Menispermaceae and the diversification of tropical rainforests near the Cretaceous-Paleogene boundary

Modern tropical rainforests have the highest biodiversity of terrestrial biomes and are restricted to three low-latitude areas. However, the actual timeframe during which tropical rainforests began to appear on a global scale has been intensely disputed. Here, we used the moonseed family (Menispermaceae), an important physiognomic and structural component of tropical rainforests on a worldwide basis, to obtain new insights into the diversification of this biome. We integrated phylogenetic, biogeographic and molecular dating methods to analyse temporal and spatial patterns of global diversification in Menispermaceae. Importantly, a burst of moonseed diversification occurred in a narrow window of time, which coincides with the Cretaceous-Paleogene (KPg) boundary. Our data also suggest multiple independent migrations from a putative ancestral area of Indo-Malay into other tropical regions. Our data for Menispermaceae suggest that modern tropical rainforests may have appeared almost synchronously throughout the three major tropical land areas close to, or immediately following, the K-Pg mass extinction.