Angiosperm association from the Rio Turbio Formation (Eocene-?Oligocene) Santa Cruz, Argentina: revision of Hunicken's (1955) fossil leaves collection

摘要

The Rio Turbio Formation (Eocene-?Oligocene) is of particular paleobotanical interest owing to its combination of high fossil plant diversity associated with the coexistence of warm-temperate and cool-temperate components. As the first suite of fossils related to a documented stratigraphic section, Hunicken's fossil plant collection is one of the most important from the Paleogene of South America. A total of 34 angiosperm species from the collection were reviewed and taxonomically updated, with Nothofagus as the dominant genus. The taxa identified indicate a warm and humid climate with the development of some elements of a cool-temperate climate marked by a transitional climate change to cooler conditions. The comparison of angiosperms from different paleofloras from the southernmost of South America confirms that the assemblage of Rio Turbio Formation was similar to that of the Rio Pichileufu area, both from Patagonia, Argentina.