Fig. 1.

Chronogram showing estimated divergence times among photosynthetic eukaryotes. Blue bars are the central 95% of estimates from 300 Bayesian posterior trees. Red bars are the central 95% of dates inferred during fossil cross-validation. Bayesian posterior probabilities <0.95 are shown. References for the fossil calibrations are given in the text. The green circle indicates the most recent common ancestor of Paulschulzia pseudovolvox and Volvox carteri, the divergence used to calibrate the fine-scale analyses.