Branch lengths are in millions of years. Krajewski et al. (2010) calculated divergence dates in parallel analyses using a standard deviation of 0.5, 1.0, and 1.5 on the lognormal priors of the age calibration points based on crane fossil records. We used branch lengths derived from 0.5 standard deviation because it produced a highly resolved topology, however still with a polytomy comprising nodes 12.5 and 11. We used the median value of the 95% highest posterior density interval as our branch length for node 12.5 to resolve the tree