quagga mussel, Dreissena rostriformis bugensis (Andrusov, 1897). During our study, the
quagga mussel was found at several locations in the Dutch and Belgian section. Both
quagga and zebra mussels (Dreissena polymorpha Pallas, 1771) were sampled and the
species identity was confirmed by morphological analysis. Plausible dispersion patterns and
colonization routes of Dr bugensis in the Meuse River are suggested.