FOSSILS of a “primeval beaver” have been discovered in New Mexico, shining a light on a new species that outlived the dinosaurs.

The discovery has allowed scientists to identify a new, previously unknown group of furry animals, which are said to have flourished when dinosaurs were wiped off the earth.

Scientists in New Mexico discovered the creatures and have since been working alongside the University of Edinburgh, which has a dedicated team of workers situated in the western US, one of the best places in the world to find dinosaur fossils.

The rodent-like creature originated about 100 million years before the dinosaurs became extinct, and is distinctive because of its complex teeth, which were suited to a diet of plants and leaves.

Researches have said they hope that studying the creatures will help them further understand mass extinctions, as the vegetarian mammals thrived in the aftermath of one.

The group of creatures grew rapidly in a period around 500,000 years after the extinction of the dinosaur, evolving from a small creature to one weighing between 10kg and 40kg.

The new species, which is known as the Kimbetopsalis simmonsae, is believed to have evolved into a large beaver-like creature that weighed up to 100kg.

Dr Steve Brusatte of the University of Edinburgh was involved in the research, and the geosciences professor said the discovery offers the chance to find out how mammals became the dominant species on earth.

“This is one of those mammals that was living in the whole new world after the dinosaurs were cleared out, where mammals had their chance to rise up,” Brusatte said.

“These were big mammals, much bigger than any that lived with the dinosaurs. Although mammals and dinosaurs originated about the same time, the dinosaurs took off and became big while mammals stayed small, none bigger than the size of a badger.

“What we are seeing with these new fossils is that right after the dinosaurs disappeared, these mammals that survived took advantage and they started growing bigger, and started doing new things, such as changing their diets.”

Despite the events taking place millions of years ago, Brusatte insisted they still had relevance today, saying that understanding what happened after the extinction of the dinosaur could help us predict future events.

“We hope that all of this gives some sort of insight into what maybe we can expect in the future if climates continue to get warmer, and can maybe help us to mitigate some of that stuff,” he said.

Although the species died out about 35 million years ago, scientists are still unclear why they became extinct, when they were replaced by newly emerging rodents.

Some championed theories include the newer species growing quicker, reproducing faster or just being smarter than the previous animals, giving them an advantage when competing for natural resources.

Teams from the New Mexico Museum of Natural History and Science and the University of Nebraska were also heavily involved in the research.

Dr Thomas Williamson of the New Mexico Museum, who led the research, said: “It’s interesting that this odd, now extinct group, was among the few to survive the mass extinction and thrive in the aftermath. It may be because they were among the few mammals that were already well-suited to eating plants when the extinction came.

“This new species helps to show just how fast they were evolving to take advantage of conditions in the post-extinction world.”