Rare Tiny T. Rex Unearthed in Montana

In 2016, students from the Natural History Museum at Kansas University found a relatively small dinosaur pelvis in the Hell Creek formation in Montana. It was the end of their dig season and they didn’t have the time to unearth the rest of the remains. But the fossil was worth the wait; when they returned last summer, they found part of a jaw, teeth and skull segment of what appears to be a 66.5-million-year-old juvenile T. rex, reports Laura Geggel at LiveScience.

In the last 100 years of excavations, fewer than five juvenile T. rex have come out of Hell Creek, which boasts an impressive assemblage of ancient remains. And the latest find may be the best so far. ”[T]his is probably the most preserved and most complete,” Kyle Atkins-Weltman, who is helping to prepare the fossil at KU tells Geggel. “This is a 1-in-100-million specimen.”

While the researchers believe the fossil is of a juvenile T. rex, they aren’t yet one hundred percent certain. “The teeth suggest it’s a Tyrannosaurus rex; however, there is still more work to be done,” David Burnham, preparator of vertebrate paleontology at the KU Biodiversity Institute, says in a press release. “Because a young T. rex is so rare, there are only a few that have been found over the years, so it’s difficult to discern what are changes due to growth or if the differences in the bones reflect different species.”