A small group Marginellidae species were moved between genera several times by different authors, described as Marginella, sometimes called Glabella, classified under Dentimargo, and also reclassified as being Eratoidea species. This group of very small Marginellidae has their own unique shell characteristics within the family, and are described here within a new genus: Africosta. Four known species are discussed along with the description of two new species from KwaZulu-Natal, South Africa within the new genus.