- 著者
- Sakiko Orui Sakaguchi Hiroshi Ueda
- 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.13, no.4, pp.173-179, 2018-11-21 (Released:2018-11-14)
- 参考文献数
- 22
- 被引用文献数
- 6
Pseudodiaptomus inopinus, a common estuarine calanoid copepod in the Northwest Pacific, has been suggested to be a species complex. The population of the mainland of Japan consists of two allopatric forms that are distinguishable by the length of the posterior processes of the genital operculum; the forms with short and long processes are tentatively called SP- and LP-forms, respectively. We analyzed the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear ribosomal internal transcribed spacer 1 (ITS1) gene of 34 individuals (12 SP- and 22 LP-forms) collected from various localities. The genetic differences between the two forms were 12–15% for COI and 7–10% for ITS1. They were clearly separated into different clades in both COI and ITS1 trees. These results confirmed that the two forms belong to different species. The SP-form is a distinct species because the shape of the genital operculum of P. inopinus s. str. has long posterior processes as in the LP-form. Pseudodiaptomus japonicus Kikuchi, 1928, which is the SP-form and was once synonymized with P. inopinus, is revived. The genetic comparison using available sequence data indicates that Pseudodiaptomus koreanus Soh et al., 2012 is the same species as P. japonicus.
- 著者
- Hiroshi Ueda Sakiko Orui Sakaguchi
- 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.14, no.1, pp.29-38, 2019-02-27 (Released:2019-03-12)
- 参考文献数
- 26
- 被引用文献数
- 3
The brackish-water calanoid copepod known as Pseudodiaptomus inopinus in the mainland of Japan consists of two genetically separate species. One is P. japonicus, which was once synonymized with P. inopinus but was recently revived. This paper describes the other species as Pseudodiaptomus yamato n. sp., which is confirmed to have morphological differences from P. inopinus s.s. based on specimens from the type locality (Lake Taihu, China) of the latter. We also redescribe P. japonicus and P. inopinus s.s. for comparative purposes. The three species are distinguishable by the combination of the following morphologies: 1) weak or prominent posterior round projections of the female last pediger; 2) relative length of posterior processes of the female genital operculum; 3) presence or absence of medial spinules on the first exopodal segment of the female leg 5; and 4) the size of spinules at the center of the ventral surface of the male second urosomite. Significant inter-population variation is observed in some spinules of P. japonicus. The past and present records indicate that Pseudodiaptomus yamato n. sp. is endemic to Japan and confined to the coasts affected by the warm Kuroshio Current from western Kyushu to the middle of Honshu, while P. japonicus is widespread in northern East Asia without overlapping the range of P. yamato n. sp. The range of Pseudodiaptomus inopinus s.s. most certainly does not extend to those of P. yamato n. sp. and P. japonicus.