著者

Kajihara Hiroshi Gibson Ray Mawatari Shunsuke F.

出版者

日本動物学会

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.20, no.4, pp.491-500, 2003-04

被引用文献数

7

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Potamostoma shizunaiense gen. et sp. nov. (Nemertea: Hoplonemertea: Monostilifera) is described from the mouth of the River Shizunai, Hokkaido, Japan. This genus is readily distinguished from other monostiliferans by an oesophagus opening far anteriorly into the rhynchodaeum, a well developed excretory system extending the whole body length, terminals of the excretory collecting tubules situated between the body wall circular muscle layer and the dermis, and bilobed testes in males.

著者

Matsumoto Yu Kajihara Hiroshi Kakui Keiichi

出版者

Sociedade Brasileira de Carcinologia

雑誌

Nauplius (ISSN:23582936)

巻号頁・発行日

vol.31, pp.e2023005, 2023

被引用文献数

1

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A new podocerid amphipod, Leipsuropus seisuiae sp. nov., from 338-340 m depth in the Kumano Sea, Japan, Northwestern Pacific, is described. This is the deepest record of any Leipsuropus species. Leipsuropus seisuiae sp. nov. is distinguished from four other congeneric species in having: i) pereonites 2-5 each with five narrow spiniform projections on tergal plate, ii) one dorsal tubercle on the telson, and iii) one small, proximal, denticulate projection on gnathopod-2 palmar margin. A key to males of the species of Leipsuropus is provided.

著者

KAJIHARA Hiroshi

出版者

Seto Marine Biological Laboratory, Kyoto University

雑誌

Publications of the Seto Marine Biological Laboratory (ISSN:00372870)

巻号頁・発行日

vol.43, pp.92-102, 2015-09-15

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A new species of heteronemertean with branched proboscis, Gorgonorhynchus albocinctus sp. nov., is described based on the external feature and DNA sequences from a specimen collected subtidally among coral rubbles at a depth of about 6 m in a reef area around Taketomi Island in the Yaeyama Islands, southwestern Japan. It can be classified in the genus because the mode of proboscis branching is dichotomous, rather than alternating laterally. From the two known congeners G. repens Dakin and Fordham, 1931 and G. bermudensis Wheeler, 1940, the new species can be differentiated by having a brown body colour with a white band near the tip of the head. The new species is placed in a molecular phylogenetic context with a maximum-likelihood analysis using the nuclear 18S rRNA and 28S RNA genes, as well as the mitochondrial cytochrome c oxidase subunit I gene, together with 20 species of heteronemerteans, for which those sequences were available in the public databases. The results indicate that G. albocinctus is closely related to Cerebratulus leucopsis (Coe, 1901), a species that is supposed to have a non-branched proboscis.

著者

Tomioka Shinri Kondoh Tomohiko Sato-Okoshi Waka Ito Katsutoshi Kakui Keiichi Kajihara Hiroshi

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.33, no.5, pp.545-554, 2016-10

被引用文献数

29

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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.

著者

Kakui Keiichi Kajihara Hiroshi Kobayashi Norio

出版者

The Crustacean Society

雑誌

Journal of Crustacean Biology (ISSN:02780372)

巻号頁・発行日

vol.32, no.1, pp.127-139, 2012-01

被引用文献数

10

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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.

著者

Kajihara Hiroshi

出版者

Zoological Society of Japan

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.24, no.4, pp.287-326, 2007-04

被引用文献数

39

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A literature-based taxonomic catalogue of the nemertean species (Phylum Nemertea) reported from Japanese waters is provided, listing 19 families, 45 genera, and 120 species as valid. Applications of the following species names to forms previously recorded from Japanese waters are regarded as uncertain: Amphiporus cervicalis, Amphiporus depressus, Amphiporus lactifloreus, Cephalothrix filiformis, Cephalothrix linearis, Cerebratulus fuscus, Lineus vegetus, Lineus bilineatus, Lineus gesserensis, Lineus grubei, Lineus longifissus, Lineus mcintoshii, Nipponnemertes pulchra, Oerstedia venusta, Prostoma graecense, and Prostoma grande. The identities of the taxa referred to by the following four nominal species require clarification through future investigations: Cosmocephala japonica, Dicelis rubra, Dichilus obscurus, and Nareda serpentina. The nominal species established from Japanese waters are tabulated. In addition, a brief history of taxonomic research on Japanese nemerteans is reviewed.

著者

Tomioka Shinri Kakui Keiichi Kajihara Hiroshi

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.35, no.5, pp.436-445, 2018-10

被引用文献数

4

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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.

著者

Kakui Keiichi Katoh Toru Hiruta Shimpei F. Kobayashi Norio Kajihara Hiroshi

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.28, no.10, pp.749-757, 2011

被引用文献数

34

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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.

著者

Yamasaki Hiroshi Kajihara Hiroshi

出版者

日本動物分類学会

雑誌

Species diversity : an international journal for taxonomy, systematics, speciation, biogeography, and life history research of animals (ISSN:13421670)

巻号頁・発行日

vol.17, no.1, pp.109-118, 2012-05-25

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Echinoderes ohtsukai sp. nov. is described from an intertidal flat in the Seto Inland Sea, Japan, based on observations with light and scanning electron microscopy. Echinoderes ohtsukai is characterized by 1) a short middorsal spine on segment 4; 2) lateroventral tubules on segments 5 and 8; 3) short laterodorsal tubules on segment 10; 4) a trunk 315-395μm long; 5) a lack of lateral terminal accessory spines in both sexes; and 6) lateral terminal spines of about 50% trunk length. The species has modified type-II glandular cell outlets, which have previously been reported among congeners only in E. rex Lundbye, Rho and Sorensen, 2011 from the Korea Strait.