Researchers on Monday said they may have discovered a new species of gliding possums.

The so far unnamed marsupial has a much longer and thinner face than the well-known sugar glider, according to Charles Darwin University (CDU) in Australia's Northern Territory.

Gliding possums have webbed legs and leap from tree to tree by gliding through the air.

Researchers feared the known species could be threatened by the dramatic decline in the number and diversity of mammals in northern Australia over the past two decades, and began a research project.

"Nobody has ever studied the gliders up here before," said CDU professor Sue Carthew, part of a team monitoring gliders via radio chips.

"And there has always been an assumption that it is a thing called a sugar glider and we're discovering it's not; it's something new.

"This species has a much longer face and a thinner face, which is more like another species of glider, which is called the squirrel glider.

"We don't even know what they are eating or what trees they are living in."