Steinernema bakwenae n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from South Africa

Abstract

Summary Steinernema bakwenae n. sp. isolate SF857 has been isolated from a soil sample from the North West province of South Africa. The infective juveniles were isolated using Cobb’s decanting and sieving method, hand-picked from the nematode population and inoculated directly onto wax moth larvae. Morphological and molecular characterisation provides evidence for placing the new species in the Khoisanae -clade, adding a fifth member to this all-African clade. The new species is characterised by the following morphological features: third-stage infective juveniles with a body length of 1106 (1013-1233) μ m, a distance from the anterior end to the excretory pore of 90 (81-103) μ m, and a tail length of 87 (76-103) μ m. The first-generation males can be recognised by a spicule length of 80 (66-89) μ m and by a gubernaculum length of 51 (44-56) μ m. The new species was confirmed by means of crossbreeding and characterised by means of sequences of the internal transcribed spacer (ITS), the partial 28S regions (D2-D3) of the ribosomal DNA and the mitochondrial cytochrome oxidase subunit (COI). Phylogenetic analyses show that S. innovationi and S. tophus are the closest relatives to S. bakwenae n. sp. in the Khoisanae -clade.