Novu Tamura/Levi bernardo/Wikimedia Commons (CC-BY 3.0) Ichthyosaurs, a diverse group of marine reptiles, lived between 252 million and 95 million years ago. He’s a vertebrate paleontologist at the University of Bristol in England. So far, paleontologists have discovered and named more than 100 different species of them, notes Benjamin Moon. On the whole, ichthyosaurs were very successful. Their name even means “fish-lizard” in Greek. Ichthyosaurs were among the earliest lizards to take to the seas. But scientists are still finding new species and discovering new information on what these animals looked like and how they lived. People have been unearthing fossils of such sea creatures for hundreds of years. Their descendants evolved to become plesiosaurs, pliosaurs and mosasaurs. Much later, after additional mass extinctions, other land-dwelling reptiles took to the seas. These animals evolved to become ichthyosaurs (IK-thee-oh-saurs). With so many ocean species gone, some land creatures tried an aquatic lifestyle - and succeeded. After the devastated ecosystems recovered, the few species that survived evolved to better fit in with the new environmental conditions. Overall, about 90 percent of ocean species and 70 percent species on land disappeared. As a result, large numbers of animals, plants and other species died out. At that time, huge volcanoes erupted in what is now Siberia. Marine reptiles of the same time period lacked such holes.Ībout 252 million years ago, there was a mass extinction. He’s a vertebrate paleontologist at Virginia Tech in Blacksburg. But they lacked the distinctive hip structure that only dinos had.Ī dinosaur had distinctive holes in its pelvis where its thighbones were attached, notes Sterling Nesbitt. Some were as large and as long as a school bus. Some of these marine reptiles were shaped like dolphins and probably could swim fast. And they would have made the oceans very dangerous. Many were top predators, the sharks and killer whales of their time. The oceans had their own cadre of reptiles. Many that dwelled on land were dinosaurs. For millions of years, reptiles dominated the Earth.
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