Highlights• Past connections between the two main South American rainforests, the Amazon and the Atlantic forests, were explored using published pollen records and botanical surveys.• The pollen assemblage Podocarpus-Ilex-Hedyosmum-Myrsine is observed today in the Brazilian highelevation grassland physiognomy of the Cerrado and Atlantic Forest biomes, and the southern Brazil coastal forests (restinga) and Andean Forest, where it is associated with cooler climatic conditions.• Podocarpus-Ilex-Hedyosmum-Myrsine is present in marine, continental and coastal pollen records from glacial periods.• The simultaneous increase in Podocarpus-Ilex-Hedyosmum-Myrsine in late-glacial continental and marine pollen records suggests a shift of highelevation grassland taxa to the lowlands with a broad expansion through the Cerrado and restinga pathways.• The Cerrado and restinga represent ancient biotic corridors that have linked the Atlantic, Amazon and Andean forests since the early Pleistocene.