New records of the sponge Radiospongilla inesi (Porifera: Spongilidae) and the slug Omalonyx matheroni (Gastropoda: Succineidae) in the Vale do Paraíba, southeast Brazil

This report provides the new record of the sponge Radiospongilla inesi and the slug Omalonyx matheroni for the Vale do Paraiba, State of Sao Paulo, southeastern Brazil, besides the symbiosis among R. inesi and individuals of some benthic macroinvertebrates. Monthly collections were carried out in the Ribeirao dos Mottas, with a 0.5 cm sieve in the edge vegetation, as well as collections by hand. Three specimens of R. inesi were found, from a lotic environment under pebbles. In addition, individuals of four insect families, Sisyridae, Hydropsychidae, Chironomidae e Simuliidae, were found on the sponge aquiferous system. Six individuals of the semi-aquatic slug O. matheroni were also caught under rocks and cans. Despite the sponges are commonly found in the most of the environments, the freshwater species represents one of the most unknown animal groups of the world.  R. inesi was report at first time in Brazil in Pernambuco State, northeastern Brazil region, and this report represents just the second record of this species in Brazil, and the first time to the southeastern region. The presence of individuals of four insect families pointing out the importance of R. inesi on the life history of these animals. Despite some records of Omalonix sp. to the Sao Paulo State, this report seems to be the first record of the O. matheroni to the Vale do Paraiba, northern of the Sao Paulo State.