Researcher Profile and Settings

Affiliation

• Faculty of Science　Biological Sciences　Biodiversity

Job Title

• Lecturer

Degree

• Ph. D（Hokkaido University）

URL

https://sites.google.com/site/tnidjpn/

Research funding number

• 70723360

ORCID ID

•  https://orcid.org/0000-0003-4630-9065

J-Global ID

• 201201066133264498

Research Interests

• 寄生   Tanaidacea   Crustacea   Taxonomy   Phylogeny   性表現   生殖様式   雌雄同体   糸   

Research Areas

• Life sciences / Biodiversity and systematics / Phylogeny and Taxonomy of Crustaceans

Educational Organization

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

Association Memberships

• THE CRUSTACEAN SOCIETY   THE CARCINOLOGICAL SOCIETY OF JAPAN   THE ZOOLOGICAL SOCIETY OF JAPAN   THE JAPANESE SOCIETY OF SYSTEMATIC ZOOLOGY   

Research Activities

Published Papers

• Description of a new Cruranthura species from the Miyako Islands, Japan, with its DNA barcode (Isopoda: Anthuroidea: Paranthuridae)

  Shoki Shiraki, Keiichi Kakui

  Species Diversity 29 (1) 65 - 72 1342-1670 2024/05/25 [Refereed][Not invited]
  
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• Molecular phylogeny confirmed “Pseudolepeophtheirus” schmidti Gusev, 1951 is a member of Lepeophtheirus (Crustacea, Copepoda, Caligidae)

  Keiichi Kakui

  Spixiana 46 (2) 173 - 177 2024/04/30 [Refereed][Not invited]
  
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• Ontogenetic Changes in Pigmentation Pattern in Mesanthura Miyakoensis (Crustacea: Isopoda: Anthuridae)

  Shoki Shiraki, Keiichi Kakui

  Zoological Science 41 (3) 0289-0003 2024/04/22
• A new parasitic barnacle (Crustacea, Cirripedia, Rhizocephala, Mycetomorpha) from the abyssal zone in the northwestern Pacific

  Keiichi Kakui

  Zoosystematics and Evolution 100 (2) 385 - 390 1435-1935 2024/04/03 [Refereed][Not invited]
   

  I describe the parasitic barnacle Mycetomorpha abyssalissp. nov. from the crangonid shrimp Sclerocrangon zenkevitchi collected from 3893–3890 m depth off the eastern coast of Iwate, Japan, northwestern Pacific. This is the first Mycetomorpha rhizocephalan from the abyssal zone and the third species in Mycetomorpha. Mycetomorpha abyssalissp. nov. differs from its congeners M. vancouverensis and M. albatrossi in (1) triangular shield lacking, (2) stalk one-quarter of length from posterior end of externa, (3) mantle opening clearly anterior to stalk, (4) different host genus, and (5) depth range much deeper. I determined partial sequences for the mitochondrial cytochrome c oxidase subunit I (COI) and 16S rRNA genes and nuclear 18S rRNA and 28S rRNA genes from M. abyssalissp. nov. for future DNA barcoding and phylogeny. Kimura 2-parameter distances between M. abyssalissp. nov. and M. vancouverensis were 21.2% (16S), 0.6% (18S), and 1.5% (28S).
• Review on studies of fossils in Tanaidacea (Crustacea: Malacostraca: Peracarida)

  Keiichi Kakui

  Fossils 115 65 - 76 2024/03/31 [Refereed]
  
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• Marine macroinvertebrate fauna of the shallow coastal waters of the Shiretoko Peninsula, a World Natural Heritage at Hokkaido, Japan

  Takeshi Sonoda, Susumu Chiba, Tomoyasu Yamazaki, Takahiro Nobetsu, Hideaki Fujiya, Tomoyuki Komai, Noboru Nunomura, Michitaka Shimomura, Ko Tomikawa, Keiichi Kakui, Takashi Hosono, Atsushi Ito, Toshihiko Fujita, Itaru Kobayashi, Seiji Goshima

  Plankton and Benthos Research 19 (1) 1 - 16 1880-8247 2024/02/28 [Refereed][Not invited]
  
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• A smaller species releases proportionally larger juveniles in Apseudes (Crustacea: Peracarida: Tanaidacea)

  Keiichi Kakui, Chizue Hiruta

  CBM-Cahiers de Biologie Marine 65 35 - 37 2024/01/26 [Refereed][Not invited]
   

  We compared the body size (carapace width, CW) of the first free-living instar individuals, or mancae 2, and of the smallest ovigerous individuals, between two simultaneously hermaphroditic tanaidacean species, Apseudes nipponicus Shiino, 1937 and Apseudes sp. The former species is 2.2 times larger, with a CW of 2.61 mm in the smallest ovigerous individual, compared to 1.17 mm in the latter. Average CWs of manca 2 individuals were 0.51 mm (A. nipponicus, n = 3, 0.50-0.51 mm) and 0.38 mm (Apseudes sp.: n = 9, 0.38-0.39 mm), meaning that A. nipponicus mancae 2 were 20% as large as the smallest ovigerous individuals, whereas those of Apseudes sp. were 32% as large. The proportionally larger juveniles in the smaller species are consistent with the progenetic hypothesis that Apseudes sp. is achieving earlier maturation as females.
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• Flatworm cocoons in the abyss: same plan under pressure

  Keiichi Kakui, Aoi Tsuyuki

  Biology Letters 20 20230506  2024/01/24 [Refereed][Not invited]
  
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• A New Species of Coralliidae (Cnidaria: Octocorallia) Collected from Eastern Japan

  Masanori Nonaka, Nozomi Hanahara, Keiichi Kakui

  Species Diversity 28 (2) 231 - 243 1342-1670 2023/11/09 [Refereed][Not invited]
  
• A new species of free-living marine nematode, Fotolaimus cavus sp. nov. (Nematoda, Oncholaimida, Oncholaimidae), isolated from a submarine anchialine cave in the Ryukyu Islands, southwestern Japan

  Shimada D, Kakui K, Fujita Y

  Zoosystematics and Evolution 99 (2) 519 - 533 1435-1935 2023/11/06 [Refereed][Not invited]
   

  Fotolaimus cavussp. nov. was described from a submarine anchialine cave called Akuma-no-yakata on the Shimoji Island, Miyako Island Group, Ryukyu Islands, southwestern Japan. This is the first free-living marine nematode isolated from a submarine cave in Japan, and the third species of the genus Fotolaimus. This new species differs from its congeners by its small body size, wide amphids, long buccal cavity, long conico-cylindrical tail, and proximally curved gubernaculum. We provide amended dichotomous keys to genera in the subfamily Oncholaiminae and species in Fotolaimus. We also analyzed partial DNA sequences encoding ribosomal small subunit RNA and cytochrome c oxidase subunit I from Fotolaimus cavussp. nov. and six other species of Oncholaimidae collected from Japanese waters. The phylogenetic tree based on the ribosomal small subunit RNA sequences using maximum likelihood analysis suggested a close relationship between Fotolaimus and Wiesoncholaimus as well as Oncholaimus. The topology of the tree was similar to those from previous studies; however, it suggested a new phylogenetic position of Adoncholaimus as a sister clade for Viscosia and Oncholaimus.
• Two new species in Leptocheliidae (Crustacea: Peracarida: Tanaidacea) from Japan, with notes on their phylogenetic position and aspects of morphology

  Akari Sato, Kazuharu Arakawa, Keiichi Kakui

  Zoologischer Anzeiger 306 51 - 68 0044-5231 2023/08/31 [Refereed][Not invited]
  
• 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 1175-5326 2023/08/24 [Refereed][Not invited]
   

  We establish the new podocerid genus Capropodocerus gen. nov. for the two new species Capropodocerus tagamaru gen. et sp. nov. (collected from 775–800 m depth in the Kumano Sea, Japan) and Capropodocerus kamaitachi gen. et sp. nov. (collected from 840–873 m depth off the eastern coast of Miyagi, Japan). Capropodocerus shares elongate pereonites 1–3 with Neoxenodice but differs from the latter in lacking uropod 2 and in having pereonite 3 at least twice as long as pereonite 4. Capropodocerus is also similar to Laetmatophilus and Leipsuropus in having only two pairs of uropods but differs from them in having i) pereonite 1 longer than the head and ii) pereonite 3 at least twice as long as pereonite 4; Capropodocerus has three urosomes and Laetmatophilus has two urosomes. The two species in Capropodocerus differ in i) the length ratio of the antenna 1 peduncle to the flagellum, ii) the shape of the gnathopod 2 palm, iii) the presence or absence of a mid-posterior triangular projection on the gnathopod 2 dactylus, and iv) the length ratio of the basis to the merus of pereopod 3. A key to all genera in Podoceridae is provided.
• Differential masculinization of the chelipeds in two simultaneously hermaphroditic Apseudes tanaidaceans (Crustacea: Malacostraca)

  Keiichi Kakui, Chizue Hiruta

  Zoologischer Anzeiger 305 23 - 27 0044-5231 2023/07 [Refereed][Not invited]
  
• New sea spider species (Pycnogonida: Austrodecidae) from a submarine cave in Japan

  Keiichi Kakui, Yoshihisa Fujita

  Journal of the Marine Biological Association of the United Kingdom 103 e44  2023/06/23 [Refereed][Not invited]
  
• 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 68 413 - 419 1230-2821 2023/06/21 [Refereed][Not invited]
  
• Phototaxis in Two Shallow-Water Zeuxo Species (Crustacea: Tanaidacea)

  Nobuya Okamoto, Keiichi Kakui

  Zoological Science 40 (3) 203 - 207 0289-0003 2023/06/01 [Refereed][Not invited]
  
• A new Sphaeronella species (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on Euphilomedes sp. (Ostracoda: Myodocopa: Philomedidae) from Hokkaido, Japan, with an 18S molecular phylogeny

  Keiichi Kakui, Mizuho Munakata

  Systematic Parasitology 100 (2) 121 - 131 0165-5752 2023/03 [Refereed][Not invited]
  
• Freshwater Ostracoda (Crustacea) from Rishiri Island, Hokkaido, Japan

  Mizuho Munakata, Shinri Tomioka, Keiichi Kakui

  Rishiri Studies 42 5 - 18 2023/03 [Not refereed][Not invited]
  
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• A new species of Leipsuropus Stebbing, 1899 (Amphipoda: Podoceridae) from Japan

  Yu Matsumoto, Hiroshi Kajihara, Keiichi Kakui

  Nauplius 31 e2023005  2023/02/20 [Refereed][Not invited]
  
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• On the original publications for six tanaidacean names proposed by Sueo M. Shiino

  MASAATSU TANAKA, KEIICHI KAKUI

  Zootaxa 5231 (2) 192 - 194 1175-5326 2023/01/27 [Refereed][Not invited]
  
• Integrative taxonomy of Zeuxo (Crustacea: Peracarida: Tanaidacea) from Japan, with the description of a new species

  Nobuya Okamoto, Keiichi Kakui

  Biologia 77 (9) 2497 - 2506 2022/10/31 [Refereed][Not invited]
  
• Protogynous hermaphroditism in Crustacea: a new example from Tanaidacea

  Keiichi Kakui, Chizue Hiruta

  Canadian Journal of Zoology 100 (8) 481 - 487 0008-4301 2022/08 [Refereed][Not invited]
   

  Hermaphroditism has been widely reported in the Crustacea, but protogyny, in which females change to males, is apparently rare and restricted to the peracarid orders Isopoda and Tanaidacea. In the latter, protogyny has been demonstrated in only seven species representing six genera by rearing experiments and indicated for several other genera and species through morphology. Here, we show through rearing experiment and histological observations, protogynous hermaphroditism in the tanaidacean species Nesotanais sp. aff. ryukyuensis Kakui, Kajihara and Mawatari, 2010. Our rearing experiment and size distribution data for wild individuals showed that females can change sex at various sizes (= ages). We found one individual identified externally as a female containing both ovaries and testes, indicating that overt female individuals undergo a short transitional phase as simultaneous hermaphrodites before the sex-change molt. We discuss the relationship among the wide size distribution of sex-changing females, the short life span of males, and the tube-dwelling mode of life.
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• First report of Hyssuridae (Isopoda: Anthuroidea) from Japan, with the description of a new Kupellonura species

  Shoki Shiraki, Michitaka Shimomura, Keiichi Kakui

  Nauplius 30 e2022023  2022/08 [Refereed][Not invited]
  
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• A new brackish tanaidacean, Sinelobus kisui sp. nov. (Crustacea, Peracarida, Tanaidacea), from Japan, with a key to Sinelobus species and barcode information from two loci

  Kyoko Hirano, Keiichi Kakui

  Zoosystematics and Evolution 98 245 - 256 2022/06/29 [Refereed][Not invited]
  
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• Biological notes on Zeuxo ezoensis Okamoto et al., 2020 (Crustacea: Peracarida: Tanaidacea).

  Yoshinobu Hayakawa, Keiichi Kakui

  Aquatic Animals 2022 AA2022-10  2022/06/09 [Refereed][Not invited]
  
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• Observations on Predation in Paranthura japonica Richardson, 1909 (Isopoda: Cymothoida: Paranthuridae)

  Shoki Shiraki, Keiichi Kakui

  Zoological Science 39 (3) 270 - 274 0289-0003 2022/06/06 [Refereed][Not invited]
  
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• Dive into the sea: first molecular phylogenetic evidence of host expansion from terrestrial/freshwater to marine organisms in Mermithidae (Nematoda: Mermithida)

  K. Kakui, D. Shimada

  Journal of Helminthology 96 0022-149X 2022/05 [Refereed][Not invited]
   

  Abstract We report the first mermithid nematode found to be parasitic in a marine tanaidacean crustacean. Ten host tanaidaceans were collected from a depth of 52 m in Otsuchi Bay, Iwate, Japan, north-western Pacific, and identified as a species in the tanaidid genus Zeuxo Templeton, 1840. Nematodes occurred in the host's body cavity; in one case, at least two individuals inhabited a single host. We provide a brief description and illustrations of the morphology of the nematode. In a phylogenetic reconstruction based on the 18S ribosomal RNA gene, the nematode nested in a clade otherwise containing mermithids from terrestrial or freshwater hosts, showing an expansion in host utilization in Mermithidae Braun, 1883 from terrestrial/freshwater hosts to a marine organism.
• Taxonomy and natural history of Cavernocypris hokkaiensis sp. nov., the first ostracod reported from alpine streams in Japan

  Mizuho Munakata, Hayato Tanaka, Keiichi Kakui

  Zoosystematics and Evolution 98 (1) 117 - 127 1435-1935 2022/04/05 [Refereed][Not invited]
   

  We describe the cypridoidean ostracod Cavernocypris hokkaiensis sp. nov. from riverbed sediments in an alpine stream at an elevation of ca. 1850 m in the Taisetsu Mountains, Hokkaido, Japan. This species differs from congeners in having (1) the outer surface of the carapace smooth, with sparse, tiny setae, but without shallow pits; (2) the carapace elongate rather than triangular in lateral view; (3) the antennula consisting of seven podomeres; (4) first palpal podomere of maxillula with five dorsodistal and one ventro-subdistal setae; (5) the fifth limb lacking setae b and d; and (6) the fifth limb lacking a vibratory plate. We provided the key to the Cavernocypris species. We determined partial sequences for the cytochrome c oxidase subunit I (COI; cox1) and 18S rRNA (18S) genes in C. hokkaiensis. Our sample contained only females, and we obtained a partial 16S rRNA sequence for the endosymbiotic bacterium Cardinium from C. hokkaiensis, indicating the possibility that this ostracod species reproduces parthenogenetically. Our field survey and observations of captive individuals suggested that C. hokkaiensis may be endemic to the Taisetsu Mountains, with a low population density, narrow distributional range, and slow maturation to sexual maturity.
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• Digenean Metacercariae Parasitic in a Staurozoan Cnidarian

  Keiichi Kakui

  Zoological Science 39 (2) 0289-0003 2022/04/01 [Refereed][Not invited]
  
• A new neotenous genus and species, Deltanthura palpus gen. et sp. nov. (Isopoda, Anthuroidea, Paranthuridae) from Japan, with a revised key to the genera in Paranthuridae

  Shoki Shiraki, Michitaka Shimomura, Keiichi Kakui

  Zoosystematics and Evolution 98 (1) 109 - 115 1435-1935 2022/03/31 [Refereed][Not invited]
   

  We describe a new paranthurid isopod genus and species, Deltanthura palpusgen. et sp. nov., collected from a depth of 805–852 m off the southern coast of Mie prefecture, Japan. Deltanthura is similar to Pseudanthura Richardson, 1911 in having a triangular pleotelson, acute mandible with a 3-articulate palp, a maxillipedal endite, and a tapering uropodal exopod, but differs in having eyes and neotenous characters (reduced pereonite 7 and pereopods 7 lacking). Deltanthura and four paranthurid genera (Califanthura Schultz, 1977, Colanthura Richardson, 1902, Cruranthura Thomson, 1946, and Cruregens Chilton, 1882) share neotenous characters, but in Deltanthura the mandible is acute, with a 3-articulate palp and maxillipedal endites are present. Califanthura minuta Kensley & Heard, 1991 may belong in Deltanthura as they share the triangular pleotelson and tapering uropodal exopod, but we refrain from transferring it to Deltanthura as its description lacks the other diagnostic characters of Deltanthura. We provide a revised key to all genera in Paranthuridae Menzies & Glynn, 1968.
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• The protozoan Lagenophrys sp. (Peritrichida: Sessilida: Lagenophryidae) symbiotic on Cryptocandona sp. (Ostracoda: Podocopa: Candonidae) from Hokkaido, Japan.

  Keiichi Kakui, Mizuho Munakata

  Bulletin of the Otaru Museum 35 13 - 16 2022/03/20 [Not refereed][Not invited]
  
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• Predation of tanaidacean crustaceans by Haliclystus tenuis (Cnidaria: Staurozoa) in captivity

  Keiichi Kakui

  Bulletin of the Otaru Museum 35 9 - 12 2022/03/20 [Not refereed][Not invited]
  
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• Three Free-Living Marine Nematodes from Sagami Bay, Japan, with a Description of Wiesoncholaimus jambio sp. nov. (Nematoda: Oncholaimidae)

  Daisuke Shimada, Keiichi Kakui

  Zoological Science 39 (1) 106 - 114 0289-0003 2022/02/01 [Refereed][Not invited]
  
• Description of a New Hamatipeda Species, with an 18S Molecular Phylogeny (Crustacea: Tanaidacea: Typhlotanaidae)

  Keiichi Kakui, Chizue Hiruta

  Zoological Science 39 (1) 140 - 146 0289-0003 2022/02/01 [Refereed][Not invited]
   

  We describe a new typhlotanaid species, Hamatipeda kohtsukai sp. nov., collected from between 167 and 488 m depth in the Sagami Sea, Japan. This is the first record of Hamatipeda from the northern hemisphere. Hamatipeda kohtsukai resembles Hamatipeda trapezoida from the Subantarctic region in having pereonites 1-3 widest anteriorly (not rectangular), but differs from it in the length ratio of antennal articles 4/5; the number of setae on the dactyli of pereopods 1-3, ischia of pereopods 4-6, and carpi of pereopods 4-6; the shape of the unguis of pereopods 4-6; and the shape of the uropodal endopod. We determined partial sequences for the cytochrome c oxidase subunit I (COI; cox1) and 18S rRNA (18S) genes in H. kohtsukai. A phylogenetic reconstruction based on the 18S sequences recovered a highly supported Typhlotanaidae clade containing H. kohtsukai and Typhlotanais mixtus, with Paranarthrura sp. (Agathotanaidae) as the sister taxon. A key to species of Hamatipeda is presented.
• First record of Scutariella japonica (Platyhelminthes: Rhabdocoela) from Hokkaido, Japan, and notes on its host shrimp Neocaridina sp. aff. davidi (Decapoda: Caridea: Atyidae)

  Keiichi Kakui, Tomoyuki Komai

  Aquatic Animals 2022 AA2022-1  2434-8643 2022/01 [Refereed][Not invited]
  
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• Comprehensive Transcriptome Sequencing of Tanaidacea with Proteomic Evidences for Their Silk

  Keiichi Kakui, James F Fleming, Masaru Mori, Yoshihiro Fujiwara, Kazuharu Arakawa

  Genome Biology and Evolution 13 (12) evab281  2021/12 [Refereed][Not invited]
   

  Tanaidaceans are small benthic crustaceans that mainly inhabit diverse marine environments, and they comprise one of the most diverse and abundant macrofaunal groups in the deep sea. Tanaidacea is one of the most thread-dependent taxa in the Crustacea, constructing tubes, spun with their silk, for shelter. In this work, we sequenced and assembled the comprehensive transcriptome of 23 tanaidaceans encompassing 14 families and 4 superfamilies of Tanaidacea, and performed silk proteomics of Zeuxo ezoensis to search for its silk genes. As a result, we identified two families of silk proteins that are conserved across the four superfamilies. The long and repetitive nature of these silk genes resembles that of other silk-producing organisms, and the two families of proteins are similar in composition to silkworm and caddisworm fibroins, respectively. Moreover, the amino acid composition of the repetitive motifs of tanaidacean silk tends to be more hydrophilic, and therefore could be a useful resource in studying their unique adaptation of silk use in a marine environment. The availability of comprehensive transcriptome data in these taxa, coupled with proteomic evidence of their silk genes, will facilitate evolutionary and ecological studies.
• A new species of Expanathura (Crustacea: Isopoda: Anthuroidea) from Iriomote Island, Japan, with a note on male polymorphism

  SHOKI SHIRAKI, MICHITAKA SHIMOMURA, KEIICHI KAKUI

  Zootaxa 5047 (3) 377 - 390 1175-5326 2021/09/30 [Refereed][Not invited]
   

  We describe Expanathura monile sp. nov. from Iriomote Island, Okinawa, Japan, northwestern Pacific. This species resembles E. collaris, E. macronesia, and E. haddae in having very broad uropodal rami, a broad telson, and a moderately shortened pleopod 1 endopod, but differs from these three species in the female having (1) the head with a dorsal V-shaped band of brown pigmentation, (2) the antennular flagellum with 3–4 articles, (3) antennal peduncular article 2 with an outer triangular projection, (4) the uropodal endopod longer than wide, (5) the uropodal exopod with an acute triangular projection, (6) an oval telson, and (7) the posterolateral setae on the telson similar in length. We present a revised key to known species in the genus Expanathura and briefly discuss the male polymorphism observed in E. monile.
• A new cave-dwelling genus and species of Nerillidae (Annelida) from the Ryukyu Islands, Japan

  Katrine Worsaae, Malte J. Hansen, Oscar Axelsen, Keiichi Kakui, Peter R. Møller, Karen J. Osborn, Alejandro Martínez, Brett C. Gonzalez, Norio Miyamoto, Yoshihisa Fujita

  Marine Biodiversity 51 (4) 1867-1616 2021/07/21 [Refereed]
  
• Mismatch between similarity of mitochondrial gene order and phylogenetic distance in Podocopa (Crustacea: Ostracoda)

  Keiichi Kakui, Mizuho Munakata, Hayato Tanaka, Chizue Hiruta

  Zoologischer Anzeiger 293 145 - 148 0044-5231 2021/07 [Refereed][Not invited]
  
• First report of marine horsehair worms (Nematomorpha: Nectonema) parasitic in isopod crustaceans

  Keiichi Kakui, Jun Fukuchi, Daisuke Shimada

  Parasitology Research 120 (7) 2357 - 2362 0932-0113 2021/07 [Refereed][Not invited]
  
• Presumptive stridulatory organs in Paranthura cf. japonica Richardson, 1909 (Isopoda: Cymothoida: Paranthuridae)

  Keiichi Kakui, Shoki Shiraki

  Journal of Crustacean Biology 41 (2) 2021/06/11 [Refereed][Not invited]
  
• First Complete Mitochondrial Genome of a Tanaidacean Crustacean (Arctotanais alascensis)

  Keiichi Kakui, Yasunori Kano

  Zoological Science 38 (3) 267 - 272 0289-0003 2021/06/01 [Refereed][Not invited]
  
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• Heterocypris spadix sp. nov. (Crustacea: Ostracoda: Cypridoidea) from Japan, with Information on Its Reproductive Mode

  Mizuho Munakata, Hayato Tanaka, Keiichi Kakui

  Zoological Science 38 (3) 287 - 296 0289-0003 2021/06/01 [Refereed][Not invited]
  
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• Two New Species of Free-living Marine Nematodes (Nematoda: Axonolaimidae and Tripyloididae) from the Coast of Antarctica

  Daisuke Shimada, Atsushi C. Suzuki, Megumu Tsujimoto, Satoshi Imura, Keiichi Kakui

  Species Diversity 26 (1) 49 - 63 1342-1670 2021/03/22 [Refereed][Not invited]
   

  Two new species of free-living marine nematodes, Odontophora odontophoroides sp. nov. and Parabathylaimus jare sp. nov., are described from the coastal sand of Langhovde, Lützow-Holm Bay, Dronning Maud Land, Antarctica. Odontophora odontophoroides sp. nov. is the only species in Odontophora Bütschli, 1874 that has bicuspidate odontia. Odontophora odontophoroides sp. nov. is similar to species in Odontophoroides Boucher and Helléouët, 1977 and Synodontium Cobb, 1920 in having bicuspidate odontia, but differs in having a didelphic reproductive system in females. Parabathylaimus jare sp. nov. differs from congeners in the unjointed inner labial and cephalic sensilla, the outer labial sensilla three-jointed in males and two-jointed in females, the position of the amphids, the shorter spicules, and the conical tail without long subterminal setae. Modified generic diagnoses and keys to species are included for Odontophora and Parabathylaimus De Coninck and Schuurmans Stekhoven, 1933. A new combination, Parabathylaimus arthropappus (Wieser and Hopper, 1967) comb. nov., is established.
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• Zeuxo ezoensis (Crustacea: Tanaidacea) from an open-air pool on Rishiri Island

  Keiichi Kakui, Mizuho Munakata, Shinri Tomioka

  Rishiri Studies 40 21 - 24 2021/03/01 [Not refereed][Not invited]
  
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• Tube-constructing paratanaoidean tanaidaceans (Crustacea: Peracarida): a brief review

  Keiichi Kakui

  Aquatic Animals AA2021 AA2021-4  2021/02/12 [Refereed][Not invited]
  
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• Dirivultidae (Copepoda: Siphonostomatoida) from hydrothermal vent fields in the Okinawa Trough, North Pacific Ocean, with description of one new species

  Daisuke Uyeno, Keiichi Kakui, Hiromi K. Watanabe, Yoshihiro Fujiwara

  Journal of the Marine Biological Association of the United Kingdom 100 (8) 1283 - 1298 0025-3154 2021/02/10 [Refereed][Not invited]
   

  Two species of dirivultid copepod (Siphonostomatoida), Stygiopontius senckenbergi Ivanenko & Ferrari, 2013 and Dirivultus kaiko sp. nov., were discovered from hydrothermal vent fields in the Okinawa Trough, the western North Pacific. Since S. senckenbergi was originally described based on two adult males from the New Ireland Fore-Arc system, Papua New Guinea, the discovery here represents the second record. This species was attached on ventral setae covered with filamentous bacteria of the deep-sea squat lobster Shinkaia crosnieri (Decapoda: Munidopsidae). The female of S. senckenbergi is described for the first time as well as the nauplius I and the copepodid IV. Sexual dimorphism is shown on several appendages (i.e. antennule, leg 2 and leg 5). The nauplius I shows typical lethithotrophic characteristics. Dirivultus kaiko sp. nov., which was found on the tentacular crown of the siboglinid tubeworm Lamellibrachia columna, differs from its two congeners by the antennule, maxilliped and leg 5 of both sexes. These are the second and third dirivultid species to be reported from Japan.
• A New Species of Free-living Marine Nematode, Proplatycoma tsukubae sp. nov. (Enoplida: Leptosomatidae), from Japan

  Daisuke Shimada, Keiichi Kakui

  Species Diversity 25 (2) 205 - 211 1342-1670 2020/11/30 [Refereed][Not invited]
  
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• Unexpected low genetic differentiation between Japan and Bering Sea populations of a deep-sea benthic crustacean lacking a planktonic larval stage (Peracarida: Tanaidacea)

  Keiichi Kakui, Hidetaka Nomaki, Hironori Komatsu, Yoshihiro Fujiwara

  Biological Journal of the Linnean Society 131 (3) 566 - 574 0024-4066 2020/11/06 [Refereed][Not invited]
   

  Information on the extent, diversity and connectivity of populations is lacking for most deep-sea invertebrates. Species of the order Tanaidacea (Crustacea), one of the most diverse and abundant macrofaunal groups in the deep sea, are benthic, lack a planktonic larval stage, and thus would be expected to have narrow distributional ranges. However, with molecular evidence from the COI gene, we show here that the deep-sea tanaidacean Carpoapseudes spinigena has a distributional range spanning at least 3700 km, from off northern Japan to the south-eastern Bering Sea. Living individuals found in a sediment core indicated that the species is a sedentary burrower. COI analyses revealed a low level of genetic diversity overall, and low differentiation (p-distance, 0.2–0.8%) between the Japan and Bering Sea populations. One hypothesis to explain the low genetic diversity over a broad region is that the Japan population was founded by individuals transported by ocean currents from the Bering Sea. However, due to limited data, other explanations cannot be ruled out. Our results indicate that continued sampling is of fundamental importance to understanding how genetic and taxonomic diversity originate and are maintained in the deep sea.
• A new species of Zeuxo (Crustacea: Peracarida: Tanaidacea) from Japan, with remarks on carapace pigmentation as a potentially useful taxonomic character

  Nobuya Okamoto, Yuki Oya, Keiichi Kakui

  Marine Biology Research 16 (5) 411 - 422 1745-1000 2020/10/22 [Refereed][Not invited]
   

  © 2020 Informa UK Limited, trading as Taylor & Francis Group. We describe Zeuxo ezoensis sp. nov. from Hokkaido, Japan. This species closely resembles Z. phytalensis, Z. shitipingensis and Z. turkensis in having the pleopodal endopod with one inner plumose seta, maxillipedal palp article 4 with one outer simple seta, the left mandible with a wide, denticulate lacinia mobilis and one bifurcate accessory seta, and the right mandible with a peg-like lacinia mobilis and two accessory setae. It differs from them in having (1) antennal article 6 longer than wide, (2) the distal region of the maxillipedal endite with four spiniform setae and two circumplumose setae, (3) maxillipedal palp article 2 with one outer simple seta, (4) the chelipedal carpus with three or four dorsodistal simple setae, (5) the chelipedal dactylus with one inner simple seta, (6) the pereopod-1 basis with one or two ventrodistal simple setae, (7) the pereopod-1 carpus with one ventrodistal simple seta, and (8) the uropod with four or five articles (basal article plus three or four ramus articles). Partial nucleotide sequences for the cytochrome c oxidase subunit I (COI) gene (655 nt) from Z. ezoensis specimens from four localities in Hokkaido showed Kimura 2-parameter (K2P) divergences of 0–0.5% and 0.6–1.5% within and between populations, respectively. Based on the COI data, we examined the phylogenetic position of Z. ezoensis within Zeuxo. Six specimens used for morphological observations and 10 specimens used for COI sequencing showed a similar dorsal pigmentation pattern on carapace. We briefly discuss the validity of using this pattern as a diagnostic character in Zeuxo taxonomy. http://zoobank.org/urn:lsid:zoobank.org:pub:6CB565DB-DAFF-41EF-A06D-EAAE2F619C31.
• A new species of Pantopipetta (Pycnogonida: Austrodecidae) from the North Pacific, with a note on the palp articulation

  Yushi Hosoda, Keiichi Kakui

  Marine Biology Research 16 (5) 390 - 395 1745-1000 2020/10/22 [Refereed][Not invited]
  
• New replacement name for a homonym in Lepeophtheirus (Crustacea: Copepoda: Caligidae)

  Kakui K, Uyeno D

  Zootaxa 4852 (1) 143 - 144 1175-5326 2020/09/14 [Refereed][Not invited]
   

  Markevich (1940) established Pseudolepeophtheirus Markevich, 1940 for Pseudolepeophtheirus longicauda Markevich, 1940 based on copepods collected from the pleuronectid fish Platichthys stellatus (Pallas, 1787). Dojiri & Ho (2013) synonymized the genus and the species with Lepeophtheirus Nordmann, 1832 and Lepeophtheirus parvicruris Fraser, 1920, respectively. Later, Homma et al. (2020) resurrected Markevich’s species as a member of Lepeophtheirus, i.e., as L. longicauda (Markevich, 1940). The last component of the names of both genera is ‘phtheirus’ (transliterated from the Greek φθειρ; Nordmann 1832: 30), a masculine noun, and thus under Article 30.1.2 of the International Code of Zoological Nomenclature (hereinafter, Code; International Commission on Zoological Nomenclature 1999), both generic names are also masculine. The species-group name longicauda might be regarded as either a noun in apposition or as an adjective in the feminine gender, and Markevich (1940) did not specify his intention in this regard. Bearing in mind that ‘cauda’, meaning ‘tail’, actually is a feminine Latin noun and that Markevich did not change the final ‘-a’ to ‘-us’ to match the masculine gender of the genus, we deem that longicauda Markevich, 1940 is a noun in apposition, a position supported by Article 31.2.2 of the Code.
• A new species of Nicippe from the Bering Sea (Crustacea, Amphipoda, Pardaliscidae), with a redescription of N. tumida

  Ko Tomikawa, Keiichi Kakui, Yoshihiro Fujiwara

  ZooKeys 965 (965) 37 - 53 1313-2989 2020/09/03 [Refereed][Not invited]
   

  A new pardaliscid amphipod, Nicippe beringensis, is described from the Bering Sea at depths between 520 and 536 m, and N. tumida Bruzelius, 1859 is redescribed based on specimens from Fredrikshald, Norway, near the species’ type locality. Nucleotide sequences of mitochondrial cytochrome c oxidase subunit I (COI) from the holotype and a paratype of N. beringensissp. nov. are reported. While N. beringensissp. nov. is similar to N. tumida, it differs from the latter in having an asetose palp article 1 of maxilla 1, a gnathopod 1 coxa with a straight distal edge, and in the posterior margin of the basis of gnathopods 1 and 2, and pereopod 3, being heavily setose in females. A key to species of Nicippe is provided.
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• First in situ observations of behavior in deep-sea tanaidacean crustaceans

  Kakui K, Fujiwara Y

  Zoological Science 37 (4) 303 - 306 0289-0003 2020/08/03 [Refereed][Not invited]
   

  We report on the behavior of a deep-sea tanaidacean, Gigantapseudes sp. (Apseudomorpha: Gigantapseudidae), recorded at the depths of 6446-6447 m by the manned submersible Shinkai 6500. From recordings of at least three individuals walking on the sea floor, we confirm that Gigantapseudes sp. is epibenthic, as previously inferred from leg shape. One individual was recorded entering a hole. All individuals in the videos kept pereopods 4 raised from the seafloor while walking, implying that those legs have a function other than for walking, such as mechano- or chemoreception, or posture control. Our in situ observations of behavior are the first for any deep-sea tanaidacean and illustrate the importance of recording high-resolution videos in the deep sea and archiving them for future use. Our identification of Gigantapseudes sp. from video footage provides the first record of this genus from Japanese waters and extends the northern limit of the known generic distribution.
• Integrative taxonomy of Pseudolepeophtheirus longicauda (Crustacea: Copepoda: Caligidae) parasitic on Platichthys stellatus (Actinopterygii: Pleuronectidae)

  Homma R, Uyeno D, Kakui K

  Parasitology International 78 102135  1383-5769 2020/07/24 [Refereed][Not invited]
  
• First record of a tanaidacean crustacean fed upon by an arrow worm (Chaetognatha)

  Kakui K

  Bulletin of the Kitakyushu Museum of Natural History and Human History Series A (Natural History) 18 1 - 4 2020/03/31 [Refereed][Not invited]
  
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• Paradoxapseudes shimojiensis sp. nov. (Crustacea: Tanaidacea: Apseudidae) from a submarine limestone cave in Japan, with notes on its chelipedal morphology and sexual system

  Kakui K, Fujita Y

  Marine Biology Research 16 (3) 195 - 207 2020/03/15 [Refereed][Not invited]
  
• First record of Conchoderma auritum (Linnaeus, 1767) (Crustacea: Cirripedia: Lepadidae) from Rishiri Island

  Tomioka S, Kakui K, Kado R, Sato M

  Rishiri Studies 39 7 - 10 2020/03 [Not refereed][Not invited]
  
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• Shell-exchange behavior in a hermit-crab-like tanaidacean (Crustacea: Malacostraca)

  Kakui K

  Zoological Science 36 468 - 470 0289-0003 2019/12 [Refereed][Not invited]
  
• First report of Teleotanaidae (Crustacea: Tanaidacea) from the Northwestern Pacific, with the description of a new species

  Tanabe Y, Kakui K

  Species Diversity 24 181 - 187 2189-7301 2019/11 [Refereed][Not invited]
  
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• Benthic deep-sea fauna in south of the Kii Strait and the Sea of Kumano, Japan. Second report

  Kimura Taeko, Kimura Shoichi, Kakui Keiichi, Hookabe Natsumi, Kuramochi Toshiaki, Fujita Toshihiko, Ogawa Akito, Kobayashi Itaru, Jimi Naoto, Okanishi Masanori, Yamaguchi Haruka, Hirose Masato, Yoshikawa Akihiro, Fukuchi Jun, Shimomura Michitaka, Kashio Sho, Uyeno Daisuke, Fujiwara Kyoji, Naruse Tohru, Kushida Yuka, Kise Hiroki, Maekawa Yoichi, Nakamura Toru, Okumura Junya, Tanaka Kazuki

  Annals of Field Research and Technology Mie University 三重大学大学院生物資源学研究科 17 (17) 1 - 29 1349-6824 2019/11 [Not refereed][Not invited]
   

  Preliminary results of the deep-sea faunal survey conducted from the TR/V Seisui-maru of Mie University in April 2019 are presented. A total of 20 taxonomists and ecologists working on a wide variety of animal taxa participated in this survey. Surveyed areas included the Kumano Sea（off Mie Prefecture）and south of the Kii Strait（off Tanabe Bay, Wakayama Prefecture）， at depths of 112－775 m. Sampling gears employed were beam trawl and biological dredge. The collection is represented by macrobenthos and meiobenthos from nine animal phyla, including echinoderms, arthropods, molluscans and annelids. The number of phyla occurring in each station varied from seven to eight. The station with most diverse fauna at the phylum level was St. 3B（south of the Kii Strait, 775－661 m depth, mud bottom）．Meiofauna includes priapulids, nematodes and small arthropods such as copepods, tanaidaceans, amphipods, isopods and cumaceans. In addition to freeliving species, cnidarians symbiotic on a gastropod and an antipatharian, and crustaceans parasitic on a fi sh and sea urchins were also collected. Preliminary identifi cations are given for Asteroidea, Ophiuroidea, Holothuroidea, Crinoidea, Cyclopoida, Siphonostomatoida, Tanaidacea, Isopoda, Decapoda, Mollusca, polychaetes, Bryozoa, Cnidaria and Nemertea.
• On the authorship of the genus-group name Curtipleon (Crustacea: Tanaidacea: Metapseudidae)

  Kakui K, Nakano T

  Species Diversity 24 179 - 180 2189-7301 2019/11 [Refereed][Not invited]
  
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• Sexual system in the tanaidacean Falsapseudes bowmani (Crustacea: Malacostraca: Peracarida)

  Kakui K, Hiruta C, Uyeno D

  Invertebrate Biology Wiley 138 (3) e12257  1077-8306 2019/09 [Refereed][Not invited]
  
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• Two Hexapleomera species from Japan, with a new species description and discussion of phylogenetic relationships within Hexapleomera (Crustacea: Tanaidacea)

  Tanabe Y, Kakui K

  Zootaxa 4648 318 - 336 1175-5326 2019/07 [Refereed][Not invited]
   

  We describe Hexapleomera sasuke sp. nov. and provide a supplemental redescription of Hexapleomera urashima Tanabe et al., both of which are based on specimens collected in Japan. Hexapleomera sasuke closely resembles H. urashima, sharing a uropod with four articles, maxillipedal endites with two tiny dorso-subdistal and two distal spiniform setae, a labium with the palp fused to the outer lobe, and the pereopod-1 propodus with an inner subdistal plumose seta. The new species differs from H. urashima in having the basal article of pleopod 3 with three outer plumose setae, the chelipedal carpus with three or four dorsodistal simple setae, the region between the bases of the chelipedal dactylus and fixed finger with three or four simple setae, and deeply pigmented pleopodal rami. We determined partial sequences of the cytochrome c oxidase subunit I (COI) gene (655 nt) from H. sasuke, which proved to be 15.0–15.3% divergent from H. urashima in Kimura 2-parameter (K2P) distance; also in partial sequences of 18S rRNA gene (1888 nt after alignment), 0.8% divergent (K2P distance) was detected between two species. Based on morphology and molecular data, we discuss phylogenetic relationships within Hexapleomera, and propose two morphologically distinct groups, the robusta group and the wombat group.
• Two new and one known species of Phanodermatidae (Nematoda: Enoplida) from Sagami Bay, Japan

  Shimada D, Kakui K

  Zootaxa 4608 484 - 500 1175-5326 2019/05 [Refereed][Not invited]
   

  Two new and one known species of free-living marine nematode belonging to the family Phanodermatidae are described. They were collected during the 12th Japanese Association for Marine Biology (JAMBIO) Coastal Organism Joint Survey off Jogashima, Japan in Sagami Bay, North Pacific Ocean. Phanodermopsis kohtsukai sp. nov. differs from the congeners by the shape of the tail, the longer spicules, and the absence of the gubernaculum. Micoletzkyia nakanoi sp. nov. differs from the congeners by the absence of a circle of cervical setae, the proportion of the tail, the cylindrical gubernaculum without projection, and the position of the vulva. Crenopharynx caudata (Filipjev, 1927) comb. nov. is transferred from the genus Phanodermopsis based on the presence of the long spicules. The morphological characters of the newly collected specimens of C. caudata comb. nov. are in excellent agreement with those shown in the original description of the specimens from Arctic Russia and the previous redescription of the specimens from Skagerrak. The new diagnoses and species lists for these three genera and two dichotomous keys to the males of Micoletzkyia and Crenopharynx are provided. 
• Topotype-based DNA barcode of the parasitic isopod Pseudione nephropsi (Bopyridae), with a supplementary morphological description

  Kakui K, Shimomura M, Kimura S, Kimura T

  Species Diversity 24 103 - 108 2189-7301 2019/05 [Refereed][Not invited]
  
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• First molecularly confirmed conspecific male and female pair in Konariinae (Crustacea: Tanaidacea), with the description of a new species

  Kakui K, Uyeno D, Naruse T

  Species Diversity 24 (1) 49 - 60 2189-7301 2019/05 [Refereed][Not invited]
  
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• First record of Hemichela nanhaiensis (Pycnogonida: Ammotheidae) from Japanese waters, with the first description of females

  Hosoda Y, Tomioka S, Kakui K

  Species Diversity 23 215 - 218 1342-1670 2018/11 [Refereed][Not invited]
  
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• Benthic deep-sea fauna in the Sea of Kumano, Mie Prefecture, Japan

  Kimura Taeko, Kimura Shoichi, Jimi Naoto, Kakui Keiichi, Tomioka Shinri, Oya Yuki, Matsumoto Yu, Tanabe Yuki, Hasegawa Naohiro, Hookabe Natsumi, Homma Riko, Hosoda Yushi, Fujimoto Shinta, Kuramochi Toshiaki, Fujita Toshihiko, Ogawa Akito, Kobayashi Itaru, Ishida Yoshiaki, Tanaka Hayate, Onishi Haruka, Shimetsugu Miho, Yoshikawa Akihiro, Tanaka Masaatsu, Kushida Yuka, Maekawa Yoichi, Nakamura Toru, Okumura Junya, Tanaka Kazuki

  Annals of Field Research and Technology Mie University 三重大学大学院生物資源学研究科 16 (16) 1 - 32 1349-6824 2018/10 [Not refereed][Not invited]
   

  In this study, we had investigated the benthic deep-sea fauna using the dredge and beam trawl in the region from the continental shelf to the continental slope of the Sea of Kumano, Mie Prefecture, during the No．1722 research voyage of the training ship Seisui-Maru of Mie University. The survey was carried out at 16 stations covering a depth range of 113－1059 m. The results of the survey, 14 phyla had been confirmed. Arthropod, echinoderm, annelid and molluscan macrobenthos were collected from all of the stations. The phylum number of each station was in the range from 4 to 11. The largest number of phyla had been confi rmed at St．10D of boulders bottom（768－800 m depth）. Meiobenthos confi rmed in our sample were kinorhynchs, nematodes, tardigrades, loriciferans and small arthropods such as tanaidaceans, copepods and cumaceans. In addition to free-living species, parasitic copepods, isopods, platyhelminthes, acanthocephalans and nematodes had been found in fish, crustaceans and polychaetes.
• Molecular Phylogeny of the Family Capitellidae (Annelida)

  Shinri Tomioka, Keiichi Kakui, Hiroshi Kajihara

  ZOOLOGICAL SCIENCE 35 (5) 436 - 445 0289-0003 2018/10 [Refereed][Not invited]
   

  Capitellids have emerged as monophyletic in most but not all recent molecular phylogenies, indicating that more extensive taxon sampling is necessary. In addition, monophyly of most or all capitellid genera was questionable, as some diagnostic characters vary ontogenetically within individuals. We tested the monophyly of Capitellidae and eight capitellid genera using phylogenetic analyses of combined 18S, 28S, H3, and COI gene sequences from 36 putative capitellid species. In our trees, Capitellidae formed a monophyletic sister group to Echiura, and Capitella was also monophyletic, separated by a long branch from other capitellids. Well-supported clades each containing representatives of different genera, or containing a subset of species within a genus, indicated that Barantolla, Heteromastus, and Notomastus are likely not monophyletic. We mapped three morphological characters traditionally used to define capitellid genera (head width relative to width of first segment, number of thoracic segments, and number of segments with capillary chaetae) onto our tree. While Capitella showed unique character states, states in the other genera were decidedly not phylogenetically informative. Morphology-based capitellid taxonomy will require a fine-scale reevaluation of character states and detection of new characters.
• First report of the chelonophilic tanaidid Hexapleomera urashima from an environment other than the surface of sea turtles

  Keiichi Kakui

  Fauna Ryukyuana 45 5 - 8 2018/09 [Refereed][Not invited]
  
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• Targeted gene disruption by use of CRISPR/Cas9 ribonucleoprotein complexes in the water flea Daphnia pulex

  Chizue Hiruta, Keiichi Kakui, Knut E. Tollefsen, Taisen Iguchi

  Genes to Cells 23 (6) 494 - 502 1365-2443 2018/06/01 [Refereed][Not invited]
   

  The microcrustacean Daphnia pulex is an important model for environmental, ecological, evolutionary and developmental genomics because its adaptive life history displays plasticity in response to environmental changes. Even though the whole-genome sequence is available and omics data have actively accumulated for this species, the available tools for analyzing gene function have thus far been limited to RNAi (RNA interference) and TALEN (the transcription activator-like effector nuclease) systems. The development of the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated 9) system is thus expected to further increase the genetic tractability of D. pulex and to advance the understanding of this species. In this study, we developed a genome editing system for D. pulex using CRISPR/Cas9 ribonucleoprotein complexes (Cas9 RNPs). We first assembled a CRISPR single-guide RNA (sgRNA) specific to the Distal-less gene (Dll), which encodes a homeodomain transcription factor essential for distal limb development in invertebrates and vertebrates. Then, we injected Cas9 RNPs into eggs and evaluated its activity in vivo by a T7 endonuclease I assay. Injected embryos showed defective formation of the second antenna and disordered development of appendages, and indel mutations were detected in Dll loci, indicating that this technique successfully knocked out the target gene.
• Tsuranarthrura shinsei, a new genus and species in Anarthruridae (Crustacea: Tanaidacea) from the Northwestern Pacific

  Keiichi Kakui, Shinri Tomioka

  Species Diversity 23 (1) 61 - 68 1342-1670 2018 [Refereed][Not invited]
   

  We establish the new anarthrurid genus Tsuranarthrura gen. nov. based on the new species T. shinsei sp. nov. collected from 1890 m depth offthe eastern coast of Japan, northwestern Pacific Ocean. Tsuranarthrura gen. nov. is the third paratanaoid genus with members having a fused segment composed of pereonite 6 and the pleon, a character state previously restricted to the genera Coalecerotanais Larsen, 2003 (Family incertae sedis) and Metagathotanais Bird and Holdich, 1988 (Family Agathotanaidae). Among anarthrurid genera, Tsuranarthrura gen. nov. is similar to Anarthrura Sars, 1882, Anarthrurella Bird, 2004, and Crenicarpus Drumm and Bird, 2016 in having the labrum not laterally compressed and the antenna with naked fourth and fifth articles from the distal end. However it differs from the latter three in having pereonite 6 fused with the pleon, the maxillipedal endite with a distal seta, the chelipedal merus with a ventral simple seta, and the merus naked on pereopods 2 and 3. We also present the nucleotide sequence for part of the cytochrome c oxidase subunit I (COI) gene in T. shinsei for future use in DNA barcoding or phylogeny.
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• Haimormus shimojiensis, a new genus and species of Pseudozeuxidae (Crustacea: Tanaidacea) from a submarine limestone cave in Northwestern Pacific

  Keiichi Kakui, Yoshihisa Fujita

  PeerJ 2018 (4) e4720  2167-8359 2018 [Refereed][Not invited]
   

  We establish a new pseudozeuxid genus Haimormus gen. nov. based on a new species Haimormus shimojiensis sp. nov. which was collected from a submarine limestone cave with the entrance at 35 m depth, in the Northwestern Pacific Ocean. H. shimojiensis differs from the other confamilial members, Pseudozeuxo belizensis Sieg, 1982 and Charbeitanais spongicola Bamber & Bird, 1997, in having the pleonite 1 without the pleopod, the pereopods 2 and 3 propodus with a ventral spiniform seta, and the pereopods 4-6 propodus with one long and two short dorsodistal setae. A key to females of species of Pseudozeuxidae is presented. This is the first tanaidacean report from submarine caves around Japan.
• A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella

  Hiroaki Nakano, Hideyuki Miyazawa, Akiteru Maeno, Toshihiko Shiroishi, Keiichi Kakui, Ryo Koyanagi, Miyuki Kanda, Noriyuki Satoh, Akihito Omori, Hisanori Kohtsuka

  BMC Evolutionary Biology 18 (1) 1471-2148 2017/12/18 [Refereed][Not invited]
   

  After publication of Nakano et al. (2017) [1], the authors became aware of the fact that the new species-group name erected for the two specimens of a Japanese xenoturbellid species in the article is not available because Nakano et al. (2017) [1] does not meet the requirement of the amendment of Article 8.5.3 of the International Code of Zoological Nomenclature (the Code) [2]. The authors therefore describe the two xenoturbellids as a new species again in this correction article. Methods for morphological observation, DNA extraction and sequencing were as described in Nakano et al. (2017) [1]. The holotype and paratype specimens are deposited in the National Museum of Nature and Science, Tsukuba (NSMT), Japan. The DNA sequences obtained were deposited in the International Nucleotide Sequence Database (INSD). Genus Xenoturbella Westblad, 1949 [3] Xenoturbella japonica sp. nov. http://zoobank.org/6C4EA6F8-8AC1-4511-A59B-BCB 60729A85A (Figs. 1-3, Additional files 1-3 in Nakano et al. (2017) [1]) Etymology. Named for the locality where the specimens were collected. Holotype.NSMT-Xe 2, female (Figs. 1, 3, Additional files 1, 2 in Nakano et al. (2017) [1]), off Jogashima, Miura, Kanagawa, Japan, 35°06.93" N 139°33.72" E to 35°06.95" N 139°33.33" E, 380-554 m depth, December 9th, 2015. Paratype. NSMT-Xe 1, juvenile, sex unknown (Figs. 2, 3, Additional files 1, 3 in Nakano et al. (2017) [1]), Sanriku coast, Iwate, Japan, 39°37.86" N 142°18.22" E to 39°37. 00" N 142°17.60" E, 517-560 m depth, July 18th, 2013. Description of female. Based on holotype. Body 5.3 cm in length pale orange with coloration getting darker toward the anterior. In live specimens, muscles hold the dorsal body wall in a W-shape (three ridges and two troughs). Body shape actively changes by contracting and elongating when alive. Ring furrow and side furrow are present. Ventral mouth present, oval-shaped, just anterior to ring furrow. Glandular network present over ventral surface, starting near anterior tip of body and ending just in front of ring furrow. Internally, body wall with epidermis, circular and longitudinal muscles, parenchyma and gastrodermis present. Oocytes present within intestine. Statocyst situated near anterior tip of body, just inside side furrow. Description of juvenile. Based on paratype. Similar to female, but differs as follows: body 1.1 cm in length pale orange in color dorsal body surface in live specimen smooth, lacking longitudinal ridges and troughs, similar to that of X. bocki gametes not observed. Ventral glandular network not detected externally, but observed with microCT imaging. Genetic information. Whole mitochondrial genome sequences (15,244 bp in holotype 15,249 bp in paratype) and partial Histone H3 gene sequences (346 bp in holotype 413 bp in paratype) were determined and deposited as INSD accession numbers LC228486, LC228485, LC228579 and LC228578, respectively. Remarks. The same species name presented in Nakano et al. (2017) [1] is nomen nudum as the publication does not meet the requirement of the amendment of Article 8.5.3 of the Code [2]. The present erratum fully meets the amended provisions of the Code, and thus this work makes the specific name japonica in the combination of Xenoturbella japonica available. Acknowledgements The authors would like to thank Takafumi Nakano for discussions concerning this erratum.
• A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella

  Hiroaki Nakano, Hideyuki Miyazawa, Akiteru Maeno, Toshihiko Shiroishi, Keiichi Kakui, Ryo Koyanagi, Miyuki Kanda, Noriyuki Satoh, Akihito Omori, Hisanori Kohtsuka

  BMC EVOLUTIONARY BIOLOGY 17 (1) 245  1471-2148 2017/12 [Refereed][Not invited]
   

  Background: Xenoturbella is a group of marine benthic animals lacking an anus and a centralized nervous system. Molecular phylogenetic analyses group the animal together with the Acoelomorpha, forming the Xenacoelomorpha. This group has been suggested to be either a sister group to the Nephrozoa or a deuterostome, and therefore it may provide important insights into origins of bilaterian traits such as an anus, the nephron, feeding larvae and centralized nervous systems. However, only five Xenoturbella species have been reported and the evolutionary history of xenoturbellids and Xenacoelomorpha remains obscure. Results: Here we describe a new Xenoturbella species from the western Pacific Ocean, and report a new xenoturbellid structure - the frontal pore. Non-destructive microCT was used to investigate the internal morphology of this soft-bodied animal. This revealed the presence of a frontal pore that is continuous with the ventral glandular network and which exhibits similarities with the frontal organ in acoelomorphs. Conclusions: Our results suggest that large size, oval mouth, frontal pore and ventral glandular network may be ancestral features for Xenoturbella. Further studies will clarify the evolutionary relationship of the frontal pore and ventral glandular network of xenoturbellids and the acoelomorph frontal organ. One of the habitats of the newly identified species is easily accessible from a marine station and so this species promises to be valuable for research on bilaterian and deuterostome evolution.
• Oncholaimus langhovdensis sp. nov. (Nematoda: Enoplea: Oncholaimida), a new species of free-living marine nematode from Langhovde, Dronning Maud Land, East Antarctica

  Daisuke Shimada, Atsushi C. Suzuki, Megumu Tsujimoto, Satoshi Imura, Keiichi Kakui

  Species Diversity 22 (2) 151 - 159 1342-1670 2017/12/01 [Refereed][Not invited]
   

  A new species of free-living marine nematode, Oncholaimus langhovdensis sp. nov., is described from the intertidal zone of Langhovde (near Syowa Station), Dronning Maud Land, East Antarctica. It closely resembles 11 congeners in the conico-cylindrical tail shape present in males and amphid and excretory pore positions, short spicules, and Demanian system structure present in females. However, it mainly differs from these congeners in body size, de Man's ratios, tail length and shape, and Demanian system structure present in females. Oncholaimus langhovdensis sp. nov. also resembles four congeners known only by females, but it can be distinguished from them based on the tail length and uvette position. In addition to O. langhovdensis sp. nov., two undescribed species (Tripyloididae gen. sp. and Axonolaimidae gen. sp.) and four unidentified species (Sphaerolaimus sp., Oncholaimidae gen. sp., Comesomatidae gen. sp., and Chromadorida fam. gen. sp.) were found from the same locality.
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• Hexapleomera urashima sp nov (Crustacea: Tanaidacea), a tanaidid epibiotic on loggerhead sea turtles at Yakushima Island, Japan

  Yuki Tanabe, Ryota Hayashi, Shinri Tomioka, Keiichi Kakui

  ZOOTAXA 4353 (1) 146 - 160 1175-5326 2017/11 [Refereed][Not invited]
   

  We describe Hexapleomera urashima sp. nov. from the carapaces of loggerhead sea turtles (Caretta caretta) on Yakushima Island, southwestern Japan, the primary nesting site for the North Pacific population of this turtle. Hexapleomera urashima closely resembles H. edgari Bamber collected from Australian loggerheads (South Pacific population), sharing a uropod with four articles and maxillipedal endites with distal spiniform setae, but differs in having the maxillipedal coxa with two simple setae, the maxillipedal endite with two tiny dorsosubdistal and two distal spiniform setae, the labial palp fused to the outer lobe of the labium, and the basal article of pleopod 3 without inner setae. Several characters (e.g., size or presence/absence of a dorsal triangular process on the male fixed finger; number of inner setae on the pleopodal endopod), assumed to be diagnostic for species in Hexapleomera, actually vary within H. urashima, indicating that reassessment of species diagnoses is warranted. Hexapleomera urashima showed two COI haplotypes differing by one substitution, but separated from representatives of four other genera by 32.2-48.4% K2P distance. Indices of saturation substitution indicated that COI is not useful for phylogeny reconstruction within Tanaididae.
• Tube construction by a tanaidacean crustacean using a novel mucus secretion system involving the anal opening

  Keiichi Kakui, Chizue Hiruta

  ZOOLOGICAL LETTERS 3 2056-306X 2017/11 [Refereed][Not invited]
   

  Background: Animals in diverse aquatic groups construct tubes using mucus and filaments, and the acquisition of this capability has likely played an important role in the evolution and diversification of small benthic animals. Tanaidacea is a crustacean order that includes tube-constructing species, most of which belong to Tanaidoidea and Paratanaoidea, with a few in Kalliapseudidae (Apseudoidea). Two previously reported systems used in tube construction are the thoracic-gland system, with secretory glands in thoracic segments (pereonites), and the pereopodal-gland system, with glands in pereopods. Results: Parapseudidae (Apseudoidea) also includes a tube-constructing species, Parapseudes algicola (Shiino, 1952), which lacks large secretory glands in all pereonites and pereopods, but has a pair of acinar glands in the pleotelson, lateral to the gut. Each gland connects to the gut via a short duct, and thence to the exterior via the anal opening. Secretions released from these glands are used to construct tubes, and contain acidic and neutral mucopolysaccharides. Conclusion: We report in P. algicola a third, novel secretory system, here termed the pleotelsonal-gland system, used for tube construction in Tanaidacea. It is similar to the secretory system in some "thalassinidean" decapods; both systems have secretory glands connecting to the gut and thence to the anal opening as the outlet; however, these gland systems likely evolved independently. Recent discoveries of novel secretory systems for tube construction in Tanaidacea suggest that information from smaller, less well-known groups will be necessary to understand how acquisitions of tube-constructing capability affected diversification in animals.
• Morphology of a newly recorded species, Eremaeozetes octomaculatus Hammer, 1973 from Indonesia (Acari: Oribatida: Eremaeozetidae), with its genetic information

  Badamdorj Bayartogtokh, Satoshi Shimano, Wataru Hagino, Keiichi Kakui, Shimpei F. Hiruta, Sri Hartini

  International Journal of Acarology 43 (6) 444 - 449 0164-7954 2017/08/18 [Refereed][Not invited]
   

  Herein, the supplementary description of adults of Eremaeozetes octomaculatu along with illustrations is provided, which is recorded for the first time from Indonesia. Eremaeozetes octomaculatus is an Oriental and Oceanian species, currently known from the Western Samoa Island of Polynesia, Luzon and Mindanao Islands of the Philippines, Okinawa Island in the Ryukyu Archipelago of Japan, and recently we found it in the Java Island of Indonesia. This species appears to be primarily an inhabitant of tropical forests, and it prefers mosses and fungi growing on stones, tree trunks, as well as forest floors and decomposed plant debris. Data of analysis on 28S D3 gene sequence of this species is provided. Comparison of the E. octomaculatus sequence with other oribatid mites 28S D3 sequences identifies that Scapheremaeus is the closest relative to E. octomaculatus with regard to the species included in this analysis, but the relationship was supported by week bootstrap value.
• A new species of Tanaopsis (Crustacea: Tanaidacea) from Japan, with remarks on the functions of serial ridges and grooves on the appendages

  Keiichi Kakui, Daisuke Shimada

  ZOOTAXA 4282 (2) 324 - 336 1175-5326 2017/06 [Refereed][Not invited]
   

  We describe Tanaopsis japonica sp. nov. from intertidal and nearshore habitats around Hokkaido Island, northern Japan. This species closely resembles T. chotkarakde Bird & Bamber, 2000 and T. rawhitia Bird, 2011 in having the uropod with the endopod biarticulate and the exopod uniarticulate, but differs from them in the following characters: pereonite 4 as long as pereonite 5; mandibles lacking the molar; the number of simple setae on the antenna, propodal palm, and dactylus of pereopods 1-3; the number of spiniform setae on the cutting surface of the chelipedal dactylus; and the number of setae on the pleopods. We also determined a nearly complete nucleotide sequence for the 18S rRNA gene in T. japonica. In both sexes, Tanaopsis japonica sp. nov. bears serial ridges and grooves on the chela, antennule, and antenna. Parallel, fringed hatch marks on the chelipedal dactylus may function in stridulation. A series of denticulate ridges on the dorsal surface of antennal article 2 faces the ventral side of article 1 of the antennule, where there is a ventral series of slight grooves. Although the ranges of motion of the antennule and antenna were unclear, the ridges and grooves on the antenna and antennule may also function in producing sound. Two outer series of ridges on the chela, together with an outer furrow on the chela, may function in digging, by allowing bottom-sediments to be efficiently pushed aside.
• Difference in Size at Maturity in Annual and Overwintering Generations in the Tanaidacean Zeuxo sp in Oshoro Bay, Hokkaido, Japan

  Keiichi Kakui, Yoshinobu Hayakawa, Haruo Katakura

  ZOOLOGICAL SCIENCE 34 (2) 129 - 136 0289-0003 2017/04 [Refereed][Not invited]
   

  We investigated the life cycle of the tanaidid Zeuxo sp. 1 (Crustacea: Peracarida: Tanaidacea), which lives epiphytically in dwelling tubes on the algae Sargassum spp. and Neorhodomela aculeata in Oshoro Bay, Hokkaido, Japan. We obtained data on its population size distribution, age structure, and reproductive phenology through monthly sampling from April 2011 to June 2012. From these data, we detected an overwintering group (F-0) that arises from mancae that are released in autumn, overwinters, reproduces the following spring, and then disappears. The overwintering group produces mancae (F-1) that reach maturity and themselves reproduce within six weeks after release; the F-1 mancae give rise to an F-2 and possibly an F-3 generation within a single summer. We refer to individuals that reproduce in the same summer that they were released as the 'annual group'. Reproduction overall was restricted to the period from May to October, when the seasurface temperature exceeded 10 degrees C. During both years, overwintering females first became reproductive in May. Reproduction in the annual group began in June and continued through mid-October. Mancae were observed in samples from June through October. The two groups differed significantly in size at reproduction; compared to the annual group, females in the overwintering group reproduced at larger minimum and average body sizes, and males began to express enlarged chelae, a secondary sexual character, at a larger size. The difference in size at maturity may be related to the differences in water temperature during the main period of growth and maturation.
• Habitat of a tanaidacean Apseudes nipponicus Shiino, 1937

  Kakui K, Suzuki A, Nakano H, Kohtsuka H

  Bulletin of the Kitakyushu Museum of Natural History and Human History Series A (Natural History) 15 1 - 3 2017/03 [Refereed][Not invited]
  
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• Rediscovery and redescription of the abyssal squat lobster Munidopsis petalorhyncha Baba, 2005 (Crustacea: Decapoda: Munidopsidae) from the Northwest Pacific

  Tomoyuki Komai, Ivan Marin, Keiichi Kakui

  ZOOTAXA 4226 (1) 93 - 102 1175-5326 2017/01 [Refereed][Not invited]
   

  A poorly known abyssal squat lobster, Munidopsis petalorhyncha Baba, 2005 [= Munidopsis subsquamosa latimana Birstein & Zarenkov, 1970], is redescribed on the basis of the holotype from the Kuril Trench at depths of 5060-5130 m and two recently collected specimens from off Japan at depths of 5353-5382 m. Examination of those specimens enabled us to reassess diagnostic characters of the species. Munidopsis petalorhyncha appears closest to M. thieli Trkay, 1975, known from abyssal plain of the eastern Atlantic, but the spinulose lateral margins of the rostrum, the presence of a distinct lateral eye spine, the presence of a distomesial spine on article 3 of the antennal peduncle and spinose ventral (flexor) margins of meri of pereopods 2-4 distinguish M. petalorhyncha from M. thieli.
• 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 1175-5326 2017/01 [Refereed][Not invited]
   

  A new species of polychaete, Flabegraviera fujiae sp. nov., is described and the first report of F. mundata (Gravier, 1906) from the shallow water around Syowa Station, Antarctica, is presented. Flabegraviera fujiae sp. nov. resembles F. profunda Salazar-Vallejo, 2012 but is discriminated from the latter by having eyes and an exposed cephalic cage. The specimen of F. mundata was collected from a depth of 8 m, providing the shallowest record of this species to date.
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• Review of the taxonomy, diversity, ecology, and other biological aspects of Order Tanaidacea from Japan and surrounding waters

  Kakui K

  In: Motokawa M, Kajihara H (Eds) Species Diversity of Animals in Japan, Springer 603 - 627 2016/12 [Refereed][Invited]
  
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• An overview of recent marine-biodiversity research in Japan

  Kajihara H, Kakui K

  In: Motokawa M, Kajihara H (Eds) Species Diversity of Animals in Japan, Springer 25 - 45 2509-5536 2016/12 [Refereed][Invited]
  
• Opisa takafuminakanoi, a new species of Opisidae from Hokkaido, Japan (Crustacea: Amphipoda)

  Yukiko Narahara-Nakano, Keiichi Kakui, Ko Tomikawa

  ZOOTAXA 4200 (2) 335 - 339 1175-5326 2016/11 [Refereed][Not invited]
  
• 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 0289-0003 2016/10 [Refereed][Not invited]
   

  Capitella teleta Blake et al., 2009 is an opportunistic capitellid originally described from Massachusetts (USA), but also reported from the Mediterranean, NW Atlantic, and North Pacific, including Japan. This putatively wide distribution had not been tested with DNA sequence data; intraspecific variation in morphological characters diagnostic for the species had not been assessed with specimens from non-type localities, and the species status of the Japanese population(s) was uncertain. We examined the morphology and mitochondrial COI (cytochrome c oxidase subunit I) gene sequences of Capitella specimens from two localities (Ainan and Gamo) in Japan. Specimens from Ainan and Gamo differed from C. teleta from Massachusetts in methyl-green staining pattern, shape of the genital spines, and shape of the capillary chaetae; we concluded that these characters vary intraspecifically. Species delimitation analyses of COI sequences suggested that worms from Ainan and Massachusetts represent C. teleta; these populations share a COI haplotype. The specimens from Gamo may represent a distinct species and comprise a sister group to C. teleta s. str.; we refer to the Gamo population as Capitella aff. teleta. The average Kimura 2-parameter (K2P) distance between C. teleta s. str. and C. aff. teleta was 3.7%. The COI data indicate that C. teleta actually occurs in both the NW Atlantic and NW Pacific. Given the short planktonic larval duration of C. teleta, this broad distribution may have resulted from anthropogenic dispersal.
• Three new brackish-water thalassocypridine species (Crustacea: Ostracoda: Paracyprididae) from the Ryukyu Islands, southwestern Japan

  Shimpei F. Hiruta, Keiichi Kakui

  ZOOTAXA 4169 (3) 515 - 539 1175-5326 2016/09 [Refereed][Not invited]
   

  We describe three new species of brackish-water ostracods representing two genera in the ostracod tribe Thalassocypridini from mangrove forests in the Ryukyu Islands, subtropical southwestern Japan, and provide their barcoding sequences for the mitochondrial cytochrome c oxidase subunit I (COI) gene. Mangalocypria ryukyuensis sp. nov. was found on Okinawa Island. We also found a Mangalocypria population on Ishigaki Island that was morphologically identical to M. ryukyuensis on Okinawa, but an individual differed by 4.7% in COI sequence (K2P distance) from an individual from Okinawa. This is the first record for Japan of a species in Mangalocypria. Paracypria longiseta sp. nov., obtained from Okinawa Island, is similar to Pontoparta hartmanni. Paracypria plumosa sp. nov. from Ishigaki Island is similar to Pa. adnata described from Yakushima Island, Japan. The COI genetic distance between individuals of Pa. longiseta and Pa. plumosa was roughly as large as that between either of these species and individuals in the Mangalocypria populations. Our study underscores that genera in Thalassocypridini may not represent natural groups, and that this tribe needs taxonomic revision.
• Diversity of sexual and reproductive systems in Tanaidacea

  Kakui K

  Cancer 日本甲殻類学会 25 (25) 131 - 136 0918-1989 2016/08 [Not refereed][Invited]
  
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• Multiple processes generate productivity-diversity relationships in experimental wood-fall communities

  Craig R. McClain, James P. Barry, Douglas Eernisse, Tammy Horton, Jenna Judge, Keiichi Kakui, Chris Mah, Anders Waren

  ECOLOGY 97 (4) 885 - 898 0012-9658 2016/04 [Refereed][Not invited]
   

  Energy availability has long been recognized as a predictor of community structure, and changes in both terrestrial and marine productivity under climate change necessitate a deeper understanding of this relationship. The productivity-diversity relationship (PDR) is well explored in both empirical and theoretical work in ecology, but numerous questions remain. Here, we test four different theories for PDRs (More-Individuals Hypothesis, Resource-Ratio Theory, More Specialization Theory, and the Connectivity-Diversity Hypothesis) with experimental deep-sea wood falls. We manipulated productivity by altering wood-fall sizes and measured responses after 5 and 7 years. In November 2006, 32 Acacia sp. logs were deployed at 3203 m in the Northeast Pacific Ocean (Station Deadwood: 36.154098 degrees N, 122.40852 degrees W). Overall, we found a significant increase in diversity with increased wood-fall size for these communities. Increases in diversity with wood-fall size occurred because of the addition of rare species and increases of overall abundance, although individual species responses varied. We also found that limited dispersal helped maintain the positive PDR relationship. Our experiment suggests that multiple interacting mechanisms influence PDRs.
• Mesoscale morphology at nanoscale resolution: serial block-face scanning electron microscopy reveals fine 3D detail of a novel silk spinneret system in a tube-building tanaid crustacean

  Tomonari Kaji, Keiichi Kakui, Naoyuki Miyazaki, Kazuyoshi Murata, A. Richard Palmer

  FRONTIERS IN ZOOLOGY 13 1742-9994 2016/03 [Refereed][Not invited]
   

  Background: The study of morphology is experiencing a renaissance due to rapid improvements in technologies for 3D visualization of complex internal and external structures. But 3D visualization of the internal structure of mesoscale objects - those in the 10-1000 mu m range - remains problematic. They are too small for microCT, many lack suitable specific fluorescent markers for confocal microscopy, or they require labor-intensive stacking and smoothing of individual TEM images. Here we illustrate the first comprehensive morphological description of a complete mesoscale biological system at nanoscopic resolution using ultra-modern technology for 3D visualization - serial block-face scanning electron microscopy (SBF-SEM). The SBF-SEM machine combines an in-chamber ultramicrotome, which creates a serial array of exposed surfaces, with an SEM that images each surface as it is exposed. The serial images are then stacked automatically by 3D reconstruction software. We used SBF-SEM to study the spinneret (thread-producing) system of a small, tube-dwelling crustacean that weaves tubes of silk. Thread-producing ability is critical for the survival of many small-bodied animals but the basic morphology of these systems remains mysterious due to the limits of traditional microscopy. Results: SBF-SEM allowed us to describe - in full 3D - well-resolved components (glands, ducts, pores, and associated nerves and muscles) of the spinneret system in the thoracic legs and body segments of Sinelobus sp. (Crustacea, Peracarida, Tanaidacea), a tube-building tanaid only 2 mm in body length. The 3D reconstruction by SBF-SEM revealed at nanoscale resolution a unique structure to the gland and duct systems: In each of three thread-producing thoracic segments, two separate ducts, derived from two separate glands located in the body, run through the entire leg and merge at the leg tip just before the spinneret pore opening. We also resolved nerves connecting to individual setae, spines and pores on the walking legs, and individual muscles within each leg segment. Conclusions: Our results significantly expand our understanding of the diversity of spinneret systems in the Crustacea by providing the first well-resolved view of spinneret components in the peracarid crustacean order, Tanaidacea. More significantly, our results reveal the great power of SBF-SEM technology for comprehensive studies of the morphology of microscopic animals.
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• Descriptions of two new species of Rhizorhina Hansen, 1892 (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on tanaidacean crustaceans, with a note on their phylogenetic position

  Keiichi Kakui

  SYSTEMATIC PARASITOLOGY 93 (1) 57 - 68 0165-5752 2016/01 [Refereed][Not invited]
   

  Two new species of nicothoid copepod are described. Rhizorhina ohtsukai n. sp. found on a leptocheliid (Leptochelia sp.) collected at depths of 151-136 m in the North Pacific Ocean is most similar to Rhizorhina aesthetes Boxshall & Harrison, 1988 but can be distinguished by the possession of a narrower body with a rounded anterior end, and in the position of the gonopores. Rhizorhina soyoae n. sp. found on an apseudid (Fageapseudes sp.) collected at depths of 1,595-1,557 m in East China Sea most closely resembles Rhizorhina tanaidaceae Gotto, 1984 but differs in having a narrower body with a rounded anterior end. Partial nucleotide sequences of the cytochrome c oxidase subunit I (COI) gene were obtained from the two copepods in order to enable future barcoding. A phylogenetic reconstruction based on the 18S rRNA gene placed the copepods within the Siphonostomatoida Burmeister, 1835, with the nicothoid Choniosphaera maenadis (Bloch & Gallien, 1933), and separate from the Rhizorhina spp. clade, suggesting that the family Nicothoidae Dana, 1849 is not monophyletic. This is the third report of copepods parasitic on tanaidacean crustaceans.
• 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 0289-0003 2015/12 [Refereed][Not invited]
   

  Based on specimens collected subtidally (similar to 10 m in depth) in Tomioka Bay, Japan, we describe the palaeonemertean Tubulanus tamias sp. nov., which differs from all its congeners in body coloration. In molecular phylogenetic analyses based on partial sequences of the nuclear 18S and 28S rRNA genes and histone H3, as well as the mitochondrial 16S rRNA and cytochrome c oxidase subunit I genes, among selected palaeonemerteans, T. tamias nested with part of the congeners in Tubulanus, while the genus as currently diagnosed appears to be non-monophyletic. Molecular cloning detected polymorphism in 28S rDNA sequences in a single individual of T. tamias, indicating incomplete concerted evolution of multiple copies. Tubulanus tamias is peculiar among tubulanids in having 9-10 pigment-cup eyes in the epidermis on either side of the head anterior to the cerebral sensory organs, and remarkably there are two types of eyes. The anterior 8-9 pairs of eyes, becoming larger from anterior to posterior, are completely embedded in the epidermis and proximally abutting the basement membrane; each pigment cup contains bundle of up to seven, rod-shaped structure that resemble a rhabdomeric photoreceptor cell. In contrast, the posterior-most pair of eyes, larger than most of the anterior ones, have an optical cavity filled with long cilia and opening to the exterior, thus appearing to have ciliary-type photoreceptor cells. The size and arrangement of the eyes indicate that the posterior-most pair of eyes are the remnant of the larval (or juvenile) eyes.
• The first record of a species of Clausiidae (Copepoda: Cyclopoida) from Japanese waters, with the proposal of a new genus.

  Uyeno D, Kakui K

  Species Diversity 20 (2) 153 - 158 1342-1670 2015/11 [Refereed][Not invited]
  
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• 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 2352-4855 2015/11 [Refereed][Not invited]
   

  JAMBIO, Japanese Association for Marine Biology, has been organizing JAMBIO Coastal Organism Joint Surveys at Shimoda Marine Research Center, University of Tsukuba, and Misaki Marine Biological Station, the University of Tokyo. The aims of the Surveys are to uncover the benthic marine fauna of the coastal areas in and around Sagami Bay, and to form a collaborative network between marine biologists across Japan. We have so far performed six surveys, with over 100 participants in total, using common equipment such as dredges, bottom mud samplers, and epibenthic sleds. Even in Sagami Bay, one of the most intensively studied marine environments in the world, we have succeeded in collecting about 50 probable undescribed species. Other species were collected for the first time from Sagami Bay or found from previously unreported depth. The Surveys could be useful for ecological and environmental studies as well. We plan to continue the JAMBIO Coastal Organism Joint Surveys to further reveal the rich biodiversity within and around Sagami Bay and to accelerate nationwide research collaborations. We also hope to expand the Surveys to include plants and protists, and to perform them at other areas in Japan. Through the Surveys, we aim to develop new cross-disciplinary research areas and to record the long-term transition of biota along the Japanese coast. (C) 2015 Elsevier B.V. All rights reserved.
• Indoapseudes bamberi sp nov (Crustacea: Tanaidacea: Pagurapseudidae: Hodometricinae) from Iriomote Island, Ryukyu Islands, southwestern Japan

  Keiichi Kakui, Tohru Naruse

  ZOOTAXA 3995 (1) 138 - 148 1175-5326 2015/08 [Refereed][Not invited]
   

  We describe Indoapseudes bamberi sp. nov., based on a specimen from Funaura Bay, Iriomote Island, Japan. This species can be distinguished from its five congeners by having the combination of the antenna with a squama and pereopods 1 and 2 with one dorsal spine on the basis. We also determined part of the nucleotide sequence for the cytochrome c oxidase subunit I (COI) gene in I. bamberi, and present a key to Indoapseudes species.
• First record of the free-living marine nematode Deontostoma magnificum (Timm, 1951) Platonova, 1962 (Nematoda: Leptosomatidae) from Japan.

  Shimada D, Kakui K

  Nematological Research 45 (1) 13 - 18 2015/07 [Refereed][Not invited]
  
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• Phylogenetic position of the queer, backward-bent entoproct Loxosoma axisadversum (Entoprocta: Solitaria: Loxosomatidae).

  Kajihara H, Tomioka S, Kakui K, Iseto T

  Species Diversity 日本動物分類学会 20 (1) 83 - 88 1342-1670 2015/05 [Refereed][Not invited]
   

  The solitary entoproct Loxosoma axisadversum Konno, 1972 was found on the body surface of the maldanid polychaete Nicomache personata Johnson, 1901 obtained among roots of the seagrass Phyllospadix iwatensis Makino collected at a depth of about 1m in Oshoro Bay, Hokkaido, Japan. The species had previously been known from elsewhere in northern Japan, attached to another maldanid, Nicomache minor Arwidsson, 1907. The morphology of the new material is briefly described with photographs taken in life. A preliminary phylogenetic analysis using concatenated partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene, as well as the nuclear 18S and 28S rRNA genes, placed L. axisadversum as the sister taxon to all the rest of Solitaria included in the analysis, indicating non-monophyly of the genus Loxosoma Keferstein, 1862.
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• Two new shallow-water species of Agathotanais (Crustacea: Tanaidacea) from Japan.

  Kakui K, Kohtsuka H

  Species Diversity 日本動物分類学会 20 (1) 45 - 58 1342-1670 2015/05 [Refereed][Not invited]
   

  We describe two shallow-water species of Agathotanais, A. misakiensis sp. nov. and A. toyoshioae sp. nov., from Japan. Agathotanais misakiensis was collected from 211-493m depth in the Sagami Sea, North Pacific Ocean. It closely resembles A. ghilarovi Kudinova-Pasternak, 1989, but differs in having shorter pereonites 3 and 4, all pleonites narrower than pereonite 6, and a shorter article 3 in the antennule. Agathotanais toyoshioae, collected from 95m depth in the Genkai Sea, Sea of Japan, is very similar to A. spinipoda Larsen, 1999. The former can be distinguished from the latter by its narrower pleonites, the presence of a ventral keel on pleonites 1 and 2, and the presence on the basis and absence on the carpus and propodus of small spines on pereopods 4-6.
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• First report of Zeuxo sp. (Crustacea: Tanaidacea) as prey for the forktongue goby, Chaenogobius annularis Gill, 1859. [in Japanese with English abstract]

  Kakui K

  Rishiri Studies 34 1 - 6 2015/03 [Not refereed][Not invited]
  
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• A novel transmission pathway: first report of a larval trematode in a tanaidacean crustacean.

  Kakui K

  Fauna Ryukyuana 17 13 - 22 2014/12 [Refereed][Not invited]
  
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• Northernmost records of Antedon serrata A. H. Clark from Hokkaido. [in Japanese with English abstract]

  Kohtsuka H, Kakui K, Kajihara H

  Bulletin of the Biogeographical Society of Japan 69 185 - 188 2014/12 [Refereed][Not invited]
  
• タナイスの糸.

  角井敬知

  うみうし通信 84 2 - 3 2014/09 [Not refereed][Invited]
  
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• Diverse Pereopodal Secretory Systems Implicated in Thread Production in an Apseudomorph Tanaidacean Crustacean

  Keiichi Kakui, Chizue Hiruta

  JOURNAL OF MORPHOLOGY 275 (9) 1041 - 1052 0362-2525 2014/09 [Refereed][Not invited]
   

  Among arthropods, various insects, spiders, and crustaceans produce thread. The crustacean Tanaidacea include species that use thread mainly to construct dwelling tubes. While thread production was previously known only in Tanaoidea and Paratanaoidea, it was recently discovered in two species in Kalliapseudidae (Apseudoidea), although information on the morphology of the thread-producing system was lacking. Using histology, light and scanning electron microscopy, we found that the kalliapseudid Phoxokalliapseudes tomiokaensiscomb. nov. lacks the sort of glandular structures associated with thread production in the pereonites, but has these structures in pereopods 1-6. We observed four types of glandular systems defined by the types and distribution of glands they contain: Type A (pereopod 1), Type B (pereopods 2 and 3), Type C (pereopods 4 and 5), and Type D (pereopod 6). All types have small rosette glands and lobed glands; Type A additionally has large rosette glands. The inferred thread-producing apparatus in P. tomiokaensis is very different from that in Tanaoidea and Paratanaoidea, suggesting that kalliapseudids evolved thread production independently from the latter two groups. J. Morphol. 275:1041-1052, 2014. (c) 2014 Wiley Periodicals, Inc.
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• Tanaidaceans from Rishiri Island [in Japanese with English Abstract].

  Kakui K, Tomioka S, Yamasaki H

  Rishiri Studies 33 7 - 12 2014/03 [Not refereed][Not invited]
  
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• Tanaidaceans from Rishiri Island (Crustacea: Peracarida)

  Kakui, K., Tomioka, S., Yamasaki, H.

  Rishiri Studies 33 2014
• Nototanaids (Crustacea: Tanaidacea) from Japan, with the description of a new species of Nototanoides.

  Kakui K, Yamasaki H

  Species Diversity 2013 (18) 2 - 245-254 2013/12 [Refereed][Not invited]
  
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• Description of three species of Halmyrapseudes (Crustacea: Tanaidacea: Parapseudidae), with a discussion of biogeography

  Keiichi Kakui, Saowapa Angsupanich

  ZOOTAXA 3736 (4) 345 - 367 1175-5326 2013/11 [Refereed][Not invited]
   

  We describe Halmyrapseudes gutui sp. nov. from a mangrove area on Lidee Island, southern Thailand. This species closely resembles H. cooperi, H. killaiyensis, and H. thaumastocheles, but differs in having the lacinia mobilis with three teeth, and the pereopod 1 carpus with 0,1 or 1,1 ventral simple setae proximal to each spiniform seta. We redescribed and synonymized two species of questionable affiliation, Apseudes cooperi and A. digitalis, placing them in Halmyrapseudes, and partly redescribed Halmyrapseudes killaiyensis. Halmyrapseudes and Pseudohalmyrapseudes have disjunct distributions. Halmyrapseudes is similar in distribution to two freshwater fish taxa whose distributions are considered to reflect the breakup of Gondwana and subsequent continental drift. Pseudohalmyrapseudes occurs around Australia, and its distribution seems to be separated from that of Halmyrapseudes by Wallace's Line or Huxley's Line, which are distributional barriers for both terrestrial organisms and an amphidromous shrimp. The adjacent distributions and morphological similarities suggest that Halmyrapseudes and Pseudohalmyrapseudes are sister taxa.
• Selfing in a malacostracan crustacean: why a tanaidacean but not decapods

  Keiichi Kakui, Chizue Hiruta

  NATURWISSENSCHAFTEN 100 (9) 891 - 894 0028-1042 2013/09 [Refereed][Not invited]
   

  The crustacean class Malacostraca, with over 22,000 species, includes commercially important members, such as crabs, shrimps, and lobsters. A few simultaneous hermaphrodites are known in this group, but self-fertilization was unknown. Here we show, through microscopy and breeding experiments, that the simultaneously hermaphroditic malacostracan Apseudes sp. (order Tanaidacea) can self-fertilize; individuals reared in isolation become hermaphroditic via a male-like phase and produce eggs that develop into fertile adults. Although selfing occurs in crustaceans like the Branchiopoda, in which simultaneous hermaphrodites have the sex ducts united, in decapods the separation of gonadal ducts and gonopores, specialized mating organs, and complex mating behavior appear to have constrained the evolution of selfing. In contrast, in most tanaidaceans, sperm is released externally by a male and reaches the eggs in the female brood pouch, where fertilization occurs. This mode of fertilization permitted Apseudes sp. to achieve selfing without large modifications in morphology or behavior.
• New record of Cardiodectes medusaeus (Wilson, 1908) (Copepoda: Siphonostomatoida: Pennellidae) from a stranded pearly lanternfish, Myctophum nitidulum Garman (Myctophiformes: Myctophidae) from the Ryukyu Islands, southern Japan. [in Japanese]

  Uyeno D, Kakui K, Nagasawa K

  The Biological Magazine Okinawa 沖縄生物学会 51 (51) 67 - 72 0474-0394 2013/05 [Refereed][Not invited]
  
• 第166回農林交流センターワークショップ「分子系統学の理論と実習」体験記.

  角井敬知

  日本進化学会ニュース 14 (1) 23 - 25 2013/03 [Not refereed][Invited]
  
• A new species of deep-sea nematode, Micoletzkyia mawatarii sp. nov. (Nematoda: Enoplida: Phanodermatidae) from Northern Japan.

  Shimada D, Kakui K, Kajihara H

  Species Diversity 17 (2) 221 - 226 2012/12 [Refereed][Not invited]
  
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• A new species of Stegidotea Poore, 1985 (Isopoda: Chaetillidae) from Japan.

  Shimomura M, Kakui K

  Crustaceana Monographs 17 303 - 314 2012/09 [Refereed][Invited]
  
• BIRDOTANAIS SONGKHLAENSIS, A NEW GENUS AND SPECIES OF NOTOTANAIDAE (CRUSTACEA: TANAIDACEA) FROM THAILAND

  Keiichi Kakui, Saowapa Angsupanich

  RAFFLES BULLETIN OF ZOOLOGY 60 (2) 421 - 432 0217-2445 2012/08 [Refereed][Not invited]
   

  We establish the new genus Birdotanais, based on the new species B. songkhlaensis collected from brackish Songkhla Lagoon in Thailand. Birdotanais shows close similarity to members of Families Nototanaidae and Tanaissuidae; we place it in former based on the type species having black eyes and the mandibular molar bearing a broad masticatory region. Birdotanais differs from confamilial genera in having an oval pleopodal endopod with one mid-inner plumose seta, and a nearly straight dactylus-unguis bearing a tiny unguis, on pereopods 4-6. We present a key to genera in Families Nototanaidae and Tanaissuidae.
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• PHYLOGENETIC POSITION OF ARCTOTANAIS IN TRE SUBORDER TANAIDOMORPHA (PERACARIDA: TANAIDACEA)

  Keiichi Kakui, Norio Kobayashi, Hiroshi Kajihara

  JOURNAL OF CRUSTACEAN BIOLOGY 32 (1) 127 - 139 0278-0372 2012/02 [Refereed][Not invited]
   

  Lack of an ischium on pereiopods 1-6 was previously considered a synapomorphy for the tanaidacean superfamily Tanaoidea, although descriptions of Arctotanais alascensis (Richardson, 1899), the sole species in Arctotanais, indicated presence or absence of the ischium. To resolve this ambiguity, we examined newly collected specimens of A. alascensis (including males, which had not previously been described) from Hokkaido, Japan, using light and scanning electron microscopy. We also conducted molecular phylogenetic analyses based on partial sequences of the 18S rRNA gene to examine the phylogenetic position of A. alascensis. Here we describe in detail the morphology of the male of A. alascensis, which proved to be similar to that of the females. This species bears an ischium on pereiopods 1-6, which contradicts the current diagnoses of Tanaoidea and Tanaidae, although other synapomorphies remain valid. Molecular phylogenetic analyses strongly supported the placement of A. alascensis in Tanaoidea, and consequently we amended the diagnoses for Tanaoidea and Tanaidae to include either presence or absence of the ischium on the pereiopods.
• 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 0289-0003 2011/10 [Refereed][Not invited]
   

  Phylogenetic relationships within Tanaidacea were analyzed based on sequence data for the 18S rRNA gene. Our results strongly supported a monophyletic group composed of Neotanaidae, Tanaoidea, and Paratanaoidea, with the first two taxa forming a clade. These results contradict three previously suggested hypotheses of relationships. Based on the molecular results, and considering morphological similarities/differences between Neotanaidomorpha and Tanaidomorpha, we demoted Suborder Neotanaidomorpha to Superfamily Neotanaoidea within Tanaidomorpha; with this change, the classification of extant tanaidaceans becomes a two-suborder, four-superfamily system. This revision required revision of the diagnoses for Tanaidomorpha and its three superfamilies. The results for Apseudomorpha were ambiguous: this taxon was monophyletic in the maximum likelihood and Bayesian analyses, but paraphyletic in the maximum parsimony and minimum evolution analyses.
• A NEW SPECIES OF THE GENUS INGOLFIELLA HANSEN, 1903 (PERACARIDA, AMPHIPODA) FROM THE OGASAWARA ISLANDS, SOUTHERN JAPAN

  Michitaka Shimomura, Keiichi Kakui

  CRUSTACEANA 84 (5-6) 543 - 551 0011-216X 2011/05 [Refereed][Not invited]
   

  A new ingolfiellid amphipod. Ingolfiella ogasawarensis n. sp. is described from shallow water off the Ogasawara Islands, southern Japan. The new species differs from its congeners primarily by having a moderately thick body; pereionites 2-7, pleonites 1-3, and urosomites 1-3 each bearing a pair of dorsal setae; a broad dorsal crest on the basis of gnathopod 1; 6 minute teeth, 1 long stout palmar angle spine, 1 short stout seta, and 8 slender simple setae on the ventral margin of the carpus of gnathopocl 2; propodi of pereiopods 3 and 4 longer than the carpi; uropod 1 shorter than uropod 2; and the first spine on the inner ramus of uropod 1 larger than the following three spines.
• 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).

  Kakui K, Kajihara H

  Bulletin of the National Museum of Nature and Science National Museum of Nature and Science Suppl 5 53 - 70 1881-9052 2011/02 [Refereed][Not invited]
  
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• Digital illustration techniques using graphics software. [in Japanese with English abstract]

  Hiruta SF, Kakui K

  TAXA, Proceedings of the Japanese Society of Systematic Zoology 日本動物分類学会 29 (29) 19 - 30 1342-2367 2010/08 [Refereed][Not invited]
   

  Personal computers (PCs) are now indispensable to any field of study, and it is important to master efficient ways to compose documents, analyze data, and manage literature. This is especially true of illustrations, which take much time and repeated editing prior to use in publications, posters, presentations, and so on. Although some reports exist on techniques for making digital illustrations there has been rapid progress in the development of new PC hardware and software, so that some types of previously intractable digital graphical processing methods are now feasible and even routine. ...
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• A New Species of Psammogammarus (Amphipoda: Melitidae) from Kuchinoerabu Island, Japan, with a Noteon its Feeding Habits

  Ko Tomikawa, Keiichi Kakui, Hiroshi Yamasaki

  ZOOLOGICAL SCIENCE 27 (7) 615 - 626 0289-0003 2010/07 [Refereed][Not invited]
   

  A new melitoid Amphipoda, Psammogammarus mawatarii, is described from Kuchinoerabu Island, Kagoshima Prefecture, Japan. This is the first record of the genus from Asia. The new species is morphologically similar to P. garthi, but differs from the latter in the following features: 1) lateral cephalic lobe of head not strongly produced; 2) head lacking antennal sinus; and 3) posteroventral corner of epimeral plate 3 rounded. Morphology of maxillae 1 and 2, and mandible, and gut contents (harpacticoid Copepoda) of P. mawatarii indicate that the feeding type of the species seems to be, at least facultatively, carnivorous.
• 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 1313-2989 2010 [Refereed][Not invited]
   

  The new species Nesotanais ryukyuensis sp. n. is described from Japan. Nesotanais ryukyuensis most closely resembles N. rugula Bamber, Bird & Angsupanich, 2003, but can be distinguished by the length of simple seta on maxillipedal basis and the shape of cheliped in male. A key to species of the genus Nesotanais is given. The male chelipeds of N. rugula are redescribed. The serial ridges on the inner surface of the chelipedal propodus and dactylus in Nesotanais ryukyuensis and N. rugula are likely to be stridulating ridges that might produce sound.
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• Two new sphyrapodid species (Crustacea : Tanaidacea : Apseudomorpha) from southwestern Japan

  Keiichi Kakui, Hiroshi Kajihara, Shunsuke F. Mawatari

  ZOOTAXA 1563 (1563) 37 - 54 1175-5326 2007/08 [Refereed][Not invited]
   

  Two new species, Kudinopasternakia balanorostrata and Pseudosphyrapus quintolongus are described from Japan. Kudinopasternakia balanorostrata is characterized by an acorn-shaped rostrum. It most closely resembles K. siegi (Viskup & Heard, 1989), but can be distinguished by the shape of the rostrum, the number of setae on article 2 of the mandibular palp, and the setation on the outer lobe of the fixed endite of the maxilla. Pseudosphyrapus quintolongus is characterized by an unusually large lateral process on pleonite 5, which distinguishes it from all other species in the genus. Keys to species of Kudinopasternakia and Pseudosphyrapus are given.

Books etc

• 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創立100周年記念出版編集委員会 (Contributorタナイスの多様性研究)
  京都大学学術出版会 2022/11 (ISBN: 9784814004492)
• 動物学の百科事典

  日本動物学会 (Contributor動物界の分類群・系統)
  丸善出版 2018/09 (ISBN: 9784621303092) xxv, 770p, 図版 [8] p
• 平成28年 理科年表 第89冊

  東京天文台, 国立天文台 (Supervisor動物分類表 甲殻亜門（2015年以降監修継続中）)
  東京天文臺 2015/11 (ISBN: 9784621089651) 冊

Awards & Honors

• 2012/10 日本動物学会 平成24年度川口賞（川口四郎基金による若手研究者国際会議渡航補助）
   

  受賞者: 角井敬知

Research Grants & Projects

• 網羅的サンプリングに基づく深海底生動物の多様化機構解明

  日本学術振興会：科学研究費助成事業 基盤研究(B)

  Date (from‐to) : 2022/04 -2026/03 

  Author : 狩野 泰則, 遊佐 陽一, 岡西 政典, 角井 敬知
• Marine and anchialine cave biodiversity in the Ryukyu Islands, Japan

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2020/04 -2025/03 

  Author : 藤田 喜久, 下村 通誉, 藤井 琢磨, 井口 亮, 岡西 政典, 角井 敬知, 斉藤 知己

   

  本研究では、１）洞窟水圏性動物の種多様性、２）洞窟水圏性動物の分子系統・適応進化、３）洞窟水圏における動物群集の構造と個体群維持機構の3つの主要研究テーマに注力した調査研究を実施し、当該地域の洞窟水圏における生物多様性の全容を解明することを目的としている。 2021年度は、沖縄島と伊江島の海底洞窟における合同野外調査を実施し、さらに徳之島・与論島・与那国島における陸域の洞窟での予備的な野外調査を実施し、2022年度以降の合同調査に備える予定であったが、新型コロナウイルス感染症の影響で調査対象の島々への渡航が厳しく制限される状況に陥り、予定を変更することになった。 実際、海底洞窟の合同調査は規模を縮小して沖縄島のみで実施し、陸域の洞窟調査は沖永良部島、与論島、多良間島の３カ所に変更した。しかし、初年度（2020年度）及び2021年度にて得られたデータをもとに、以下のような実績を挙げることができた。 「１）洞窟水圏性動物の種多様性」と「２）洞窟水圏性動物の分子系統・適応進化」については、対象洞窟にて採集された生物の種同定を進め、DNAバーコーディング作業を予定通り進めることができた。 一方、「３）洞窟水圏における動物群集の構造と個体群維持機構」については、共同研究者が考案した海底洞窟の3D測量手法を沖縄島の海底洞窟にて試験実施した。3D測量図は洞窟形態の特性を可視化するものであり、生物研究を劇的に進展させることが予想されることから、次年度（2022年度）に早急な完成を目指す予定である。また、多良間島において、同島固有の地下水性甲殻類（タラマメアミ）を保護・保全するための生態研究を開始した。 これらの研究成果（の一部）として、3編の研究論文の出版と、１題の学会発表を実施することができた。また、さらに複数（3編）の論文投稿も行い、これらは2022年度に出版を予定している。
• 海の底から泳ぎ出す：小型底生甲殻類による泳ぐ矮雄の獲得と進化史

  日本学術振興会：平成31年度科研費基盤研究（Ｃ）

  Date (from‐to) : 2019/04 -2024/03 

  Author : 角井敬知
• 南西諸島における汽水性タナイス目甲殻類の多様性と進化史

  公益信託ミキモト海洋生態研究助成基金：平成30年度研究助成

  Date (from‐to) : 2018/09 -2020/08 

  Author : 角井敬知
• 微小水生甲殻類タナイス目の性表現と生殖様式に関する研究

  公益財団法人秋山記念生命科学振興財団：2018年度研究助成＜奨励＞

  Date (from‐to) : 2018/07 -2019/03 

  Author : 角井敬知
• 深海性タナイス目甲殻類の分類学的研究

  東京大学大気海洋研究所：平成30年度共同研究（柏地区外来研究員）

  Date (from‐to) : 2018/04 -2019/03 

  Author : 角井敬知
• 底生動物による海藻葉上固着生活獲得までの進化史の解明

  日本学術振興会：平成28年度科研費若手研究（Ｂ）

  Date (from‐to) : 2016/04 -2019/03 

  Author : 角井敬知
• 八重山周辺海域に分布する小型甲殻類相のデータベース構築：１．内湾環境

  琉球大学：平成28年度琉球大学共同利用研究

  Date (from‐to) : 2016/04 -2017/03 

  Author : 上野大輔, 下村通誉, 角井敬知
• 汽水生小型甲殻類ネソタナイスの分類学的・生殖生物学的研究

  公益財団法人藤原ナチュラルヒストリー振興財団：平成26年度（第23回）学術研究助成

  Date (from‐to) : 2015/04 -2016/03 

  Author : 角井敬知
• タナイス目で見つかった，軟甲綱で初となる自家受精種の総合的研究

  公益財団法人日本科学協会：平成26年度笹川科学研究助成 学術研究部門

  Date (from‐to) : 2014/04 -2015/03 

  Author : 角井敬知
• 死サンゴ片堆積場（ガレ場）における小型無脊椎動物の多様性調査

  琉球大学：平成26年度琉球大学共同利用研究

  Date (from‐to) : 2014/04 -2015/03 

  Author : 角井敬知
• うみさわ会（若手海洋生物研究者フィールドワークショップ）

  マリンバイオ共同推進機構（JAMBIO）：２０１４年度マリンバイオ共同推進機構（JAMBIO）公募型「共同利用・共同研究」

  Date (from‐to) : 2014/04 -2015/03 

  Author : 山崎博史, 角井敬知
• タナイス目甲殻類の系統進化学的研究－出糸能力獲得の起源について－

  財団法人水産無脊椎動物研究所：育成研究助成

  Date (from‐to) : 2012/04 -2014/03 

  Author : 角井敬知
• タナイス目甲殻類の多様性を生み出した“脚型”の進化史の解明

  日本学術振興会：特別研究員奨励費

  Date (from‐to) : 2010/04 -2012/03 

  Author : 角井敬知

   

  本研究はタナイス目甲殻類の多様化に関係する第1歩脚の機能・形態("脚型")の進化史解明を目指すもので,本年度は以下の成果を挙げた. タナイス目の分子系統解析の論文を公表した.亜目・上科間の系統関係を初めて明らかにし,得られた系統関係と形態的特徴に基づき分類体系を現行の3亜目3上科から2亜目4上科に変更した. 所属上科に議論のあったArctotanais alascensisの系統位置を決定,論文として公表した.詳細な形態観察および分子系統解析により,本種がタナイス上科に属することを明らかにした.また,本種に鋏脚座節という,同上科のTanais属と近縁とされるネオタナイス上科のみで報告されていた構造を確認し,2上科の近縁性についてより強い支持を得た. アプセウデス亜目の側系統性を示唆する結果を得た.Longiflagrum属とカリアプセウデス科は現在アプセウデス亜目に属しているが,進行中の分子系統解析の結果には,2分類群がタナイス亜目と姉妹群を形成するという結果も含まれた.なお,カリアプセウデス科はタナイス亜目のみで知られる「出糸型」生活も行う可能性が示唆されている科であるため,「出糸型」がアプセウデス亜目に起源するという仮説を立て,組織学的手法も導入した研究を計画中である. アプセウデス亜目内で祖先的な脚型と考えられている「俳徊型」を呈する2科のDNAサンプルを作成した.パグラプセウドプシス科は,タイでDr.Angsupanichと共同調査を行い採集した.ギガンタプセウデス科は,琉球海溝から得られた1個体を貸借できた.現在解析を進めているところであるが,前者は貝棲型のグループと姉妹群を形成する派生的なグループであるという結果が得られている. なお本年度は上記研究以外に,採集調査中に得た標本に基づき2報の記載論文を共同で執筆し,成果を学会大会で発表した.

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• 2024/04 - Today   The Japanese Society of Systematic Zoology   選挙管理委員会
• 2023/05 - Today   World Register of Marine Species (WoRMS)   Taxonomic editor (Tanaidacea)