Temporal range: Mid Triassic
|Pistosaurus longaevus from the middle Triassic of Europe|
Pistosaurus was a advanced nothosaur-like body with a plesiosaur-like head. Is presently known only from the Middle Triassic. Even if it is a nothosaur it is acknowledged to be closely related to the ancestors of plesiosaurs.
Although it is unlikely that Pistosaurus was a direct ancestor of the plesiosaurs, the mixture of features suggests that it was closely related to that group.