Its tail allowed it to cruise along at a reasonable pace unlike the ichthyosaurs in the future. This tail however would have allowed it to use its tail to accelerate into massive bursts of speed which would perfect for an ambush hunter since it could would be swimming along with fish surrounding it then all of a sudden it would use its tail to accelerate and grab a large fish without giving the fish any time to notice or escape. This ichthyosaur would have also been a predator of larger prey like smaller sea reptiles or possibly even dinosaurs that had fallen into the sea.
Popular in Culture
A Cymbospondylus named Cretaceous was one of the main antagonists in Ice Age: The Meltdown. In reality, Cymbospondylus had fins and stayed in the water unlike in the movie which can be on land and had fresh water crocodyliform-like legs.