Fossils of a species of beaver never seen before have been discovered in eastern Oregon. Paleontologist Joshua Samuels said that a fossilized skull and teeth of the beaver that lived 28 million years ago have been unearthed.

Samuels has termed the finding to be significant one. The species discovered seems to be related to the modern beaver. The species has been named as Microtheriomys brevirhinus.

The beaver is less than half the size of a modern beaver. Samuels said that the beaver is related to beavers from Asia that crossed Bering land bridge to North America around 7 million years ago. The discovered species used to roam in the area during the Oligocene period, around 30 million years after the dinosaurs.

It was present at the time when three-toed horses, a two-horned rhinos, giant pigs, saber-tooth, rabbits and many species of dogs. The fossils were described in the journal Annals of Carnegie Museum. University of Oregon paleontologist Samantha Hopkins said that it would be exciting to assess the find.

"While there is relatively little castorid (beaver species) diversity today, there are hundreds of species (many of which are really important members of their faunal communities) in the fossil record of the Northern Hemisphere", said she.

Better understanding of them will unveil about the unknown processes that have led mammalian evolution continuing for over the last 40 million years.

Samuels said the age of beaver fossils was determined with the help of the location where they were found. They were placed between two layers of volcanic ash and research dated them from radioactive isotopes. Around 100 species of mammals have been discovered on the monument, affirmed Samuels.