In Europe, native terrestrial flatworms are a paradigm of the cryptic edaphic fauna in humid forests because they are small, difficult to collect, and externally very similar. Their Neotropical counterparts are good biodiversity indicators in the assessment of the conservation status of their habitat. While the diversity of terrestrial planarians in the Neotropics is high, the diversity of European microplanid land flatworms is comparatively scarce. Nonetheless, recent molecular barcoding studies have uncovered an increasing diversity. Furthermore, for Microplana terrestris (Müller, 1774) it was shown that its recent evolutionary history was mainly driven by Pleistocene climatic events. Intensive sampling throughout Europe revealed that nominal M. terrestris consists of a complex of cryptic species, sharing similar external appearance but differing at molecular and anatomical levels, thus constituting a prime example of zoological crypsis. Since these species can be differentiated on the basis of anatomical features, they do actually form pseudo-cryptic species. Temperate European forests show a comparatively high diversity of terrestrial flatworms, although never reaching the biodiversity level of the Neotropics. A better understanding of their ecological role and adequate measures to protect these land planarians depend on an increased effort to properly detect these organisms in their environment.