Hyalella terrasolis, a new epigean species of freshwater amphipod (Crustacea, Peracarida, Hyalellidae) from southern Brazil

In this study, a new species of Hyalella is described based on specimens collected in wetlands located in northeast region of the state of Rio Grande do Sul. Hyalella terrasolis sp. nov. is characterized by presenting smooth body surface, epimeral plates not acuminated, five serrate setae with accessory setae and seven to eight simple setae on the inner face of gnathopod 1, very pronounced lobe of the propodus of gnathopod 2, inner ramus of uropod 1 of males with one curved seta and ten cuspidate setae apically (being a row of six cuspidade setae), uropod 3 with nine or ten cuspidate setae with accessory seta, telson as long as wide (square) with ten short and long cuspidate setae with an accessory seta.

We increase to 43 the number of species of Hyalella in Brazil, and 18 to state of Rio Grande do Sul, Brazil.