Paleontologists Uncover First Known Tracks From Club-Tailed Armored Dinosaur

Ankylosaurs, a group of dinosaurs often compared to Pokémon, were built like walking tanks, with bony armor plating their backs and sides. They lived during the Late Jurassic (164 to 145 million years ago) and Cretaceous (145 to 66 million years ago) periods, and consisted of two main subgroups: the nodosaurids, which lacked tail clubs and typically had four toes on both hands and feet; and the ankylosaurids, which had distinctive clubbed tails and usually three toes on their hind feet. While paleontologists have unearthed four-toed ankylosaur footprints throughout North America, three-toed ones have remained elusive—until now.

An international team of researchers has identified the first ankylosaurid footprints known to science. The 100-million-year-old fossilized footprints, discovered in Canada’s Peace Region (spanning the provinces of British Columbia and Alberta), represent a new ankylosaurid species, which the team named Ruopodosaurus clava. The discovery also fills in a notorious gap in North America’s fossil records from the middle of the Cretaceous period.

“While we don’t know exactly what the dinosaur that made Ruopodosaurus footprints looked like, we know that it would have been about 5-6 metres long [16 to over 19 feet long]spiky and armoured, and with a stiff tail or a full tail club,” Victoria Arbour, the curator of paleontology at the Royal BC (British Columbia) Museum, said in a Taylor & Francis Group statement. Arbour and her colleagues’ work is detailed in a study published today in the Journal of Vertebrate Paleontology, which is published by Taylor & Francis Group.

Ruopodosaurus clava means “the tumbled-down lizard with a club/mace,” according to the statement, honoring both the mountain terrain that preserved the footprints and the dinosaur’s sledgehammer-like tail club.

The researchers dated the footprints to the middle of the Cretaceous period, sometime between 100 and 94 million years ago. This makes the footprints doubly exceptional—prior to their discovery, some scholars had suggested that ankylosaurids did not exist in North America during that time range, given the lack of fossil evidence. The newly discovered tracks fill in this gap in North America’s fossil record, and also demonstrate that nodosaurids and ankylosaurids shared this region millions of years ago.

The investigation began when Charles Helm, a co-author of the study and a scientific advisor at Tumbler Ridge Museum, documented three-toed tracks around Tumbler Ridge, a municipality in the foothills of British Columbia’s Canadian Rockies, which is also in the Peace Region.

“Ever since two young boys discovered an ankylosaur trackway close to Tumbler Ridge in the year 2000, ankylosaurs and Tumbler Ridge have been synonymous. It is really exciting to now know through this research that there are two types of ankylosaurs that called this region home, and that Ruopodosaurus has only been identified in this part of Canada,” said Helm.

“This study also highlights how important the Peace Region of northeastern BC is for understanding the evolution of dinosaurs in North America—there’s still lots more to be discovered,” Arbour added.

By following in the footsteps of dinosaurs that walked the Earth tens of millions of years ago, the team secured a first-of-its-kind discovery, as well as one more piece of the ankylosaur fossil record puzzle.