Area, tempo and mode of palm diversification. (a) Paleomap representing the distribution of landmasses in the mid-Cretaceous period, dark grey upland land, light grey lowland (100 million years (Ma), adapted from Beerling and Woodward ). Laurasia, which is the most likely ancestral area reconstructed for the crown node of palms, is highlighted. (b) Chronogram showing the three different biomes assigned to each genus. Red: tropical rain forest; green: mangrove; blue: not tropical rain forest; grey: ambiguous. Yellow circles indicate fossil calibration points. The vertical black lines highlight the five subfamilies of palms with an illustration (drawings by Marion Ruff Sheehan, L.H. Bailey Hortorium, Cornell University, except top one (Arecoideae), which is reproduced with permission from Springer from Kahn and de Granville . (c) Semilogarithmic mean lineage-through-time (LTT) plot averaged over 1,000 posterior trees from the Bayesian analysis (left axis, triangles) and percentage of missing taxa as a function of time (right axis, grey line). Short dashed line = upper 95% confidence interval; long dashed line = lower 95% confidence interval; filled square = extant number of palms species. Vertical black line indicates threshold up to which the LTT plot is considered reliable even under incomplete taxon sampling. Palm fossil indicates time of earliest known unequivocal fossil for the family (Sabalites fossil leaf image reproduced by permission of the Board of Trustees, National Museums Liverpool, Liverpool, UK).
Couvreur et al. BMC Biology 2011 9:44 doi:10.1186/1741-7007-9-44