A new species of entomopathogenic nematode, Steinernema fabii n. sp., was
isolated by trapping with wax moth (Galleria mellonella) larvae from soil in an Acacia mearnsii
plantation in the Mpumalanga province of South Africa. The new species is morphologically
characterised by the length of the infective juvenile (IJ) of 641 (590-697) μm, by a tail length of
58 (52-64) μm, ratio a = 24 (21-41), H% = 53 (37-61) and E% = 93 (83-105). The pattern of the
lateral field of the IJ of the new species is 2, 5, 2 ridges (3, 6, 3 incisures). The male of the first
generation can be recognised by the long spicule of 90 (79-106) μm and gubernaculum of 66
(56-77) μm; D% = 64 (52-75) and GS% = 73 (63-86). The first generation female can be
recognised by a protruding vulva, with a short double flapped epiptygmata and the lack of a
postanal swelling, while the second generation differs with a post anal swelling and conical and
sharply pointed tail. Analysis of DNA sequences for the ITS and D2D3 gene regions showed S.
fabii n. sp. to differ from all other Steinernema species and to belong to a new monophyletic
group, the ‘Cameroonian’ clade, consisting of S. cameroonense, S. nyetense, S. sacchari and S.
fabii n. sp., all from the African continent. This group is closely related to species in the feltiaekraussei-
oregonense Clade III.