Behavioral evidence for two-stage sleep in spiders

Posted by
  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 scorpions of the Estación de Biología Chamela, Jalisco, Mexico with the description of a new species of Mesomexovis (Scorpiones, Vaejovidae) and an identification key

Posted by

 

The scorpions of the Estación de Biología Chamela, Jalisco, Mexico with the description of a new species of Mesomexovis (Scorpiones, Vaejovidae) and an identification key

Abstract

Mesomexovis Gonzalez-Santillan & Prendini, 2013 is a scorpion genus of the Vaejovidae family that comprises seven species, all endemic to Mexico. The present study describes a new species from Estación de Biología Chamela, Jalisco, related to M. occidentalis (Hoffmann, 1931), M. atenango (Francke & Gonzalez-Santillan, 2006), and M. subcristatus (Pocock, 1898). Mesomexovis caxcan sp. nov. differs from these species in several respects. Firstly, the carinae of the pedipalp chelae are vestigial. Secondly, the ventral lateral carinae of metasomal segments I–IV are granular, and the ventral submedian carinae of segments I–IV are costate to granular. A microstructural separation between the subex and the basal carina of the capsular area of the hemispermatophore is described for the first time. Mesomexovis caxcan sp. nov. represents the eighth species of the genus and the fifth reported in the Estación de Biología Chamela. The other scorpions identified in this location are Centruroides chamela Ponce-Saavedra & Francke, 2011, C. elegans (Thorell, 1876) (Buthidae), Konetontli chamelaensis (Williams, 1986), and Thorellius intrepidus (Thorell, 1876) (Vaejovidae).

de Araujo Lira AF, González-Santillán E (2025) The scorpions of the Estación de Biología Chamela, Jalisco, Mexico with the description of a new species of Mesomexovis (Scorpiones, Vaejovidae) and an identification key. ZooKeys 1243: 241-267. https://doi.org/10.3897/zookeys.1243.146978