A rare Panamanian tree frog, a rodent from Madagascar and two lizards found only in the Philippines are among over 17,000 species threatened with extinction, a leading environmental group said Tuesday.

The Rabb's fringe-limbed tree frog, only discovered four years ago, is one of 1,895 amphibian species that could soon disappear from the wild because of deforestation and infection, the International Union for Conservation of Nature said.

SLIDESHOW: Endangered Species List Grows

The Switzerland-based group surveyed 47,677 animals and plants for this year's "Red List" of endangered species, determining that 17,291 of them are at risk of extinction.

More than one in five of all known mammals, over a quarter of reptiles and 70 percent of plants are under threat, according to the survey, which featured over 2,800 new species compared with 2008.

"These results are just the tip of the iceberg," said Craig Hilton-Taylor, who manages the list. He said many more species that have yet to be assessed could also be under serious threat.

The only mammal added to the list this year was the Eastern Voalavo, a rodent that lives in the mountainous forests of Madagascar. IUCN classified it as "endangered" — two steps from extinction in the wild — because its habitat is being destroyed by slash-and-burn farming.

The Red List already includes species such as the tiger, of which only 3,200 are thought to exist in the wild and whose habitat in Asia is steadily shrinking due to encroachment by humans. Governments and international conservation bodies use the list as guidance when deciding which species to place under legal protection.

The group added almost 300 reptiles this year, including the Panay monitor lizard and the sail-fin water lizard, both of which are hunted for food and threatened by logging in their native Philippines.

IUCN also surveyed 3,120 freshwater fishes, up 510 species from last year, and found 1,147 of them threatened with extinction. They include the brown mudfish in New Zealand, whose wetland habitats have been virtually destroyed through drainage schemes, irrigation and land development.

Some species have recovered thanks to conservation efforts, the group said. The Australian grayling, a freshwater fish, graduated from "vulnerable" to "near threatened" thanks to fish ladders at dams and other protection measures.

But for many other species, conservation efforts are likely to come too late.

The Kihansi spray toad of southern Tanzania is now thought to be extinct in the wild. A dam upstream of Kihansi Falls has dried up the gorge where it lived, and an aggressive fungal disease known as chytridiomycosis appears to have pushed the toad population over the edge, the group said.

The same fate could soon befall the unusually large Rabb's fringe-limbed tree frog, which glides through the forest using its big webbed feet to steer safely to the ground. It is the only known frog species where the tadpoles feed off skin shed by the male while he guards the young.

The chytrid fungus that causes chytridiomycosis reached central Panama in 2006, a year after scientists first discovered the tree frog. Since then the fungus — believed to be spread by international trade and global warming — has virtually wiped out the wild frog population.

"Only a single male has been heard calling since," IUCN said.

Zoo Atlanta scientist Joseph Mendelson, part of the group that identified the frog as a distinct species, said it is likely that dozens or even hundreds of other amphibians have become or are going to be extinct before they are even discovered.

"This one we caught right before it went off the planet, but other species surely we didn't catch in time," Mendelson told The Associated Press in a telephone interview.

"When you name a new species you're attached to it, and when that species disappears so quickly it's impossible not to have feelings associated with that," he said. "I'm pretty sad to be honest, really sad."