshi Kajihara
  Zoological Science, 33, 2, 179, 185, Apr. 2016, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A molecular phylogenetic study of pheretimoid species (Megascolecidae) in Mindanao and associated islands, Philippines
  Nonillon M. Aspe; Hiroshi Kajihara; Samuel W. James
  European Journal of Soil Biology, 73, 119, 125, Mar. 2016, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Occurrence and molecular barcode of the freshwater heteronemertean Apatronemertes albimaculosa (Nemertea: Pilidiophora) from Japan
  Hiroshi Kajihara; Mariko Takibata; Mark J. Grygier
  Species Diversity, 21, 2, 105, 110, Japanese Society of Systematic Zoology, 2016, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Records of Notospermus tricuspidatus (Quoy & Gaimard, 1833) (Nemertea: Pilidiophora) in Japanese waters, with a review of warm-water green-bodied heteronemerteans from the Indo–West-Pacific
  Hiroshi Kajihara; Ira Hosokawa; Koji Hosokawa; Ryuta Yoshida
  Fauna Ryukyuana, 28, 59, 65, 2016, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs
  Eijiroh Nishi; Kanako Matsuo; Maria Capa; Shinri Tomioka; Hiroshi Kajihara; Elena K. Kupriyanova; Gianluca Polgar
  Zootaxa, 4052, 5, 555, 568, 07 Dec. 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• DNA taxonomy of Paranemertes (Nemertea: Hoplonemertea) with spirally fluted stylets
  Yue Hao; Hiroshi Kajihara; Alexei V. Chernyshev; Robert K. Okazaki; Shi-Chun Sun
  Zoological Science, 32, 6, 571, 578, Dec. 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Tubulanus tamias sp. nov. (Nemertea: Palaeonemertea) with two different types of epidermal eyes
  Hiroshi Kajihara; Keiichi Kakui; Hiroshi Yamasaki; Shimpei F. Hiruta
  Zoological Science, 32, 6, 596, 604, Dec. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Special Issue: Proceedings of the 8th International Conference on Nemertean Biology
  Shi-Chun Sun; Hiroshi Kajihara; Alexei V. Chernyshev
  Zoological Science, 32, 6, 499, 500, Dec. 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• JAMBIO Coastal Organism Joint Surveys reveals undiscovered biodiversity around Sagami Bay
  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, Nov. 2015, [International Magazine]
  English, Scientific journal
• A histology-free description of the branched-proboscis ribbonworm Gorgonorhynchus albocinctus sp. nov. (Nemertea: Heteronemertea)
  Hiroshi Kajihara
  Publications of the Seto Marine Biological Laboratory, 43, 92, 102, Sep. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Trilobodrilus itoi sp. nov., with a re-description of T. nipponicus (Annelida: Dinophilidae) and a molecular phylogeny of the genus
  Hiroshi Kajihara; Maho Ikoma; Hiroshi Yamasaki; Shimpei F. Hiruta
  Zoological Science, 32, 4, 405, 417, Aug. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Records of the poorly known ribbon worm Nipponnemertes ogumai (Nemertea: Monostilifera) and its phylogenetic position
  Hiroshi Kajihara; Eijiroh Nishi; Michiyo Kawabata; Hisanori Kohtsuka; Daisuke Uyeno
  Marine Biodiversity, 45, 2, 175, 182, Jun. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Phylogenetic position of the queer, backward-bent entoproct Loxosoma axisadversum (Entoprocta: Solitaria: Loxosomatidae).
  Hiroshi Kajihara; Shinri Tomioka; Keiichi Kakui; Tohru Iseto
  Species Diversity, 20, 1, 83, 88, Japanese Society of Systematic Zoology, 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal, 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.
• Sonnenemertes cantelli gen. et sp. nov. (Heteronemertea)—a new Oxypolella-like nemertean from the abyssal plain adjacent to the Kuril–Kamchatka Trench
  Alexei V. Chernyshev; Shushi Abukawa; Hiroshi Kajihara
  Deep-Sea Research II, 111, 119, 127, Jan. 2015, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• DNA barcoding supports identification of Malacobdella species (Nemertea: Hoplonemertea)
  Jose E. F. Alfaya; Gregorio Bigatti; Hiroshi Kajihara; Malin Strand; Per Sundberg; Annie Machordom
  Zoological Studies, 54, 10, Jan. 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Sea cucumbers of the genus Stichopus Brandt, 1835 (Holothuroidea, Stichopodidae) in Straits of Malacca with description of a new species
  Sau Pinn Woo; Zulfigar Yasin; Shau Hwai Tan; Hiroshi Kajihara; Toshihiko Fujita
  ZooKeys, 545, 1, 26, 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Northernmost records of Antedon serrata A. H. Clark from Hokkaido
  幸塚 久典; 角井 敬知; 柁原 宏
  日本生物地理学会会報, 69, 185, 188, 日本生物地理学会, 20 Dec. 2014, [Last author], [Domestic magazines]
  Japanese, Scientific journal
• Partial revision of Japanese pectinariidae (Annelida: Polychaeta), including redescriptions of poorly known species
  Eijiroh Nishi; Kanako Matsuo; Maki Kazama-Wakabayashi; Atsushi Mori; Shinri Tomioka; Hiroshi Kajihara; Masami Hamaguchi; Naoto Kajihara; Pat Hutchings
  Zootaxa, 3895, 3, 433, 445, 16 Dec. 2014, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A transcriptomic approach to ribbon worm systematics (Nemertea): resolving the Pilidiophora problem
  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, Dec. 2014, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Two kinorhynch species (Cyclorhagida, Echinoderidae, Echinoderes) show different distribution patterns across Tsugaru Strait, northern Japan
  Hiroshi Yamasaki; Shimpei F. Hiruta; Hiroshi Kajihara; Matthew H. Dick
  Zoological Science, 31, 7, 421, 429, Jul. 2014, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• 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, Mar. 2014, [Last author], [Domestic magazines]
  Japanese, Research institution
• Description and molecular phylogeny of a new species of Phoronis (Phoronida) from Japan, with a redescription of topotypes of P. ijimai Oka, 1897
  Masato Hirose; Ryuma Fukiage; Toru Katoh; Hiroshi Kajihara
  ZooKeys, 398, 398, 1, 31, 2014, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• An objective junior synonym of a ribbon-worm genus name (Nemertea: Heteronemertea)
  Hiroshi Kajihara
  Munis Entomology and Zoology, 9, 1, 588, 588, 2014, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Two new species of free-living marine nematodes of Adoncholaimus Filipjev, 1918 (Oncholaimida: Oncholaimidae: Adoncholaiminae) from Hokkaido, northern Japan, with a key to species and discussion of the genus
  Daisuke Shimada; Hiroshi Kajihara
  Nematology, 16, 4, 437, 451, 2014, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Two new species of Mediomastus (Annelida, Capitellidae) from Tokyo Bay, Japan
  Shinri Tomioka; Eijiroh Nishi; Hiroshi Kajihara
  ZooKeys, 422, 115, 126, 2014, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Taxonomic identity of a tetrodotoxin-accumulating ribbon-worm Cephalothrix simula (Nemertea: Palaeonemertea): a species artificially introduced from the pacific to Europe
  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, 11, Nov. 2013, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Description of Mediomastus opertaculeus sp. nov. (Annelida: Capitellidae) from Hokkaido, northern Japan.
  Shinri Tomioka; Shimpei F. Hiruta; Hiroshi Kajihara
  Species Diversity, 18, 1, 105, 110, Japanese Society of Systematic Zoology, May 2013, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal, 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.
• Molecular phylogeny of kinorhynchs
  Hiroshi Yamasaki; Shimpei F. Hiruta; Hiroshi Kajihara
  Molecular Phylogenetics and Evolution, 67, 2, 303, 310, May 2013, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Highly toxic ribbon worm Cephalothrix simula containing tetrodotoxin in Hiroshima Bay, Hiroshima Prefecture, Japan
  Manabu Asakawa; Katsutoshi Ito; Hiroshi Kajihara
  Toxins, 5, 2, 376, 395, Feb. 2013, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First record of Euborlasia nigrocincta Coe, 1940 (Nemertea: Heteronemertea) from the western Pacific
  Hiroshi Kajihara; Eijiroh Nishi
  Check List, 9, 4, 826, 828, Centro de Referencia em Informacao Ambiental, 2013, [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Ovicides paralithodis (Nemertea, Carcinonemertidae), a new species of symbiotic egg predator of the red king crab Paralithodes camtschaticus (Tilesius, 1815) (Decapoda, Anomura)
  Hiroshi Kajihara; Armand M. Kuris
  ZooKeys, 258, 258, 1, 15, 258, 2013, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Northward range extension of Baseodiscus hemprichii (Nemertea: Heteronemertea)—due to rising sea-surface temperatures?
  Luna Yamamori; Mamiko Hirose; Hiroshi Kajihara
  Marine Biodiversity Records, 6, Cambridge University Press, 2013, [Last author, Corresponding author], [International Magazine]
  English, Scientific journal
• First report of kinorhynchs from Hokkaido, Japan, including a new species of Pycnophyes (Pycnophyidae: Homalorhagida)
  Hiroshi Yamasaki; Hiroshi Kajihara; Shunsuke F. Mawatari
  Zootaxa, 3425, 3425, 23, 41, Aug. 2012, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Disentangling ribbon worm relationships: multi-locus analysis supports traditional classification of the phylum Nemertea
  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, Apr. 2012, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Phylogenetic position of Arctotanais in the suborder Tanaidomorpha (Peracarida: Tanaidacea)
  Keiichi Kakui; Norio Kobayashi; Hiroshi Kajihara
  Journal of Crustacean Biology, 32, 1, 127, 139, Feb. 2012, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new brackish-water species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Seto Inland Sea, Japan.
  Hiroshi Yamasaki; Hiroshi Kajihara
  Species Diversity, 17, 109, 118, 2012, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new species of deep-sea nematode, Micoletzkyia mawatarii sp. nov. (Nematoda: Enoplida: Phanodermatidae) from northern Japan.
  Daisuke Shimada; Keiichi Kakui; Hiroshi Kajihara
  Species Diversity, 17, 2, 221, 226, 2012, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• First record of Baseodiscus mexicanus (Bürger, 1893) (Nemertea: Heteronemertea) from Japanese waters.
  Hiroshi Kajihara; Ryuta Yoshida; Daisuke Uyeno
  Check List, 8, 4, 754, 755, 2012, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Redescription of Scoliorhapis lindbergi comb. nov. (Echinodermata: Holothuroidea: Apodida: Chiridotidae), with special reference to the ultrastructure of sigmoid bodies.
  Junko Inoue; Hiroshi Kajihara
  Species Diversity, 17, 1, 15, 20, 2012, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A new species of Hedgpethia (Arthropoda, Pycnogonida, Colossendeidae) from southwestern Japan
  Yoshie Takahashi; Hiroshi Kajihara; Shunsuke F. Mawatari
  ZooKeys, 175, 69, 74, 2012, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Three species of Amphicorina (Annelida, Sabellida, Sabellidae) from Japan, with descriptions of two new species
  Taiki Yoshihara; Shimpei F. Hiruta; Toru Katoh; Hiroshi Kajihara
  ZooKeys, 187, 45, 62, 2012, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Sea spiders of the genus Nymphon (Arthropoda: Pycnogonida) from waters around the Nansei Islands, Japan.
  Yoshie Takahashi; Hiroshi Kajihara; Shunsuke F. Mawatari
  JOURNAL OF NATURAL HISTORY, 46, 21-22, 1337, 1358, 2012, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Molecular systematics of Tanaidacea (Crustacea: Peracarida) based on 18S sequence data, with an amendment of suborder/superfamily-level classification
  Keiichi Kakui; Toru Katoh; Shimpei F. Hiruta; Norio Kobayashi; Hiroshi Kajihara
  Zoological Science, 28, 10, 749, 757, Oct. 2011, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Systematics and phylogeny of the hoplonemertean genus Diplomma (Nemertea) based on molecular and morphological evidence
  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, Apr. 2011, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• First record of the poorly known pelagic nemertean Protopelagonemertes beebei (Nemertea: Hoplonemertea: Polystilifera: Pelagica) from Japanese waters, with discussion of the species identity
  Hiroshi Kajihara; Toru Katoh; Dhugal J. Lindsay
  Marine Biodiversity Records, 4, e13, Apr. 2011, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Pseudosphyrapus cuspidiger sp. nov. from the Nansei Islands, Japan, with a supplementary description of Kudinopasternakia balanorostrata Kakui, Kajihara and Mawatari, 2007 (Crustacea: Tanaidacea: Apseudomorpha: Sphyrapodidae).
  Keiichi Kakui; Hiroshi Kajihara
  Bulletin of the National Museum of Nature and Science, Series A, Supplement 5, 53, 70, National Museum of Nature and Science, 2011, [Peer-reviewed], [Last author], [International Magazine]
  English, Research institution
• Carinoma hamanako sp. nov. (Nemertea: Palaeonemertea), the first representative of the genus from the Northwest Pacific
  Hiroshi Kajihara; Hiroshi Yamasaki; Sónia C; S. Andrade
  Species Diversity, 16, 3, 149, 165, Japanese Society of Systematic Zoology, 2011, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, 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.
• First record of Phoronis psammophila Cori, 1889 (Phoronida) from Japan.
  Masato Hirose; Ryuma Fukiage; Hiroshi Kajihara
  Biogeography, 13, 105, 110, Biogeographical Society of Japan, 2011, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Comments on the nomenclatural status of two subgeneric names for marine gastrotrichs (Gastrotricha: Xenotrichulidae)
  Shushi Abukawa; Hiroshi Kajihara
  Zootaxa, 2732, 2732, 68, 68, Jan. 2011, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• Statistical parsimony networks and species assemblages in cephalotrichid nemerteans (Nemertea)
  Haixia Chen; Malin Strand; Jon L. Norenburg; Shichun Sun; Hiroshi Kajihara; Alexey V. Chernyshev; Svetlana A. Maslakova; Per Sundberg
  PLOS ONE, 5, 9, e12885, Sep. 2010, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Dinonemertes shinkaii sp nov., (Nemertea: Hoplonemertea: Polystilifera: Pelagica) a new species of bathypelagic nemertean
  Hiroshi Kajihara; Dhugal J. Lindsay
  Zootaxa, 2429, 2429, 43, 51, Apr. 2010, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Rhynchocoel vessel in Cephalotrichidae (Nemertea: Palaeonemertea)
  Hiroshi Kajihara
  Journal of Natural History, 44, 37-40, 2321, 2329, 2010, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• A new species of Nesotanais Shiino, 1968 (Crustacea, Tanaidacea) from Japan, with a key to species and a note on male chelipeds
  Keiichi Kakui; Hiroshi Kajihara; Shunsuke F. Mawatari
  ZooKeys, 33, 33, 1, 17, 2010, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Character-matrix based descriptions of two new nemertean (Nemertea) species
  Per Sundberg; Alexey V. Chernyshev; Hiroshi Kajihara; Tobias Kanneby; Malin Strand
  Zoological Journal of the Linnean Society, 157, 2, 264, 294, Oct. 2009, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Baseodiscus hemprichii (phylum Nemertea) from Phuket, Thailand
  Hiroshi Kajihara; Tetsuya Kato
  Phuket Marine Biological Center Research Bulletin, 69, 1–5, 2009, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Research institution
• Three new species of free-living marine nematodes (Nematoda: Enoplida) from northern Japan
  Daisuke Shimada; Hiroshi Kajihara; Shunsuke F. Mawatari
  Species Diversity, 14, 137–150, 2009, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Checklist of nemertean genera and species published between 1995 and 2007.
  Hiroshi Kajihara; Alexei V. Chernyshev; Shi-Chun Sun; Per Sundberg; Frank B. Crandall
  Species Diversity, 13, 245–274, 2008, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Morphology of Lineopselloides albilineus (Nemertea: Heteronemertea: Lineidae) from Japanese waters, with complementary redescription of the holotype.
  Hiroshi Kajihara; Yuji Ise
  Bulletin of the Kitakyushu Museum of Natural History and Human History, Series A (Natural History), 6, 1–12, 2008, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  English, Research institution
• Two species of Nemertopsis (Nemertea: Hoplonemertea: Monostilifera) living in association with Capitulum mitella (Crustacea: Cirripedia: Thoracica: Lepadomorpha)
  Hiroshi Kajihara
  Zootaxa, 1146, 1446, 43, 58, Apr. 2007, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Callinera emiliae sp. nov. (Nemertea : Palaeonemertea) from Negros Island, the Philippines
  Hiroshi Kajihara
  Zootaxa, 1454, 1454, 39, 47, Apr. 2007, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• A taxonomic catalogue of Japanese nemerteans (Phylum Nemertea)
  Hiroshi Kajihara
  Zoological Science, 24, 4, 287, 326, Apr. 2007, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• 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, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
  English, Research institution
• Two new sphyrapodid species (Crustacea : Tanaidacea : Apseudomorpha) from southwestern Japan
  Keiichi Kakui; Hiroshi Kajihara; Shunsuke F. Mawatari
  Zootaxa, 1563, 1563, 37, 54, 2007, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Ototyphlonemertes dolichobasis sp. nov. (Nemertea: Hoplonemertea: Monostilifera: Ototyphlonemertidae), a new species of interstitial nemertean from Japan.
  Hiroshi Kajihara
  Species Diversity, 12, 57, 66, 2007, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Four palaeonemerteans (Nemertea: Anopla) from a tidal flat in middle Honshu, Japan
  Hiroshi Kajihara
  Zootaxa, 1163, 1, 1, 1, 30 Mar. 2006, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• Hygrobates (Hygrobates) capillus sp. nov. (Arachnida: Acari: Hydrachnidia: Hygrabatidae) from south-central Honshu, Japan, with records of two allied species
  Noriko Matsumoto; Hiroshi Kajihara; Shunsuke F. Mawatari
  Species Diversity, 10, 1, 27–36, 36, Japanese Society of Systematic Zoology, 2005, [Peer-reviewed], [International Magazine]
  English, Scientific journal, 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.
• Usamaro Takakura (1867–1944), Japanese pioneer nemertean researcher
  Hiroshi Kajihara
  Archives of Natural History, 31, 2, 208, 213, Oct. 2004, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Immunoenzymatic visualization of tetrodotoxin (TTX) in Cephalothrix species (Nernertea: Anopla: Palaeonemertea: Cephalotrichidae) and Planocera reticulata (Platyhelminthes: Turbellaria: Polycladida: Planoceridae)
  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, Oct. 2004, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Paralytic toxicity in the ribbon worm Cephalothrix species (Nemertea) in Hiroshima Bay, Hiroshima Prefecture, Japan and the isolation of tetrodotoxin as a main component of its toxins
  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, Jun. 2003, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Potamostoma shizunaiense gen. et sp nov (Nemertea: Hoplonemertea: Monostilifera): a new brackish-water nemertean from Japan
  Hiroshi Kajihara; Ray Gibson; Shunsuke F. Mawatari
  Zoological Science, 20, 4, 491, 500, Apr. 2003, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• 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, [Lead author, Corresponding author], [Domestic magazines]
  English, Research institution
• New taxa of Japanese and New Zealand eurystomellidae (Phylum Bryozoa) and their phylogenetic relationships
  Dennis P. Gordon; Shunsuke F. Mawatari; Hiroshi Kajihara
  Zoological Journal of the Linnean Society, 136, 2, 199, 216, Oct. 2002, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Two new species of Zygonemertes (Nemertea: Enopla: Monostilifera) from Hokkaido, Japan
  Hiroshi Kajihara
  Species Diversity, 7, 2, 121, 143, 2002, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• A new genus and species of monostiliferous hoplonemertean (Nemertea: Enopla: Monostilifera) from Japan
  Hiroshi Kajihara; Ray Gibson; Shunsuke F. Mawatari
  Hydrobiologia, 456, 1/3, 187, 198, 15 Jul. 2001, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• The status of four Japanese nemertean species of Yamaoka
  Frank B. Crandall; Hiroshi Kajihara; Shunsuke F. Mawatari; Fumio Iwata
  Hydrobiologia, 456, 1-3, 175, 185, Jul. 2001, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Records of some marine invertebrates (nemerteans, asellotes and phyllodocids) from the coast around Otsuchi Bay.
  Michitaka Shimomura; Tetsuya Kato; Hiroshi Kajihara
  Otsuchi Marine Science, 26, 46, 50, The University of Tokyo, 2001, [Peer-reviewed], [Last author], [Domestic magazines]
  English, Research institution
• Redescription and taxonomic reassessment of Nemertellina minuta Friedrich, 1935, sensu Yamaoka, 1940 (Nemertea, Hoplonemertea, Monostilifera)
  Hiroshi Kajihara; Ray Gibson; Shunsuke F. Mawatari
  Zoological Science, 17, 2, 265, 276, 2000, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal

• 会長就任にあたって
  柁原宏, タクサ：日本動物分類学会誌, 60, 1, 2, 31 Mar. 2026, [Invited], [Lead author, Corresponding author], [Domestic magazines]
  Japanese, Introduction other
• Dr. Daisuke Shimada (1984–2024) in memoriam
  柁原 宏, Taxa, Proceedings of the Japanese Society of Systematic Zoology, 58, 1, 5, 28 Feb. 2025
  Dr. Daisuke Shimada (1984–2024), a distinguished Japanese taxonomist with expertise in marine free-living nematodes, passed away unexpectedly on 19 November 2024 at the age of 40 due to an unidentified cause. His passing constitutes an irreplaceable loss to Japan’s zoological academia as well as the international nematological community., The Japanese Society of Systematic Zoology, Japanese
• 日本近海のEchinorhynchus属鉤頭虫の分子系統解析に基づく,Echinorhynchus属の分類学的課題
  北悠樹; 柁原宏, 日本寄生虫学会大会プログラム・抄録集, 93rd, 2024
• Raymond Gibson (1938–2023): in memoriam
  ALEXEI V. CHERNYSHEV; JOSÉ E. FERNÁNDEZ ALFAYA; NURIA ANADÓN; SÓNIA C. S. ANDRADE; THOMAS BARTOLOMAEUS; JÖRN VON DÖHREN; FERNANDO ÁNGEL FERNÁNDEZ-ÁLVAREZ; GONZALO GIRIBET; JUAN JUNOY; HIROSHI KAJIHARA; WILLIAM R. KEM; ARMAND KURIS; SEBASTIAN KVIST; ANNIE MACHORDOM; ERIC G. MCEVOY; JON L. NORENBURG; ROBERT K. OKAZAKI; ALEX D. ROGERS; MALIN STRAND; SHI-CHUN SUN; PER SUNDBERG; MARTIN THIEL, Zootaxa, 5311, 4, 596, 599, 03 Jul. 2023, ［Internationally co-authored］, [International Magazine]
  N, Magnolia Press, English, Others
• Palaecanthocephala of marine fishes from Okinawa
  北悠樹; 柁原宏, 日本寄生虫学会大会プログラム・抄録集, 92nd, 2023
• Northernmost record of Nipponnemertes ogumai (Nemertea: Mo nostilifera) in Otomo-ura, Iwate Prefecture, Japan
  Abe, Hirokazu; Kan, Kotaro; Matsumasa, Masatoshi; Suzuki, Takao; Kajihara, Hiroshi, みちのくベントス, 6, 21, 27, Mar. 2022
  みちのくベントス研究所, Japanese
• Molecular systematics of the genus Gorgonorhynchus (Nemertea: Pilidiophora).
  波々伯部夏美; XU Cong-Mei; 露木葵唯; 自見直人; 大矢佑基; SUN Shi-Chun; 柁原宏, 日本ベントス学会・日本プランクトン学会合同大会講演要旨集, 2021, 2021
• Tip Extending Torus Mechanism based on Nemertea Proboscis-Proposal of hydrostatic skeleton structure capable of retraction while bending-
  高橋知也; 波々伯部夏美; 渡辺将広; 柁原宏; 山崎剛史; 多田隈建二郎; 昆陽雅司; 田所諭, 日本機械学会ロボティクス・メカトロニクス講演会講演論文集(CD-ROM), 2020, 0, 1P2, J12, 2020
  Japan Society of Mechanical Engineers
• ヒモムシ吻の伸展・湾曲・分岐構造を抽能したトーラス機構
  高橋知也; 波々伯部夏美; 小澤悠; 渡辺将広; 柁原宏; 山崎剛史; 多田隈建二郎; 昆陽雅司; 田所諭, 日本ロボット学会学術講演会予稿集(CD-ROM), 37th, ROMBUNNO.3D2‐03, 03 Sep. 2019
  Japanese
• 日本産ラキドニア科(環形動物門多毛類)の分類学的研究
  波々伯部夏美; 自見直人; 土田真二; 藤原義弘; 柁原宏, 日本ベントス学会・日本プランクトン学会合同大会講演要旨集, 2019, 2019
• Recent progress and future potential in faunal studies of the submarine caves in the Ryukyu Islands
  Kajihara Hiroshi; Takaku Gen; Fujita Yoshihisa; Kakui Keiichi, Taxa, Proceedings of the Japanese Society of Systematic Zoology, 46, 0, 1, 2, 2019
  <p>Although the 2018 symposium of the Japanese Society of Systematic Zoology, entitled 'Recent progress and future potential in faunal studies of the submarine caves in the Ryukyu Islands' was scheduled to be held on the occasion of the 89th annual meeting of the Zoological Society of Japan in Hokkaido, it was unfortunately canceled due to the earthquake '2018 Hokkaido Eastern Iburi Earthquake'. However, the five interesting articles were given by the special invited authors: 1) Yoshihisa Fujita 'The fauna of decapod crustaceans in submarine caves of the Ryukyu Islands, with special reference to environmental factors in the caves', 2) Yuji Ise 'Preliminary report of submarine cave sponges in Shimoji Island, Miyako Islands, Okinawa', 3) Mitchitaka Shimomura 'Review of recent taxonomic studies of peracarid crustaceans in submarine and anchialine caves of the Ryukyu Islands', 4) Masanori Okanishi and Yoshihisa Fujita 'Ophiuroids from submarine caves of the Ryukyu Islands, Japan', and 5) Akira Iguchi, Masaru Mizuyama, Takefumi Yorisue and Yoshihisa Fujita 'Current situation and future issues of DNA studies of submarine caves of the Ryukyu Islands'. In this paper, we introduce the purpose and the contents of this special issue.</p>, The Japanese Society of Systematic Zoology, Japanese
• 同所的に生息する2種のヘラムシが見せる異なる集団構造
  蛭田 眞平; 生駒 真帆; 加藤 徹; 柁原 宏; Dick Matthew H, うみうし通信, 96, 6, 8, Sep. 2017
  東京 : 水産無脊椎動物研究所, Japanese
• 間隙性ヒモムシ類サザレヒモ(和名新称)の多様性研究 : 分子分類学が不可欠な,柔らかい体を持つ生き物たち (特集 浅海の微小動物(メイオベントス)の多様性と進化)
  柁原 宏, 遺伝 : 生物の科学, 71, 4, 347, 352, Jul. 2017
  エヌ・ティー・エス, Japanese
• 【随筆】分類群の「数」について
  柁原 宏, タクサ：日本動物分類学会誌, 42, 0, 54, 63, 2017
  日本動物分類学会, Japanese
• 追悼 萩谷盛雄先生を偲ぶ
  柁原 宏, タクサ : 日本動物分類学会誌 = Taxa : proceedings of the Japanese Society of Systematic Zoology, 41, 8, 10, 30 Aug. 2016
  日本動物分類学会, Japanese
• Interstitial annelids in Japan
  柁原 宏, 海洋. 号外 = Kaiyo monthly : カラー版, 57, 93, 102, 2016
  海洋出版, Japanese
• 日本産Capitella属の1種について
  冨岡森理; 近藤智彦; 大越和加; 伊藤克敏; 柁原宏, 日本ベントス学会・日本プランクトン学会合同大会講演要旨集, 2015, 2015
• 【随筆】書誌雑感
  柁原 宏, タクサ : 日本動物分類学会誌, 37, 37, 46, 49, Aug. 2014
  日本動物分類学会, Japanese
• 北海道網走産イトゴカイ科多毛類について
  冨岡森理; 柁原宏, 日本ベントス学会・日本プランクトン学会合同大会講演要旨集, 2014, 2014
• 北日本沿岸におけるイワフジツボの系統地理
  我那覇生将; 蛭田眞平; 柁原宏; DICK Matthew, 日本動物学会大会予稿集, 85th, 2014
• サナダヒモムシ属(紐形動物門・異紐虫綱)の系統分類学
  柁原宏; 虻川修士, 日本動物学会大会予稿集, 85th, 2014
• 北日本沿岸におけるオホーツクヘラムシIdotea ochotensisの系統地理
  生駒真帆; 蛭田眞平; 柁原宏; DICK Matthew, 日本動物学会大会予稿集, 85th, 2014
• 【書評】ダニ・マニア, 島野智之(著), 八坂書房
  柁原 宏, タクサ : 日本動物分類学会誌, 34, 34, 83, 84, Feb. 2013
  書評, 日本動物分類学会, Japanese
• 二種類の眼点を持つクリゲヒモムシ属の未記載種(紐形動物門:古紐虫類)
  柁原宏; 山崎博史; 角井敬知; 蛭田眞平, 日本動物学会大会予稿集, 84th, 2013
• Phylogeography of Japanese mammals(PROCEEDINGS, JSSZ SYMPOSIUM, 2011)
  Kajihara Hiroshi, タクサ : 日本動物分類学会誌, 32, 5, 6, 20 Feb. 2012
  日本動物分類学会, Japanese
• ZooBank and mandatory registration(PROCEEDINGS, JSSZ SYMPOSIUM, 2010)
  Kajihara Hiroshi, タクサ : 日本動物分類学会誌, 30, 9, 16, 20 Feb. 2011
  ZooBank is intended as the official registry of Zoological Nomenclature, according to the International Commission on Zoological Nomenclature. Since its launch in 2005, more than 73, 000 records of Nomenclatural Acts, >29, 000 Publications, and >11, 000 Authors have been deposited in ZooBank as of this writing. An explanatory introduction for ZooBank and proposed three scenarios for mandatory registration of names governed by the International Code of Zoological Nomenclature is given in the Japanese language to popularize relevant issues in domestic taxonomic researchers., 日本動物分類学会, Japanese
• 深海底から見つかった動吻動物の報告
  山崎博史; 柁原宏; DICK Matthew H., 日本動物学会大会予稿集, 82nd, 2011
• 【書評】動物の系統分類と進化(新・生命科学シリーズ), 藤田敏彦著, 裳華房
  柁原 宏, タクサ : 日本動物分類学会誌, 29, 29, 51, 52, Aug. 2010
  日本動物分類学会, Japanese
• 日本沿岸に生息する数種紐形動物の毒性
  安井かおり; 藤田雄介; 石本泰之; 金田拓磨; 日比野由衣; 志田保夫; 孫世春; 柁原宏; 浅川学, 日本水産学会大会講演要旨集, 2010, 2010
• 北海道の海岸に生息する多様な無脊椎動物 (特集 北海道の海岸--豊かなる境界線)
  柁原 宏; 広瀬 雅人; 蛭田 眞平; 角井 敬知; 山崎 博史, モーリー, 20, 12, 14, Jul. 2009, [Invited]
  北海道新聞社, Japanese, Introduction commerce magazine
• Taxonomic Study of Kinorhyncha in Satsunan Islands
  山崎博史; 馬渡峻輔; 柁原宏, 日本動物学会大会予稿集, 80th (Web), 2009
• カブトガニ飼育水槽中に大量発生したモエデヒモムシ(新称)
  柁原宏; 藤田宜伸, うみうし通信, 58, 2008
• 紐形動物の系統分類学
  柁原 宏, 生物科学ニュース, 429, 26, 30, 20 Aug. 2007
  Japanese
• Inventorying of Dr. Shiro Okuda's polychaete collection
  Mai Ishida; Hiroshi Kajihara; Tetsuya Kato; Shunsuke F. Mawatari, ZOOLOGICAL SCIENCE, 22, 12, 1440, 1440, Dec. 2005
  English, Summary international conference
• The Marine Invertebrate Taxonomy Scene : its Current Situation, Challenges, and Efforts(PROCEEDINGS, JSSZ SYMPOSIUM, 2004)
  Kajihara Hiroshi, タクサ : 日本動物分類学会誌, 18, 1, 2, 20 Feb. 2005
  日本動物分類学会, Japanese
• ヒモムシおよびヒラムシにおけるフグ毒の組織内微細分布
  モホセナ ベガム タヌ; 荒川修; マハムッド ヤヒア; 柁原宏; 浅川学; 宮沢啓輔; 川津健太郎; 浜野米一; 野口玉雄, 日本水産学会大会講演要旨集, 2004, 2004
• 日本分類学会連合による日本産生物種数調査 (特集:日本の生物はどこまでわかっているか--既知の生物と未知の生物)
  柁原 宏, 生物科学, 55, 2, 71, 78, Jan. 2004
  資料形態 : テキストデータ プレーンテキスト
  コレクション : 国立国会図書館デジタルコレクション > デジタル化資料 > 雑誌, 日本生物科学者協会, Japanese
• 21. 分類学データベースの構築(日本動物分類学会第38会大会講演抄録)
  柁原 宏, タクサ : 日本動物分類学会誌, 13, 13, 44, 45, 20 Aug. 2002
  日本動物分類学会, Japanese
• Data Exchange Method for Biological Diversity Information Databases
  SATO AKIRA; YTOW NOZOMI; ONO SATOSHI; KAJIHARA HIROSHI; SHIMURA JUNKO, IPSJ SIG Notes, 2002, 67, 255, 262, 17 Jul. 2002
  For an investigation of the animate nature influenced from the phenomenon of the earth scale, it is important to integrate the biological information which was accumulated between the some recent centuries. The biological information is accessed by scientific name. The scientific name is dynamically changing because new species is discovered. We must develop a access method using the key which domain is dynamically change. This paper discuss a system which allow the individuality of each database of biological information, integrate voucher information and search biological information by s..., 一般社団法人情報処理学会, Japanese
• Data Exchange Method for Biodivercity Information Databases
  SATO Akira; YTOW Nozomi; ONO Satoshi; KAJIHARA Hiroshi; SHIMURA Junko, IEICE technical report. Data engineering, 102, 208, 103, 108, 11 Jul. 2002
  For an investigation of the animate nature influenced from the phenomenon of the earth scale, it is important to integrate the biological information which was accumulated between the some recent centuries. The biological information is accessed by scientific name. The scientific name is dynamically changing because new species is discovered. We must develop a access method using the key which domain is dynamically change. This paper discuss a system which allow the individuality of each database of biological information, integrate voucher information and search biological information by scientific name., The Institute of Electronics, Information and Communication Engineers, Japanese
• 18. 日本およびニュージーランド産種に基づくEurystomellidae科のrevision(日本動物分類学会第38会大会講演抄録)
  馬渡 峻輔; 柁原 宏, タクサ：日本動物分類学会誌, 13, 44, 2002
  日本動物分類学会, Japanese
• PROFESSOR USAMARO TAKAKURA (1867-1944) : LIFE AND THE FATE OF HIS JAPANESE NEMERTEAN COLLECTION(Taxonomy and Systematics)(Proceedings of the Seventy-Third Annual Meeting of the Zoological Society of Japan) :
  Kajihara Hiroshi; Kasai Fumie; Watanabe Makoto M.; Shimura Junko, Zoological science, 19, 12, 1423, 1423, 2002
  Zoological Society of Japan, English
• 3. 単針類(紐形動物門・有針綱)の系統解析(日本動物分類学会第37会大会講演抄録)
  柁原 宏; 馬渡 俊輔, タクサ : 日本動物分類学会誌, 11, 11, 26, 26, 20 Aug. 2001
  日本動物分類学会, Japanese
• TWO Zygonemertes SPECIES FROM HOKKAIDO, JAPAN(Taxonomy and Systematics)(Proceeding of the Seventy-Third Annual Meeting of the Zoological Society of Japan) :
  Kajihara H.; Mawatari S. F., Zoological science, 18, 46, 46, 2001
  Zoological Society of Japan, English
• UNDESCRIBED SPECIES OF JAPANESE AND NEW ZEALAND EURYSTOMELLIDAE (PHYLUM BRYOZOA) AND THEIR PHYLOGENETIC RELATIONSHIPS(Taxonomy and Systematics)(Proceeding of the Seventy-Third Annual Meeting of the Zoological Society of Japan) :
  Mawatari S. F.; Gordon D. P.; Kajihara H., Zoological science, 18, 43, 43, 2001
  Zoological Society of Japan, English
• MONOSTILIFEROUS HOPLONEMERTEAN FROM OTSUCHI BAY, JAPAN(Taxonomy and Systematics)(Proceedings of the Seventieth Annual Meeting of the Zoological Society of Japan) :
  Kajihara H.; Mawatari S. F., Zoological science, 16, 39, 39, 1999
  Zoological Society of Japan, English
• 4. 岩手県大槌湾から採れた間隙生紐虫について(日本動物分類学会第34回大会)
  柁原 宏; 馬渡 峻輔, タクサ : 日本動物分類学会誌, 5, 5, 17, 17, 20 Aug. 1998
  日本動物分類学会, Japanese
• String insect living in gap. Nemertean which lives in gap of sand.
  柁原宏, うみうし通信, 19, 1998
• 19. 日本で初めて採集された間隙生ヒモムシOtotyphlonemertes属(単針類)について(日本動物分類学会第33回大会)
  柁原 宏; 馬渡 峻輔, タクサ : 日本動物分類学会誌, 3, 3, 30, 30, 20 Aug. 1997
  日本動物分類学会, Japanese

• カラー図解 水の中の小さな美しい生き物たち: 小型ベントス・プランクトン百科
  紐形動物
  朝倉書店, 04 Aug. 2025, 4254171951, 372, Japanese
• ヒモムシ・ウズムシのなかま In: プランクトン: クラゲ・ミジンコ・小さな水の生物 (小学館の図鑑NEO POCKET)
  山崎 博史; 仲村 康秀; 田中 隼人; 堀口, 和重; 峯水, 亮; 眼遊; ねこのしっぽラボ; 奥, 修; 合木, 茂
  小学館, 25 Jun. 2024, 4092172974, 176, Japanese, [Joint work]
• 水産海洋ハンドブック = A handbook on fisheries science
  竹内, 俊郎; 中田, 英昭; 和田, 時夫; 上田, 宏; 有元, 貴文; 渡部, 終五; 長谷, 成人; 橋本, 牧; 浅川, 典敬
  生物研究社, Mar. 2024, 9784909119407, xi, 735p, 85-89, Japanese
• 海産無脊椎動物多様性学 : 100年の歴史とフロンティア
  京都大学フィールド科学教育研究センター瀬戸臨海実験所
  京都大学学術出版会, Nov. 2022, 9784814004492, 8,697p, Japanese
• 小学館の図鑑NEO 深海生物 DVDつき (小学館の図鑑・NEO 26)
  藤原 義弘; 遠藤, 広光; 伊勢, 優史; 松沢, 陽士
  小学館, 24 Jun. 2021, 4092172265, 183, Japanese
• 動物の事典
  末光, 隆志
  朝倉書店, Nov. 2020, 9784254171662, xxiii, 746p, Japanese
• 北大総合博物館のすごい標本 = Amazing specimens of the Hokkaido University Museum
  北海道大学総合博物館
  北海道新聞社, Mar. 2020, 9784894539747, 239p, Japanese
• 動物学の百科事典
  公益社団法人日本動物学会
  丸善出版, 28 Sep. 2018, 4621303090, 800

  
• Species Diversity of Animals in Japan (Diversity and Commonality in Animals)
  Masaharu Motokawa; Hiroshi Kajihara
  Springer, 30 Nov. 2016, 4431564306, 721

  
• 岩波 生物学辞典 第5版
  巌佐 庸; 倉谷 滋; 斎藤 成也; 塚谷 裕一
  岩波書店, 27 Feb. 2013, 400080314X, 2192

  
• 進化学事典
  日本進化学会
  共立出版, 25 Apr. 2012, 4320057775, 975

  
• 地球と生命の進化学―新・自然史科学〈1〉 (新・自然史科学 1)
  沢田 健; 西 弘嗣; 栃内 新; 馬渡 峻輔; 綿貫 豊; 秋元 信一; 阿波根 直一; 大原 昌宏; 柁原 宏; 片倉 春雄; 倉本 圭; 小林 快次; 鈴木 徳行; 高橋 英樹; 堀口 健雄; 前川 光司; 増田 道夫; 増田 隆一; 沢田 健; 西 弘嗣; 馬渡 峻輔; 綿貫 豊
  北海道大学図書刊行会, 31 Mar. 2008, 4832981838, 272, [Joint work]

  
• 種を記載する : 生物学者のための実際的な分類手順
  Winston, Judith E.; 馬渡, 峻輔; 柁原, 宏
  ジュディス・E; ウィンストン, 新井書院, 2008, 9784903981000, 653p, Japanese, [Joint translation]

  
• レーヴン ジョンソン 生物学〈下〉
  P. レーヴン; J. ロソス; S. シンガー; G. ジョンソン; Peter H. Raven; Susan R. Singer; Jonathan B. Losos; George B. Johnson; R J Biolo; 翻訳委員会
  培風館, May 2007, 4563077976, 1295

  
• マクロ進化と全生物の系統分類
  佐藤, 矩行; 柁原, 宏; 馬渡, 峻輔; 長谷川, 政美; 大野, 照文; 西田, 治文; 川上, 紳一; 石川, 統
  岩波書店, Dec. 2004, 4000069217, ix, 222p, Japanese, [Joint work]

  

• サナダヒモムシ属(紐形動物門・異紐虫綱)の系統分類学
  柁原宏; 虻川修士
  日本動物学会大会予稿集, 07 Aug. 2014, Japanese
• 二種類の眼点を持つクリゲヒモムシ属の未記載種(紐形動物門:古紐虫類)
  柁原宏; 山崎博史; 角井敬知; 蛭田眞平
  日本動物学会大会予稿集, 12 Aug. 2013, Japanese
• 21. 分類学データベースの構築(日本動物分類学会第38会大会講演抄録)
  柁原 宏
  タクサ : 日本動物分類学会誌, 20 Aug. 2002, Japanese
• 3. 単針類(紐形動物門・有針綱)の系統解析(日本動物分類学会第37会大会講演抄録)
  柁原 宏; 馬渡 俊輔
  タクサ : 日本動物分類学会誌, 20 Aug. 2001, Japanese
• 4. 岩手県大槌湾から採れた間隙生紐虫について(日本動物分類学会第34回大会)
  柁原 宏; 馬渡 峻輔
  タクサ : 日本動物分類学会誌, 20 Aug. 1998, Japanese
• 19. 日本で初めて採集された間隙生ヒモムシOtotyphlonemertes属(単針類)について(日本動物分類学会第33回大会)
  柁原 宏; 馬渡 峻輔
  タクサ : 日本動物分類学会誌, 20 Aug. 1997, Japanese

• 自然史科学特別講義Ⅲ, 2024年, 修士課程, 理学院
• 分類学概論, 2024年, 修士課程, 理学院
• 多様性生物学基礎論, 2024年, 修士課程, 環境科学院
• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 大学院共通授業科目（教育プログラム）：博物館学, 2024年, 修士課程, 大学院共通科目
• 多様性生物学研究法, 2024年, 修士課程, 理学院
• 環境と人間, 2024年, 学士課程, 全学教育
• 科学・技術の世界（1単位）, 2024年, 学士課程, 全学教育
• 生物多様性概論, 2024年, 学士課程, 理学部
• 臨海実習Ⅰ, 2024年, 学士課程, 理学部
• 臨海実習Ⅰ, 2024年, 学士課程, 理学部
• ISP生物科学研究Ⅰ, 2024年, 学士課程, 理学部
• ISP生物科学研究Ⅱ, 2024年, 学士課程, 理学部
• ISP生物科学研究Ⅲ, 2024年, 学士課程, 理学部
• ISP生物科学研究Ⅳ, 2024年, 学士課程, 理学部
• 基礎生物学実習, 2024年, 学士課程, 理学部
• 基礎生物学実習, 2024年, 学士課程, 理学部
• 基礎生物学研究実習, 2024年, 学士課程, 理学部
• 基礎生物学研究実習, 2024年, 学士課程, 理学部
• 生物学Ⅱ, 2024年, 学士課程, 全学教育
• 生物学特別実習Ⅰ, 2024年, 学士課程, 理学部
• 生物学特別実習Ⅱ, 2024年, 学士課程, 理学部
• 生物科学文献講読, 2024年, 学士課程, 理学部
• 生物科学研究実習, 2024年, 学士課程, 理学部
• 系統分類学a, 2024年, 学士課程, 理学部
• 系統分類学Ⅰ, 2024年, 学士課程, 理学部
• ISP生物科学実習Ⅰ・a, 2024年, 学士課程, 理学部
• ISP生物科学実習Ⅰ・b, 2024年, 学士課程, 理学部
• 動物系統分類学実習, 2024年, 学士課程, 理学部
• 動物系統分類学実習, 2024年, 学士課程, 理学部
• 環境と人間, 2024年, 学士課程, 全学教育
• 多様性生物学Ⅰ, 2024年, 学士課程, 理学部
• 研究林実習, 2024年, 学士課程, 理学部
• 多様性生物学Ⅱ, 2024年, 学士課程, 理学部

• 日本動物分類学会
• 日本動物学会

• ロボット機構駆使によるヒモムシ吻動作の生物構成論的解明及び瓦礫内推進技術への応用
  科学研究費助成事業
  01 Apr. 2025 - 31 Mar. 2028
  多田隈 建二郎; 柁原 宏; 波々伯部 夏美
  日本学術振興会, 基盤研究(B), 大阪大学, 25K01185
• 爬行亜目ヒモムシ類の新種記載を加速するための基盤構築
  科学研究費助成事業
  01 Apr. 2025 - 31 Mar. 2028
  柁原 宏
  日本学術振興会, 基盤研究(C), 北海道大学, 25K09751
• Establishing a method for estimating species numbers for each taxon in interstitial environment
  Grants-in-Aid for Scientific Research
  01 Apr. 2020 - 31 Mar. 2023
  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, Grant-in-Aid for Scientific Research (C), Hokkaido University, 20K06780
• Studies on species biodiversity and evolution of enigmatic parasitic dinoflagellates, Haplozoon spp., which acquired multicellularity.
  Grants-in-Aid for Scientific Research
  Apr. 2020 - Mar. 2023
  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, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20H03304
• Exploring the evolutionary background by raring planktonic larvae of heteronemerteans that become extremely long
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
  01 Apr. 2017 - 31 Mar. 2020
  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, Grant-in-Aid for Scientific Research (C), Hokkaido University, 17K07520
• Interstitial fauna in the islands of the south-west Pacific and the records of present beach environment
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2014 - 31 Mar. 2019
  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, Grant-in-Aid for Scientific Research (B), Shizuoka University, 26304011
• The general study of natural history treasure
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2014 - 31 Mar. 2018
  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, Grant-in-Aid for Scientific Research (B), Hokkaido University, 26282067
• Anatomy of a Marine Dispersal Barrier
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2011 - 31 Mar. 2016
  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, Grant-in-Aid for Scientific Research (B), Hokkaido University, Coinvestigator not use grants, Competitive research funding, 23370038
• Does Diurodrilus form a new phylum?
  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
  01 Apr. 2013 - 31 Mar. 2015
  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.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 25650133
• 北海道産十脚甲殻類の卵塊寄生虫相の調査と防除法の探索
  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
  2011 - 2012
  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。
  ノーステック財団, Principal investigator, Competitive research funding
• 海底隠蔽環境に生息する微小後生動物の分類学的研究
  2009 - 2010
  柁原 宏
  成茂動物科学振興基金, Principal investigator, Competitive research funding
• 紐形動物の体系学的研究
  2008 - 2009
  柁原 宏
  スカンジナビア・ニッポンササカワ財団, Principal investigator, Competitive research funding
• 紐形動物の系統分類学的研究
  2008 - 2009
  柁原 宏
  昭和聖徳記念財団, Principal investigator, Competitive research funding
• フグ毒蓄積性ホソヒモムシ類の分類学ならびに毒性地理変異と生活史の解明
  個別助成
  2008 - 2009
  柁原 宏
  財団法人水産無脊椎動物研究所, Principal investigator, Competitive research funding
• Systematic study of the phylum Nemertea based on mitochondrial genome sequences
  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
  2008 - 2009
  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, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 20770061
• Fauna and flora of Daikoku-jima Island, Hokkaido, northern Japan: model study of the complete eucaryotic biota in an area
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
  2004 - 2007
  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.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, Coinvestigator not use grants, Competitive research funding, 16207005
• トポティピック・リファレンスコレクション構築によるヒモムシ類分類再検討の試み
  科学研究費助成事業 若手研究(B)
  2004 - 2006
  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。
  日本学術振興会, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 16770059
• Marine invertebrate systematics
  Competitive research funding