Tomikawa Ko, Nishimoto Yuichiro, Nakahama Naoyuki, Nakano Takafumi
Graduate School of Humanities & Social Sciences, Hiroshima University, Higashi-Hiroshima 739-8524, Japan,
Matsusaka, Mie 515-0063, Japan.
Zoolog Sci. 2022 Oct;39(5):489-499. doi: 10.2108/zs220030.
The subterranean amphipod genus is diverse in Far East Asia, including the Japanese Archipelago. However, species have not been recorded from the Ryukyu Islands, which extend southwest of the Japanese Archipelago. This study describes a new species of , sp. nov., from Yonaguni Island, Ryukyu Islands, Japan. Phylogenetic analyses revealed that sp. nov. is a sister species to sp. 4 from Honshu Island, Japan. In addition, three monophyletic groups were found in , although the phylogenetic positions of several species remain unknown. Our divergence dating indicates that the differentiation of major lineages of , which contains species from both the Asian continent and the Japanese Archipelago, is concentrated around 20 MYA. These results suggest that the opening of the Sea of Japan is one of the major factors promoting the speciation of endemic to the archipelago.
地下 amphipod 属在包括日本群岛在内的远东地区具有多样性。然而，在日本群岛西南部延伸的琉球群岛尚未记录到该属的物种。本研究描述了一种来自日本琉球群岛与那国岛的新物种，即[属名]新种。系统发育分析表明，[属名]新种是来自日本本州岛的[属名]物种4的姐妹物种。此外，在[属名]中发现了三个单系类群，尽管几个物种的系统发育位置仍然未知。我们的分歧时间估计表明，包含来自亚洲大陆和日本群岛物种的[属名]主要谱系的分化集中在约2000万年前。这些结果表明，日本海的开放是促进该群岛特有[属名]物种形成的主要因素之一。
