著者

Genki Kobayashi Shigeaki Kojima

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.131-136, 2021-06-17 (Released:2021-06-17)

参考文献数

34

被引用文献数

4

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A new species of the genus Travisia Johnson, 1840, the single genus of the family Travisiidae, is described. Specimens of Travisia sanrikuensis sp. nov. were collected in the Sanriku region, Japan, from the lower bathyal zone (871–1684 m depth) of the northwestern Pacific. Molecular phylogenetic analysis based on partial 16S rRNA gene sequences revealed that the new species is phylogenetically close to Travisia brevis Moore, 1923, but differs from all congeneric species by the following morphological characters: 25 segments, 20 chaetigers, and 19–20 pairs of cirriform branchiae starting from chaetiger 2.

著者

Genki Kobayashi Hajime Itoh Gen Kanaya Hirokazu Abe Shigeaki Kojima

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.1, pp.13-20, 2023-02-28 (Released:2023-03-02)

参考文献数

57

被引用文献数

1

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Genetic homogeneity among populations of marine organisms with high dispersal potential is maintained by high gene flow whereas genetic differentiation is often formed under the presence of dispersal barriers. One of the possible dispersal barriers for intertidal species in Japan is the Sea of Japan because several tidal-flat species are absent in the region due to the small tidal range. In this study, we aimed to validate this possibility by examining the population genetic structure of the intertidal crab Macrophthalmus japonicus, which possesses a long planktonic larval period indicating high dispersal potential but is absent on the Sea of Japan side in Honshu Island. In total, 83 haplotypes of the mitochondrial cytochrome c oxidase subunit I were recovered from 154 specimens collected from 10 Japanese sampling sites and three GenBank sequences from China and Korea. All populations showed high genetic diversity except for the northernmost population at Asadokoro site in Mutsu Bay. The ΦST values among populations were low, even between populations with great distances such as the Pacific side of northeastern Honshu and Kyushu Islands (ca. 1500 km). On the other hand, the ΦST values between Asadokoro site and the other Japan sites were high. The isolation of the northernmost population despite the high dispersal potential of M. japonicus is probably because of the absence of neighboring populations that can supply larvae to the northernmost population and the invasion of larvae from the Pacific side is blocked by ocean currents.