Figure 4. Echinoid divergence times estimated using two alternative node age prior calibration schemes.

Bars on nodes represent the 95% HPD of the node age and are colored by the two prior calibration schemes used: red bars  =  uniform priors; blue bars  =  informative gamma priors; purple  =  overlap of 95% HPD from both approaches. The tree represents the highest a posteriori chronogram for the analyses run with informative gamma priors, and the nodes are placed at the mean of the posterior distribution of node age. The bright red vertical dash on each node bar represents the mean of that node's age from the posterior distribution of the analyses run with uniform priors. Nodes are numbered as in Table 2, and calibration nodes are indicated with an asterisk. The scale at the bottom of the figure is in millions of years before present (Ma), and the time scale is binned by 50 Ma intervals. The tips of the tree are labeled by genus name as in Smith et al. [21], [38]. Posterior clade probabilities are provided in Figure S1.