著者

Natsumi Hookabe Yuki Oya Shinji Tsuchida Yoshihiro Fujiwara Rei Ueshima

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.28, no.2, pp.199-204, 2023-08-31 (Released:2023-08-31)

参考文献数

23

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Monostiliferous nemerteans are mostly benthic and free-living, but a few are recognized as commensal and parasitic species. We describe Tetrastemma carneum sp. nov. based on five specimens found from demosponges collected by the use of remotely operated vehicle at a depth of 398 m, off Ofunato, Japan. The new species resembles T. appendiculatum Chernyshev, 1998 described based on specimens discovered from demosponge Esperiopsis digitata (Miklucho-Maclay, 1870) (now accepted as Amphilectus digitatus) trawled at depths of 40–60 m in Peter the Great Bay, in having a pale-colored body with four conspicuously large eyes (approximately 50 µm in the maximum width). However, it is differentiated from T. appendiculatum in possessing a mid-dorsal line on the dorsal surface of the head as well as the number of proboscis nerves. In our molecular phylogenetic tree based on partial sequences of 16S rRNA, cytochrome c oxidase subunit I, 18S rRNA, 28S rRNA, and histone H3 genes, Tetrastemma carneum sp. nov. was nested in the clade of Tetrastemma Ehrenberg, 1828 as a sister taxon to Tetrastemma sp. IP Iturup reported from Peter the Great Bay.

著者

Yuki Oya Morio Hagiya

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.28, no.2, pp.255-262, 2023-11-24 (Released:2023-11-24)

参考文献数

14

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We establish a new genus of candimboidid polyclad, Chimaeriplana gen. nov., based on a new species, C. japonica sp. nov., collected from Kanagawa, the coast of Sagami Bay, Japan. Chimaeriplana japonica sp. nov. is characterized by (i) an interpolated prostatic vesicle with a seminal vesicle, (ii) a penis stylet with a split tip, (iii) numerous prostatoid organs in the male atrium, (iv) a bursa copulatrix, and (v) without Lang’s vesicle. In addition, we modify the definition of Candimboididae.

著者

Naoto Jimi Naohiro Hasegawa Masanori Taru Yuki Oya Hisanori Kohtsuka Shinji Tsuchida Yoshihiro Fujiwara Sau Pinn Woo

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.27, no.1, pp.101-111, 2022-04-15 (Released:2022-04-15)

参考文献数

15

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Members of the family Flabelligeridae are distributed worldwide, inhabiting the underside of rocks or within mixed sand sediments. Some genera of the family have gelatinous tunics with hooked chaetae. The genus Flabelligera Sars, 1829 is one of the members of the gelatinous free-living groups of Flabelligeridae. A fan-shaped cephalic cage, thick gelatinous tunic, and hooked neurohooks distinguish members of this genus. In Japan, Flabelligera affinis Sars, 1829 [Japanese name: Kanten-habouki] has been known as the sole Japanese species of Flabelligera inhabiting several locations. We reviewed Japanese species of Flabelligera from several sites from Hokkaido to Honshu and concluded that the Japanese “F. affinis” contained at least five different species under the specific name. In this study, we described them as five new species. All new species were collected from the underside of rocks in shallow to deep-sea depths. We have also provided mitochondrial cytochrome c oxidase subunit I sequences for DNA barcodes of the new species.

著者

Yuki Oya Hiroshi Kajihara

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.24, no.1, pp.1-6, 2019-05-25 (Released:2019-01-25)

参考文献数

28

被引用文献数

6

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

著者

Yuki Oya Aoi Tsuyuki Hiroshi Kajihara

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.25, no.2, pp.189-196, 2020-09-18 (Released:2020-09-18)

参考文献数

26

被引用文献数

2

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We describe a new species of ilyplanid polyclad, Zygantroides serpulidicola sp. nov., from Amakusa, Kumamoto, Japan. This is the third member of Zygantroides Faubel, 1983 and the first record of the genus from the Pacific Ocean. Zygantroides serpulidicola sp. nov. is characterized by i) the mouth opening near the common gonopore, ii) the sperm ducts separately entering a pear-shaped seminal vesicle, iii) an elongated Lang’s-vesicle duct, and iv) the horseshoe-shaped Lang’s vesicle located posterior to the common gonopore. We provide a partial sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene (712 bp) as a DNA barcode for the species. Our phylogenetic analyses based on concatenated sequences of the 16S, 18S, and 28S ribosomal DNA and COI indicate that Z. serpulidicola sp. nov. is nested in a clade comprised of Discocelidae and Ilyplanidae; the latter does not appear to be monophyletic.

著者

Aoi Tsuyuki Yuki Oya Hiroshi Kajihara

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.24, no.2, pp.137-143, 2019-07-25 (Released:2019-07-25)

参考文献数

21

被引用文献数

2

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

著者

Yusuke MATSUOKA Masato FUNATSU Takahisa KANEDA Yuki OYA

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.93, 2023 (Released:2023-12-21)

参考文献数

9

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When a sample return capsule enters the Earth's atmosphere, a strong shock wave is generated in front of the capsule and it receives severe aerodynamic heating. An ablation method is the effective thermal protection one to protect the capsule from the heating. In the future, capsules are expected to be larger and to increase reentry speed. Therefore, the capsules will be exposed to more severe aerodynamic heating. In this experiment, porous carbons with different pore diameters (5 μm, 10 μm, and 25 μm), and porous carbons impregnated with cyanoacrylate were used as test pieces. It was found that there were differences in wear time and wear behavior depending on the test pieces. Furthermore, the effective heat of ablation was calculated by conducting an experiment using an automatic position control system that can detect the tip of the test piece and control it to the target position. The effective heat of ablation of porous carbon impregnated with cyanoacrylate (5 μm) was about 2.8 MJ/kg.

著者

Yusuke Matsuoka Yuki Oya Masato Funatsu

雑誌

33rd International Symposium on Space Technology and Science, 10th Nano-Satellite Symposium & 14th IAA Low-Cost Planetary Missions Conference

巻号頁・発行日

2021-12-01