In this review (third part), several species within the Nassarius pauperus complex from the eastern Indian Ocean and western Pacific are treated, including a revised concept of Nassa paupera Gould, 1850, type species of the genus Reticunassa Iredale, 1936. In the most recent taxonomic revision, several species had been synonymized with Nassarius pauperus (Gould, 1850), despite distinctive differences among these species in shell morphology. We sequenced a fragment of the mitochondrial COI and the nuclear 28S genes of all available Nassarius pauperus complex species. Automatic barcode gap discovery and reciprocal monophyly were applied to propose species delimitation hypotheses and to support a new concept of the genus. Using morphological and molecular characters, Reticunassa is elevated to full genus rank. Six new species are described: Reticunassa visayaensis sp. nov., R. poppeorum sp. nov., R. annabolteae sp. nov., R. goliath sp. nov., R. intrudens sp. nov. and R. thailandensis sp. nov., while R. tringa (Souverbie, 1864) is recognized as a valid species.