igure 1 — A) The nectridean Urocordylus wandesfordii and B) associated tail vertebrae, showing the flattened neural and haemal arches and hourglass-shaped centrum. C) Forelimb showing a lack of a hard wrist bone. D) The skull of Diplocaulus. Abbreviations: c, centrum; h, humerus; ha, haemal arch; na, neural arch; p, phalanges; r, radius; u, ulna; uc, unossified carpals. Scale bar is 20 mm for A, 6 mm for B, 4 mm for C and 50 mm for D. Adapted from Carroll et al. 1998.