Specimen represents entirely new genus
Researchers have discovered a new carnivorous water rat on the island of Sulawesi that’s so unique it represents an entirely new genus. They believe many more rodent species await discovery in this relatively undisturbed part of Indonesia, but mining and other types of development may threaten vital habitat before it’s even surveyed.
Named Waiomys mamasae and described in a study recently published in the journal Zootaxa, the species is known by a single animal that was caught by hand in a small stream in Western Sulawesi’s mountainous interior. A team of scientists from institutions in Indonesia, Australia, and the U.S. was conducting a mammal survey of the area, and was alerted to the species’ existence by local people who use it as a talisman to protect their homes against fire.
The first specimen of Waiomys mamasae ever seen by scientists. Photo by Kevin C. Rowe.
The new species is described in the study as being small and grey, with dense fur that stands upright and can “be brushed any direction.” Its eyes are small and its snout is covered in long whiskers that may help it to detect its aquatic invertebrate prey. Its tail is also whiskered, and is long – nearly 25 percent longer than its body. On the bottoms of its toes are small, fleshy pads that may help it hold onto the streambed when hunting underwater.
Water rats occur all over the world, from Australia to South America. However, while they all possess similar aquatic adaptations, these appear to have arisen independently in many species via a process called “convergent evolution.” Indeed, the new water rat isn’t even closely related to similar-looking water rats that live on the nearby island of New Guinea. Genetic analyses indicates this new species is actually more closely related to Sulawesi’s terrestrial carnivorous rodents.
“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 Jacob Esselstyn, curator of mammals at Louisiana State University’s Museum of Natural Science, and part of the research team that discovered W. mamasae.
The new water rat was caught in this very stream on Mount Gandangdewata. Photo by Kevin C. Rowe.
The new water rat isn’t the only unique mammal on Sulawesi. With more than 10 million years of separation from other landmasses, the island has one of the highest concentrations of endemic fauna in the world. Thirty-one percent of its birds are found nowhere else, as are 62 percent of its mammals. Of the known mammal species, approximately 30 percent are rodents, all of which are endemic and which have evolved in many different directions to take advantage of the varied environments of the island. Among them is Paucidentomys vermidax, which eats primarily worms and has no back teeth (it’s the only known rodent without molars), and the Sulawesi giant rat (Paruromys dominator).
“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.
The researchers believe many more new rodent species may be hiding in the highlands of Sulawesi, which features large swaths of old-growth forest that have been left untouched by the deforestation that’s affecting much of the rest of Indonesia. The researchers attribute this to the traditional forestry practices of local communities.
“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.”
The researchers named the new species Waiomys mamasae to honor the contributions of the Mamasan communities who helped bring the water rat to the attention of the scientific world, as well as protecting its habitat.
While Sulawesi hasn’t been as heavily deforested as many other parts of Indonesia, it is still losing its forest cover at a rapid clip. The area where W. mamasae was found, indicated by the yellow circle, has not been systematically surveyed but may be targeted by mining companies in the future. Map courtesy of Global Forest Watch.Click to enlarge.
However, danger looms for the region as it contains high-value mineral deposits attractive to mining companies. In addition, human habitation is increasing inward from the coast as populations rise, and logging is already felling large swaths of lowland forest. According to data from Global Forest Watch, the province of West Sulawesi, where the new water rat was found, lost more than 10 percent of its forest cover from 2001 to 2013.
Few surveys into Sulawesi’s highlands have been conducted, but the researchers say those that have been done indicate the area is very biologically important and unique, and is worthy of increased study and protection.
“The discovery of Waiomys [and other species] and their apparent absence from the relatively intensely studied areas around Lore Lindu in the east-central region, lend further support to the biogeographic significance of the west-central highlands of Sulawesi’s central core,” the authors write.
“However, the persistence of these forests, despite their remoteness, is uncertain, particularly because of the high mineral value of the region and the expansion of development in the new province of Sulawesi Barat.”
Citations:
- Rowe, K.C., Achmadi, A.A., and Esselstyn, J.A. (2014). Convergent evolution of aquatic foraging in a new genus and species (Rodentia: Muridae) from Sulawesi Island, Indonesia. Zootaxa, 3816 (4): 541-564.
Related articles
Indonesian logger: cleared peat forest doesn’t have high conservation value
(06/17/2014) An Indonesian logging company says that clearing of peat forest on an island off Sumatra is ‘in line with its Sustainable Forest Management Policy’ because the area wasn’t found to be of high conservation value. In a letter responding to concerns raised by environmental groups, Asia Pacific Resources International Holdings Limited (APRIL) said its forest policy applies to all its concessions, including the Pulau Padang concession where Greenpeace documented deep peat clearance last month.
‘Borne by the rest of the world’: deforestation has global impact, reduces food security
(06/13/2014) Research indicates that areas with more forest cover tend to have superior food resilience compared to areas with less. In addition, the loss of forest cover to deforestation has long-term impacts not only locally, but also globally. These topics were discussed by international experts during the 2020 Conference on Building Resilience for Food and Nutrition Security, held last month in Addis Ababa, Ethiopia.
Despite green pledge, Wilmar partner continues to destroy forest for palm oil
(06/12/2014) Two palm oil companies partially owned by Wilmar are continuing to destroy rainforests in Indonesia despite a high profile zero deforestation pledge, alleges a new report published by Greenomics.
Another year of fires, another year of inaction
(06/06/2014) With a 70% chance of an El Niño this year, Indonesia could soon be facing the ire of its nearest neighbors yet again as the dry season approaches with the ever present threat of vegetation fires.
Mining company attacks scuba diving tourists in Indonesia
(06/05/2014) Conflict from mining activities on Bangka Island off North Sulawesi, entered a new chapter after a local resort manager voiced concern over an incident involving its clients and mining staff last Saturday.
(06/05/2014) In 1997, Gabriella Fredriksson, then a young PhD student, was studying sun bears in East Kalamantan, Indonesia, when massive forest fires broke out in the park. ‘It quickly became clear that there was no government agency, NGO, or private company in the area interested in assisting putting out these fires, which were threatening to burn down the entire reserve,’ Fredriksson told mongabay.com.
Colorful bird on remote Indonesian islands should be classified as distinct species, say scientists
(06/04/2014) A colorful bird found on the Wakatobi islands south of Sulawesi in Indonesia is sufficiently distinct from birds in nearby areas to be classified as a unique species, argue scientists writing in the current issue of the open-access journal PLoS ONE.
Logger continues to destroy Indonesian rainforest despite green promises (Photos)
(06/03/2014) Indonesian logging giant Asia Pacific Resources International Limited (APRIL) is continuing to destroy endangered rainforests on Sumatra despite a high profile commitment to clean up its operations, reveal aerial photos captured by Greenpeace last month.
Facebook, Twitter to carry 24 hours of live rainforest animal sightings on Monday
(05/29/2014) Next week, the rainforests of Southeast Asia are going live. On June 2nd, 11 organizations in the region will be posting lives video, photos, and wildlife sightings over 24 hours on Facebook and Twitter (see #rainforestlive). Dubbed Rainforest: Live, the initiative hopes to raise awareness of quickly vanishing ecosystems and species.
Credits
Morgan Erickson-Davis Editor
