From Massive Eyes to Shark-Like Tails, Seven Amazing Adaptations That Helped Prehistoric Reptiles Thrive at Sea

From Massive Eyes to Shark-Like Tails, Seven Amazing Adaptations That Helped Prehistoric Reptiles Thrive at Sea Riley Black - Science Correspondent Get our newsletter! Get our newsletter! The Mesozoic wasn't just the age of dinosaurs. Reptiles of all sorts thrived through the Triassic, Jurassic and Cretaceous at the same time our favorite dinosaurs were roaming on land. Long-necked plesiosaurs, shark-shaped ichthyosaurs, toothy mosasaurs and many more saurians were swimming through the ancient seas, their success underwritten by a suite of anatomical specializations.

From the time the four-paddled, long-necked Plesiosaurus was named in 1821, paleontologists generally thought of marine reptiles as comparable to lizards, snakes and crocodiles in the terrestrial realm. Marine reptiles were thought to be cold-blooded, their body temperature determined by the surrounding seawater. And scientists didn't know whether the ancient creatures had blubber, scales, smooth skin or some other sort of body covering.



During the past three decades, however, a new wave of paleontological interest has fundamentally changed how experts think about the likes of Mosasaurus and Ichthyosaurus. The repeated evolution of reptiles that lived entirely at sea was possible thanks to an array of adaptations that are still being uncovered by researchers. This list highlights the features that allowed Mesozoic marine reptiles to thrive beneath the surface.

Blubbery bodies Many millions of years before whales and seals would evolve blubber, marine reptiles were already enjoying the benefits of the thick subcutaneous fat. In 2018, paleontologists described a fossil of the Early Jurassic ichthyosaur Stenopterygius that preserved parts of the marine reptile's skin as well as remnants of fats and proteins that made up the animal's flesh. By 180 million years ago, the fossil revealed, ichthyosaurs had smooth skin.

Clues from those fossil tissues also hinted that Stenopterygius was darker above and...

Riley Black.