Advancing the systematics of Araneae: ultraconserved elements phylogenomics demonstrates the non-monophyly of Miturgidae Simon, 1886 and supports the Familial Rank of Systariidae Deeleman-Reinhold, 2001

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  Advancing the systematics of Araneae: ultraconserved elements phylogenomics demonstrates the non-monophyly of Miturgidae Simon, 1886 and supports the Familial Rank of Systariidae Deeleman-Reinhold, 2001 Abstract The systematic status of the family Miturgidae Simon, 1886 and related subfamilies has long been problematic, primarily due to challenges in interpreting morphological characters and limited molecular sampling. In this study, we reconstruct the phylogeny of Miturgidae using ultraconserved elements and estimate its divergence time. Our results suggest that Systariinae does not belong to Miturgidae, but rather is sister to all other families of the Dionycha B clade. Consequently, we elevate it to family rank as Systariidae Deeleman-Reinhold, 2001 and discuss its morphological synapomorphies. Furthermore, our analyses place Miturgidae as the sister clade to Viridasiidae + Selenopidae under multiple phylogenetic methods. Divergence time estimates indicate an ancient origin of...

Spider nest-retreat origin, diversification, and architectural plasticity link to historical and current temperature fluctuations

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Spider nest-retreat origin, diversification, and architectural plasticity link to historical and current temperature fluctuations

Abstract

Ongoing climate change mandates improved understanding of how temperature fluctuations influence organismal evolution and behavior. Detritus-based nest-retreats in spiders have originated multiple times in parallel—hypothesized to be an adaptive response to climatic fluctuations. We investigated the potential role of climate change in shaping the evolution of nest-retreats over geological timescales, and the short-term effect of temperature on the morphology and energy investment of nest-retreats in Campanicola campanulata (Theridiidae). Phylogenetic analyses reconstruct twelve origins of nest-retreats, first appearing in the Eocene, and diversifying during the Late Cenozoic Icehouse period. Spiders respond to experimentally lowered temperatures by making larger nest-retreats, indicating a direct impact of temperature on retreat architecture. Our results for the first time affirm the thermoregulatory function of spider nests and suggest that temperature impacts nest-retreats across both evolutionary and ecological timescales. Nest-retreat spiders can serve as a model to study the origins of thermoregulatory nest-building in animals and how it may be impacted by ongoing climate change.
Zhong, R., Chang, J., Wang, Y., Zhang, H., Peng, Y., Agnarsson, I., & Liu, J. (2026). Spider nest-retreat origin, diversification, and architectural plasticity link to historical and current temperature fluctuations. Molecular Phylogenetics and Evolution, 214, 108478. https://doi.org/10.1016/j.ympev.2025.108478