The Slender-toed Geckos (Nactus) currently have four recognized species in New Guinea, and these species divide into two sister clades: a pelagicus clade and a vankampeni clade (Heinicke et al. 2010). The latter contains three dwarf species. The former consists of five bisexual populations, of which numerous New Guinea populations are uncharacterized nomenclaturally and lumped under the epithet ‘pelagicus.’ This report and description of a new species of the pelagicus group from Manus Island in the Admiralty Islands encourages us to offer a preliminary assessment of morphology and diversity in New Guinea ‘pelagicus’ populations.