In the remote mountain forests of Halmahera (map), the largest island of the Maluku archipelago in Indonesia lurks the newest member of the rodent family sporting spiky brown fur and a stubby tail.
Scientists first discovered the distinctive rodent, called the Boki Mekot rat (Halmaheramys bokimekot), while on an expedition to Halmahera in 2010. When lead researcher Pierre-Henri Fabre, of the University of Copenhagen in Denmark, realized it might represent something new, “I was very excited, but I didn’t trust that it could belong to a new genus,” he said.
Genetic work, and anatomical comparisons that revealed—among other things—subtle differences in its skull and teeth from other rat species, confirmed that the new rat didn’t fit into the existing rodent family tree. Instead, Fabre and colleagues found that it belonged to an entirely new genus, and that several million years of evolution separated it from relatives like common brown and black rats.
The researchers named the new species after the Boki Mekot region of Halmahera Island. They published their findings September 20 in the Zoological Journal of the Linnaean Society.
A Handsome Find
The new rodent has spiky brown fur with white highlights, as well as a long face and a relatively short, stumpy, white-tipped tail.
“All in all I think this is quite a handsome rat,” said study co-author Kristofer Helgen, curator of mammals at the National Museum of Natural History in Washington, D.C. Helgen was recently involved in discovering another new species, the Olinguito. (Related: “Newly Discovered Carnivore Looks Like Teddy Bear.”)
“This is one of the least known parts of the world in terms of mammals,” Helgen said. The Maluku islands bridge Asia and Australia, and house incredible plant and animal diversity, both between islands and also within islands. “As a mammalogist, these islands really get me excited, they’re an ideal place to go to find new species of mammals,” he said.
Lawrence Heaney, curator of mammals at the Field Museum of Natural History, Chicago, said he wasn’t surprised at the discovery of a new rodent species on Halmahera, given how little researchers know about the island’s rich biodiversity.
“But the fact that [the spiny rat is] different at the genus level rather than at a species level is interesting from an evolutionary perspective,” Heaney said. “It shows the tremendous diversification of rodents in the region.”
Researchers used toasted coconut and peanut butter treats to lure the spiny Boki Mekot rats into little cages. And so far, Fabre and colleagues have only captured three males and three females.
The rat’s short tail, and the fact that it was found on the ground, suggest that it is terrestrial, rather than arboreal or aquatic, said Fabre.
The researchers found fruit and insect remains in one rat’s stomach, but they will need more information to determine the rodents’ actual diet.
Fabre hopes to go back and catch more Boki Mekot rats so that he can learn more about this new species. He also expects to find other new mammalian and bird species on the island.
Finding more animal species on Halmahera would help researchers understand how organisms spread out and diversified in the archipelago.
“It’s a tremendous crucible of evolution, with species from east and west mixing on the central island, Halmahera,” said Helgen. “It’s only now that we’re starting to discover many of the animals that live on these islands, and each one that we discover can give us new clues into the millions of years of interaction between the two great continents, Asia and Australia.”
Studying the Maluku islands’ biodiversity would also allow scientists to determine how humans are impacting the area. With a growing human population and increased logging and mining on the islands, Fabre said he hoped that the discovery of the new rat species would help emphasize the need to conserve the island’s rich flora and fauna.