Occurrence of two exotic decapods,

New information on the occurrence of two alien decapod crustaceans, Macrobrachium nipponense and Procambarus virginalis, was summarized for Ukraine. The invasive potential of both species was estimated in the context of local environmental and socio-economic issues. Their history as non-native species is marked by the early use of alien decapods as a natural resource by local residents. Both intentional and unintentional introductions occurred for M. nipponense, while the ornamental trade was an important source of non-native P. virginalis. New records of M. nipponense and P. virginalis from open freshwater habitats in the Odesa and Kharkiv provinces suggest continuing expansion of these decapods. We conducted a molecular phylogenetic analysis of COI sequences, which confirmed morphological identifications of invasive M. nipponense. This reinforces the presumed pathway of this species, including its pathway from China to south-western Ukraine. Procambarus fallax was found to be paraphyletic in relation to P. virginalis, which was probably caused by analyzing only one mitochondrial gene, which could be impacted by the recent emergence of the latter species.