A Portland State University researcher discovered that a rabbit known for centuries to exist in South America is different enough from its cousins to be its own unique species.

"At a time when species are going extinct every day, it's encouraging to know we can add one back on the list of survivors," said PSU biology professor Luis Ruedas.

His findings will be published May 17 in the Journal of Mammalogy.

Ruedas made his discovery after studying rabbit specimens at the Naturalis museum in Leiden, in The Netherlands. The specimens, collected in 1983 from the small country of Suriname on South America's northeast coast, were labeled as South American cottontails.

Ruedas studied the anatomy of the museum specimens and determined they were larger and shaped differently than other rabbits throughout South America -- so much so that they deserved to be classified as a distinct species.

The creature will be only the third new rabbit species named in South America since the start of the modern classification system 260 years ago.

The discovery follows another finding that Ruedas published this year showing that the South American cottontail, which was considered to be a single species distributed over a vast area from Mexico to most of South America, really only occupies a small area of Brazil. The other rabbits on the continent -- perhaps as many as 35 species in all -- will have to be renamed, he said.

The rabbit from Suriname will be the first on that list.

Ruedas -- who has traveled around the world studying small mammals and discovering new species -- said the rabbit discovery in South America could affect how animal species are identified as unique, which is an important step when determining if a species is endangered. Ruedas said it could also lead to conservation efforts in Suriname, where environmental degradation is threatening the rabbit's habitat.