Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones

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  Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones ABSTRACT Chemical secretion deployment is a widespread defensive strategy in arthropods, typically aimed at surviving encounters with predators. However, the ecological forces shaping variation in its use across species remain unclear. We quantified chemical secretion behavior in 11 sympatric species of Prionostemma within the understudied arachnid order Opiliones. We surveyed species in two distinct forests in Costa Rica and tested their secretion propensity when stimulated, and whether these differences correlate with interspecific variation in morphology, leg-loss levels, or social behavior. We found that species varied in their tendency to release chemical secretions, forming a continuous gradient from taxa that rarely secreted to those that secreted in nearly all encounters. However, this variation was not explained by body size or leg loss. Spec...

Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain

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Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain

Abstract

A taxonomic revision of the species of Nemesia Audouin, 1826, distributed in the vicinity of Córdoba City, southern Spain, is presented. Four new species are described: Nemesia morana sp. nov. (female), N. kodama sp. nov. (male and female), N. rosae sp. nov. (male and female), and N. tamajoni sp. nov. (male and female). These species are distinguished by distinct morphological characters, including the shape of the spermathecae, palpal bulbs, and spinnerets, as well as by burrow architecture. Fieldwork was conducted across two of the three major habitat types in the region—the humid, forested mountains of Sierra Morena and the croplands and riparian forests of the Guadalquivir Valley—while the third, the “campiña”, which is mainly composed of agricultural landscapes, remains poorly explored. Sampling methods included pitfall trapping and the direct excavation of burrows. The study also provides an identification key to the species from Córdoba and emphasises the importance of microhabitat features in species distribution. The present results suggest that the regional diversity of Nemesia is likely underestimated. They underscore the significance of fine-scale biodiversity surveys of cryptic mygalomorph spiders in achieving a more comprehensive understanding of the Mediterranean arachnofauna.

Pertegal, C. (2026). Hidden diversity in plain sight: Four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain. Zoosystematica Rossica, 35(1), 128–153. https://doi.org/10.31610/zsr/2026.35.1.128