Abstract
This paper presents important faunistic records including location data with all details conducted in the Czech and Slovak Republics during 2020. Four new non-native species, Arion intermedius, Ambigolimax valentianus, Clathrocaspia knipowitschii and Krynickillus melanocephalus, were recorded outdoors in Slovakia.
Radix lagotis was genetically confirmed for the first time from several sites in the Czech Republic and Slovakia. Corbicula fluminea, recorded in Moravia for the first time in 2018, was found in another river, ca 50 km far from the first occurrence.
Cepaea nemoralis, recorded in Slovakia for the first time in 2015, seems to have started spreading. New sites of Cornu aspersum were noticed in Prague and Bratislava; for the first time it was also found in Brno.
There are also new records of several endangered species, e.g. Vertigo moulinsiana, Pisidium hibernicum,P. globulare, and Pseudanodonta complanata, presented.