Let’s learn about dinosaurs’ fearsome neighbors

Pterosaurs and plesiosaurs are just the beginning

While pterosaurs, such as this flock of Quetzalcogtlus, are often mixed up with dinosaurs, these flying reptiles weren’t actually dinosaurs.

Mark Stevenson/UIG/Getty Images

If you’re thinking of the Mesozoic Era — the Triassic, Jurassic and Cretaceous periods — you probably think DINOSAURS! You’re not wrong. That era, 252 million to 66 million years ago, was when dinosaurs evolved, reigned and died. But you’d also be missing out on a lot of other amazing creatures, especially other reptiles.

Dinosaurs are only one group of Mesozoic reptiles. Other land-dwellers included ancestors of modern-day crocodiles, called Batrachopus. Meanwhile, the air was ruled by pterosaurs.

Though pterosaurs often come in sets of play dinosaurs, they were only dinosaur relatives. Well-adapted for flying, they had hollow, air-filled bones, similar to modern birds. Their wings, though, were usually covered with thin membranes rather than feathers. (Some pterosaurs, though, may have been covered in fuzzy protofeathers.) Pterosaurs ranged in size. Some were as small as eagles. The largest known, Quetzalcoatlus, had a wingspan of some 10 meters (33 feet).

The Mesozoic seas were dominated by other non-dinosaur reptiles. These included the ichthyosaurs, or “fish-lizards.” Scientists have discovered fossils of more than 100 species of these animals. Among them are the remains of one unlucky reptile who likely died from trying to eat a meal as big as itself. Plesiosaurs had long necks with dozens of bones. Their giant flippers let them swim through the water like a penguin. Although big, plesiosaurs still had plenty of worries. These included giant mosasaurs that preyed on plesiosaurs. You might recognize those giant sea monsters from the aquatic show in Jurassic World.

While the Mesozoic Era is often called the Age of Reptiles, reptiles weren’t the only animals around, of course. Fish still swam the seas. Insects and other invertebrates were numerous. And mammals — our ancestors — were just getting their start.

Want to know more? We’ve got some stories to get you started:

That’s no dino! Not all ancient reptiles were dinosaurs. Some soared, many swam the seas and still others looked like dinos — but actually weren’t. (6/12/2015) Readability: 6.6

The real sea monsters No known dinosaurs lived in the oceans. But there were lots of big aquatic reptiles that were every bit as ferocious and awesome. (6/19/2015) Readability: 7.3

Early dino-era start for modern mammals Fossils of an extinct group of rodent-sized mammals suggest they were related to modern mammals. These ancient remains push back the origin of mammals by many millions of years. (10/1/2014) Readability: 7.3

Dinosaurs may get most of our attention, but there were plenty of other reptiles that roamed Earth during the Mesozoic — the Age of Reptiles.

Explore more

Scientists Say: Jurassic

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Explainer: Understanding geologic time

Fossil hunting can start as child’s play

These crocodile ancestors lived a two-legged life

These fuzz-covered flying reptiles had catlike whiskers

This ancient reptile’s last meal may have truly been a killer

Activities

Word Find

Download and print Pterosaurs: A Card Game from the American Museum of Natural History. The game, based on the museum’s collections and exhibits, challenges players to gain points by building their own food chains and breaking their opponent’s.

Sarah Zielinski is managing editor of Science News for Students. She has degrees in biology and journalism and likes to write about ecology, plants and animals. She has two cats, Oscar and Saffir.

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