Carnivorous water rat discovered in Indonesia

June 18, 2014 by Billy Gomila, Louisiana State University

(Phys.org) —Jacob Esselstyn, curator of mammals at LSU's Museum of Natural Science, was part of a research team that discovered a carnivorous water rat in central Indonesia. The species was previously known only to local people in the western highlands of Sulawesi Island, and has been used as a talisman by area residents to protect homes from fire.

Published in the zoological taxonomy journal Zootaxa, the discovery of the new genus and species of mammal, "Waiomys mamasae," documents the first known water rat from Sulawesi and the wider Southeast Asian region. Other semi-aquatic rats are known from New Guinea, Australia, Africa and South America. The authors indicated that, like other semi-aquatic rats, the feeds on aquatic insects that attach themselves to stream bottoms.  

The scientists used DNA sequences to demonstrate that the new species is not a close relative of any other water rat species, including those of New Guinea and Australia. This indicates that the morphological features the Sulawesi water rat shares with other water rat species are the result of convergent evolution – meaning that these distantly related animals have been living in similar environments and independently evolved similar adaptations.

"The Sulawesi water rat and the water rats of New Guinea are no more closely related to each other than either is to the house mouse or the lab rat, but they live in similar environments, which may explain their convergent morphologies," said Esselstyn.

The local people know the animal as "balau wai," or water rat in their language, Mamasa Toraja.  The scientific name, "Waiomys mamasae" meaning "water rat of Mamasa," recognizes their prior knowledge as well as their contribution to the scientific discovery of this .

"The forests near Mamasa are some of the most intact on Sulawesi," said Anang Achmadi, a scientist at Museum Zoologicum Bogoriense in Indonesia and co-author of the study. "Their excellent condition is a testament to the Mamasan people, who limit clearing of forests to the base of the mountain."

In the 19th century, Alfred Wallace, co-discoverer of natural selection, described Sulawesi as an "anomalous island" because the animals he found there were so unusual.
"Sulawesi's ancient history of geographic isolation, along with its many high mountains help explain why it is home to so many strange animals," said Esselstyn.

He added, "It's a real thrill to follow in the footsteps of early naturalists and to still be discovering so many new animals. But the fact that the people of Mamasa knew of Waiomys and keep them as talismans suggests the research community has a lot of work to do before tropical biodiversity will be well documented."

Explore further: 'Toothless' rat discovered on the island of Sulawesi

Related Stories

Zoologists discover bird species in Indonesia

June 6, 2014

(Phys.org) —Zoologists from Trinity College Dublin have discovered a currently unrecognised bird species in a biodiversity hotspot in Indonesia. They propose that the colourful bird, which is found only on one small chain ...

Rainforest essential for world's smallest kangaroo

May 5, 2014

(Phys.org) —The discovery of musky rat-kangaroo fossils has prompted experts to call for better protection of tropical rainforests after new links show the tiny marsupial cannot survive outside that environment.

Recommended for you

Cells lacking nuclei struggle to move in 3-D environments

January 20, 2018

University of North Carolina Lineberger Comprehensive Cancer Center researchers have revealed new details of how the physical properties of the nucleus influence how cells can move around different environments - such as ...

Microbial communities demonstrate high turnover

January 19, 2018

When Mark Twain famously said "If you don't like the weather in New England, just wait a few minutes," he probably didn't anticipate MIT researchers would apply his remark to their microbial research. But a new study does ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.