Hunting ecology predicts eye arrangements in the modular visual system of spiders

  Hunting ecology predicts eye arrangements in the modular visual system of spiders Summary Vision is one of the most important senses used by animals and contributes to fundamental behaviors, including foraging, navigation, and mate detection and selection. 1 Although much is known about how eye position and orientation correlate to ecology in the context of binocularity, 2 animals with multipartite visual systems (more than two eyes) remain comparatively neglected. Spiders are highly successful predators that occupy a range of ecological niches and usually possess eight eyes. Here, we use three-dimensional geometric morphometrics and evolutionary modeling to test whether eye positions, orientations, and interocular angles correlate with hunting strategies in 52 species across the spider phylogeny. We demonstrate that eye configurations diversified from an ancestral medial cluster, as seen in modern trapdoor spiders, to a halo-like configuration in orb-weavers, and to the fronta...

A place for everything, and everything in its place: A new genus for the spiny Australian crab spiders (Araneae: Thomisidae)

 


A place for everything, and everything in its place: A new genus for the spiny Australian crab spiders (Araneae: Thomisidae)

Abstract

Recent phylogenetic analyses have shown consistent evidences that the composition of some Stephanopinae genera, as well as their distribution, were wrongly assigned throughout the 20th century. Inaccurate descriptions and vague diagnoses resulted in groups that are actually formed by multiple genera, which were repeatedly recovered as polyphylies. The present work is part of a long-term morphological study that aims to better understand and delineate the taxonomic boundaries of the Australian stephanopines. Hereinafter, we present a new combination for a group of spiders hitherto considered as part of Sidymella Strand, 1942, officially elevating it to a generic rank and highlighting its diagnostic features. The genus Spinaarachne gen.nov. is proposed not only to comprise the new species S. aculeata sp. nov. and S. pilosa sp. nov. but also to accommodate the transference of S. hirsuta (L. Koch, 1874) comb. nov. Brief notes regarding the plausible reasons of why S. hirsuta comb. nov. was previously attributed to a Neotropical genus are presented, and new distribution records are also provided.

Machado, M. and R. A. Teixeira. 2025. A place for everything, and everything in its place: A new genus for the spiny Australian crab spiders (Araneae: Thomisidae). Records of the Australian Museum 77(5): 271-283. https://doi.org/10.3853/j.2201-4349.77.2025.1913