Redescription of Steinernema longicaudum Shen & Wang (Nematoda : Steinernematidae); geographic distribution and phenotypic variation between allopatric populations

Steinernema longicaudum Shen & Wang is redescribed based on a comparative m orphological study of specimens from the type isolate from China, and two o ther isolates recovered from Korea and the USA. For the first and second ge neration female, the location of the vulva, shape of the vulval lips, and s hape and length of the tail were newly observed diagnostic characters. A mo re detailed description of the morphology of the male spicules and gubernac ulum, and the arrangement of the genital papillae is included. A descriptio n, based on scanning electron microscopy observations, of the lateral field pattern of the third-stage infective juveniles is also provided. Additiona lly, restriction fragment length polymorphism profiles based on the interna l transcribed spacer region, and cross-breeding tests supplement the descri ption of this species.