One of the smallest frogs in the world, the species was spotted inside and around pitcher plants in Malaysian rain forests on the island of Borneo (map), which is divided among Brunei, Indonesia, and Malaysia.
The new species was announced Wednesday, but the frogs have been hiding in plain view for more than a century.
“I saw some specimens in museum collections that are over a hundred years old,” co-discoverer Indraneil Das said in a statement.
“Scientists presumably thought they were juveniles of other species,” said Das, a herpetologist at Universiti Malaysia Sarawak in Malaysia. “But it turns out they are adults of this newly discovered microspecies.”