This huge plant eater thrived in the age of dinosaurs — but wasn’t one of them

A new species of hulking ancient herbivore would have overshadowed its relatives.

Fossils found in Poland belong to a new species that roamed during the Late Triassic, a period some 237 million to 201 million years ago, researchers report November 22 in Science. But unlike most of the enormous animals who lived during that time period, this new creature isn’t a dinosaur — it’s a dicynodont.

Dicynodonts are a group of ancient four-legged animals that are related to mammals’ ancestors. They’re a diverse group, but the new species is far larger than any other dicynodont found to date. The elephant-sized creature was more than 4.5 meters long and probably weighed about nine tons, the researchers estimate. Related animals didn’t become that big again until the Eocene, 150 million years later.

“We think it’s one of the most unexpected fossil discoveries from the Triassic of Europe,” says study coauthor Grzegorz Niedzwiedzki, a paleontologist at Uppsala University in Sweden. “Who would have ever thought that there is a fossil record of such a giant, elephant-sized mammal cousin in this part of the world?” He and his team first described some of the bones in 2008; now they’ve made the new species — Lisowicia bojani — official.

The creature had upright forelimbs like today’s rhinoceroses and hippos, instead of the splayed front limbs seen on other Triassic dicynodonts, which were similar to the forelimbs of present-day lizards. That posture would have helped it support its massive bodyweight.