Based on distinctive morphological and vocal characters we describe a new species of jewel-babbler (genus Ptilorrhoa) from the forested karst of the Southern Fold Mountains in Papua New Guinea. The description is based on camera trap data and is presented in accordance with ICZN Declaration 45. The new species is currently known only from the type locality at the top of Iagifu Ridge (1335–1400 m above sea level), a limestone anticline isolated from the main body of New Guinea's central cordillera, where it is uncommon. Given the importance of competitive exclusion in determining Ptilorrhoa distributions, and the near ubiquitous occurrence of congeners, we speculate that Iagifu Ridge may support part of a highly fragmented population that occupies isolated low mountains that do not support Ptilorrhoa leucosticta of higher elevations. Potentially suitable sites may be restricted to the area between Mt Bosavi and Mt Karimui in southern Papua New Guinea.
