Pliosauroidea

Pliosauroidea is a superfamily of marine reptiles within the order Plesiosauria. They lived from the Early Jurassic into the Early Cretaceous and are best known for containing some of the largest predator-held forms in Mesozoic seas. They are one of the major lineages that split from the long-necked elasmosaurians, which are their sister group.

Morphology and anatomy are the most distinctive features of pliosauroids. They typically possess a relatively short neck and a large skull with powerful jaws, along with forelimbs and hindlimbs modified into broad paddles. This combination yielded a robust, high-worce swimming body adapted to fast pursuit and the grappling of sizable prey. Teeth are generally large and conical, suited to grasping fish, cephalopods, and even other marine reptiles.

Classification and diversity are subjects of ongoing study. Within Plesiosauria, Pliosauroidea comprises the pliosaurids and related forms, with some classifications grouping the larger-bodied lineages into a clade such as Thalassophonea. Well-known genera include Pliosaurus, Liopleurodon, and Kronosaurus, illustrating a range of sizes and ecologies.

Ecology and paleobiogeography indicate that pliosauroids were apex predators of their marine ecosystems. They inhabited diverse environments and achieved a global distribution, with fossils found in Europe, Africa, South America, and Australia. Their success in the Jurassic and early Cretaceous reflects a brief but prominent era of large, marine carnivores within plesiosaur diversity.