Description and phylogenetic relationships of Rodentolepis gnoskei n. sp. (Cyclophyllidea: Hymenolepididae) from a shrew Suncus varilla minor in Malawi

Rodentolepis gnoskei n. sp. is described based on specimens obtained from a lesser dwarf shrew Suncus varilla minor collected in the Nyika National Park, Malawi. The new species is one of the smallest hymenolepidids known from African shrews and is morphologically closest to two other miniature hymenolepidids from African shrews, Staphylocystis loossi and S. khalili. The new species differs from both of them by a much smaller strobila size and fewer proglottids. The rostellar hooks in the new species are more numerous and smaller in size than in S. loossi. The rostellar hooks in R. gnoskei n. sp. are almost three times shorter than hooks in S. khalili. The hook shape in both S. loossi and S. khalili is substantially different from that in the new species. Molecular phylogenetic analysis indicates that the new species is close to Rodentolepis fraterna, a parasite of rodents. The new species clearly differs from R. fraterna by the much shorter strobila, larger hooks, relatively longer cirrus sac, rate of proglottid development, the number of eggs per proglottid and parasitism in shrews. Although the new species fits the current diagnosis of Rodentolepis, its generic allocation is provisional and will likely be revised in the future because the type species of Rodentolepis, R. straminea, belongs to a different well supported clade. Thus, a new genus needs to be established for the lineage that includes R. fraterna and R. gnoskei n. sp. However, this systematic rearrangement is not recommended until Staphylocystis pistillum, the type species of Staphylocystis, is included in future phylogenetic analyses. Rodentolepis gnoskei n. sp. is the first tapeworm species reported from shrews in Malawi and the first species of cestode reported from S. varilla minor and any member of Suncus in Africa.