Jumping spiders (Araneae: Salticidae) possess a visual system that is exceptional among arthropods, mainly due to its unmatched acuity. Although vision of these spiders has been studied for decades, some of its main aspects remain unclear. One such aspect is the light spectrum visible to salticids, which is surprisingly heterogenous and involves various underlying physiological mechanisms. The results of the behavioral experiments with the regal jumping spider (Phidippus regius) presented in this study provide evidence that these vision-dependent spiders are able to capture their prey even under red (longwave) light, which is usually not perceived by spiders. Broader use of this experimental design in studies of spider vision is discussed.

A cuticle fragment found in an Early Devonian (Emsian) macerate from the Strathpeffer–Struie outlier in the Northern Highlands of Scotland represents the isolated pectinal tooth of a scorpion. This remarkable find includes a distinctive field of small projections in rounded sockets consistent with the peg sensilla of extant scorpions. This is the oldest evidence for the presence of these characteristic sensory organs, which in modern scorpions play an important role in chemo- and mechanoreception. The fossil indicates that some scorpions had developed anatomically modern pectinal teeth at least 395 million years ago, suggesting that the pectines of these early scorpions played a similar role, physiologically and behaviorally, to those of living species.

Eleven new species from the Scytodoidea group are described from mainland Ecuador: in the family Drymusidae, Drymusa pristirana sp. nov. (female) and in the family Scytodidae, Scytodes amazonica sp. nov. (male, female); S. argelia sp. nov. (female), S. ayampe sp. nov. (female), S. choco sp. nov. (male, female), S. costa sp. nov. (female), S. jaguar sp. nov. (male), S. loja sp. nov. (female), S. minus sp. nov. (male); S. orellana sp. nov. (male, female); and S. tayos sp. nov. (male). The new species D. pristirana sp. nov. presents a unique morphological character on the ventral surface of the female abdomen. The type specimens of S. lineatipes Taczanowski, 1874 from French Guiana and S. luteola Simon, 1893 from Venezuela are imaged for the first time, and S. romitii Caporiacco, 1947 is removed from synonymy with S. lineatipes.

The open-holed trapdoor spiders of the Teyl damsonoides-group (formerly included in the now synonymized genus Merredinia Main, 1983) are revised, and 20 new species are described from the biodiversity hotspot of south-western Western Australia. The only previously described species, T. damsonoides (Main, 1983), is further re-described and re-illustrated, and molecular data from seven genes for a subset of nine species are analyzed using Bayesian methods. The damsonoides-group of Teyl are unusual for their stunning bi-colored appearance and the bowed morphology of the male metatarsus I, and we here document the known diversity and biology of these little-known spiders.