To date seven species of the genus Sphaerotarsus Womersley, 1936 have been described namely, three exclusively from larvae, three from postlarval forms and one from larvae and postlarval forms. In this study, the larvae of a fifth species are described and illustrated from Iran, namely: Sphaerotarsus sadafae sp. nov. collected from soil and litter under oak trees, (Quercus spp). Also, a key to the world larval species is provided.
