Representative individuals of Perissodini species included in shape analyses. (A) Perissodus straeleni; (B) P. microlepis; (C) P. paradoxus; (D) P. elaviae; (E) P. multidentatus; (F) P. hecqui; (G) Haplotaxodon microlepis. Both the left and right sides of the head were photographed and analysed for all species except H. microlepis for which only the left-hand side was examined, as this species does not exhibit an overt jaw asymmetry. Landmarks represent functionally significant points that characterize the geometry of the skull and were adapted from Cooper and Westneat . Images are of representative Perissodini species with head shapes that are close to the species mean for craniofacial shape (that is, at the centre of each species' two-dimensional distribution shown in Figure 2). Corresponding warps represent the average two-dimensional head shape (including both the left and right sides of the head) in each species.