Redescription of two species of the genus Tricirronema Siddiqi, 1993 (Rhabditida, Bicirronematidae) from Vietnam, including SEM study for both species

Summary Two species of the genus Tricirronema : T. tamdaoense and T. tentaculatum , are studied from agricultural soils of Vietnam. Both species are morphologically and morphometrically characterised based on LM and SEM studies. These species are mainly differentiated by the morphology of the vagina, sigmoid in T. tamdaoense and straight in T. tentaculatum , and males with more robust spicules in T. tamdaoense . SEM studies of both species are provided. Molecular analysis based on 18S and 28S rDNA fragments is included for T. tentaculatum , showing relationship with members of the genus Eucephalobus . In addition, a key to species identification of the genus Tricirronema is included, as well as illustrations and a compendium table with the main measurements of the three species.