This species is so new to science that it hasn’t been formally described, hence the placeholder scientific name, Mallomys species nova.
The Bosavi woolly rat was discovered in 2009, during the filming of a BBC nature documentary about the forest within Mount Bosavi crater. This extinct volcano crater, located in Papua New Guinea’s southern highlands, is nearly 2.5 miles wide and has walls nearly half a mile high. It’s rarely visited by local communities. A team of Smithsonian biologists, BBC filmmakers, and trackers from the nearby Kasua village spent weeks within the crater, documenting several species new to science.
First found by a tracker in the middle of the night, the Bosavi woolly rat is absolutely massive: measuring 32 inches from nose to tail and weighing 3.5 pounds. (You can see photos here.) Little is known about this new species, but scientists suspect that it feeds on leaves and roots, and nests underground beneath rocks and tree roots. Writing in The Guardian, one of the filmmakers said the woolly rat was entirely unafraid of humans, and “…sat quietly in camp, chewing on a fern and wondering what all the fuss was about as we rushed around him filming and taking photographs.”
Other mammal highlights from the expedition include the new subspecies of silky cuscus and capturing rare footage of a Doria’s tree kangaroo. The expedition also discovered 16 new frogs, a gecko, three fish, and at least 20 species of insects and spiders. There are 6 additional species in the woolly rat (Mallomys) genus. All are found in the New Guinean highlands, and most are relatively unknown to science. Three of these species, including the Bosavi woolly rat, are not yet formally described.