Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution

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  Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution Abstract The Savignia genus group includes nine morphologically complex yet similar genera where species were assigned based mainly on the cephalic lobes. Among these genera, males of Diplocephalus Bertkau, 1883, Savignia Blackwall, 1833 and Araeoncus Simon, 1884 show some of the most extraordinary cephalic lobes among dwarf spiders (Linyphiidae, Erigoninae). In this study we undertake the first phylogenetic analysis of the Savignia genus group. We use 269 morphological characters (175 newly defined) and 70 taxa (59 ingroup taxa) to reconstruct the relationships and evolutionary trends of cephalic lobes in this lineage. Our findings show that cephalic lobes with varying shapes and sizes appear in several Savignia genus group lineages, highlighting that it is not a good diagnostic character. The high support in several clades allows the redefinition of t...

A history of accidental widow spider (genus Latrodectus) introductions on the island of Ireland with a new irish record for Latrodectus hesperus (Chamberlin and Ivie, 1935), and additional records of Latrodectus geometricus (C.L. Koch, 1841).

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A history of accidental widow spider (genus Latrodectus) introductions on the island of Ireland with a new irish record for Latrodectus hesperus (Chamberlin and Ivie, 1935), and additional records of Latrodectus geometricus (C.L. Koch, 1841).

ABSTRACT

The widow spiders of the genus Latrodectus (Araneae: Theridiidae) have a well-documented global medical significance due to the potent venom many of them possess. This medical importance partially stems from the global range expansion the genus has undergone, facilitated in part by human trade. This expansion has had an impact on human health in countries where Latrodectus spiders establish populations. Ireland has a detailed report history of accidental widow spider introductions, spanning over 30 years, which assists in understanding the potential such species have for establishing. Here we present three additional cases: a second and third record of Latrodectus geometricus (C.L. Koch, 1841) and the first record of Latrodectus hesperus (Chamberlin and Ivie, 1935). We also review all published reports of Latrodectus introductions in Ireland and discuss the potential for populations to establish. While case histories suggest that L. hesperus and L. geometricus can survive Irish winters, it is not certain that they can complete an egg-to-egg life cycle or even reproduce. Nevertheless, it seems possible they could do so in favourable micro-habitats in anthropogenic habitats such as hot houses. Identification of instances of Latrodectus introductions into Ireland is essential to prevent potential establishments that could lead to envenoming cases.

Collier, B.L., et al. "A history of accidental widow spider (genus Latrodectus) introductions on the island of Ireland with a new irish record for Latrodectus hesperus (Chamberlin and Ivie, 1935), and additional records of Latrodectus geometricus (C.L. Koch, 1841)." Biology and Environment: Proceedings of the Royal Irish Academy 123, no. 3 (2023): 111-120. https://doi.org/10.1353/bae.2023.a915306.