Boxplot showing the distribution of the length/width ratio of the predentary in a sample of iguanodontoidean
ornithopods. 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 length and width of the predentary were measured, exemplified in Protohadros byrdi (SMU 74582).
Grey horizontal lines delimit character states.