Evolution of the angiosperms: calibrating the family tree

Growing evidence of morphological diversity in angiosperm flowers, seeds an d pollen from the mid Cretaceous and the presence of derived lineages from increasingly older geological deposits both imply that the timing of early angiosperm cladogenesis is older than fossil-based estimates have indicated . An alternative to fossils for calibrating the phylogeny comes from diverg ence in DNA sequence data. Here, angiosperm divergence times are estimated using non-parametric rate smoothing and a three-gene dataset covering ca. 7 5% of all angiosperm families recognized in recent classifications. The res ults provide an initial hypothesis of angiosperm diversification times. Usi ng an internal calibration point, all independent evaluation of angiosperm and eudicot origins is performed. The origin of the crown group of extant a ngiosperms is indicated to be Early to Middle Jurassic (179-158 Myr), and t he origin of eudicots Jurassic to mid Cretaceous (147-131 Myr). Both estima tes, despite a conservative is resolved as Late calibration point, are olde r than current fossil-based estimates.