Protostegidae were a family of large extinct marine turtles that lived during the Cretaceous Period, approximately 110–66 million years ago. They were among the largest turtles ever to exist and inhabited the warm shallow seas that covered parts of the ancient world.
Unlike modern sea turtles, many protostegids had unique body shapes with reduced or partially developed shells, making them lighter and more streamlined for open-ocean swimming. They possessed large paddle-like flippers, a flattened body, and strong jaws adapted for catching prey such as jellyfish, mollusks, and other marine animals.
The largest member of the group, Archelon, reached lengths of around 4–5 meters (13–16 feet) and was one of the largest turtles known from the fossil record. Other well-known protostegids include Protostega and Santanachelys.
Protostegids lived alongside marine reptiles such as mosasaurs, plesiosaurs, and ichthyosaurs, occupying important roles in Cretaceous marine ecosystems. The group disappeared during the Cretaceous–Paleogene extinction event around 66 million years ago.
Protostegidae
Protostegidae were giant prehistoric sea turtles from the Cretaceous known for their large size, powerful flippers, and oceanic lifestyle.
