Mind the gap! First records of the harvestman Leiobunum religiosum Simon, 1879 from Belgium (Opiliones: Sclerosomatidae)

 

Mind the gap! First records of the harvestman Leiobunum religiosum Simon, 1879 from Belgium (Opiliones: Sclerosomatidae)

Abstract 

The harvestman Leiobunum religiosum Simon, 1879 is reported for the first time in Belgium. This large and long-legged species is easy to identify by its contrasting dorsal colour pattern and conspicuous black bands on the leg coxae. Originally an endemic species of the southwestern Alps, it has also been recorded in recent decades from Germany, the Grand Duchy of Luxembourg and the Netherlands. The first confirmed Belgian records date from 2025 in Tellin (Wallonia, province of Luxembourg). It later turned out that a subadult female had already been photographed at the same location in 2017, but only identified later. The species was found on vertical rock surfaces in an old quarry. Based on this finding, an extra search was performed on citizen science platforms, adding eight additional localities for the species in the southeast of the country. As a rock-dwelling species, man-made habitats like artificial caves, dams, walls of buildings and quarries are suitable habitat, but the species also colonizes natural rock formations near rivers. The species has probably been introduced into the Grand Duchy of Luxembourg years ago. A warming climate may then have promoted its northern expansion from there onwards. 

De Smedt, Pallieter & Gosseries, Axel & Lock, Koen & Logghe, Garben & Wijnhoven, Hay. (2026). Mind the gap! First records of the harvestman Leiobunum religiosum Simon, 1879 from Belgium (Opiliones: Sclerosomatidae). 2026.