Scientists Find First Evidence of Dinosaurs in Wash. State
80M-year-old femur belonged to a theropod
By Elizabeth Armstrong Moore,  Newser Staff
Posted May 21, 2015 7:18 AM CDT
Christian Sidor, curator of paleontology at Burke Museum in Seattle, and Brandon Peecook, University of Washington grad student, hold up the fossil and cast of a Daspletosaurus femur (left).   (The Burke Museum)

(Newser) – It appears that around 80 million years ago, a theropod dinosaur roughly the size of a transit bus died near the sea and was jostled by waves, and at some point part of its femur became wedged into a rocky outcrop alongside clam fossils in Washington state's San Juan Islands. So surmise paleontologists at the University of Washington, who excavated the 17-inch-long bone a month after it was found by other scientists looking for extinct marine invertebrates in April 2012, reports LiveScience. The team spent the next year and a half preparing the fossil before they sorted out that what they had on their hands was in fact the first dinosaur bone ever found in the state. (T. rex is a type of theropod, by the way, though at 36 feet this dinosaur was a bit smaller.)

"For the longest time, I was unconvinced that we were going to be able to say anything else besides, 'It's a large bone,'" one researcher says. "I couldn't tell if it was a dinosaur, couldn't tell if it was a marine reptile, couldn't tell anything about it." They were "lucky," he adds, that it was preserved enough for them to find two clues. First, the bone has a hollow cavity, and second, a feature called a "fourth trochanter," both suggesting a theropod, they report this week in PLoS ONE. The find makes Washington the 37th state to lay claim to a dino fossil; the area was in fact largely underwater at the time, reports the Seattle Times. A few theories are floating around about why a land roamer has been found there, including that it made its way north from Oregon or California. (Dinosaurs appear to have first emerged in South America.)