Researchers find new species of beaver

Chuck Bednar for – @BednarChuck

Oregon is nicknamed “The Beaver State,” so it’s no surprise that paleontologists recently unearthed a new species of beaver and several other never-before-seen creatures at the John Day Fossil Beds National Monument.

According to the Associated Press, the experts recovered the fossilized skull and teeth from a new type of beaver, which they believe lived 28 million years ago. Palentologist Dr. Joshua Samuels stated that this new animal appears to be a distant relative of the modern beaver.

The new species has been named Microtheriomys brevirhinus, and according to reports, it was less than half the size of a modern beaver. The creature is believed to be a relative of the beavers that crossed the Bering land bridge from Asia to North America roughly seven million years ago, and it likely lived during the Oligocene period.

The new beaver, along with fossils of 20 other rodent species, were reported in a recent edition of the journal Annals of Carnegie Museum. Along with Dr. Samuels, Dr. William Korth of the Carnegie Museum of Natural History and the Rochester Institute of Vertebrate Paleontology was involved in the research.

One out of many

In an email to the wire service, University of Oregon paleontologist Samantha Hopkins said that it would be exciting to take a closer look at the fossils in an evolutionary framework. Hopkins said that there is “relatively little castorid (beaver species) diversity today,” but noted this wasn’t always the case.

“There are hundreds of species (many of which are really important members of their faunal communities) in the fossil record of the Northern Hemisphere, and a better understanding of their diversity and evolutionary relationships has a lot to tell us about processes driving mammalian evolution over the last 40 million years,” she told the AP.

In addition to Microtheriomys brevirhinus, other new species discovered at the site include a dwarf tree squirrel (Miosciurus covensis) smaller than any living in North America today, an early pocket mouse (Bursagnathus aterosseus), and a birch mouse (Plesiosminthus fremdi) named in honor of a retired colleague, the Monument said in a statement.

“This study fills some substantial gaps in our knowledge of past faunas, specifically smaller mammals,” said Dr. Samuels. “Some of the new species are really interesting in their own right, and will ultimately help improve our understanding of the evolution of beavers and pocket mice. These finds show that despite this area being studied for well over 100 years, new discoveries continue to be made. Each new discovery helps to give us a fuller picture of Oregon’s past.”


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