Biologist Muse Opiang of the Papua New Guinea Institute of Biological Research holds a Bosavi silky cuscus, a newly discovered marsupial from central Papua New Guinea, in early 2009.
The animal's dense fur keeps it warm in the cold elevations of Mount Bosavi, a volcano that became inactive about 200,000 years ago. After being separated from other cuscuses living in the hot, steamy lowlands, the Bosavi animal likely evolved into a new subspecies, said Smithsonian biologist Kristofer Helgen.
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The BBC expedition that revealed the silky cuscus, filmed between January and March 2009, highlights how evolution can work in isolated pockets to create unusual new creatures, Helgen said.
These "are the areas that so exciting for exploration, because they yield new things, but observing [them] teaches us a lot about conservation and the unique importance of these limited areas."
Photograph courtesy Kristofer Helgen