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Dorcopsulus, thought to be the world's smallest species of kangaroo (Photo: Tim Laman / National Geographic)

Tiny new kangaroo: "spectacular find"

  • BY Amy Middleton |
  • May 18, 2010

What may be the smallest member of the kangaroo family is among a batch of new species discovered in the remote forests of New Guinea.

AN EXPEDITION INTO THE MOUNTAINS of Papua New Guinea has revealed what may be the world's smallest species of kangaroo.

A research team that ventured into the Foja Mountains in 2008 have this week released their findings of a number of species new to science, including a new dwarf wallaby, Dorcopsulus. The wallaby inhabits the floor of the montane forests, and has been called "beautiful" and "gentle" by expeditioner Dr Kristofer Helgen, a zoologist at the Smithsonian Institution of Washington DC.

Kangaroo expert Dr Euan Ritchie, of James Cook University in Queensland, told Australian Geographic that the new species may represent a major find. "It is indeed possible it represents the smallest known kangaroo species, and it would seem certain it's new to science," he says. "If this is true, it's a truly spectacular find."

Click here to see a gallery of images from the expedition

Tiny and exciting

Euan compared the appearance of the species to a distant relative, the hypsi, or musky-rat kangaroo, which is found on rainforest floors in Australia's wet tropics and weighs between 360 and 680 grams. By comparison, Australian wallabies are generally less than or equal to 20 kg. Both the new species and the hypsi are unique in that they are active largely during the day only, whereas most other kangaroos and wallabies are largely nocturnal.

Kangaroo relatives, known as macropods,  fall into three families. The hypsi is unique in its family, Hypsiprymnodontidae. New Guinea wallabies, including the tiny new find, fall into the same family, Macropodidae, as do kangaroos, wallabies, quokkas, and other Australian macropods. The third family, Potoroidae, includes all potteroos and bettongs. All macropods show similarities in appearance and ecology, such as having large feet and moving by hopping.

It is not yet confirmed to which family the new species belongs, and Euan is hesitant to take a guess. "Using morphological information in isolation from genetic information (DNA), to describe a species, would be very dicey indeed," he says.

The discovery of several new species is no surprise to the expedition scientists. Expedition leader Bruce Beehler of Conservation International, an NGO based in New York City, estimates that any where from 1 - 5 million species are yet to be named and catalogued. "Fewer than half the Earth's species have been named," says Bruce, "and certainly not enough effort and resources are being deployed today in the study of the Earth's biodiversity."

Pressures on a unique ecosystem

Since the expedition in 2008, the scientists involved have spent months analysing their new discoveries. Bruce says that after a possible new species is discovered, experts "can take many months or years doing the museum work — there are no field guides for easy identification for most of these groups."

He adds that the Foja Mountains generate biodiversity because of their geographical isolation and because the height of the habitat creates a unique climate that is constantly cool, wet and cloudy. On top of this, the mountains have been in place for 1.5 million years or more, which is long enough for isolated species of plant and animal to have evolved.

Biologist Dr John Rodger of the University of Newcastle, New South Wales, says that New Guinea is rarely explored, and pressures are intense on wildlife in the region. "We know that across both Indoensia and independent Papua New Guinea, there are lots of pressures on wildlife, particularly those that are used as food or have totemic or ceremonial significance."

Other new discoveries made by the expedition team include an amphibian, a reptile, several new mammals and 12 new insects. Click here to see a gallery of the new discoveries. The research team was made of explorers from Conservation International and the US National Geographic Society.

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