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Newly identified ichthyosaur was the king of Nevada seas 240 million years ago

Scientists have identified a new type of marine reptile, which 240 million years ago roamed the sea that became the Nevada desert.

Berlin-Ichthyosaur State Park Judging by the size and sharpness of its teeth, the recently-discovered ichthyosaur was a fierce predator that ate various prey including its fellow fish-lizards, researchers said. When the find was reported at a conference in England in September, Science News said the specimen could be the "T-Rex of the seas."

Nadia Fröbisch, a vertebrate paleontologist at the University of Chicago, and her team unearthed the fossil in the Augusta Mountains of central Nevada in 2008 and are studying it. She said ichthyosaurs, Nevada's state fossil, have been dug up in the region for decades, but the recent specimen is bigger than a killer whale and might be a new species or even a new genus.

Other types of ichthyosaurs have conical teeth for ripping fish or smaller marine reptiles or have blunt teeth for cracking shellfish. The new specimen, about 40-feet long, has diamond-shaped teeth, 5 inches long, which are serrated on the front and back. That gave the beast an edge for tearing the flesh of large animals. The adults probably had no natural enemies, Frobish said.

"There were a large variety of ichthyosaurs, but until now, no major predators had been found," she said. "This find fills the gap "» It was a huge animal and clearly the top predator in the ecosystem."

The creature probably took major chunks out of its large ichthyosaur relatives and other large marine reptiles and fish. The fossil was discovered in late summer of 1998 by another team of scientists, but wasn't excavated, she said.

"When we saw the field notes about the cutting edges on its teeth, we were real interested," Fröbisch said.

She said the fossil was excavated and the pieces were flown out by helicopter in 2008. Museum technicians in Chicago are still extracting the fossil from hard carbonate rock, she said.

When studies are finished, she said, the new type of marine reptile will get a name.

When marine reptiles swam, North America was still part of a supercontinent called Pangea and what became the Augusta Mountains was the bed of a shallow sea.

Ichthyosaurs first appeared about 245 million years ago and disappeared about 90 million years ago, about 25 million years before dinosaurs became extinct.

The sleek ichthyosaurs breathed air and gave birth to live young. They have bony rings around their eyes, suggesting they might have hunted in dark water, scientists said.

"They had a very successful run," Fröbisch said. "Their diversity decreased before they went extinct. It wasn't a sudden extinction. A lot of other marine reptiles were successful later on, in the Mezozoic Era (more than 65 million years ago), so maybe they were out-competed.

"Maybe their time was just up."

Source: Reno Gazette Journal

TANN

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