Multiple genetic lineages of the invasive brown widow spider (Araneae: Theridiidae) from inland areas in the Kanto region, Japan

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  Multiple genetic lineages of the invasive brown widow spider (Araneae: Theridiidae) from inland areas in the Kanto region, Japan Abstract The brown widow spider, Latrodectus geometricus Koch, 1841, is a medically important invasive species that possesses neurotoxic venom capable of causing latrodectism in humans. This species has recently been found in inland areas of the Kanto region in Japan, raising concerns about its ongoing range expansion and associated public health risks. Here, we analyzed partial sequences of mitochondrial cytochrome c oxidase subunit I (cox1) and 16S ribosomal DNA from 99 individuals (3 males and 96 females) collected from multiple sites in Tokyo and Kanagawa prefectures, evaluating their phylogenetic positions and introduction history. The analysis revealed two major lineages, with six cox1 haplotypes (LGc1–LGc6) and five 16S rDNA haplotypes (LGs1–LGs5). One lineage comprised previously unreported basal haplotypes, including LGc5 and LGc6 in cox1 and L...

Systematics of cybaeid spiders endemic to the Japanese Archipelago, and their historical biogeographic implications (Araneae: Cybaeidae)

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Systematics of cybaeid spiders endemic to the Japanese Archipelago, and their historical biogeographic implications (Araneae: Cybaeidae)

Abstract

The epigean and subterranean spiders of the genus Cybaeus L. Koch, 1868 are distributed in the Holarctic, and are highly diversified in western North America and Japan. More than 100 species have been described from the Japanese Archipelago and several species assemblages have also been recognised among the Japanese Cybaeus based on their morphological similarities. However, their phylogenetic backbone remains unclear. Moreover, genus-level classification of several of the Japanese species appear to be questionable. In this study we performed extensive molecular analyses of the family Cybaeidae in East Asia, mainly the Japanese Archipelago, to clarify their fundamental phylogenetic relationships. We also conducted a divergence time estimation to provide insights into their historical biogeography and evolutionary history. Our divergence dating results indicate that the diversification of the major lineages of the East Asian cybaeid spiders might be related to the opening of the Sea of Japan c. 20 million years ago. On the basis of the morphological evaluation and obtained phylogenies, some East Asian species formerly placed in Cybaeus are transferred to the cybaeid genera Allocybaeina Bennett, 2020, Sincybaeus Wang & Zhang, 2022 and Cybaeina Chamberlin & Ivie, 1932, i.e. Allocybaeina petegarina (Yaginuma, 1972), comb. nov., Sincybaeus monticola (Kobayashi, 2006), comb. nov., Sincybaeus rarispinosus (Yaginuma, 1970), comb. nov., Sincybaeus yoshiakii (Yaginuma, 1968), comb. nov., and Cybaeina whanseunensis (Paik & Namkung, 1967), comb. nov. Our results clarify the genus-level richness of cybaeids in the Japanese Archipelago for the first time, and reveal the fine-scale phylogenetic relationships of Cybaeus species endemic to the Japanese Archipelago and adjacent regions.

Sugawara Yusuke, Ihara Yoh, Koike Naoki, Seo Hong-Yul, Prozorova Larisa A., Zhang Zhi-Sheng, Nakano Takafumi (2024) Systematics of cybaeid spiders endemic to the Japanese Archipelago, and their historical biogeographic implications (Araneae: Cybaeidae). Invertebrate Systematics 38, IS24058.

https://doi.org/10.1071/IS24058