First European record of the giant ramshorn snail Marisa cornuarietis

First European record of the giant ramshorn snail Marisa cornuarietis (Linnaeus, 1758) (Gastropoda: Ampullariidae) from northern Spain The South American giant ramshorn snail Marisa cornuarietis is reported for the first time in Europe, inhabiting a freshwater natural ecosystem in northern Spain. We present a diagnosis of the species in order to facilitate the recognition of this new European alien species and its differentiation from other native freshwater snails. We also include brief notes on its biology and ecology at its new locality. Finally, we discuss its invasive potential and the possible impacts that it may cause in the native ecosystems if it becomes invasive