Chronogram of Heterobranchia. Showing estimated divergence times obtained from BEAST v1.5.3 under the uncorrelated lognormal relaxed clock model. Numbers at nodes refer to node ages in this presented tree (maximum-clade-credibility-tree); bars express 95% highest posterior density (HPD) (only presented for nodes with a PP > 0.5). Red circles indicate calibration points. Geological timescale is based on the International Stratigraphic Chart by the International Commission on Stratigraphy (2009).