FIGURE 11.7. The ichthyosaurs evolved from lizard-like forms with asymmetric tails (Utatsusaurus and
Chaohusaurus), primitive amniote skulls, and primitive hands and feet, to the highly specialized ichthyosaurs
with symmetrical tails, large dorsal fins, big eyes, long fish-catching snouts with conical teeth, and highly
modified flippers. (A) A complete articulated skeleton of the very primitive lizard-like ichthyosaur
Chaohusaurus from the Early Triassic of China. (B) Diagram showing the evolutionary transformations from
more primitive to more specialized ichthyosaurs. (© Ryosuke Motani, http://ichthyosaur.org))
(A)
(B)