Tiny fossil shark teeth trapped in the matrix — that’s the matrix of rock and other material that once encased the world’s most famous T. rex — represent a new species. The find is helping researchers recreate a Cretaceous environment that might not be what you’d expect.

Sue the T. rex has called The Field Museum in Chicago home for nearly 20 years, and the iconic fossil is a huge draw for tourists and paleontologists alike. With more than 90 percent of it recovered, it’s the most complet