New Species in Denmark: Pseudoscorpion Appears in the Wilderness

For the first time, the pseudoscorpion Mesochelifer ressli has been found in Denmark. The discovery was made in Saksfjed Wilderness on southern Lolland – a large-scale rewilding area spanning 800 hectares.

It’s a discovery with the X factor. Pseudoscorpions look like something from another world – tiny predators with venomous pincers and a scorpion-like appearance

“It’s a discovery with the X factor. Pseudoscorpions look like something from another world – tiny predators with venomous pincers and a scorpion-like appearance. And now, the species Mesochelifer ressli has been recorded in Denmark for the very first time,” says ecologist and spider specialist Frederik Leck Fischer, who made the discovery.

A Rare Creature with a Dramatic Appearance

Pseudoscorpions are a relatively small group globally, and in Denmark, 20 species had been recorded – now 21. Very few people are aware of their existence, as all species are very small and hide in places few would think to look.

Mesochelifer ressli measures just 3 mm, but it is a highly effective miniature predator. The species uses venom in its pincers to subdue small prey and spends most of its life in nests it constructs using silk from a gland in its mouth.

The first Danish discovery was made in Saksfjed Wilderness, where more than 10 individuals were found. The pseudoscorpions were located inside self-spun nests beneath bark, built from small pieces of organic material, including their shed exoskeletons—indicating that the species remains in the same nest for a prolonged part of its life cycle.

The species has very few known occurrences across Europe, making the finding all the more remarkable. It was recently discovered in neighboring countries, but whether this Danish record reflects a true northward spread or a previously overlooked presence remains uncertain.

Over 110 Spider Species in the Wilderness

The discovery is part of a systematic monitoring project in Saksfjed Wilderness, where Frederik Leck Fischer is conducting Denmark’s largest mapping of the area’s spider fauna as part of biodiversity monitoring.

Already, over 110 different spider species have been recorded in the first 15 survey plots – more than one-sixth of all known Danish species. The study has also led to the discovery of a new spider species for Danish nature: the orb-weaver Zilla diodia.

“Nature in Denmark lacks space, and biodiversity is declining. That’s why it’s crucial to closely track developments when we create new nature like in Saksfjed Wilderness. By mapping even the overlooked species, we gain knowledge that not only strengthens rewilding but also supports nature and the opportunity to bring back more biodiversity to Denmark,” says Thor Hjarsen, senior ecologist and project manager at the Hempel Foundation, who leads the rewilding work and species monitoring in Saksfjed Wilderness.

Saksfjed Wilderness – A Large-Scale Rewilding Project

Saksfjed Wilderness is one of Denmark’s most ambitious rewilding projects. The former farmland is being transformed into wild nature, and the discoveries of both demanding and rare species underscore the area’s vast potential as a habitat for specialized wildlife.

Facts about the Pseudoscorpion Mesochelifer ressli

• Discovered in Denmark for the first time in 2025
• About 3 mm long, predator with venomous pincers
• Harmless to humans