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...

On the actual identity of the genus Castianeira Keyserling, 1879 (Araneae: Corinnidae: Castianeirinae): the type species and its relatives

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On the actual identity of the genus Castianeira Keyserling, 1879 (Araneae: Corinnidae: Castianeirinae): the type species and its relatives

Abstract

The identity of the type species of Castianeira Keyserling, 1879 is clarified, enabling a diagnosis of Castianeira sensu stricto, which comprises four species from northern South America and Panama. The type species, C. rubicunda Keyserling, 1879, is recorded from Venezuela, Colombia, and Panama, with the specimens from Barro Colorado Island (Panama) having previously been misidentified as C. memnonia (C. L. Koch, 1841). Based on photographs of the holotype of the later species, it is transferred to Mazax O. Pickard-Cambridge, 1898 and recognized as the senior synonym of M. mokana Silva-Junior, Martínez, Villarreal & Bonaldo, 2024 syn. nov.. Since M. memnonia comb. nov. is the type species of Thargalia Karsch, 1880, Thargalia is removed from the synonymy of Castianeira and treated as a synonym of Mazax, as a nomen oblitum, while Mazax is declared a nomen protectum under the provisions of the International Code of Zoological Nomenclature. Three new species are described: Castianeira leda sp. nov. (♂) and C. pollux sp. nov. (♂♀), both from Colombia, Peru, and Brazil, and C. castor sp. nov. (♂♀) from Venezuela and Brazil.

Silva-Junior, C.J. & Bonaldo, A.B. (2026) On the actual identity of the genus Castianeira Keyserling, 1879 (Araneae: Corinnidae: Castianeirinae): the type species and its relatives. Zootaxa, 5763 (1), 39–68. https://doi.org/10.11646/zootaxa.5763.1.2