European Palaeobotany and Palynology Conference 2026

The Cretaceous–Paleogene (K–Pg) transition marked a major ecological reorganization that reshaped South American forests. Latest Cretaceous and earliest Paleogene paleofloras reveal strong geographic variation in vegetation composition and recovery following the end-Cretaceous extinction. In Patagonia, Late Cretaceous forests were dominated by Cheirolepidiaceae, Araucariaceae, and Podocarpaceae, accompanied by ferns, tree ferns, and diverse angiosperms, including Proteaceae, Cunoniaceae, and early Nothofagaceae and the extinct Normapolles and Triprojectacites complexes. Central and northwestern Argentine floras document mixed angiosperm–conifer communities, whereas contemporaneous floras from Brazil indicate increasingly tropical vegetation with conifers, palms, and diverse flowering plants. Paleocene records from Peru, Bolivia, Venezuela, and Colombia document the expansion of tropical lowland forests rich in palms, legumes, and Lauraceae. Colombian assemblages preserve the oldest known Neotropical rainforest, demonstrating the rapid establishment of complex rainforest ecosystems after the K–Pg event. By the early Eocene, South American forests reached exceptional diversity. Patagonian paleofloras record warm-temperate to subtropical rainforests containing lineages now centered in Southeast Asia and the western Pacific, including Casuarinaceae, Castanopsis, Eucalyptus, and several conifers. These assemblages reveal remarkable biogeographic connections among South America, Antarctica, Australasia, and Southeast Asia during the early Paleogene. At the same time, Patagonian forests retained characteristic Gondwanan elements, including Araucariaceae, Podocarpaceae, Proteaceae, Cunoniaceae, and Nothofagaceae. Together, South American fossil forests record heterogeneous responses to the K–Pg extinction, from the persistence of conifer-rich Gondwanan communities in the south to the diversification of angiosperm-dominated rainforests in tropical regions, illuminating the origins and the dynamic assembly of Southern Hemisphere forests.