Figure 1.

Acanthomorph morphometrics. (a) Landmark scheme. Fixed landmarks are indicated by circles filled in grey and marked by numerals, while semilandmarks are marked by circles filled in white. Grey-filled circles containing an asterisk indicate fixed landmarks that serve as anchor points for intervening semilandmarks. Fixed landmarks record (moving clockwise, starting with the snout): 1, anterior tip of upper jaw (premaxilla); 2, joint between braincase and vertebral column; 3, posterodorsal tip of braincase (supraoccipital crest); 4, anterior insertion of dorsal fin; 5, posterior insertion of dorsal fin; 6, insertion of first ray of dorsal lobe of caudal fin; 7, distal tip of first principal ray of caudal fin (dorsal lobe); 8, posterior margin of caudal fin between dorsal and ventral lobes; 9, distal tip of first principal ray of caudal fin (ventral lobe); 10, insertion of first ray of ventral lobe of caudal fin; 11, posterior insertion of anal fin; 12, anterior insertion of anal fin; 13, ventral tip of pectoral girdle; 14, lower jaw joint. (b) Mean species values plotted on RW1 and RW2, which together account for over 62 per cent of overall variance. Symbols marking species indicate geological interval (eLK, early Late Cretaceous; lLK, late Late Cretaceous; P–eE, Palaeocene–early Eocene; mE–lE, Middle–Late Eocene; O, Oligocene; M, Miocene). Deformation grids indicate shapes found at extreme values along each axis, and fossils correspond to taxa approximating these morphologies. Higher axes given in the electronic supplementary material.