Since polycotylids are known primarily from the Late Cretaceous after the extinction of ichthyosaurs, they appear to have replaced the "fish lizards" as fast-swimming marine predators that preyed on cephalopods and small fish.
(polycotylids; are known primarily; ) (they; appear; ) (they; to have replaced; the "fish lizards; as fast-swimming marine predators) (fast-swimming marine predators; preyed; on cephalopods and small fish)
polycotylids they they fast-swimming marine predators
are known primarily appear to have replaced preyed
the "fish lizards as fast-swimming marine predators
on cephalopods and small fish