It was not until their final morning in camp, after weeks of searching for mammals within the isolated rainforests of West Sulawesi, Indonesia, that Museum Victoria's Dr. Kevin Rowe and his team were handed a new species, completely unknown to science.

 

"Three local Mamasa guides brought us a dead rat… to most people it looked just like any other small, soft-furred rat but to a biologist it was particularly interesting because it was specialized to an aquatic lifestyle." Dr. Rowe says.

 

Dr. Kevin Rowe and his colleagues from Indonesia and the US published their discovery last month in the journal Zootaxa. The new species is the first known water rat in Sulawesi.

 

The Sulawesi water rat has been given the scientific name Waiomys mamasae after the local Mamasa people who have known about the animal for centuries and have used it traditionally as a talisman to protect their houses from fire.

 

The species was discovered within the Mount Gandangdewata plateau, one of the last intact areas of old growth rainforest in West Sulawesi.

 

Sulawesi is a volcanic island in Indonesia that has been isolated from other land-masses for around 10 million years, allowing unique species of animals and plants to evolve.

 

DNA testing of the Sulawesi water rat confirms that it is more closely related to the land rats on Sulawesi than to water rat species found in other parts of the world and has therefore evolved special water adaptations independently through a process known as 'convergent evolution'.

 

Dr. Rowe describes the new species as having small ears and eyes, whiskers on the underside of its tail which help it to maneuver around in the water and small, fleshy pads on the underside of its toes which may help it to hold onto the stream bed when hunting underwater.

 

The finding also offers new scientific insight into how carnivorous rodents in different regions evolve.

 

PHOTO: This rare water rat developed an aquatic lifestyle independently from other water rats. Credit: Kevin Rowe (Museum Victoria)