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

Abstract

During a survey in the Mpumalanga province of South Africa, a Steinernema species was isolated from a soil sample taken from a litchi orchard. Steinernema litchii n. sp. can be separated from other, closely related, species in the glaseri-group by morphological, morphometric and molecular analyses. The infective third-stage juvenile of the new species has a body length of 1054 (953-1146) μm, distance from head to excretory pore of 78 (64-86) μm, as well as eight ridges (i.e., nine lines) in the mid-body region. The c-ratio of 10 (9-13) is low and the tail is long at 95 (73-105) μm. First generation males have a spicule length of 86 (76-96) μm and a gubernaculum length of 65 (59-72) μm. The tail of the first generation male lacks a mucron; that of the second generation always bears one. The genital papillae total 23 and consist of 11 pairs and an unpaired precloacal papilla. The vulva of S. litchii n. sp. has a slightly asymmetrical protuberance and short, double-flapped epiptygmata. The female has a slightly protuberant postanal swelling. Phylogenetic analysis of the internal transcribed spacer (ITS) and of the 28S (D2-D3) regions of the ribosomal DNA (rDNA) confirmed the close relationship of S. litchii n. sp. to the Karii-clade. Both morphological and molecular evidence support the species status of S. litchii n. sp