Tiny frogs, spiny ants among 200 newfound species
The discoveries included almost 100 new insects, almost 100 new spiders, two new mammals and 24 new species of frog, some so small they could sit on a thumbnail.
One of the mammals — a mouse with a white, prehensile tail — has no close relative, and represents not just a new species, but a new genus.
Several of the katydids and at least one of the ants found also represent new genera, the researchers said.
Only two individuals of the spiny, tree-dwelling ant were found, at an elevation of 1,600 metres.
The new species were found during two month-long expeditions to Papua New Guinea by Conservation International's Rapid Assessment Program.
Two month-long expeditions were conducted in April and September 2009 to the rugged and remote Nakahai and Muller mountain ranges, respectively.
"With both the Nakanai Mountains and the Muller Range on UNESCO's World Heritage Tentative List, we hope that news of these amazing new species will bolster the nomination of these spectacular environments for World Heritage status," said team leader Stephen Richards, in a statement.
The sites are under threat from loggers, oil and gas exploration and agriculture, the researchers said.
During the survey in the Muller range in September 2009, researchers spent a week at three different camps at different elevations, the highest 2,875 metres above sea level.
The scientists found ants of the genus Strumigenys at an altitude of 3,000 metres, the highest ants have ever been discovered.
One of the newly discovered katydids features large, spiky legs that it holds above its head when threatened to jab at predators. Rapid Assessment Program scientist Piotr Naskrecki described the sting as "very painful."