Plesiosaurus

Here is a cast of Mary Anning’s 1823 discovery, Plesiosaurus dolichodeirus. Plesiosaurs swam fast and maneuvered nimbly using their strong flippers. Each flipper was like a penguin wing, sweeping backward to “fly” underwater. Plesiosaur shoulder and hip bones were shaped like giant plates that supported muscles for the downward and upward strokes. Today, penguins are among the speediest oceanic predators. Plesiosaurs were as quick or even quicker, because they have two pairs of wings.