Description
Ichthyosaur (ichthyosaur – "fish lizard") refers to a group of predatory marine reptiles that lived from about 250 million years ago, from the Triassic period, to about 90 million years ago, during the Cretaceous period. They originally evolved from a group of unidentified land reptiles that returned to the water, similar to how the terrestrial ancestors of today's dolphins and whales returned to the water. Following this return to the water, they took on characteristics and adaptations of fish, being an excellent example of convergent evolution. Ichthyosaurs were extremely widespread during the Triassic and early Jurassic periods, until their niche as aquatic top predator was taken over by Plesiosaurs.
Species of Ichthyosaurs They ranged from 1 to 26 meters long and resembled both modern fish and dolphins. Their limbs were completely transformed into flippers, and the caudal fin allowed for the generation of a powerful propulsive force. Their heads were sharp, and their jaws were often equipped with conical teeth to catch small animals. Some species had larger, blade-shaped teeth to catch large animals. Their eyes were very large, specialized for deep diving. Ichthyosaurs breathed air, were warm-blooded, and gave birth to live young. Many, if not all, species had a layer of fat for insulation.
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