Tropical forests and savannahs cover between 15 and 20% of the Earth’s land surface, and dominate the tropics of South America, Australia, Asia and Africa. These two biomes exert a profound control on temperature, precipitation and carbon storage, and are also important centres of biodiversity. The evolutionary history of tropical forests and savannahs is of major international concern, and an understanding of the controls on tropical plant diversity can inform conservation efforts designed to prevent tropical plant extinction during the current anthropogenic biodiversity and climate crises. Project MioVAT (Miocene Vegetation of the African Tropics) will investigate the evolutionary history of the tropical forest and savannah biomes in West Africa during the Miocene (23-5.3 million years ago) using fossilized pollen and spores. The Miocene was a critical period in the evolution of West African tropical vegetation when grasses utilizing the C4 photosynthetic pathway began an explosive phase of ecological expansion that resulted in the birth of the savannah biome. The objectives of Project MioVAT are as follows: (1) To generate a c.20 million-year record of tropical plant diversity in West Africa from the latest Oligocene to the earliest Pliocene; (2) To quantify the nature and timing of plant extinction in the Miocene of tropical west Africa; (3) To quantify the taxonomic diversity of grasses during the birth of the savannah biome in the Late Miocene using fossil pollen grains. This research is designed to investigate the long-term controls on tropical plant diversity such as global temperature, investigate the role of extinction in shaping the tropical vegetation of West Africa, and understand the biome-scale diversification history that underlies the evolutionary success of grasses. Project MioVAT will create long-term collaborations, share knowledge, and result in mutually beneficial research co-operation between Europe and the United States.