研究者基本情報

• 修士（環境学）, 東京大学大学院, 2019年09月
• 博士（環境学）, 東京大学大学院, 2023年03月

• https://researchmap.jp/ohtamizukimushi

• https://orcid.org/0000-0003-1375-8876
• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=202301012346439056
• https://sites.google.com/view/aselloooohta/

• https://orcid.org/0000-0003-1375-8876

• 202301012346439056

• 系統学
• 分類学
• ミズムシ亜目
• 等脚目
• 深海

• ライフサイエンス, 多様性生物学、分類学, 分類、深海生物

研究活動情報

• Three new species of Betamorpha Hessler & Thistle, 1975 (Isopoda: Asellota: Munnopsidae) from the Japan and Kuril-Kamchatka Trenches, with an updated key to the species of the genus
  Mizuki Ohta; Keiichi Kakui
  Journal of Crustacean Biology, 46, 3, Oxford University Press (OUP), 2026年08月, ［査読有り］, ［筆頭著者］
  研究論文（学術雑誌）, Abstract
  
  Three new species of the genus Betamorpha Hessler & Thistle, 1975, collected from depths of 2,886–7,654 m in the Japan and Kuril-Kamchatka Trenches in the northwestern Pacific are described. These new species, Betamorpha crista sp. nov., Betamorpha fossa sp. nov., and Betamorpha ellipsoidea sp. nov., are distinguished from each other and their congeners based on morphological characters of the cephalothorax, pereonites I–V, and coxal plates. The specimens were collected at different depths and not sympatrically: 2,886–3,176 m for B. crista sp. nov., 5,702–5,738 m for B. fossa sp. nov., and 6,169–7,654 m for B. ellipsoidea sp. nov. We determined partial nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene, constructed a COI-based phylogenetic tree of Betamorpha, and calculated intra- and interspecific genetic distances. A key to the species of Betamorpha is provided., 51348300
• Three Ilyarachna species (Isopoda: Asellota: Munnopsidae) showing different bathymetric distributions in Japan and Kuril-Kamchatka Trenches, with descriptions of two new species
  Mizuki Ohta; Keiichi Kakui; Shigeaki Kojima; Michitaka Shimomura
  Deep Sea Research Part I: Oceanographic Research Papers, 230, 2026年06月, ［査読有り］, ［筆頭著者］
  研究論文（学術雑誌）, 51348300
• High connectivity of a new Eurycope (Asellota: Munnopsidae) species from Japanese waters and the Bering Sea with intraspecific genetic divergence among local populations
  Mizuki Ohta; Shigeaki Kojima; Stefanie Kaiser; Angelika Brandt
  Progress in Oceanography, 239, 103588, 103588, Elsevier BV, 2025年12月, ［査読有り］, ［筆頭著者］
  研究論文（学術雑誌）, 51348300
• 龍泉洞外河川(清水川)から採集された地下水生微小甲殻類
  太田瑞希; 元村優介; 宗像みずほ; 安藤奏音; 渡辺修二
  水生動物, 2025, 34, 2025年09月, ［査読有り］, ［筆頭著者］
  日本語
• Integrative taxonomy of Janirella (Isopoda: Asellota: Janirellidae), with descriptions of two new species from the Japan Trench and an amended classification of the genus
  Mizuki Ohta; Keiichi Kakui; Shigeaki Kojima; Michitaka Shimomura
  Biologia, Springer Science and Business Media LLC, 2025年03月11日, ［筆頭著者］
  研究論文（学術雑誌）
• Benthos meets plankton: isopods sampled in the Japan Trench by means of plankton nets fixed to large bottom trawls
  Angelika Brandt; Franziska Bergmeier; Anchita Casaubon; Yasunori Kano; Andreas Kelch; Henry Knauber; Kai Okamoto; Mizuki Ohta; Shoki Shiraki; Daiki Yamamoto; Shigeaki Kojima
  Marine Biodiversity, 54, 3, Springer Science and Business Media LLC, 2024年05月18日
  研究論文（学術雑誌）, Abstract
  
  During the KH-23–5 expedition aboard the RV Hakuho Maru to the Kuril-Kamchatka (KKT) and Japan Trenches (JT) in September 2023, we deployed bottom trawls equipped with plankton nets, resulting in a high number of supra- and epibenthic benthic organisms, particularly of isopod crustaceans (Peracarida, Malacostraca). In total, we sampled 2656 specimens of Isopoda spanning at least 14 families and the suborder Epicaridea across 28 stations. Notably, five families were represented by more than 100 specimens each: Munnopsidae led with the highest number of specimens (1123 individuals), followed by Haploniscidae with 564, Macrostylidae with 430, Ischnomesidae with 245, and Desmosomatidae with 188 individuals. Station C8 yielded the highest number of individuals (502), while only one isopod was retrieved from station F11. Our findings document the efficacy of employing additional plankton nets,and we recommend the increased use of bottom trawls deployed with plankton nets in future expeditions.
• Discovery and Genetic Characterization of a Vestimentiferan, Lamellibrachia satsuma, from the Submarine Volcano Omuro Dashi in the Izu-Ogasawara Arc
  Haruka Kamei; Kai Okamoto; Mizuki Ohta; Hajime Itoh; Hiromi Kayama Watanabe; Hironori Komatsu; Shigeaki Kojima
  Zoological Science, 40, 6, Zoological Society of Japan, 2023年10月19日
  研究論文（学術雑誌）
• A new species of Janiralata Menzies, 1951 (Isopoda: Janiridae) from Japanese bathyal waters, with a review of the associations with invertebrates among the species of Janiralata
  Mizuki Ohta; Tsuyoshi Takano; Shigeaki Kojima; Yoji Narimatsu
  Journal of Crustacean Biology, 43, 3, Oxford University Press (OUP), 2023年08月31日, ［筆頭著者］
  研究論文（学術雑誌）, Abstract
  
  Isopods of the genus Janiralata Menzies, 1951 (Asellota: Janiridae) are known from shallow and deep waters of the Northern Hemisphere. Most species are free-living, but some are symbiotic on the surface of other benthic invertebrates. We obtained from three beam- and four otter-trawl hauls 18 Janiralata asellote specimens from the bathyal zone off the Pacific coasts of Tohoku, northeastern Japan. Partial nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene (505 bp) were determined for 16 of the 18 collected specimens. Non-significant genetic differences (< 0.8%) indicated that the individuals were conspecifics. Morphological analysis indicated that all the specimens belonged to a single species, Janiralata planasp. nov. based on the unique morphology of the anterolateral and distolateral projections on the head and pleotelson, surface and lateral margins of the body, antennula article 1, and of the male pleopod 1. Six of the 18 collected specimens were found attached to the surface of an unidentified sea anemone (Hormathiidae), ten to the solasterid starfish Crossaster borealis Fisher, 1906 and two were obtained from the bottom sediment. Three COI haplotypes of the new species were shared by individuals from two neighboring sites, which suggests that genetic isolation occurs on a relatively narrow horizontal scale, although the bathymetric distribution range was rather wide. We describe a case study of the geographic and bathymetric distributions of an asellote species with low dispersal ability and its genetically differentiated populations. Such approach could help elucidate the diversity and distribution of deep-sea organisms and their diversification processes.
• Geographic Distribution and Genetic Structures of the Tideland Snails Pirenella nipponica and P. asiatica in Taiwan and Japan
  Shintaro Kato; Mizuki Ohta; Hiroaki Fukumori; Te-Hua Hsu; Tin-Yam Chan; Shigeaki Kojima
  Zoological Studies, 62, 43, 1, 8, 2023年08月
• Diexanthema hakuhomaruae sp. nov. (Copepoda: Siphonostomatoida: Nicothoidae) from the Hadal Zone in the Northwestern Pacific, with an 18S Molecular Phylogeny
  Keiichi Kakui; Jun Fukuchi; Mizuki Ohta
  Acta Parasitologica, Springer Science and Business Media LLC, 2023年04月04日
  研究論文（学術雑誌）
• A new species of Janirella Bonnier, 1896 (Isopoda: Asellota: Janirellidae) from western Japan Trench
  Mizuki Ohta; Shigeaki Kojima; Michitaka Shimomura
  Crustacean Research, 49, 89, 97, Carcinological Society of Japan, 2020年06月12日, ［筆頭著者］
  研究論文（学術雑誌）
• 利尻島沿岸の等脚目甲殻類（節足動物門）
  太田瑞希; 小林元樹; 阿部博和; 伊藤 萌; 冨岡森理; 小島茂明
  利尻研究, 39, 47, 54, 2020年03月, ［筆頭著者］
  日本語
• 日本海の木材に穿孔する大型キクイムシ属2種（等脚目）
  吉野 広軌; 太田 瑞希; 上田 祐司
  CANCER, 27, 45, 49, 2018年08月
  日本語

• ミズムシ亜目等脚類をモデルとした深海帯以深に生息する生物の種分化メカニズムの解明
  科学研究費助成事業
  2024年04月 - 2027年03月
  太田 瑞希
  日本学術振興会, 特別研究員奨励費, 北海道大学, 24KJ0003