著者

Hisanori Kohtsuka Kohei Oguchi Yusuke Yamana Masanori Okanishi

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.16, no.3, pp.228-236, 2021-08-06 (Released:2021-07-31)

参考文献数

60

被引用文献数

1

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More than 100 individuals of sea cucumber larvae were collected in the Japanese coastal sea of Moroiso, Sagami Bay, Kanagawa Prefecture, central-eastern Japan, in January 2018. Based on an obtained sequence of mitochondrial 16S rRNA gene region of one juvenile, it was identified as Sclerodactyla multipes by BLAST search with 0.3% genetic distance. The developmental process of the S. multipes was observed for three months, in which time, they grew from 250 µm to about 4 mm in length; here they showed distinct tentacles and dermal ossicles. Detailed morphological features of this species were described based on stereomicroscopic, fluorescence and SEM observations for the first time. This is the first description of life history through planktonic larva to juveniles in the family Sclerodactylidae.

著者

Aoi Tsuyuki Hisanori Kohtsuka Natsumi Hookabe Hiroshi Kajihara

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.17, no.2, pp.147-155, 2022-05-30 (Released:2022-05-31)

参考文献数

26

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The cotylean polyclad flatworm Bulaceros porcellanus Newman & Cannon, 1996 has so far only been recorded in a few tropical locations in the Indo-Pacific Ocean, including the Lakshadweep Islands (India), the Great Barrier Reef (Australia), and the Marshall Islands (Republic of the Marshall Islands). In this study, we report B. porcellanus for the first time from Japanese waters based on specimens collected in Misaki (Kanagawa) along the Pacific coast of Honshu. This new record expands the species’ known geographic distribution northward to include the warm temperate region of Japan. Our molecular phylogenetic analysis revealed that B. porcellanus formed a clade with Pseudoceros harrisi Bolaños, Quiroga & Litvaitis, 2007, and was separated from the monophyletic group composed of 19 other species of Pseudoceros Lang, 1884, including its type species Proceros velutinus Blanchard, 1847 (now Pseudoceros velutinus). Based on the morphological and phylogenetic closeness between P. harrisi and B. porcellanus (type species of Bulaceros Newman & Cannon, 1996), we transfer P. harrisi into Bulaceros with a revision of the diagnosis of Bulaceros.

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

Yusuke Yamana Yuzo Ota Hisanori Kohtsuka Kazumi Yoshizaki

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.227-236, 2020-10-16 (Released:2020-10-16)

参考文献数

17

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A new dendrochirotid sea cucumber, Massinium japonicum sp. nov., is described from areas in western Japan, including the middle of the Seto Inland Sea, west of the Sea of Japan, the shore of the Amakusa Peninsula, and the shore of the Kii Peninsula. The ossicle assemblage of the new species (M. japonicum) is similar to that of M. maculosum Samyn and Thandar, 2003, the type species of Massinium Samyn and Thandar, 2003. However, the new species is readily distinguishable from M. maculosum and its congeners by the absence of rod/elongated rosette ossicles in the tentacles. The tentacle ossicles of the new species comprise only oval, simple, open rosettes, 20–40 µm in length, while the other congeners possess rods/elongated rosette-shaped ossicles in the tentacles (very rarely also table ossicles). This new species has been collected from the shallow waters of western Japan living amongst boulder area in the intertidal-subtidal zone, at a depth of approximately 0–20 m.

著者

Yuzo Ota Hisanori Kohtsuka Katsuhiko Tanaka

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.26, no.2, pp.207-216, 2021-09-10 (Released:2021-09-10)

参考文献数

32

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Adult male and larva of Gnathia capitellum sp. nov. (Crustacea: Isopoda: Gnathiidae) are described. The specimens were laboratory-reared larvae that infested host fishes collected by longline fishing in a coastal bay of Izu Peninsula and adult males found in dredge samples from shallow water (depth: 11–12 m) of Miura Peninsula, central Japan. Adult males of G. capitellum sp. nov. were easily distinguished from the other species of Gnathia Leach, 1814 from around the world by the small oval head and the inner margin of pylopod without plumose setae. Most other Gnathia species have a large rectangular head and plumose setae present on the article 1 of pylopod. Appearance of the adult male resembles the genus Afrignathia Hadfield and Smit, 2008 rather than Gnathia but Afrignathia has maxilla 1 which is absent in all known male gnathiids in the world including G. capitellum sp. nov. Fish parasitic larva of G. capitellum sp. nov. is also described herein. This larva closely resembles larvae of the genus Gnathia, but can be distinguished from the other Gnathia species by the remarkably oval-shaped basis in pereopods 2–4.