Abstract: | Nullosetigeridae nom. nov. is proposed for Phyllopodidae Brodsky, 1950, nom. nud., and Nullosetigera nom. nov. is introduced for Phyllopus Brady, 1883, non Rafinesque, 1815. A new species, Nullosetigera auctiseta, is described from Japanese waters. Nullosetigera mutica comb. nov. (Sars, 1907) and N. mutata comb. nov. (Tanaka, 1964) are redescribed. Phylogenetic analysis implies that two groups, N. auctiseta–N. mutica group and N. mutata–N. impar–N. bidentata–N. helgae group, exist within the genus Nullosetigera and that the new species first diverges with N. mutica. The relatively advanced species, N. impar, N. bidentata, and N. helgae are the most widespread, and are vertically distributed from the epipelagic to the bathypelagic layers. |