The survey is a floristic inventory of Amphipleuraceae and Diploneidadaceae from rivers of the region to be flooded for the construction of Caxias power plant, city of Capitão Leônidas Marques, southwest of Paraná State, Brazil. Samples were collected from March, 1997 to February, 1998, in the Iguaçu river and its tributaries: Cotegipe, Jaracatiá, Chopim, Tormenta, Adelaide and Guarani rivers. Amphipleuraceae family was represented by five infraspecific taxa and the Diploneidaceae by four. Frustulia vitrea Oestrup and Diploneis ovalis (Hilse) Cleve were registered for the first time to Paraná State.
Amphipleuraceae; Diploneidaceae; diatoms; Iguaçu basin; reservoir
