Neuticosaurus skeleton. (Wiki image.)
Neuticosaurus was a relative of Nothosaurus, but it was much smaller in size. This enabled it to coexist with its bigger relative probably by living closer to the shore and by feeding on much smaller animals. (Neuticosaurus was less than a meter in length.) It died out during the Triassic, just as the rest of the nothosaur family did.
In Walking with... series
Sea Monsters: Prehistoric Predators of the Deep featured Neuticosaurus as a background character.