Characterization of Acrobeloides longiuterus (Rashid & Heyns, 1990) Siddiqi, De Ley & Khan, 1992 (Rhabditida: Cephalobidae) from South Africa including the SEM study of the species

A population of Acrobeloides longiuterus was recovered during a Potato South Africa Project (PSA) in the Free State Province, South Africa. Subsequently , the soil samples were baited with the larvae of darkling beetles or mealworms (Coleoptera: Tenebrionidae) to recover as many specimens as possible for morphologic and molecular studies. This member of the Cephalobidae represents a new geographical record for the Free State Province of South Africa. Acrobeloides longiuterus is distinguished from other species of the maximus group by having one acute process at the primary axil of each lip, a dextral female genital system, vulva situated towards the left side, and spicules featuring a narrow, elongate manubrium and lamina with small dorsal hump. Description, measurements, illustrations, and phylogenetic position based on 28S rDNA are provided. Phylogenetic analysis revealed that South African A. longiuterus differs from A. camberenensis, and both species are considered valid. Additionally, the results indicate that A. camberenensis , A. longiuterus , A. maximus , and A. saeedi , all with a dextral female genital system, form a clade with 1.00 posterior probability. They can be separated from A. bodenheimeri , a species with a sinistral female genital system.