Geologica Acta, Vol.7, Nos 1-2, March-June 2009, 35-61 DOI: 10.1344/105.000000270 Available online at www.geologica-acta.com A Danian subtropical lacustrine palynobiota from South America (Bororó Formation, San Jorge Basin, Patagonia - Argentina) 1 1 2 L. SCAFATI D.L. MELENDI and W. VOLKHEIMER 1 División Paleobotánica, Museo Argentino de Ciencias Naturales “B. Rivadavia”- CONICET A. Gallardo 470, C1405DJR Buenos Aires, Argentina. E-mail:
[email protected] 2 Unid. Paleopalinología, IANIGLA-CCT-Mendoza - CONICET C.C.330, 5500 Mendoza, Argentina. E-mail:
[email protected] ABSTRACT New results on a lacustrine Danian palynological association in extra-andean northern Patagonia (lower mem- ber of the Cerro Bororó Formation, San Jorge Basin, Chubut province, Argentina) are presented. This is a con- tribution to the largely unexplored field of Paleogene freshwater environments. The palynobiota includes repre- sentatives of the kingdoms Protoctista and Plantae. Twelve of the aquatic species are Protoctista. From the nine Chlorophyta form-species, four correspond to Botryococcaceae, one to Coelastraceae and four to Zygnemat- aceae (Gelasinicysta, Schizosporis, Ovoidites, and Pseudoschizaea). The remaining forms are dinoflagellate cysts (Peridinium and dinocyst indet.) and prasinophyceans (Leiosphaeridia). Plants are represented by spores and pollen of Bryophytes (Sphagnaceae and Ricciaceae), Pteridophytes (Salviniaceae), and Angiosperms (Are- caceae, Araceae and Sparganiaceae/Typhaceae, the latter representing macrophytes living in or near the swampy areas). Other palynomorph groups closely related with biotopes of permanent moisture are dominated by spores of the families Selaginellaceae, Lycopodiaceae, Cyatheaceae, Schizaeaceae, Polypodiaceae and Psilotaceae. The palynological assemblage reflects a freshwater lacustrine environment that developed in a marine coastal zone nearby brackish coastal swamps.