Time-calibrated cladogram of hadrosaurines based on Gates et al. [3].

The strict consensus of two most parsimonious trees resulting from adding Probrachylophosaurus bergei gen. et sp. nov. to Gates et al.’s [3] matrix was plotted using the age ranges for each taxon; branch lengths do not reflect the number of character state changes. Because species within the same genus had the same codings, only genera are listed in the phylogeny. Values on branches represent bootstrap support; branches without values had less than 50% support. Tree statistics: shortest tree length = 188, Consistency Index = 0.70, Retention Index = 0.65, Rescaled Consistency Index = 0.45. Age ranges are approximate, and are based on those in Gates et al. [3], aside from Brachylophosaurini, which have been recalibrated as in Fig 1. Note that the age scale changes before and after 80 Ma. Also note that the age of Bactrosaurus has been variably proposed to be any time from late Turonian to early Maastrichtian in age [49–51].