Menispermaceae (moonseed family), a very important representative of liana families, are one of the 10 most dominant liana families in tropical rainforests. 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.
To obtain new insights into the diversification of modern tropical rainforest, scientists from CAS Institute of Botany, Xishuangbanna Tropical Botanical Garden (XTBG), and Missouri Botanical Garden jointly conducted a study. They tested the hypothesis that the establishment of modern tropical rainforests in different tropical areas was not synchronous by examining the historical diversification and biogeography of the angiosperm family Menispermaceae (moonseed family).
The researchers first reconstructed a robust phylogenetic framework for Menispermaceae using five chloroplast DNA regions with more extensive sampling at the generic level than in any previous study. By integrating phylogenetic, biogeographic and molecular dating methods, they then investigated the temporal and spatial diversification of Menispermaceae on a global basis. Finally, they used the moonseed family as an indicator to explore the diversification of tropical rainforests worldwide.
Their study showed that multiple Afrotropical, Australasian and Neotropical moonseeds evolved independently within a narrow time window (c. 60–70 Ma), and multiple lineages of the Indo-Malayan moonseeds also originated during the same period.
Their biogeographic reconstruction showed that the most recent common ancestor of Menispermaceae was likely present in the Indo-Malayan region of Laurasia. Their vegetation-type analysis demonstrated that tropical rainforest is inferred as the ancestral biome for Menispermaceae.
Their results therefore support the proposition that moonseeds originated and became differentiated in a rainforest biome of Laurasia during the mid-Cretaceous.
The study entitled “Menispermaceae and the diversification of tropical rainforests near the Cretaceous–Paleogene boundary” has been published in New Phytologist, 195(2): 470-478, DOI: 10.1111/j.1469-8137.2012.04158.x