Description of Tricirronema tamdaoense sp. n. (Rhabditida: Bicirronematidae) from Vietnam

A new species of Tricirronema, T. tamdaoense sp. n., is described from soil and litter in Tam Dao National Park, Vietnam. It adds to the diversity of the genus and extends the geographical distribution of the family Bicirronematidae. The new species is intermediate in body length between the other two known species of the genus, T. tentaculatum and T. trifilum. It is particularly characterised by the sigmoid shape of vagina, differing from the other two species, which both have a vagina with straight lumen.