Fig. 1.

Phylogenetic tree of ichthyosaurs plotted against geological time. Times runs from left to right, showing known ranges (dark gray), ghost ranges (minimal implied phylogenetic gap; light gray), and Lazarus ranges (missing within-range representation; diagonal bars). Silhouette outlines (Ca., Californosaurus; Ch., Chaohusaurus; Mi., Mixosaurus; Pl., Platypterygius; Sh, Shonisaurus; Te., Temnodontosaurus; Ut., Utatsusaurus) indicate major body morphologies in Triassic (red), Early Jurassic (blue), and Middle Jurassic–Cretaceous (green). Relative sizes of the various major ichthyosaur morphotypes are indicated by scale drawings at top right, with a 1-m scale bar indicated in the blue cloud. Phylogeny is based on the majority-rule LE50 tree (SI Appendix, Fig. 3), similar to earlier findings (7, 13), and stratigraphic ranges are from a review of the literature (SI Appendix, Fig. 4). Ichthyosaur silhouettes are based on various sources (7).