Mesorhabditis sudafricana n. sp. (Rhabditida, Mesorhabditidae), a new species with a short tail from South Africa

During a survey of soil nematodes in 2022, a free-living bacterivorous nematode, described here as Mesorhabditis sudafricana n. sp., was discovered in association with kikuyu grass in Limpopo Province, South Africa. The new species was distinguished by a relatively long body (716-815 μm in females and 605-689 μm in males), long spicules (61-66 μm), and gubernaculum (22-24 μm) and a short tail (15-20 μm in females and 18-21 μm in males). The vulva is positioned posteriad (93-95% of body length), and the distance from vulva to anus is long (1.5-1.9 times tail length). Additionally, the new species bears seven lateral field incisures and a peloderan bursa with the genital papillae in arrangement 2/3+ph+1+3, being two precloacal and eight postcloacal. The 28S rDNA BlastN showed 94% similarity with an unidentified Mesorhabditis (deposited as Bursilla (EF990722). By contrast, the ITS rDNA BlastN showed 82% similarity with Mesorhabditis paucipapillata (MT710243). The phylogenetic analysis of 28S and ITS rDNA placed the new species separately from the other Mesorhabditis. Description, measurements, illustrations and SEM micrographs for M. sudafricana n. sp. are provided.