Stenopterygius

Stenopterygius was a typical, dolphin-shaped ichthyosaur of the Lower Jurassic. It is like the poster reptile of the ichthyosaur family, "Ichthyosaurus", but with slightly narrower flippers and a smaller head. Its name means "narrow wing".
"Stenopterygius" was more streamlined than the earlier ichthyosaurs of the Triassic period, and likely swam faster in pursuit of prey.
Some "Stenopterygius" fossils have been found with the remains of juveniles inside--clearly instances of mothers dying before they could give birth. As with other ichthyosaurs, "Stenopterygius" females gave birth to live young. Their eggs developed internally before birth.