Sex Role–Dependent Behavioral and Architectural Divergence in a Jumping Spider

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  Sex Role–Dependent Behavioral and Architectural Divergence in a Jumping Spider ABSTRACT Sex differences in behavior and functional traits are often attributed to differences in mating effort intensity, but the role of sex-specific parental demands remains poorly understood. Using the jumping spider Toxeus maxillosus —where males engage in mate searching and courtship without providing parental care, while females provide extended maternal care from egg attendance to offspring maturity (around 3 months)—we conducted an exploratory investigation into whether these distinct selective pressures led to divergence in spatial behaviors and nest architecture. Results revealed that males and females showed equivalent accuracy, latency, and learning-related performance in both a route-planning test under water stress and a color-pattern associative memory task. In contrast, during nest-construction assays, females built complex, multi-entrance structures that closely matched the container'...

False scorpions (Arachnida, Pseudoscorpiones) from Lower Cretaceous Spanish amber

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False scorpions (Arachnida, Pseudoscorpiones) from Lower Cretaceous Spanish amber

Abstract

Pseudoscorpions, one of the earliest terrestrial lineages dating back to the Middle Devonian period (c. 385 Ma), have a limited fossil record mainly as inclusions in amber. The available fossils are mostly from the Cenozoic era, making it challenging to comprehensively understand their evolutionary history and diversification over time. Here, we report the first fossils of the order from Spanish Lower Cretaceous (upper Albian) ambers. Two new genera and species in the family Garypinidae are described from Álava amber (Peñacerrada II outcrop, Álava Province): Cretogarypinus zaragozai gen. et sp. nov. and Ithioreolpium alavensis gen. et sp. nov. Remarkably, the holotype of Cretogarypinus zaragozai shows preservation of internal soft tissues. The variability observed in the arolium of both fossil garypinids serves as compelling evidence for the hypothesis of diphyletism within the clade, which was already well established before the Early Cretaceous. Additionally, an incomplete specimen consisting of an isolated palp ascribed to the family Pseudogarypidae (extant genus Pseudogarypus Ellingsen), is described from San Just amber (Teruel Province). These findings represent the earliest occurrences of the families Garypinidae (superfamily Garypinoidea) and Pseudogarypidae (superfamily Feaelloidea) in the fossil record. They not only contribute to our understanding of a diverse pseudoscorpion fauna in Spanish amber but also offer valuable insights into divergence time estimations for pseudoscorpion families and potentially for biogeographic studies.

Sánchez-García, A., Palencia, L., Delclòs, X., & Peñalver, E. (2024). False scorpions (Arachnida, Pseudoscorpiones) from Lower Cretaceous Spanish amber. Papers in Palaeontology, 10(6), e1608. https://doi.org/10.1002/spp2.1608