Contribution to the knowledge of the <i>Proseriata</i>(Platyhelminthes: Rhabditophora) from southeast Brazil

The composition of the taxon Proseriata (Platyhelminthes) in the São Sebastião area (S.E. Brazil) is presented and discussed. The area was extensively studied by E. Marcus, who described a large number of species, most of which have not been found thereafter. Of the 29 species found, 16 have been described by Marcus. The new findings allowed in many cases integration of the original descriptions, of particular interest in the case of the type species of genera: Minona evelinae, Duplominona mica, Mesoda gabriellae, Pystrix thelura, Meidiama lutheri, Phylosirtis eumeca, Vannuccia martae. Nine of the species found are new, and could be formally described: Monocelis non-scripta nov. sp., Pseudomonocelis paulista nov. sp., Duplominona brasiliensis nov. sp., Archiloa polycirrus nov. sp., Archimonocelis marci nov. sp., Pseudosyrtis cebimari nov. sp., Parotoplanina antaliformis nov. sp., Monostichoplana fonsecai nov. sp., Nematoplana mirabilis nov. sp. One species is tentatively identified as Itaspis evelinae. Most of the new species came from the few subtidal samples examined, where specimens of further undescribed species, whose material was inadequate for formal description, were also found. The diversity of S.E. Brazil Proseriata appears thus far from being exhaustively known