A prehistoric “groundhog” that had its day during the reign of the dinosaurs has been identified by scientists.

The rodent-like Vintana sertichi was one of the largest known mammals of its time, weighing an estimated 20 pounds (9kg).

Scientists reconstructed a five-inch long skull of the creature that was dated to between 66 million and 70 million years old.

They believe Vintana had a powerful bite and lived on a diet of roots, seeds and nutty fruits.

The skull was rebuilt from fossil fragments unearthed in Madagascar. An analysis published in the journal Nature suggests that the animal had big eyes, good hearing and a keen sense of smell.

Vintana belonged to a group of early mammals called gondwanatherians that were previously only known from their teeth.

Along with a host of dinosaurs, they inhabited the ancient southern supercontinent of Gondwana.

US lead scientist Dr David Krause, from Stony Brook University in New York, said: “We know next to nothing about early mammalian evolution on the southern continents. This discovery, from a time and an area of the world that are very poorly sampled, underscores how very little we know. No paleontologist could have come close to predicting the odd mix of anatomical features that this cranium exhibits.”

The study, which included comparisons with living rodents, showed Vintana had massive chewing muscles that moved its jaw upwards and backwards.

Its jaws are thought to have produced higher bite forces than living rodents of similar body size.

The find is only the third mammalian skull from the Cretaceous era to be recovered in the southern hemisphere.