Fig. 25. Strict consensus of two most parsimonious trees of 229 steps; thick lines/black boxes to the left of taxon names indicate known temporal ranges, circles to the right of cetacean taxa indicate geographic occurrence(s). Bremer support values are placed below and to the left of each node. Note that the branching order of taxa is generally concordant with the first geologic occurrence of taxa, and we can infer that the immigration of cetaceans to North America occurred in the latter half of the Lutetian. The geologic durations of taxa are from Gingerich et al. (1997, 2001a, 2001b) and Uhen (1998a, 1998b).