Chaetonotus majestuosus n. sp. is described and a new group is proposed in order to include this species. Heterolepidoderma majus Remane is recorded with some morfological modifications, and the genus is reported for the first time in South America. Both species were collected from the roots of Salvinia sp., Lepidodermella squammatum (Dujardin) was found in the fitotelmata biotop of Aechmea sp. from Tucumán, Argentina. The last two species were recorded for the first time in this country.Chaetonotus majestuosus n. sp. se describe y se propone un nuevo grupo para incluir esta especie. Se registra Heterolepidoderma majus Remane con algunas modificaciones morfológicas, y el género se reporta por primera vez en América del Sur. Ambas especies se recolectaron de las raíces de Salvinia sp. Se encontró Lepidodermella squammatum (Dujardin) en el biotopo de fitotelmata de Aechmea sp. de Tucumán, Argentina. Las dos últimas especies se registraron por primera vez en este país
