Pliosauridae

Pliosauridae is a family of large marine reptiles within the superfamily Pliosauroidea, a major branch of plesiosaurs. They appeared in the Middle Jurassic and persisted into the Early Cretaceous, roughly 165–100 million years ago. Fossils are found worldwide, with notable specimens in Europe (for example Dorset), Patagonia (Kronosaurus), and other regions.

They share key features, including relatively short necks for plesiosaurs, very large skulls, powerful jaws with long, sharp teeth, and strong paddle-like limbs. This combination indicates a predatory lifestyle oriented toward sizeable prey, such as fish, ammonites, and other marine reptiles. They were among the apex marine predators of their time.

Size in the family varied widely; some individuals exceeded 10 meters in length, with famous examples such as Kronosaurus and Liopleurodon. Other members were smaller, but still large compared with many contemporaries.

Classification within Plesiosauria places Pliosauridae in the clade Pliosauroidea. They are closely related to other pliosaurid lineages, forming part of the major dichotomy with Elasmosauridae in the broader group Plesiosauria. Notable genera within Pliosauridae include Liopleurodon, Kronosaurus, and Pliosaurus.