"It's always exciting to discover a species you know to be new. However, the obviously unusual biology of this frog made its discovery especially exciting," said researcher Dr Fred Kraus from Bishop Museum in US.
"The remarkable thing about this frog is the drastic nature of its change in colour pattern as it matures from a tiny froglet into adulthood. This raises the question of what possible function the striking colours of the juveniles might serve," said Dr Kraus.
The bright pattern of the young frog could act as a warning to predators but it is a mystery why the adult then loses this colour, the researchers said in a report in the journal Copeia.
Noting that the younger ones closely resemble the general appearance of some of the poison dart frogs from the tropics, the scientists suggest that the species may also have harmful toxins in its skin.
"If this is the case this would make this species another instance of the independent evolution of such a system," Dr Kraus said adding, it is, however, yet to be affirmed.
Pointing out that the behaviour of the frog also points to the idea that its colour advertises that it is toxic, he said, "No other such instance is known in frogs".
The scientists came across the species while on an expedition to find new species on Sudest Island, Louisiade Archipelago, off the south-eastern tip of New Guinea, the BBC reported.