2011-12-03 Austria, Lower Austria, district Bruck/Leitha - Danube bayou which has fallen dry, National Park (140 msm Quadrant 7867/2).German names: Wandermuschel (Dreissena polymorpha) + Teichmuschel (Anodonta sp.)For the record low of water level exposing these mussels see remarks here.Species identified by Andreas Tiefenbach at naturbeobachtung_at: it is a neozoon which travelled up the Danube river, following water traffic (it is attaching itself to ship hulks), coming from the Black Sea - and is invasive here in Austria already.For habitat shot please click here.