Paleontologists in Washington state have unearthed a dinosaur fossil they say is the first ever discovered there.
That makes Washington the 37th U.S. state to have yielded a dinosaur fossil.
The single fossilized bone fragment, around 17 inches long, was discovered in the state's Sucia Island State Park in 2012, researchers are now reporting in the journal PLOS ONE.
Christian Sidor, curator of vertebrate paleontology of the Burke Museum of Natural History and Culture at the University of Washington, says he initially had doubts they would ever identify the source of the fossil based on just the discovered fragment.
"In the year and a half that it waited in the museum queue to be prepared, I was pretty dubious about our being able to identify it as anything more than a large bone," he says.
However, a comparison of the fragment with fossils of the same age in other museums convinced the researchers what they had found was the upper portion of the thigh of a carnivorous theropod dinosaur, only slightly smaller than the famous Tyrannosaurus rex. Those theropod dinosaurs included members of the ceratosaur, megalosauroid, allosauroid, or tyrannosauroid lines. They also found other fossil invertebrates with the sample, including the common bivalve Crassatellites conradiana, so they know it was washed into the water.
"This fossil won't win a beauty contest," Sidor says. "But fortunately it preserves enough anatomy that we were able to compare it to other dinosaurs and be confident of its identification."
The fossil has been dated to 80 million years ago, which puts it in the Late Cretaceous period, notes Burke's museum colleague Brandon Peecook.
"The fossil record of the West Coast is very spotty when compared to the rich record of the interior of North America," he says. "This specimen, though fragmentary, gives us insight into what the West Coast was like 80 million years ago, plus it gets Washington into the dinosaur club."
Washington could be the last state to make its first dinosaur fossil find, Sidor notes, as there's good reason to think the remaining 13 states won't yield anything similar.
In many Northeastern states, all traces of fossil-bearing rock would have been scraped away by ancient Ice Age glaciers, while some Southern states like Florida and Louisiana would be have been completely underwater during the age of the dinosaurs.
Oh, and Hawaii? It's only 6 million years since the island chain began to rise from the sea, long after the world's dinosaurs had disappeared.
"We may actually be the last state to find its first dinosaur," Sidor says.
As an historic first for the state, the fossil will go on display at the Burke Museum in Seattle on May 21.
