Boxplot showing the distribution of the angle formed by the slope of the rostral region of the dentary that
articulates with the predentaryand the frontal plane of the skull. The inserted smaller graph shows the Bayesian information criterion (BIC)
for various numbers of clusters in which the data can be classified. The photograph shows how the two variables of this raio were measured,
exemplified in Brachylophosaurus canadensis (MOR 1071). Grey horizontal lines delimit character states.