Plesiosaurs are a group of extinct marine reptiles that lived during the Mesozoic Era, specifically the Late Triassic to the Late Cretaceous Periods. They are characterized by their unique body structure, which includes a long neck, small head, and a large body supported by four flippers.
These reptiles were well-adapted to an aquatic lifestyle and were superb swimmers. Plesiosaurs belonged to the order Plesiosauria and were further classified into two suborders: the long-necked, small-headed Plesiosauroidea, and the short-necked, large-headed Pliosauroidea.
With regards to their feeding habits, plesiosaurs were carnivorous marine predators. The exact diet of each species varied, but it is believed that they primarily fed upon fish, cephalopods (such as squid and ammonites), and other small marine animals. Fossil evidence suggests that they were active hunters, catching their prey by ambush or pursuit.
Plesiosaurs were an important part of the Earth's prehistoric marine ecosystems, occupying a wide range of habitats and demonstrating significant diversification during their existence. They achieved global distribution and are known from various parts of the world, including North America, Europe, Australia, and Antarctica.
The first discovery of plesiosaur fossils occurred in the early 19th century, and since then, a rich variety of different species have been identified, ranging in size from a few meters to over 10 meters in length. Plesiosaurs disappeared from the Earth's seas around 66 million years ago, along with the other non-avian dinosaurs, presumably due to the widespread environmental changes caused by the asteroid impact that led to the extinction event known as the Cretaceous-Pale
