Serration structure on the growth lines of the fossil conchostracans was considered as a key character for the family Afragraptidae. SEM micrographs of some living forms indicate that there is a row of setae on the growth lines. Setal articulations of the growth lines are broken off while their insertions remain, which form an apparently serration margin along the growth lines for the fossil specimens in the external mold. The setae of the growth lines belong to annulate type without setules and probably played in sensory function. This structure was found from about 32 species in seven genera of three families for the living conchostracans and 22 fossil genera. Multi radiating costae and stout tubercles on the valves are much more important than that of serration structure in high taxonomic status for the family Afrograptidae. An emended scheme of the Afrograptidae is presented herein. This family can be better placed in the suborder Estherielliina, rather than in the Estheritina. Serration structure on the growth lines of the fossil conchostracans was considered as a key character for the family Afragraptidae. SEM micrographs of some living forms indicate that there is a row of setae on the growth lines. Setal articulations of the growth lines are broken off while their insertions remain, which form an apparently serration margin along the growth lines for the fossil specimens in the external mold. The setae of the growth lines belong to annulate type without setules and probably played in sensory function. This structure was found from about 32 species in seven genera of three families for the living conchostracans and 22 fossil genera. Multi radiating costae and stout tubercles on the valves are much more important than that of serration structure in high taxonomic status for the family Afrograptidae. An emended scheme of the Afrograptidae is presented This. family can be better placed in the suborder Estherielliina, rather than in the Estheritina.