Boxplot showing the distribution of the ratio of the medioteral expansion of the premaxilla in a sample of
iguanodontoidean taxa. 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 the premaxilla of Gryposaurus
notabilis (CMN 2278).