A Remarkable Ontogenetic Change in Color Pattern in a New Species of Oreophryne (Anura: Microhylidae) from Papua New Guinea

We describe a new species of scandent/arboreal frog from Sudest Island, Louisiade Archipelago, off the southeastern tip of New Guinea that exhibits a remarkable ontogenetic change in color pattern. Juveniles are shiny black with lemon-yellow spots; adults are uniform peach with bright blue eyes. We detail the ontogenetic changes in color-pattern elements that comprise this transformation. This ontogenetic change, uniform peach adult coloration, and blue iris all appear to be unique features within the genus Oreophryne, most of whose members are tan, brown, or gray. We presume the striking juvenile color pattern to serve an aposematic function, but this conjecture requires testing. 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.

Figure 1

Portraits showing ontogenetic transformation of dorsal color pattern in Oreophryne ezra. (A) BPBM 20474, 12.7 mm SVL; (B) BPBM 20494, 16.5 mm SVL; (C) BPBM 20492, 21.7 mm SVL; (D) BPBM 20486, 26.3 mm SVL; (E) BPBM 20493, 22.6 mm SVL; and (F) BPBM 20467, 24.7 mm SVL. Note progressive change in eye color from greenish bronze to caerulean; lightening, followed by loss, of black pigmentation; lightening, reduction, and loss of yellow spots; and gradual increase in peach coloration.

Figure 2

Portraits showing late ontogenetic transformation of ventral color pattern in Oreophryne ezra. (A) Small mature male (BPBM 20492, 22.3 mm SVL, left) and immature female (BPBM 20493, 22.6 mm SVL, right); and (B) fully transformed adult male (BPBM 20467, 25.5 mm SVL). Note late loss of blue flecking and residual dark ventral coloration remaining on BPBM 20492.

Figure 3

The pulsed structure of call notes of Oreophryne ezra (BPBM 20469, paratype) recorded at the at the type locality on 23 April 2004 at 2015 h, air temperature 20°C. (A) First note; and (B) five subsequent notes.

Figure 4

Spectrogram of call A (Table 2) of Oreophryne ezra (BPBM 20468, holotype) recorded at the at the type locality on 23 April 2004 at 1900 h, air temperature 20°C. (A) Waveform; (B) power spectrum; and (C) spectrogram.

Figure 5

Map of southeastern New Guinea and adjacent islands, showing type locality of Oreophryne ezra on Sudest Island.

Contributor Notes

Associate Editor: D. Kizirian.

¹ Department of Natural Sciences, Bishop Museum, 1525 Bernice Street, Honolulu, Hawaii 96817; E-mail: (FK) fkraus@hawaii.edu; and (AA) allison@hawaii.edu. Send reprint requests to FK.

Received: 19 Jan 2009

Accepted: 26 May 2009