Arachniden van het Roerdal: 1000-soortendag met enkele aanvullingen (Arachnida: Araneae, Opiliones, Pseudoscorpiones)

An inventory of the Arachnida fauna on several areas along the River Roer in the province of Limburg, the Netherlands, was carried out in 2013. In total, we found 94 spider, 14 harvestman and 2 pseudoscorpion species. One species, Theonina cornix Simon, 1881, appeared to be new to the Dutch fauna, while for three species (Singa nitidula C.L. Koch, 1844, Entelecara erythropus (Westring, 1851), and Mermessus denticulatus (Banks, 1898) are recorded for the first time for the province of Limburg.