Jurassic “Crocodile” Found in Oregon

—Victoria Jaggard, National Geographic

It endured a rocky ride—literally—but this ancient “sea monster” from Asia has found a place in the United States to call home.

The fossil remains of a crocodile-like reptile called Thalattosuchia have been discovered in rocks in the Blue Mountains of eastern Oregon—about 5,000 miles (8,050 kilometers) from where it most likely died, researchers announced on Monday. So far about 50 percent of the animal, including the upper leg bone and rib fragments seen here (bottom), have been unearthed.

“This creature lived in Jurassic times, so it’s 150 to 180 million years old,” retired University of Oregon geologist William Orr said in a press release. Orr provided expert advice to the excavation team.

“It probably lived in an area from Japan to East Timor, somewhere in the western Pacific in a tropical estuarine environment.”

The reptile, the oldest ever found in Oregon, is a rare discovery in North America. But similar fossils have been found throughout Southeast Asia, so experts believe that the remains were carried to the U.S. by plate tectonics. As the section of Earth’s crust containing the fossils moved eastward, the Pacific plate collided with the North American plate, pushing the bones into the mountains.

The 6- to 8-foot-long (1.8- to 2.4-meter-long) creature, shown in an artist’s conception (top), is part of a group that scientists think represents an evolutionary transition for this line of crocodilians. Features from related fossils suggest that the animals were evolving from being semiaquatic to entirely ocean dwelling.

The newfound fossils will go to the University of Iowa for further study before going on display at an Oregon museum.