First record of the New Zealand mud snail Potamopyrgus antipodarum J.E. Gray 1843 (Mollusca: Hydrobiidae) in Greece – Notes on its population structure and the associated microalgae

Potamopyrgus antipodarum (Gastropoda: Hydrobiidae), a New Zealand native species, is recorded for the first time in waterbodies of Greece, being dominant in the gastropod fauna present; waterfowl transportation is suggested as its invasion mode. This species was collected (November 2007) from the aquatic plants Myriophyllum spicatum and Nasturtium officinale in Lake Trichonis (CW Greece) and an adjacent stream. Totally, 332 individuals of various ages were recorded, females being the majority. One diatom (Cocconeis placentula var. euglypta) was found in its digestive tube, also thriving abundantly on the surface of both the invader shell and the aquatic plants, and in association with other cosmopolitan periphytic diatoms (three of them new for the area, with one new record for Greece) or endemic diatoms.