Cicileus derradji sp. nov., a new species from southern Algeria (Scorpiones: Buthidae)

Posted by
  Cicileus derradji sp. nov., a new species from southern Algeria (Scorpiones: Buthidae) Abstract A new scorpion species, Cicileus derradji sp. nov., is described from Tin Zaouatine District, In Guezzam Province, southern Algeria. The description is based on an adult male holotype, an adult female paratype and a juvenile specimen, and is supported by detailed morphological analyses, including colouration, morphometrics, carination patterns and trichobothrial arrangement. This discovery extends the known distribution of the genus Cicileus approximately 500 km southwestward within Algeria. With the addition of this species, the number of recognised species in the genus increases to six. The new species is compared with all previously known species of Cicileus , and detailed colour photographs, including images taken under ultraviolet illumination, are provided. Derradj, L., Aydın Yağmur, E., Benali, N., & Bikada, M. (2026). Cicileus derradji sp. nov., a new species from south...

Extended phenotype affects somatic phenotype in spiders: web builders have lower estimated biting forces than free hunters

Posted by

 


Extended phenotype affects somatic phenotype in spiders: web builders have lower estimated biting forces than free hunters

Abstract

Reciprocal selection between extended and somatic phenotypes is an active area of investigation. Recent research on the influence of web building on somatic evolution in spiders has produced conflicting results, with some finding no effect of web use on somatic evolution and others showing significant effects. These studies differed in focus, with the former surveying general anatomical traits and the latter concentrating on somatic systems with significant functional roles in prey capture. Here we propose and test the hypothesis that prey immobilization by webs is broadly synergistic with cheliceral biting force and that web builders have lower cheliceral forces compared to free hunters. Our analysis focused on the intercheliceral (IC) sclerite and muscles, a newly characterized system that is synapomorphic and ubiquitously distributed in spiders. Using µCT scans, we quantify IC sclerite shape and model IC muscle function. Statistical analyses show that inferred size-corrected isometric muscle force is lower in web-builders than in free-hunters. No such association was found for IC sclerite shape. In the investigation of reciprocal selective effects between extended and somatic phenotypes, our results highlight the importance that these traits be functionally linked and adaptive.

Black, C. R., Shultz, J. W., & Wood, H. M. Extended phenotype affects somatic phenotype in spiders: Web builders have lower estimated biting forces than free hunters. Evolution. https://doi.org/10.1093/evolut/qpae170