The recent discovery of Sterrastrolepis brasiliensis Volkmer-Ribeiro & De Rosa-Barbosa, 1978, a brazilian endangered freshwater sponge, at the rocky bottom of River Piquiri, Paraná Basin, Brazil, enhanced the photographing of living specimens, the improving of SEM illustration and description for some characteristics, the description of the habitat and the register of an sponge assembly composed by S. brasiliensis, Oncosclera navicella (Carter, l881) and Oncosclera tonolli (Bonetto & Ezcurra de Drago, 1968). Oncosclera tonolli has its first register for Brazilian waters and for the Parana Basin. Gemmules of O. navicella are also SEM illustrated.
Endangered species; freshwater sponges; rocky bottom; South America
