title: Steinernema sichuanense n. sp. (Rhabditida, Steinernematidae), a new species of entomopathogenic nematode from the province of Sichuan, east Tibetan Mts., China.
abstract: Steinernema sichuanense n. sp. is characterized by male, female and IJ. For male, the spicules are robust with prominent rostrum; gubernaculum has blunt anterior end; cuneus is arrow-shaped, pointed posteriorly. Second-generation male has a prominent mucron. For female, tail usually has one to four papillae-like projections on tail tip; post anal swelling is absent. For IJ, body length is about 710 microm; lateral field has six ridges; the formula of lateral field is 2, 5, 6, 4, 2 with two prominent submarginal ridges; tail usually has a dorsal depression. In Steinernema affine/intermedium group, the IJ of S. sichuanense n. sp. differs from S. affine by its absence of the internal tail spine; differs from Steinernema beddingi by its six ridges in lateral field compared to 4 for S. beddingi. For male mucron is absent in both generations of S. affine, S. intermedium and S. beddingi, whereas it is present in the second-generation of S. sichuanense sp. n. Morphology and morphometrics of spicules and gubernacula of the four species in S. affine/intermedium group are quite different based on SEM photographs. For female, the postanal swelling is absent in the first-generation of S. sichuanense n. sp. whereas S. affine and S. intermedium have slight swelling and S. beddingi has conspicuous swelling. The new species is further recognized by characterization of sequences of ITS and D2/D3 regions of the ribosomal DNA. The symbiotic bacterium associated to S. sichuanense belongs to the species Xenorhabdus bovienii.
authors.affiliation: Laboratory of Insect Pathology, Institute of Entomology, Czech Academy of Sciences, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic. mracek@entu.cas.cz
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Mrácek
authors.forename: Khuong B
authors.initials: KB
authors.lastname: Nguyen
authors.forename: Patrick
authors.initials: P
authors.lastname: Tailliez
authors.forename: Noël
authors.initials: N
authors.lastname: Boemare
authors.forename: Shulong
authors.initials: S
authors.lastname: Chen
mesh_terms: D000818:Animals; D002681:China; D018509:DNA, Helminth / Q000032:analysis; D005260:Female; D008297:Male; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017168:Rhabditida / Q000145:classification* / Q000502:physiology / Q000648:ultrastructure*; D012727:Sex Characteristics; D012987:Soil; D013045:Species Specificity
chemical_list: D018509:DNA, Helminth; D012987:Soil