The rise and diversification of spidroins in the deep-time evolution of spiders

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  The rise and diversification of spidroins in the deep-time evolution of spiders Summary The evolutionary success of spiders is often attributed to their stunning ability to produce and utilize silk, but the potential link between the molecular and phenotypic basis of silk production and spider diversification is seldom tested in a robust dated phylogenetic framework. Here, we provide a macroevolutionary context for testing hypotheses by reconstructing and dating the spider tree of life using genomic and transcriptomic data. We searched exhaustively for members of the spider silk protein (spidroin) gene family from omics data and identified them in an iterative phylogenetic pipeline. Four distinct new types of spidroins with atypical sequence characteristics are discovered to be widespread in true spiders with the potential to affect silk properties, as inferred by our phylogenetic generalized linear mixed model and phylogenetic generalized least squares analyses. Combining our ro...

Description of a new Andean species of widow spider (Araneae, Theridiidae, Latrodectus)

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Description of a new Andean species of widow spider (Araneae, Theridiidae, Latrodectus)

Abstract

We describe a new species of widow spider (Araneae, Theridiidae, Latrodectus) from the Andean region. DNA barcode sequences are provided. The species is documented from museum specimens across Peru and identified from photographs on iNaturalist, extending its inferred distribution into Ecuador, Bolivia, and Chile. We integrate specimen and citizen-science occurrences to generate a species distribution model using WorldClim bioclimatic variables, predicting highest suitability along temperate to high-elevation Andean regions. We discuss the utility and limitations of citizen-science imagery for delimiting and mapping species and summarize available information on clinical aspects of envenomation in Peru associated with the local “lucacha” widow spider.

Miller J, Kratzer CA, Griswold C (2026) Description of a new Andean species of widow spider (Araneae, Theridiidae, Latrodectus). ZooKeys 1281: 49-67. https://doi.org/10.3897/zookeys.1281.185973