Plesiosauromorpha

Plesiosauromorpha is a clade of marine reptiles that includes the plesiosaurs and their close relatives. This group first appeared during the Late Triassic period, around 228 million years ago, and diversified significantly during the Mesozoic era. Plesiosauromorphs are characterized by their elongated necks, paddle-like limbs, and streamlined bodies, which were adaptations for an aquatic lifestyle.

The most well-known members of Plesiosauromorpha are the plesiosaurs, which include forms like Elasmosaurus and Plesiosaurus. These reptiles ranged in size from small to very large, with some species reaching lengths of over 30 feet. Plesiosaurs were semi-aquatic predators, feeding on fish, squid, and other marine creatures. Their fossils have been found in various parts of the world, including Europe, North America, and Africa.

Another notable group within Plesiosauromorpha is the Pliosauridae, which includes the pliosaurs. Pliosaurs were large, predatory marine reptiles with long, serrated teeth and powerful jaws. They were active hunters, preying on a variety of marine animals.

Plesiosauromorpha went extinct at the end of the Cretaceous period, around 66 million years ago, likely due to the same factors that led to the extinction of the non-avian dinosaurs. Their fossils provide valuable insights into the evolution of marine reptiles and their adaptations to an aquatic environment.