154-Million-Year-Old Dinosaur Fossil Debuts in the U.K.—But Its Species Remains a Mystery

A remarkably complete 154-million-year-old theropod fossil, nicknamed Juliasaurus, has made its public debut at the Hollytrees Museum in Colchester, U.K. Discovered in Wyoming’s Morrison Formation in 2020 and sold by the David Aaron gallery to a private collector, the 20-foot-long specimen is currently part of the “Discover: Museum Wonders” exhibition. While initially thought to be an Allosaurus or Marshosaurus, unique anatomical features in its skull and pelvis suggest it may represent an entirely new species.