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 São Paulo, southeastern Brazil, besides the symbiosis among R. inesi and individuals of some benthic macroinvertebrates. Monthly collections were carried out in the Ribeirão 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 São Paulo State, this report seems to be the first record of the O. matheroni to the Vale do Paraíba, northern of the São Paulo State.


INTRODUCTION
Freshwater sponges of the monophyletic order Spongillida, is the unique lineage of demosponges that colonized lentic and lotic systems sometime in the PermoCarboniferous (Schuster et al. 2018;Kenny et al. 2019).
The genus Radiospongilla Penney & Racek, 1968, present gemmoscleres radially arranged on gemmules and microscleres absents. This species is widely distributed over the world and recorded in all zoogeographical regions, except for Antarctica (Manconi & Pronzato, 2007;Osborn et al. 2008). Along the 18 species described for the genus Radiospongilla, only three are recorded in the Neotropical Region, R. crateriformis (Potts, 1882), distributed in Mexico, United States, Suriname, Canada, Barbados, Cuba, Costa Rica, China and Japan (see Nicácio et al., 2011). R. amazonensis Volkmer- Ribeiro & Maciel, 1983, restricted to Brazil, distributed in seven of the twelve Brazilian hydrographic basins (Pinheiro, 2007) and R. inesi Nicácio & Pinheiro, 2011, currently recorded exclusively in Brazil, Eastern North Atlantic Basin, in the Pernambuco state.
This report provides the new record of the sponge Radiospongilla inesi and the slug Omalonyx matheroni for the Vale do Paraiba, southeastern Brazil region, in the municipality of Guaratinguetá, State of São Paulo, besides the symbiosis among R. inesi and individuals of some benthic macroinvertebrates.

MATERIAL AND METHODS
Monthly collections were carried out from September 2014 to August 2015 in the Ribeirão dos Mottas, an affluent of the Rio Paraíba do Sul river (22°53'14.55" S -45°13'2.22" W) (Figure  1), as a part of the broad aquatic macroinvertebrate research. The basin of the Ribeirão dos Mottas comprise a stream that ends on the right edge of the Paraíba do Sul river, included on the elevation system of the Serra do Mar, in northeastern of the São Paulo State. A single person performed the collections with a 0.5 cm sieve during 30 minutes per month, in the edge vegetation, as well as collections by hand. All organisms obtained during these collections were stored in labeled jars, filled with alcohol 70% and transferred to the Laboratory of Zoology of the Universidade de Taubaté to the analysis.

RESULTS AND DISCUSSION
Among the sampled material three specimens of Radiospongilla inesi ( Figure 2) were found, from a lotic environment under pebbles, in the Ribeirão dos Mottas, between September and November 2014. The taxonomic identification of the sponges was confirmed and the material is deposited in the Scientific Museum of the Universidade Federal do Pernambuco -UFPE, (#UFPEPOR 2153). 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 Omalonyx matheroni (Figure 3), were caught at May 2015, under rocks and cans thrown away as garbage, near the dam of the Ribeirão dos Mottas. These slugs remain storage in the Laboratory of Zoology of the Universidade de Taubaté.
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. Currently, the sponge fauna comprising more than 8,000 species, which less than 200 are from freshwater environments (Pinheiro, 2007). In Brazil there are circa of 25% of this total, being the most of them recorded in the Rio Grande do Sul State and Amazonic region (Nicacio et al., 2011).
Radiospongilla inesi is a yellowish color sponge that ranging from volcano-shaped, encrusting or massive, presenting a large conspicuous osculum and/or scattered small oscula. It was report at first time in Brazil in the Ribeirão do Prata, Pernambuco State, northeastern Brazil region (Nicacio et al., 2011), and this report represents just the second record of this species in Brazil, and the first time to the southeastern region.  Symbiosis interactions including sponges is widely reported, in fact they capability to establish a great diversity of relationships (mutualism, commensalism and parasitism with unicellular and multicellular organisms) (see Ávila et al., 2007) is one of their more interesting characteristics. The presence of individuals of four insect families pointing out the importance of R. inesi on the life history of these animals, as oviposition substratum (Huggibs, 1980), shelter and as source of food (Stoaks et al., 1983).
Species of the genus Omalonyx have broad distribution on the Central and South Americas, found in swamps and lake banks, or under the emergent vegetation of the freshwater systems (Poi De Neiff & Casco, 2003). The slugs Omalonyx matheroni present records especially in the Amazonian region, with some feel reports to Central West, Southeaster and South regions (Coscarelli et al., 2018). Despite some records of Omalonix sp. to the São Paulo State, this report seems to be the first record of the O. matheroni to the Vale do Paraíba, northern of the São Paulo State.

CONCLUSIONS
Despite the biological information concerning these two species remain scarce, this report provides new records of occurrence of freshwater fauna, which represents promising candidates to bioindicators for the environmental quality. Moreover, additional researches will provide meaningful help to understand the biology of the benthic organisms of the Paraiba do Sul basin, in order to subside the development of conservation policies and environmental laws.