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...

Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae)

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Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae)


Abstract

The palearctic spider genus Mastigusa Menge, 1854 is characterized by a remarkable morphology and wide ecological variability, with free-living, cave dwelling and myrmecophile populations known. This genus has a long and tangled taxonomic history and was placed in different families in the past, all belonging to the “marronoid clade”, an informal grouping of families characterized by the lack of strong synapomorphies. Three species are currently recognized, but their identity and circumscription has been long debated. A molecular approach was never applied for trying to solve these uncertainties, and doubts still remain both about its phylogenetic placement and about the taxonomic status of the described species. For the first time the genus Mastigusa is included in a molecular phylogenetic analysis and strong support is found for its placement within the family Cybaeidae, in sister relationship with the genus Cryphoeca Thorell, 1870. An analysis of Mastigusa populations spanning across the distribution range of the genus identifies a high and previously overlooked genetic diversity, with six distinct genetic lineages showing a strong geographic pattern. Divergence times between Mastigusa and its sister genus and between the distinct Mastigusa lineages are estimated, and the groundwork is laid for a taxonomic revision of the species belonging to the genus.


Filippo Castellucci, Nikolaj Scharff, Andrea Luchetti, Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae), Molecular Phylogenetics and Evolution, Volume 186, 2023, 107833, ISSN 1055-7903, https://doi.org/10.1016/j.ympev.2023.107833. 

(https://www.sciencedirect.com/science/article/pii/S1055790323001331)