Nature never runs out of surprises. Exploring Sudest Island off of Papua New Guinea, researchers discovered a new species of frog that drastically changes its appearance from juvenile to adulthood, a transformation that has never been seen in another frog.

The new species, named Oreophryne ezra, is shiny black with bright yellow spots. Yet when it matures, the frog becomes rose-colored and even its eyes change from black to blue (photos below).

"No other such instance is known in frogs," Dr. Fred Kraus, one of the frog's discoverers and herpetologist with the Bishop Museum in Hawaii, told the BBC.

The discovery, published in Copeia, has led Kraus and co-author Allen Allison also of the Bishop Museum, to speculate that in its juvenile-stage the frog may be advertising that it is poisonous, since it resembles a poison-dart frog. Yet, why the frog would then change appearances so drastically on reaching adult is puzzling to say the least. The researchers have yet to test the new species to see if it is in fact poisonous.

The species, endemic to Sudest Island, is not without potential threats.

"The new species is restricted to a relatively small patch of cloud forest perched on the highest peak of Sudest Island," the researchers write. "Climate change may pose a threat to the new species if changing rainfall or temperature regimes result in the loss of this forest."

Citation: Fred Kraus, Allen Allison. A Remarkable Ontogenetic Change in Color Pattern in a New Species of Oreophryne (Anura: Microhylidae) from Papua New Guinea. Copeia, Volume 2009, Issue 4 (December 2009).