A new shrub frog in the genus Platymantis (Ceratobatrachidae) from the Nakanai Mountains of eastern New Britain Island, Bismarck Archipelago.

We describe a new-species of high elevation rainforest shrub frog (genus Platymantis) from the Nakanai Mountains of eastern New Britain (Bismarck Archipelago), Papua New Guinea. The distinctive new species possesses a moderate body size (29.5-32.2 mm in four males), widely expanded finger and toe disks, smooth to slightly granular dorsal skin, low but distinctly protuberant supraocular and tarsal tubercles, a conspicuous series of bright yellow flank areolations, a low but distinct intraocular sagittal crest, bronze-brown iris, and a unique advertisement call. We compare the new species with congeneric New Britain taxa and to other phenotypically similar species from the Solomon-Bismarck-Admiralty archipelagos. The new species is phenotypically most similar to P macrosceles Zweifel 1975, and has been collected at only one high elevation site (Tompoi Camp). The available data suggest that the new species, known from 1700 m, is elevationally segregated from P. macroscles (to date, only recorded from 800-900 m in the Nakanai Mountains). New Britain Island has emerged as a major center of endemic ceratobatrachid species diversity. Additional species are anticipated to result from ongoing field work, especially in the western portion of the island, which remains largely unexplored.