From material collected in Santa Catarina and Rio Grande do Sul States (Brazil) two new records of Trichorhina are presented (T. argentina Vandel, 1963 and T. tomentosa (Budde-Lund, 1893) as well as a description of a new species bicolor sp.n.). Lectotypes and paralectotypes of T. argentina are designated. A key for the species in the study area is also included.
Isopoda; Oniscidea; Trichorhina; new species; Brazil