Yllenus is a spider genus of the Salticidae family (jumping spiders). Y. arenarius is peculiar in building silken nests under the sand surface of sandy dunes it inhabits.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0