Two new alien slugs, Krynickillus melanocephalus Kaleniczenko, 1851 and Tandonia kusceri (H. Wagner, 1931), are already widespread in Hungary

Two slug species (Krynickillus melanocephalus Kaleniczenko, 1851 and Tandonia kusceri (H. Wagner, 1931)) are reported from Hungary for the first time. Identification was supported by anatomical examination in both, and molecular data in the latter species. A citizen science survey applying a Realtime Social Networking Service (RSNS) method using Facebook posts revealed that both species are already widespread in Hungary, i.e. Krynickillus melanocephalus is reported from 14 and Tandonia kusceri from 25 sites. So far, we received no reports on any damage caused by these two slug species. Nevertheless, we treat them as potential horticultural pests requiring further attention.