Remarkable new ‘Colour changing’ frog discovered on New Guinea island [WildlifeExtra 2010-03-10]
Black and yellow juveniles become peach in adulthood!
February 2010. A remarkable new species of arboreal frog has been discovered on Sudest Island, in New Guinea's Louisiade Archipelago. The new frog, Oreophryne ezra, exhibits a remarkable change in colour pattern as it grows older. The frog was discovered by Dr Fred Kraus and Dr Allen Allison of Hawaii's Bishops Museum.
Juveniles are shiny black with lemon-yellow spots; adults are uniform peach with bright blue eyes. This colour change, uniform peach adult colouration, and blue iris all appear to be unique features within the genus Oreophryne, most of whose members are tan, brown, or gray.
The new species is restricted to a relatively small patch of cloud forest perched on the highest peak of Sudest Island. Climate change may pose a threat to the new species if changing rainfall or temperature regimes result in the loss of this forest.
Among frogs, changes in colour pattern are generally of a modest nature. Hoffman and Blouin (2000) noted that such changes have been observed for at least 39 species. However, most of these instances involve darkening of animals with age or transitions between green and brown colour states.
Relatively few frogs show striking differences in colour or pattern, and most of these examples are seen in the African genus Hyperolius. Many species of that genus lose or acquire pattern elements such as stripes, blotches, mottling, or hourglass markings, or they change colour with age, often acquiring striking colour patterns (Schiotz, 1971, 1999; Hoffman and Blouin, 2000).
These frogs were locally common. Adults were typically found at night while calling perched on the upper surfaces of leaves 2 m or more above the ground. One adult was found by day in a resting position on a dry leaf on the ground. Juveniles were found conspicuously perched on leaves and stems of plants 1-2 m above ground in the mid to late-afternoon..
Diet of ants
One juvenile and one adult specimen were examined for stomach contents (the larger series of types was spared further dissection). The stomach of the juvenile contained ten ants of the genus Crematogaster; that of the adult contained 30 formicine ants of an undetermined genus. Oreophryne ezra appears limited to a small patch of cloud forest that occurs on the upper elevations of Mt. Rio at 630- 800 m.