Behavioral evidence for two-stage sleep in spiders

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  Behavioral evidence for two-stage sleep in spiders Abstract Sleep is a fundamental behavioral state found across the animal kingdom, yet most of what we know about sleep is heavily vertebrate-biased. Studies are scarce or nonexistent in all but a few invertebrate lineages. A recent study of an REM sleep-like behavior in a jumping spider has reported unexpected parallels to sleep expression in vertebrates. So far, experimental evidence that these behavioral indicators truly represent sleep was lacking in spiders. Here, we present a comprehensive investigation into sleep behavior in the spider Portia fimbriata (Salticidae). We demonstrate diurnal activity, a free-running circadian rhythm, robust sleep architecture, regularly occurring REM-like behaviors, elevated arousal thresholds during those REM-like states, as well as rebound effects following sleep disruption. We conclude that the behavior we observe in spiders is behavioral sleep, providing evidence for an REM-like sleep sub...

A new species of Cyrtopholis Simon, 1892 from Montserrat, with notes on some other Caribbean theraphosines (Araneae: Theraphosidae)

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A new species of Cyrtopholis Simon, 1892 from Montserrat, with notes on some other Caribbean theraphosines (Araneae: Theraphosidae)

Abstract
A new species of the Caribbean genus Cyrtopholis Simon, 1892, Cyrtopholis montserrat sp. nov. is described from the United Kingdom Overseas Territory (UKOT) of Montserrat, based on both sexes. Cyrtopholis femoralis Pocock, 1903 is redescribed from the holotype male with the first figures of the genitalia of this Montserrat endemic spider presented. The endemic Saint Barthélemy species Cyrtopholis antillana Thorell, 1894 stat. rev. is revalidated from synonymy with Cyrtopholis bartholomaei (Latreille, 1832) and non-type specimens of both sexes are described and diagnosed. Cyrtopholis innocua (Ausserer, 1871), C. intermedia (Ausserer, 1875), C. ischnoculiformis (Franganillo, 1926), and C. obsoleta (Franganillo, 1935) are proposed as nomina dubia, and Cyrtopholis respinus Franganillo, 1935 is confirmed as a nomen nudum. 

Sherwood, Danniella & Questel, Karl. (2024). A new species of Cyrtopholis Simon, 1892 from Montserrat, with notes on some other Caribbean theraphosines (Araneae: Theraphosidae). Arachnology. 19. 1298-1307.