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...

The genus Androctonus Ehrenberg, 1828 (Scorpiones: Buthidae) in Oman

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The genus Androctonus Ehrenberg, 1828 (Scorpiones: Buthidae) in Oman

Abstract


The taxonomic position of Androctonus populations in Oman was investigated by analyzing morphological variation in a comprehensive sample representing 150 records gathered from 95 localities spread throughout the country. Two new allopatric species are described, separated by multivariate morphometric analysis and meristic characters: (1) A. omanensis sp. n., distributed across most of Oman, is characterized by wider, deeper metasomal segments IV–V, shorter legs, more robust pedipalps, more granules on lateral inframedian carinae of metasoma II–III, and sparser setation on basitarsal spurs; and (2) A. ammophilus sp. n., distributed in the dunes of the Rub’ al-Khali (Empty Quarter) of northwest Oman, and adjacent Saudi Arabia and United Arab Emirates, is characterized by narrower, shallower metasomal segments IV–V, longer legs, more elongate pedipalps, fewer granules on lateral inframedian carinae of metasoma II–III, and denser setation on basitarsal spurs. The emergence of the Rub’ al-Khali sand system during Pleistocene glaciations, and the transition to hyper-arid conditions in the region, are hypothesized to be abiotic factors promoting ecological speciation of A. ammophilus sp. n., and vicariant speciation of A. omanensis sp. n.

Lowe, G. 2025 . The genus Androctonus Ehrenberg, 1828 (Scorpiones: Buthidae) in Oman. Euscorpius, No. 424: 1-59. https://mds.marshall.edu/euscorpius/vol2025/iss424/1/