Figure 3: Mapping the evolution of morphological characters on a saurichthyid phylogeny.

(a) Evolution of the neural arches, interdorsals, haemal arches and interventrals, (b) evolution of the mid-dorsal and mid-lateral scales, and dorsal vertebral elements (neural spines+expanded intercalaries), (c), number of somites reconstructed using squared-change parsimony. Timescale produced with TSCreator (http://tscreator.org), see Methods for information regarding the phylogenetic hypothesis. Vertebral morphology modified from refs 13, 19, 20, 21, 22, 24.