FRESH-WATER SPONGES (PORIFERA, SPONGILLIDAE) OF EASTERN CANADA - TAXONOMY, DISTRIBUTION, AND ECOLOGY

During a recent survey of the freshwater sponges of eastern Canada (fr om Ontario to Newfoundland), 15 species were recorded, representing ap proximately 50% of the total number of species known from North Americ a. Radiospongilla crateriformis, Spongilla aspinosa, and Trochospongil la horrida are reported from Canada for the first time. Two problemati c species, Corvospongilla novaeterrae and Spongilla johanseni, are rev iewed and their status is revised. Detailed notes on taxonomy, morphol ogy, distribution, and ecology are given. New limits of tolerance with respect to pH, water temperature, and calcium and magnesium concentra tions are established for several species. A taxonomic key to the fres hwater sponges of eastern Canada is presented.