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Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago (Ma) and at least one species survived until about 90 million years ago, into the Late Cretaceous.
- When did ichthyosaurs first evolve?
- When did ichthyosaurs exist?
- Did Dolphins come from ichthyosaurs?
- How did ichthyosaurs reproduce?
- Can ichthyosaurs breathe underwater?
- Why do plesiosaurs have long necks?
- Where was the first mammal found?
- How were ichthyosaurs different from plesiosaurs?
- Who found first ichthyosaur?
- Why did ichthyosaurs go extinct?
- Why do ichthyosaurs look like dolphins?
- How long did ichthyosaurs rule the oceans?
- What is the Triassic period known for?
- How do ichthyosaurs swim?
- Did pterosaurs have teeth?
When did ichthyosaurs first evolve?
Ichthyosaurs were fish-like reptiles that first appeared about 250 million years ago and quickly diversified into highly capable swimmers, filling a broad range of sizes and ecologies in the early Mesozoic oceans.
When did ichthyosaurs exist?
Ichthyosaurs had a very wide geographic distribution, and their fossil remains span almost the entire Mesozoic Era (251 million to 65.5 million years ago); but they were most abundant and diverse during the Triassic and Jurassic periods (251 million to 145.5 million years ago).
Did Dolphins come from ichthyosaurs?
Although they superficially have a similar shape and they exploit similar environmental niches, we know that ichthyosaurs are reptiles and thus they are not dolphins (mammals) nor sharks (fish). ... Although fish come in all shapes and sizes and ichthyosaurs are often specifically compared with sharks.
How did ichthyosaurs reproduce?
Ichthyosaurs were viviparous; they gave birth in the water to live young (instead of laying eggs, as other reptiles do). This is known because the fossilized bones of baby Ichthysaurs have been found inside the bones of adults.
Can ichthyosaurs breathe underwater?
"Meanwhile, ichthyosaurs did not have a blocking mechanism for their nostrils. Therefore, after breathing in on the surface and submerging, the water would flow into the nostrils. Slightly open snout was its only exit. These animals breathed out the same way.
Why do plesiosaurs have long necks?
"A steady neck would be more hydrodynamic than a bent neck, and due to the pressure on a bent neck, plesiosaurs would probably only bend them when moving at slow speeds or when floating,' says Ms Troelsen. ... Several possible theories suggest that plesiosaurs may have developed long necks to extend their feeding range.
Where was the first mammal found?
Discovery of the skull of a shrewlike animal the size of a paper clip pushes back the origin of mammals, including humans, to 195 million years ago. Found in China, the tiny skull shows evidence that the first mammals evolved from reptiles 45 million years earlier than widely believed.
How were ichthyosaurs different from plesiosaurs?
Ichthyosaurs had large eyes for seeing in deep water, vertical tail fins (like tuna fish), and some species had a dorsal fin. Little is known about their ancestors – terrestrial reptiles that returned to the sea – or why they went extinct, only that plesiosaurs replaced them as the sea's top predators.
Who found first ichthyosaur?
Its discoverer, Mary Anning, lived and worked in the English coastal town of Lyme Regis, finding and selling fossils. She made many important discoveries in the Jurassic rocks there, including the first plesiosaur to be scientifically described, and many other ichthyosaur skeletons.
Why did ichthyosaurs go extinct?
Ichthyosaurs – shark-like marine reptiles from the time of dinosaurs – were driven to extinction by intense climate change and their own failure to evolve quickly enough, according to new research by an international team of scientists.
Why do ichthyosaurs look like dolphins?
Gradually sharks, ichthyosaurs, and dolphins came to look alike because natural selection favored one particular shape over all others for rapid movement through the seas. Figure legend: Convergent Evolution. Although very different species, the dolphin and the icthyasaur look alike.
How long did ichthyosaurs rule the oceans?
The downfall of the ichthyosaurs cleared the way for another group of marine reptiles, called mosasaurs, to spread throughout the oceans. They ruled the seas for about 20 million years.
What is the Triassic period known for?
The Triassic Period was a time of great change. Bookended by extinctions, this era saw huge shifts in the diversity and dominance of life on Earth, ushering in the appearance of many well-known groups of animals that would go on to rule the planet for tens of millions of years.
How do ichthyosaurs swim?
The most primitive ichthyosaurs swam by body undulations and later on they acquired broad tails for swimming by beating their tails (more efficient for fast and sustained swimming).
Did pterosaurs have teeth?
Despite their formidable size, the pterosaurs in the Azhdarchidae family had no teeth. ... Fossil records show that pterosaurs were likely the first airborne vertebrates and they took to the skies around 220 million years ago.
