Freshwater sponges (Porifera, Spongillidae) from the Lake of Geneva, Switzerland

A census of the sponge fauna in shallow-waters of the Lake of Geneva, Switzerland, displayed the presence of scattered populations of Spongilla lacustris (Linnaeus, 1758), Eunapius fragilis (Leidy, 1851), Ephydatia fluviatilis (Linnaeus, 1758), and Ephydatia muelleri (Lieberkuhn, 1855). Spongilla lacustris was the most frequent species, either alone or associated with other species it was present in numerous sites on a variety of substrata along the entire shoreline. The morphological analysis of specimens of S. lacustris of the Lake of Geneva compared with the type material of S. lacustris and Spongilla helvetica, shows a considerable Variation of skeletal and gemmular characters. Therefore, the synonymy of S. helvetica with S. lacustris is confirmed. The study also demonstrates the existence of a rich and diversified sponge fauna in the Lake of Geneva.