Ichthyosaurs are an interesting example of what is known as parallel evolution (when unrelated animals sharing the same habit come to look very similar). In this case, ichthyosaurs, dolphins and sharks evolved into almost the same shape. Ichthyosaur fossils are very common, and there were many different types. They all had long beaks lined with shark teeth for feeding on fish. The largest types were 10 m long. Although some other marine reptiles probably laid their eggs on beaches, the streamlined fish-like ichthyosaurs were completely aquatic and gave birth to live young. Unborn babies have been found inside their remains. One odd feature of the ichthyosaurs is the large ring of bony plates around their eyes.

Picture credit: google