This study aimed to survey the species of Eunotiaceae Kützing family occurring in the plankton of Sistema Lago dos Tigres (Britânia, Goiás State, 15º36'33,5"-15º22'8,7"S and 51º17'56,3"-51º16'91"W), environment composed of lotic and lentic areas. Sampling was conducted between June and November 2004 at 11 sampling stations, and samples were collected through a plankton net of 25 µm. Sistema Lago dos Tigres presented 22 taxa, one for Actinella and 21 belonging to Eunotia. Eunotia asterionelloides was the one most common species at sample stations and was recorded in all environments. Among the taxa, 10 are cited for the first time for the midwestern region of Brazil (Eunotia deficiens, E. diodonopsis, E. intermedia, E. longicollis, E. papilio, E. pileus, E. rabenhorstiana var. elongata, E. rabenhorstii var. monodon, E. trigibba, and E. tropico-arcus).
Actinella; diatom; Eunotia; phytoplankton
