Ichthyosaurs in particular were giant marine reptiles that resembled fish and dolphins
Ichtyosaure, début Trias à fin Crétacé
Tyrannosaurs were the killing machines of the Cretaceous period: these huge, powerful carnivores were all legs, trunk and teeth, and they preyed relentlessly on smaller, herbivorous dinosaurs (not to mention other theropods). The most famous tyrannosaur was Tyrannosaurus Rex, though less well-known genera (such as Albertosaurus and Daspletosaurus) were equally deadly. Technically, tyrannosaurs were theropods, placing them in the same larger group as dino-birds and raptors.
Tyrannosaurs and raptors made up only a small percentage of the bipedal, carnivorous dinosaurs known as theropods, which included such exotic families as ceratosaurs, abelisaurs, megalosaurs and allosaurs, as well as the earliest dinosaurs of the Triassic period. The exact evolutionary relationships among these theropods is still a matter of debate, but there's no doubt they were equally deadly to any herbivorous dinosaurs (or small mammals) that wandered across their path