The newly discovered rat is similar in size and weight to this one found by scientists in 2007.
LONDON, England (CNN) --
Measuring 82 centimeters (32.2 inches) from nose to tail and weighing around 1.5 kilograms (3.3 pounds), the species is thought to be one of the largest rats ever to be found.
The discovery was made by a team from the BBC Natural History Unit inside the crater of Mount Bosavi -- an extinct volcano in the Southern Highlands province of Papua New Guinea.
"This is one of the world's largest rats. It's a true rat, the same kind you find in the city sewers," said Kristofer Helgen, a biologist from the Smithsonian National Museum of Natural History, who was part of the expedition team.
Initial examinations of the rat -- provisionally named the Bosavi woolly rat -- suggest that it belongs to the Mallomys -- a genus of rodents in the muridae family which are the largest living species of rodent.
The newly discovered rats aren't the world's largest rodent species. Native to South America, capybaras -- which look more like hairy pigs than rats -- weigh in at around 55 kilograms and can be up to 1.5 meters long.
McGavin and the team spent six weeks in the region investigating species. During that time it became abundantly clear to the team just how endangered these habitats are.
"What we are trying to do," said McGavin, "is highlight the fact that these habitats are terribly threatened. In fact, only 20 miles away from where we were the wood was being extracted."
Research published in the journal Biotropica in June 2008 estimated that over a quarter of Papua New Guinea's forests had been either destroyed or damaged between 1972 and 2002.
"Humans can't seem to agree on anything, but we should at least agree that forest habitats like this one should be conserved; not only because 80 percent of the world's species live in forests, but if we are going to avoid the worst affects of global warming we've got to keep these forests," McGavin said.