Description of Caenorhabditis japonica n. sp (Nematoda: Rhabditida) associated with the burrower bug Parastrachia japonensis (Heteroptera: Cydnidae) in Japan

Caenorhabditis japonica n. sp. is described from Parastrachia japonensis from Japan. The species is closely related to species of the Caenorhabditis elegans group and shares many characters with them. It differs from these species in having blunt spicule tips of complex shape and in lacking a terminal notch in the bursa velum. Caenorhabditis japonica n. sp. is further characterised by an anterior end with the lips fused in pairs, long and pointed stegostomal teeth, long fringes on the anterior bursa margin and the form of the genital papillae (GP4 reduced). The species is integrated into the phylogenetic tree of Caenorhabditis. Some resulting consequences for character evolution within Caenorhabditis are discussed. Caenorhabditis japonica n. sp. is associated with a burrower bug, thereby adding a new component to the diverse ecology of Caenorhabditis species.