- 著者
- Kotaro Kan Yoshifumi Kuroki Masanori Sato Hiroaki Tosuji
- 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.15, no.1, pp.30-43, 2020-02-28 (Released:2020-03-25)
- 参考文献数
- 46
- 被引用文献数
- 7
The recruitment process of planktic larvae of the nereidid polychaete Hediste diadroma, which has a catadromous life cycle, was examined in an estuary in Kagoshima Bay, Southern Japan. Our laboratory experiments showed that the phototaxis of the planktic larvae changed drastically from positive to negative during the 3-chaetiger nectochaeta, 3.5–4.0 days after fertilization. During this stage, the prostomial antennae, first peristomial cirri, and anal cirri appeared and the ciliary bands used for swimming were reduced; these results suggest that larvae shifted from pelagic to demersal stage at approximately 4.0 days after fertilization. Field sampling took place in the estuary, where reproductive swarming of mature adults was observed in late February to April; planktic larvae of, mainly, 5- to 8-chaetiger stages were collected in evening high tides during the spring tides of April and May 1989, 2013, and 2015. During the same period, 5- or higher chaetiger benthic juveniles were collected at low tide from intertidal flats from a wide area of the estuary where adults inhabited. The morphology of benthic juveniles of 5- and 6-chaetiger stages differed from that of planktic larvae of the same stages in the following characteristics: (1) the long larva-specific spinigers were lost; (2) the second peristomial cirri, originating from the parapodial lobes of chaetiger 1 of the planktic larvae, appeared; and (3) the anal cirri were elongated. Our results indicate that 5- to 8-chaetiger nectochaeta are critical phases for the successful settlement of planktic larvae, which come back into an estuary with rising tides.
- 著者
- Hiroaki Tosuji Taeseo Park Yuya Goryo Kotaro Kan Hirokazu Abe Masanori Sato
- 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.18, no.3, pp.124-130, 2023-08-31 (Released:2023-08-31)
- 参考文献数
- 28
The present study was carried out to design a simple, new and accurate method for identification of the morphologically similar four species (forms A and B of P. shikueii, P. mictodonta, and P. wilsoni) of the Perinereis nuntia species complex by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) patterns of the internal transcribed spacer (ITS). Restriction digestion analysis in the following two steps generated a specific restriction pattern for each species: (1) by the first digestion of amplified ITS fragments with AluI, we can distinguish the two forms of P. shikueii from P. mictodonta and P. wilsoni; (2) by the subsequent digestion of ITS fragments with Cfr10I, we can distinguish between the forms A and B of P. shikueii, and by that with HinfI, we can distinguish P. mictodonta from P. wilsoni. Our result indicates that this method enable easy and accurate identification of these taxa. We additionally examined the distributions of the two forms of P. shikueii in Japan, Korea and Taiwan using this new method. The form B was distributed in a wide range in western Japan and Korea, whereas the form A was distributed in few limited sites in the inner parts of the Seto Inland Sea and the Ariake Sea in Japan, the western and southern coasts of Korea, and the western coast of Taiwan.