Boxplot showing the distribution of the angle between the distal articular surface of the iliac peduncle of the
ischium and the acentabular margin of the peduncle, for 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 this angle
was measured, exemplified in an ischium of Lambeosaurus lambei (ROM 1218). Horizontal lines delimit character states.