The amphibious land mollusc, P. rubiginos, is a common, wide-spread and characteristic inhabitant of the freshwater tidal region of the river Scheldt and its tributaries in NW Belgium. The sp occupies a rather narrow zone in the uppermost intertidal area, which is characterized by large amounts of tidal drift covering the bottom, and usually by a luxuriant vegetation of tall, nitrophilous herbs, often with Urtica dioica dominant. Other characteristic molluscs of this zone are Carychium minimum, Oxyloma pfeifferi, O. sarsi, Deroceras laeve, Vitrea crystallina and Zonitoides nitidus, locally also Nesovitrea hammonis. |
