James Clark is a professor of biology in George Washington University’s Columbian College of Arts and Sciences. He travels to China multiple times a year to search for and excavate fossils. His most recent discovery proved to be a new species of dinosaur, called the Limusaurus inextricabilis, or “mire lizard that could not escape.” He researches with Xu Xing of the Chinese Academy of Science in Beijing.
When and how did you find the dinosaur?
It was a series of discoveries. In 2001 we found this stack of dinosaurs, but they were all missing the front half of their skeletons. In 2002 we found another, better-preserved series. Finally in 2005, we found another stack. Our geologist figured out they were a result of animals getting mired in sticky mud. We finally got a beautiful skeleton with a beautiful skull and four limbs.
What makes this skeleton stand out?
It’s a very strange animal. It’s related to the carnivorous dinosaur, but it doesn’t have teeth. It has gizzard stones and weak forelimbs. After studying it, we learned that the hands were really interesting and relevant.
What does it tell us about the dinosaurs and evolution?
There was a ton of evidence that birds are related to dinosaurs. The really primitive theropods had five fingers, and a big group [later] had only three fingers. Birds develop with three fingers. No one has seen an intermediate step like this before with an animal that has four fingers.
What’s the next step?
[The skeleton] is in Beijing right now. I’m involved with the research, and we’re going back this summer. We still have lots of fossils that we’re working on. It’s a really interesting time period in dinosaur evolution. We’re really hoping to find things that are close to the origin of birds.
