The newly discovered 66.5 million-year-old soft-shell turtle is one of the oldest known species of its genus and lived towards the end of the Cretaceous, just before the extinction of the dinosaurs.

Hutchemys walkerorum lived at the same time as the famous “Cretaceous” giants such as Tyrannosaurus Rex and Triceratops. The discovery gives scientists a deeper understanding of soft-shell turtles and the impact of the mass extinction at the end of the Cretaceous period on their appearance. Hutchemys walkerorum belongs to the family Tryonychidae, in a distinct group known as plastomens. This creature is similar to modern soft-shelled tortoises, but the plastomena bones covering their belly were larger and stronger than those of their modern descendants. Plastomens lived during the Cretaceous and Paleogene periods between 80 and 50 million years ago. The group reached its peak of diversity at the border of the Cretaceous and Paleogene periods – about 65 million years ago.

“Until recently, we didn’t really understand these soft-shelled turtles. However, we are starting to get more information about this extinct group of turtles and better understand their evolution, including how they coped with the mass extinction,” said Stephen Jasinski, lead researcher.

The fossil specimen was discovered in 1975 along with the remains of a Triceratops, but it remained unexplored until 2013. The researchers compared the specimen with other trionychids to better understand the evolutionary relationships within the group.

“Through this study, we are gaining a better understanding of the winners and losers during the cataclysm that ended the age of the dinosaurs. The mighty dinosaurs fell, but the unpretentious turtle survived,” said Peter Dodson, a participant in the work.