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...

Molecular phylogeny of the wolf spider subfamily Allocosinae in South America (Araneae: Lycosidae)

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Molecular phylogeny of the wolf spider subfamily Allocosinae in South America (Araneae: Lycosidae)

Abstract

The wolf spiders of the subfamily Allocosinae are known for their complex taxonomy, especially in the Neotropical region. Despite previous taxonomic and phylogenetic studies, the diversity and phylogenetic relationships of the subfamily remain largely unknown. This study aims to clarify the evolutionary relationships within South American Allocosinae, hypothesizing a greater diversity than currently recognized and seeking to resolve ambiguities in genus-level classification. We used a combination of mitochondrial and nuclear gene sequences to construct phylogenetic analyses for 73 specimens across 13 species of Allocosinae. Analyses using both maximum likelihood and Bayesian frameworks were conducted to examine internal relationships and phylogenetic structure and to infer a timeline of diversification. Additionally, species delimitation was conducted to identify cryptic lineages. Our results recover the specimens considered to be representatives of the subfamily Allocosinae as a monophyletic group, and identified five major clades. Divergence time estimates suggested Allocosinae originated in the Early Miocene (15–22 million years ago), and underwent significant diversification during the Pleistocene. Species delimitation analysis based on single markers uncovered 24 lineages, indicating potentially overlooked species. Allocosinae has shown to be an interesting group to study incipient speciation processes, ecology of coastal environments and atypical behaviors such as sex role reversal. Knowing and understanding the evolutionary history and relationships within the subfamily is necessary for progress in its study in any field of biology.

Laborda Á, Simó M, Piacentini LN, Brescovit AD, Beloso C, Aisenberg A, Arnedo MA, Ramírez MJ, Bidegaray-Batista L (2025) Molecular phylogeny of the wolf spider subfamily Allocosinae in South America (Araneae: Lycosidae). Arthropod Systematics & Phylogeny 83: 353-367. https://doi.org/10.3897/asp.83.e152943