Plesiosaurus Enamel Pin (Plesiosaurus dolichodeirus)If any fossil creature deserves credit for kickstarting lake monster myths, its Plesiosaurus dolichodeirus. First described in 1824, this Early Jurassic marine reptile wasnt a dinosaur, but a sleek predator of shallow seas. With a neck longer than its body, a compact torso, and four powerful flippers, it swam like an underwater penguin armed with a periscope. Growing up to 3. 5 meters long, it likely hunted schools of fish and squid while giving