WASHINGTON -- Picture the fearsome creatures of "Jurassic Park" crossed with the shark from "Jaws." Then super-size to the biggest predator ever to roam Earth. Now add a crocodile snout as big as a person and feet like a duck's.

The result gives you some idea of a bizarre dinosaur scientists unveiled Thursday.

University of Chicago Paleontologists Paul C. Sereno, left, and Nizar Ibrahim, right, infront of a 50-foot life-size model of a Spinosaurus dinosaur that is currently on display outside entrance to the National Geographic Society in Washington, Wednesday, Sept. 10, 2014. National Geographic has put together a life-size model of the first non-bird dinosaur that could live much of the time in water. AP Photo/Pablo Martinez Monsivais

This patchwork of critters, a 50-foot predator, is the only known dinosaur to live much of its life in the water.

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The beast, called Spinosaurus aegyptiacus, was already known to scientists from a long-ago fossil discovery, but most of those bones were destroyed in Germany during World War II. Now, 70 years later, a new skeleton found in Morocco reveals that the beast was far more aquatic than originally thought.

Spinosaurus had a long neck, strong clawed forearms, powerful jaws and the dense bones of a penguin. It propelled itself in water with flat feet that were probably webbed, according to a study released Thursday by the journal Science. The beast sported a spiny sail on its back that was 7 feet tall when it lived 95 million years ago.

"It's like working on an extraterrestrial or an alien," study lead author Nizar Ibrahim of the University of Chicago said, while standing in front of a room-sized reconstruction of the skeleton at the National Geographic Society, which helped fund the research.

"It's so different than anything else around," he said.

Ibrahim described the creature as "so bizarre it's going to force dinosaur experts to rethink many things they thought they knew about dinosaurs."

Scientists had thought that all dinosaurs stuck to the land, with occasional brief trips into the water. But the new skeleton shows clear evidence of river and lake living: hip bones like a whale's, dense bones that allowed it to dive for food, and nostrils positioned high on the skull, allowing Spinosaurus to mostly submerge.

It could walk and would probably nest on land, but on land it moved more awkwardly than in water, said study co-author Paul Sereno of the University of Chicago. It lumbered on its two hind feet because its powerful forelegs with sharp curved claws were designed more for killing than walking, he said.

Sereno called it "an evolutionary experiment going into the water."

The new find is amazing and convincing, showing how wrong scientists have been about this dinosaur and about how diverse dinosaurs can be, said University of Maryland dinosaur expert Thomas Holtz Jr., who wasn't part of this study.

It's also a creature that once was lost to history and war. German paleontologist Ernst Stromer first discovered Spinosaurus bones in Egypt in 1912. The bones went back to Europe, but in 1944, most were destroyed in the bombing of Munich in World War II. Spinosaurus was lost.

But in 2008, Ibrahim was in Morocco on a quest for Spinosaurus. It wasn't going well. He had heard of a local dealer who might know where some bones were, but couldn't find him. Ibrahim had given up hope and was contemplating returning home while sitting in a cafe. He looked up and spotted the dealer walking by.

They went to a Moroccan dig site and found a mostly complete set of bones.

Spinosaurus, which grew some 9 feet longer than Tyrannosaurus rex, feasted on aquatic creatures the size of cars in an area that was history's "most dangerous place," Ibrahim said. Three giant predators nearly the size of a T. rex roamed on land. Even the sky had giant predators. And in the water 25-foot sharks, giant sawfish and six or seven types of ancient nasty crocodiles lurked.

Sereno noted that a Spinosaurus did fight a T. rex in the movie "Jurassic Park III," but it was a land battle and based on the old conception of the dinosaur. In reality, the two didn't live on the same continent or in the same time period.

In the movie, the Spinosaurus won. And Sereno said if the two species had fought in the water, Spinosaurus would have won easily.

The Spinosaurus is portrayed as an equally viscious character in the Transformers Age of Extinction, the fourth film in Michael Bay's CGI-packed series.

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